6.1 Heart Anatomy
Learning Objectives
By the end of this section, you will be able to:
- Describe the location and position of the heart within the body cavity
- Describe the internal and external anatomy of the heart
- Identify the tissue layers of the heart
- Relate the structure of the heart to its function as a pump
- Compare systemic circulation to pulmonary circulation
- Identify the veins and arteries of the coronary circulation system
- Trace the pathway of oxygenated and deoxygenated blood through the chambers of the heart
The vital importance of the heart is obvious. If one assumes an average rate of contraction of 75 contractions per minute, a human heart would contract approximately 108,000 times in one day, more than 39 million times in one year and nearly 3 billion times during a 75-year lifespan! Each of the major pumping chambers of the heart ejects approximately 70 mL blood per contraction in a resting adult. This would be equal to 5.25 litres of fluid per minute and approximately 14,000 litres per day. Over one year, that would equal 10,000,000 litres (2.6 million gallons) of blood sent through roughly 97,000 kilometres (60,000 miles) of vessels. In order to understand how that happens, it is necessary to understand the anatomy and physiology of the heart.
Location of the Heart
The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 6.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 6.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.
Everyday Connection
CPR
The position of the heart in the torso between the vertebrae and sternum (see Figure 6.1.1 for the position of the heart within the thorax) allows for individuals to apply an emergency technique known as cardiopulmonary resuscitation (CPR) if the heart of a patient should stop. In adults, pressure is applied with the flat portion of one hand on the sternum in the area between the line at T4 and T9 (Figure 6.1.2), it is possible to manually compress the blood within the heart enough to push some of the blood within it into the pulmonary and systemic circuits. This is particularly critical for the brain, as irreversible damage and death of neurons occur within minutes of loss of blood flow. Current standards call for compression of the chest at least 5 cm deep and at a rate of 100-120 compressions per minute, a rate equal to the beat in “Staying Alive,” recorded in 1977 by the Bee Gees. If you are unfamiliar with this song, a version is available on www.youtube.com. At this stage, the emphasis is on performing high-quality chest compressions, rather than providing artificial respiration, but typically compression to ventilation ratio is 30:2. CPR is generally performed until the patient regains spontaneous contraction or is declared dead by an experienced healthcare professional.
When performed by untrained or overzealous individuals, CPR can result in broken ribs or a broken sternum and can inflict additional severe damage on the patient. It is also possible, if the hands are placed too low on the sternum, to manually drive the xiphoid process into the liver, a consequence that may prove fatal for the patient. Proper training is essential. This proven life-sustaining technique is so valuable that virtually all medical personnel as well as concerned members of the public should be certified and routinely recertified in its application. CPR courses are offered at a variety of locations, including colleges, hospitals, the Australian Red Cross and some commercial companies. They normally include practice of the compression technique on a mannequin.
Shape and Size of the Heart
The shape of the heart is similar to a pinecone, rather broad at the superior surface and tapering to the apex (see Figure 6.1.1). A typical heart is approximately the size of your fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness. Given the size difference between most members of the sexes, the weight of a female heart is approximately 250–300 grams (9 to 11 ounces), and the weight of a male heart is approximately 300–350 grams (11 to 12 ounces). The heart of a well-trained athlete, especially one specialising in aerobic sports, can be considerably larger than this. Cardiac muscle responds to exercise in a manner like that of skeletal muscle. That is, exercise results in the addition of protein myofilaments that increase the size of the individual cells without increasing their numbers, a concept called hypertrophy. Hearts of athletes can pump blood more effectively at lower rates than those of nonathletes. Enlarged hearts are not always a result of exercise; they can result from pathologies, such as hypertrophic cardiomyopathy. The cause of an abnormally enlarged heart muscle is unknown, but the condition is often undiagnosed and can cause sudden death in apparently otherwise healthy young people.
Chambers and Circulation Through the Heart
The human heart consists of four chambers: The left side and the right side each have one atrium and one ventricle. Each of the upper chambers, the right atrium (plural = atria) and the left atrium, acts as a receiving chamber and contracts to push blood into the lower chambers, the right ventricle and the left ventricle. The ventricles serve as the primary pumping chambers of the heart, propelling blood to the lungs or to the rest of the body.
There are two distinct but linked circuits in the human circulation called the pulmonary and systemic circuits. Although both circuits transport blood and everything it carries, we can initially view the circuits from the point of view of gases. The pulmonary circuit transports blood to and from the lungs, where it picks up oxygen and delivers carbon dioxide for exhalation. The systemic circuit transports oxygenated blood to virtually all the tissues of the body and returns relatively deoxygenated blood and carbon dioxide to the heart to be sent back to the pulmonary circulation.
The right ventricle pumps deoxygenated blood into the pulmonary trunk, which leads toward the lungs and bifurcates into the left and right pulmonary arteries. These vessels in turn branch many times before reaching the pulmonary capillaries, where gas exchange occurs: Carbon dioxide exits the blood and oxygen enters. The pulmonary trunk arteries and their branches are the only arteries in the post-natal body that carry relatively deoxygenated blood. Highly oxygenated blood returning from the pulmonary capillaries in the lungs passes through a series of vessels that join together to form the pulmonary veins—the only post-natal veins in the body that carry highly oxygenated blood. The pulmonary veins conduct blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and on to the many branches of the systemic circuit. Eventually, these vessels will lead to the systemic capillaries, where exchange with the tissue fluid and cells of the body occurs. In this case, oxygen and nutrients exit the systemic capillaries to be used by the cells in their metabolic processes, and carbon dioxide and waste products will enter the blood.
The blood exiting the systemic capillaries is lower in oxygen concentration than when it entered. The capillaries will ultimately unite to form venules, joining to form ever-larger veins, eventually flowing into the two major systemic veins, the superior vena cava and the inferior vena cava, which return blood to the right atrium. The blood in the superior and inferior venae cavae flows into the right atrium, which pumps blood into the right ventricle. This process of blood circulation continues as long as the individual remains alive. Understanding the flow of blood through the pulmonary and systemic circuits is critical to all health professions (Figure 6.1.3).
Membranes, Surface Features and Layers
Our exploration of more in-depth heart structures begins by examining the membrane that surrounds the heart, the prominent surface features of the heart and the layers that form the wall of the heart. Each of these components plays its own unique role in terms of function.
Membranes
The membrane that directly surrounds the heart and defines the pericardial cavity is called the pericardium or pericardial sac. It also surrounds the “roots” of the major vessels, or the areas of closest proximity to the heart. The pericardium, which literally translates as “around the heart,” consists of two distinct sublayers: the sturdy outer fibrous pericardium and the inner serous pericardium. The fibrous pericardium is made of tough, dense connective tissue that protects the heart and maintains its position in the thorax. The more delicate serous pericardium consists of two layers: the parietal pericardium, which is fused to the fibrous pericardium, and an inner visceral pericardium, or epicardium, which is fused to the heart and is part of the heart wall. The pericardial cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium.
In most organs within the body, visceral serous membranes such as the epicardium are microscopic. However, in the case of the heart, it is not a microscopic layer but rather a macroscopic layer, consisting of a simple squamous epithelium called a mesothelium, reinforced with loose, irregular, or areolar connective tissue that attaches to the pericardium. This mesothelium secretes the lubricating serous fluid that fills the pericardial cavity and reduces friction as the heart contracts. Figure 6.1.4 illustrates the pericardial membranes and the layers of the heart.
Disorders of the Heart: Cardiac Tamponade
If excess fluid builds within the pericardial space, it can lead to a condition called cardiac tamponade, or pericardial tamponade. With each contraction of the heart, more fluid—in most instances, blood—accumulates within the pericardial cavity. In order to fill with blood for the next contraction, the heart must relax. However, the excess fluid in the pericardial cavity puts pressure on the heart and prevents full relaxation, so the chambers within the heart contain slightly less blood as they begin each heart cycle. Over time, less and less blood is ejected from the heart. If the fluid builds up slowly, as in hypothyroidism, the pericardial cavity may be able to expand gradually to accommodate this extra volume. Some cases of fluid in excess of one litre within the pericardial cavity have been reported. Rapid accumulation of as little as 100 mL of fluid following trauma may trigger cardiac tamponade. Other common causes include myocardial rupture, pericarditis, cancer, or even cardiac surgery. Removal of this excess fluid requires insertion of drainage tubes into the pericardial cavity. Premature removal of these drainage tubes, for example, following cardiac surgery, or clot formation within these tubes are causes of this condition. Untreated, cardiac tamponade can lead to death.
Surface Features of the Heart
Inside the pericardium, the surface features of the heart are visible, including the four chambers. There is a superficial leaf-like extension of the atria near the superior surface of the heart, one on each side, called an auricle—a name that means “ear like”—because its shape resembles the external ear of a human (Figure 6.1.5). Auricles are relatively thin-walled structures that can fill with blood and empty into the atria or upper chambers of the heart. You may also hear them referred to as atrial appendages. Also prominent is a series of fat-filled grooves, each of which is known as a sulcus (plural = sulci), along the superior surfaces of the heart. Major coronary blood vessels are located in these sulci. The deep coronary sulcus is located between the atria and ventricles. Located between the left and right ventricles are two additional sulci that are not as deep as the coronary sulcus. The anterior interventricular sulcus is visible on the anterior surface of the heart, whereas the posterior interventricular sulcus is visible on the posterior surface of the heart. Figure 6.1.5 illustrates anterior and posterior views of the surface of the heart.
Layers
The wall of the heart is composed of three layers of unequal thickness. From superficial to deep, these are the epicardium, the myocardium and the endocardium (see Figure 6.1.4). The outermost layer of the wall of the heart is also the innermost layer of the pericardium, the epicardium, or the visceral pericardium discussed earlier.
The middle and thickest layer is the myocardium, made largely of cardiac muscle cells. It is built upon a framework of collagenous fibres, plus the blood vessels that supply the myocardium and the nerve fibres that help regulate the heart. It is the contraction of the myocardium that pumps blood through the heart and into the major arteries. The muscle pattern is elegant and complex, as the muscle cells swirl and spiral around the chambers of the heart. They form a figure 8 pattern around the atria and around the bases of the great vessels. Deeper ventricular muscles also form a figure 8 around the two ventricles and proceed toward the apex. More superficial layers of ventricular muscle wrap around both ventricles. This complex swirling pattern allows the heart to pump blood more effectively than a simple linear pattern would. Figure 6.1.6 illustrates the arrangement of muscle cells.
Although the ventricles on the right and left sides pump the same amount of blood per contraction, the muscle of the left ventricle is much thicker and better developed than that of the right ventricle. In order to overcome the high resistance required to pump blood into the long systemic circuit, the left ventricle must generate a great amount of pressure. The right ventricle does not need to generate as much pressure, since the pulmonary circuit is shorter and provides less resistance. Figure 6.1.7 illustrates the differences in muscular thickness needed for each of the ventricles.
The innermost layer of the heart wall, the endocardium, is joined to the myocardium with a thin layer of connective tissue. The endocardium lines the chambers where the blood circulates and covers the heart valves. It is made of simple squamous epithelium called endothelium, which is continuous with the endothelial lining of the blood vessels (see Figure 6.1.4).
Once regarded as a simple lining layer, recent evidence indicates that the endothelium of the endocardium and the coronary capillaries may play active roles in regulating the contraction of the muscle within the myocardium. The endothelium may also regulate the growth patterns of the cardiac muscle cells throughout life, and the endothelins it secretes create an environment in the surrounding tissue fluids that regulates ionic concentrations and states of contractility. Endothelins are potent vasoconstrictors and, in a normal individual, establish a homeostatic balance with other vasoconstrictors and vasodilators.
Internal Structure of the Heart
Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because of the pairs of chambers that pump blood into the circulation. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail.
Septa of the Heart
The word septum is derived from the Latin for “something that encloses;” in this case, a septum (plural = septa) refers to a wall or partition that divides the heart into chambers. The septa are physical extensions of the myocardium lined with endocardium. Located between the two atria is the interatrial septum. Normally in an adult heart, the interatrial septum bears an oval-shaped depression known as the fossa ovalis, a remnant of an opening in the foetal heart known as the foramen ovale. The foramen ovale allowed blood in the foetal heart to pass directly from the right atrium to the left atrium, allowing some blood to bypass the pulmonary circuit. Within seconds after birth, a flap of tissue known as the septum primum that previously acted as a valve closes the foramen ovale and establishes the typical cardiac circulation pattern.
Between the two ventricles is a second septum known as the interventricular septum. Unlike the interatrial septum, the interventricular septum is normally intact after its formation during foetal development. It is substantially thicker than the interatrial septum, since the ventricles generate far greater pressure when they contract.
The septum between the atria and ventricles is known as the atrioventricular septum. It is marked by the presence of four openings that allow blood to move from the atria into the ventricles and from the ventricles into the pulmonary trunk and aorta. Located in each of these openings between the atria and ventricles is a valve, a specialised structure that ensures one-way flow of blood. The valves between the atria and ventricles are known generically as atrioventricular valves. The valves at the openings that lead to the pulmonary trunk and aorta are known generically as semilunar valves. The interventricular septum is visible in Figure 6.1.8. In this figure, the atrioventricular septum has been removed to better show the bicuspid and tricuspid valves; the interatrial septum is not visible, since its location is covered by the aorta and pulmonary trunk. Since these openings and valves structurally weaken the atrioventricular septum, the remaining tissue is heavily reinforced with dense connective tissue called the cardiac skeleton, or skeleton of the heart. It includes four rings that surround the openings between the atria and ventricles, and the openings to the pulmonary trunk and aorta, and serve as the point of attachment for the heart valves. The cardiac skeleton also provides an important boundary in the heart electrical conduction system.
Disorders of the Heart: Heart Defects
One very common form of interatrial septum pathology is patent foramen ovale, which occurs when the septum primum does not close at birth, and the fossa ovalis is unable to fuse. The word patent is from the Latin root patens for “open.” It may be benign or asymptomatic, perhaps never being diagnosed, or in extreme cases, it may require surgical repair to close the opening permanently. As much as 20–25 percent of the general population may have a patent foramen ovale, but fortunately, most have the benign, asymptomatic version. Patent foramen ovale is normally detected by auscultation of a heart murmur (an abnormal heart sound) and confirmed by imaging with an echocardiogram. Despite its prevalence in the general population, the causes of patent ovale are unknown, and there are no known risk factors. In nonlife-threatening cases, it is better to monitor the condition than to risk heart surgery to repair and seal the opening.
Coarctation of the aorta is a congenital abnormal narrowing of the aorta that is normally located at the insertion of the ligamentum arteriosum, the remnant of the foetal shunt called the ductus arteriosus. If severe, this condition drastically restricts blood flow through the primary systemic artery, which is life threatening. In some individuals, the condition may be benign and not detected until later in life. Detectable symptoms in an infant include difficulty breathing, poor appetite, trouble feeding, or failure to thrive. In older individuals, symptoms include dizziness, fainting, shortness of breath, chest pain, fatigue, headache, and nosebleeds. Treatment involves surgery to resect (remove) the affected region or angioplasty to open the abnormally narrow passageway. Studies have shown that the earlier the surgery is performed, the better the chance of survival.
A patent ductus arteriosus is a congenital condition in which the ductus arteriosus fails to close. The condition may range from severe to benign. Failure of the ductus arteriosus to close results in blood flowing from the higher-pressure aorta into the lower pressure pulmonary trunk. This additional fluid moving toward the lungs increases pulmonary pressure and makes respiration difficult. Symptoms include shortness of breath (dyspnoea), tachycardia, enlarged heart, a widened pulse pressure, and poor weight gain in infants. Treatments include surgical closure (ligation), manual closure using platinum coils or specialised mesh inserted via the femoral artery or vein, or nonsteroidal anti-inflammatory drugs to block the synthesis of prostaglandin E2, which maintains the vessel in an open position. If untreated, the condition can result in congestive heart failure.
Septal defects are not uncommon in individuals and may be congenital or caused by various disease processes. Tetralogy of Fallot is a congenital condition that may also occur from exposure to unknown environmental factors; it occurs when there is an opening in the interventricular septum caused by blockage of the pulmonary trunk, normally at the pulmonary semilunar valve. This allows blood that is relatively low in oxygen from the right ventricle to flow into the left ventricle and mix with the blood that is relatively high in oxygen. Symptoms include a distinct heart murmur, low blood oxygen percent saturation, dyspnoea or difficulty in breathing, polycythaemia, broadening (clubbing) of the fingers and toes, and in children, difficulty in feeding or failure to grow and develop. It is the most common cause of cyanosis following birth. The term “tetralogy” is derived from the four components of the condition, although only three may be present in an individual patient: pulmonary infundibular stenosis (rigidity of the pulmonary valve), overriding aorta (the aorta is shifted above both ventricles), ventricular septal defect (opening), and right ventricular hypertrophy (enlargement of the right ventricle). Other heart defects may also accompany this condition, which is typically confirmed by echocardiography imaging. Tetralogy of Fallot occurs in approximately 400 out of one million live births. Normal treatment involves extensive surgical repair, including the use of stents to redirect blood flow and replacement of valves and patches to repair the septal defect, but the condition has a relatively high mortality. Survival rates are currently 75 percent during the first year of life; 60 percent by four years of age; 30 percent by 10 years; and five percent by 40 years.
In the case of severe septal defects, including both tetralogy of Fallot and patent foramen ovale, failure of the heart to develop properly can lead to a condition commonly known as a “blue baby.” Regardless of normal skin pigmentation, individuals with this condition have an insufficient supply of oxygenated blood, which leads to cyanosis, a blue or purple coloration of the skin, especially when active.
Septal defects are commonly first detected through auscultation, listening to the chest using a stethoscope. In this case, instead of hearing normal heart sounds attributed to the flow of blood and closing of heart valves, unusual heart sounds may be detected. This is often followed by medical imaging to confirm or rule out a diagnosis. In many cases, treatment may not be needed. Some common congenital heart defects are illustrated in Figure 6.1.9.
Right Atrium
The right atrium serves as the receiving chamber for blood returning to the heart from the systemic circulation. The two major systemic veins, the superior and inferior venae cavae, and the large coronary vein called the coronary sinus that drains the heart myocardium empty into the right atrium. The superior vena cava drains blood from regions superior to the diaphragm: the head, neck, upper limbs, and the thoracic region. It empties into the superior and posterior portions of the right atrium. The inferior vena cava drains blood from areas inferior to the diaphragm: the lower limbs and abdominopelvic region of the body. It, too, empties into the posterior portion of the atria, but inferior to the opening of the superior vena cava. Immediately superior and slightly medial to the opening of the inferior vena cava on the posterior surface of the atrium is the opening of the coronary sinus. This thin-walled vessel drains most of the coronary veins that return systemic blood from the heart. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in Figure 6.1.8.
While the bulk of the internal surface of the right atrium is smooth, the depression of the fossa ovalis is medial, and the anterior surface demonstrates prominent ridges of muscle called the pectinate muscles. The right auricle also has pectinate muscles. The left atrium does not have pectinate muscles except in the auricle.
The atria receive venous blood on a nearly continuous basis, preventing venous flow from stopping while the ventricles are contracting. While most ventricular filling occurs while the atria are relaxed, they do demonstrate a contractile phase and actively pump blood into the ventricles just prior to ventricular contraction. The opening between the atrium and ventricle is guarded by the tricuspid valve.
Right Ventricle
The right ventricle receives blood from the right atrium through the tricuspid valve. Each flap of the valve is attached to strong strands of connective tissue, the chordae tendineae, literally “tendinous cords,” or sometimes more poetically referred to as “heart strings.” There are several chordae tendineae associated with each of the flaps. They are composed of approximately 80 percent collagenous fibres with the remainder consisting of elastic fibres and endothelium. They connect each of the flaps to a papillary muscle that extends from the inferior ventricular surface. There are three papillary muscles in the right ventricle, called the anterior, posterior, and septal muscles, which correspond to the three sections of the valves.
When the myocardium of the ventricle contracts, pressure within the ventricular chamber rises. Blood, like any fluid, flows from higher pressure to lower pressure areas, in this case, toward the pulmonary trunk and the atrium. To prevent any potential backflow, the papillary muscles also contract, generating tension on the chordae tendineae. This prevents the flaps of the valves from being forced into the atria and regurgitation of the blood back into the atria during ventricular contraction. Figure 6.1.10 shows papillary muscles and chordae tendineae attached to the tricuspid valve.
The walls of the ventricle are lined with trabeculae carneae, ridges of cardiac muscle covered by endocardium. In addition to these muscular ridges, a band of cardiac muscle, also covered by endocardium, known as the moderator band (see Figure 6.1.8) reinforces the thin walls of the right ventricle and plays a crucial role in cardiac conduction. It arises from the inferior portion of the interventricular septum and crosses the interior space of the right ventricle to connect with the inferior papillary muscle.
When the right ventricle contracts, it ejects blood into the pulmonary trunk, which branches into the left and right pulmonary arteries that carry it to each lung. The superior surface of the right ventricle begins to taper as it approaches the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve that prevents backflow from the pulmonary trunk.
Left Atrium
After exchange of gases in the pulmonary capillaries, blood returns to the left atrium high in oxygen via one of the four pulmonary veins. While the left atrium does not contain pectinate muscles, it does have an auricle that includes these pectinate ridges. Blood flows nearly continuously from the pulmonary veins back into the atrium, which acts as the receiving chamber, and from here through an opening into the left ventricle. Most blood flows passively into the heart while both the atria and ventricles are relaxed, but toward the end of the ventricular relaxation period, the left atrium will contract, pumping blood into the ventricle. This atrial contraction accounts for approximately 20 percent of ventricular filling. The opening between the left atrium and ventricle is guarded by the mitral valve.
Left Ventricle
Recall that, although both sides of the heart will pump the same amount of blood, the muscular layer is much thicker in the left ventricle compared to the right (see Figure 6.1.7). Like the right ventricle, the left also has trabeculae carneae, but there is no moderator band. The mitral valve is connected to papillary muscles via chordae tendineae. There are two papillary muscles on the left—the anterior and posterior—as opposed to three on the right.
The left ventricle is the major pumping chamber for the systemic circuit; it ejects blood into the aorta through the aortic semilunar valve.
Heart Valve Structure and Function
A transverse section through the heart slightly above the level of the atrioventricular septum reveals all four heart valves along the same plane (Figure 6.1.11). The valves ensure unidirectional blood flow through the heart. Between the right atrium and the right ventricle is the right atrioventricular valve, or tricuspid valve. It typically consists of three flaps, or leaflets, made of endocardium reinforced with additional connective tissue. The flaps are connected by chordae tendineae to the papillary muscles, which control the opening and closing of the valves.
Emerging from the right ventricle at the base of the pulmonary trunk is the pulmonary semilunar valve, or the pulmonary valve; it is also known as the pulmonic valve or the right semilunar valve. The pulmonary valve is comprised of three small flaps of endothelium reinforced with connective tissue. When the ventricle relaxes, the pressure differential causes blood to flow back into the ventricle from the pulmonary trunk. This flow of blood fills the pocket-like flaps of the pulmonary valve, causing the valve to close and producing an audible sound. Unlike the atrioventricular valves, there are no papillary muscles or chordae tendineae associated with the pulmonary valve.
Located at the opening between the left atrium and left ventricle is the mitral valve, also called the bicuspid valve or the left atrioventricular valve. Structurally, this valve consists of two cusps, known as the anterior medial cusp and the posterior medial cusp, compared to the three cusps of the tricuspid valve. In a clinical setting, the valve is referred to as the mitral valve, rather than the bicuspid valve. The two cusps of the mitral valve are attached by chordae tendineae to two papillary muscles that project from the wall of the ventricle.
At the base of the aorta is the aortic semilunar valve, or the aortic valve, which prevents backflow from the aorta. It normally is composed of three flaps. When the ventricle relaxes and blood attempts to flow back into the ventricle from the aorta, blood will fill the cusps of the valve, causing it to close and producing an audible sound.
In Figure 6.1.12a, the two atrioventricular valves are open and the two semilunar valves are closed. This occurs when both atria and ventricles are relaxed and when the atria contract to pump blood into the ventricles. Figure 6.1.12b shows a frontal view. Although only the left side of the heart is illustrated, the process is virtually identical on the right.
Figure 6.1.13a shows the atrioventricular valves closed while the two semilunar valves are open. This occurs when the ventricles contract to eject blood into the pulmonary trunk and aorta. Closure of the two atrioventricular valves prevents blood from being forced back into the atria. This stage can be seen from a frontal view in Figure 6.1.13b.
When the ventricles begin to contract, pressure within the ventricles rises and blood flows toward the area of lowest pressure, which is initially in the atria. This backflow causes the cusps of the tricuspid and mitral (bicuspid) valves to close. These valves are tied down to the papillary muscles by chordae tendineae. During the relaxation phase of the cardiac cycle, the papillary muscles are also relaxed and the tension on the chordae tendineae is slight (see Figure 6.1.12b). However, as the myocardium of the ventricle contracts, so do the papillary muscles. This creates tension on the chordae tendineae (see Figure 6.1.13b), helping to hold the cusps of the atrioventricular valves in place and preventing them from being blown back into the atria.
The aortic and pulmonary semilunar valves lack the chordae tendineae and papillary muscles associated with the atrioventricular valves. Instead, they consist of pocket-like folds of endocardium reinforced with additional connective tissue. When the ventricles relax and the change in pressure forces the blood toward the ventricles, the blood presses against these cusps and seals the openings.
Disorders of the Heart Valves
When heart valves do not function properly, they are often described as incompetent and result in valvular heart disease, which can range from benign to lethal. Some of these conditions are congenital, that is, the individual was born with the defect, whereas others may be attributed to disease processes or trauma. Some malfunctions are treated with medications, others require surgery, and still others may be mild enough that the condition is merely monitored since treatment might trigger more serious consequences.
Valvular disorders are often caused by carditis, or inflammation of the heart. One common trigger for this inflammation is rheumatic fever, or scarlet fever, an autoimmune response to the presence of a bacterium, Streptococcus pyogenes, normally a disease of childhood.
While any of the heart valves may be involved in valve disorders, mitral regurgitation is the most common, detected in approximately 2 percent of the population, and the pulmonary semilunar valve is the least frequently involved. When a valve malfunctions, the flow of blood to a region will often be disrupted. The resulting inadequate flow of blood to this region will be described in general terms as an insufficiency. The specific type of insufficiency is named for the valve involved: aortic insufficiency, mitral insufficiency, tricuspid insufficiency, or pulmonary insufficiency.
If one of the cusps of the valve is forced backward by the force of the blood, the condition is referred to as a prolapsed valve. Prolapse may occur if the chordae tendineae are damaged or broken, causing the closure mechanism to fail. The failure of the valve to close properly disrupts the normal one-way flow of blood and results in regurgitation, when the blood flows backward from its normal path. Using a stethoscope, the disruption to the normal flow of blood produces a heart murmur.
Stenosis is a condition in which the heart valves become rigid and may calcify over time. The loss of flexibility of the valve interferes with normal function and may cause the heart to work harder to propel blood through the valve, which eventually weakens the heart. Aortic stenosis affects approximately two percent of the population over 65 years of age, and the percentage increases to approximately four percent in individuals over 85 years. Occasionally, one or more of the chordae tendineae will tear or the papillary muscle itself may die as a component of a myocardial infarction (heart attack). In this case, the patient’s condition will deteriorate dramatically and rapidly, and immediate surgical intervention may be required.
Auscultation, or listening to a patient’s heart sounds, is one of the most useful diagnostic tools, since it is proven, safe, and inexpensive. The term auscultation is derived from the Latin for “to listen,” and the technique has been used for diagnostic purposes as far back as the ancient Egyptians. Valve and septal disorders will trigger abnormal heart sounds. If a valvular disorder is detected or suspected, a test called an echocardiogram, or simply an “echo,” may be ordered. Echocardiograms are sonograms of the heart and can help in the diagnosis of valve disorders as well as a wide variety of heart pathologies.
Career Connection
Cardiologist
Cardiologists are medical doctors that specialise in the diagnosis and treatment of diseases of the heart. The pathway to become a certified cardiologist in Australia consists of four basic steps. Firstly, a completion of an undergraduate degree (3 years full time) in either a health science or biomedical science field with provisional entry into medicine. Second step is completing either a Bachelor of Medicine/Bachelor of Surgery or a Doctor of Medicine (MD) degree which generally takes four years full time. The third step is to complete an internship/residency in a public hospital system (two years). The final stage requires further vocational training and a Fellowship in a specialised training program (e.g. Fellowship of the Royal Australasian College of Physicians (FRACP) which takes approximately three to five years to complete. The annual salary of a Cardiologist in Australia can range between $60k up to $630k.
Cardiovascular Technologist/Technician
Cardiovascular technologists/technicians are trained professionals who perform a variety of imaging techniques, such as sonograms or echocardiograms, used by physicians to diagnose and treat diseases of the heart. Nearly all of these positions require an associate degree, and include, but are not limited to, Grade 1 Cardiac Technician (~$48k – $80k per annum), radiographer (~$55k – $104k per annum), cardiac sonographer (~$62k – $135k per annum).
Coronary Circulation
You will recall that the heart is a remarkable pump composed largely of cardiac muscle cells that are incredibly active throughout life. Like all other cells, a cardiomyocyte requires a reliable supply of oxygen and nutrients, and a way to remove wastes, so it needs a dedicated, complex, and extensive coronary circulation. And because of the critical and nearly ceaseless activity of the heart throughout life, this need for a blood supply is even greater than for a typical cell. However, coronary circulation is not continuous; rather, it cycles, reaching a peak when the heart muscle is relaxed and nearly ceasing while it is contracting.
Coronary Arteries
Coronary arteries supply blood to the myocardium and other components of the heart. The first portion of the aorta after it arises from the left ventricle gives rise to the coronary arteries. There are three dilations in the wall of the aorta just superior to the aortic semilunar valve. Two of these, the left posterior aortic sinus and anterior aortic sinus, give rise to the left and right coronary arteries, respectively. The third sinus, the right posterior aortic sinus, typically does not give rise to a vessel. Coronary vessel branches that remain on the surface of the artery and follow the sulci are called epicardial coronary arteries.
The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The larger anterior interventricular artery, also known as the left anterior descending artery (LAD), is the second major branch arising from the left coronary artery. It follows the anterior interventricular sulcus around the pulmonary trunk. Along the way it gives rise to numerous smaller branches that interconnect with the branches of the posterior interventricular artery, forming anastomoses. An anastomosis is an area where vessels unite to form interconnections that normally allow blood to circulate to a region even if there may be partial blockage in another branch. The anastomoses in the heart are very small. Therefore, this ability is somewhat restricted in the heart, so a coronary artery blockage often results in death of the cells (myocardial infarction) supplied by the particular vessel.
The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system. Normally, one or more marginal arteries arise from the right coronary artery inferior to the right atrium. The marginal arteries supply blood to the superficial portions of the right ventricle. On the posterior surface of the heart, the right coronary artery gives rise to the posterior interventricular artery, also known as the posterior descending artery. It runs along the posterior portion of the interventricular sulcus toward the apex of the heart, giving rise to branches that supply the interventricular septum and portions of both ventricles. Figure 6.1.14 presents views of the coronary circulation from both the anterior and posterior views.
Diseases of the Heart: Myocardial Infarction
Myocardial infarction (MI) is the formal term for what is commonly referred to as a heart attack. It normally results from a lack of blood flow (ischaemia) and oxygen (hypoxia) to a region of the heart, resulting in death of the cardiac muscle cells. An MI often occurs when a coronary artery is blocked by the build-up of atherosclerotic plaque consisting of lipids, cholesterol and fatty acids, and white blood cells, primarily macrophages. It can also occur when a portion of an unstable atherosclerotic plaque travels through the coronary arterial system and lodges in one of the smaller vessels. The resulting blockage restricts the flow of blood and oxygen to the myocardium and causes death of the tissue. MIs may be triggered by excessive exercise, in which the partially occluded artery is no longer able to pump sufficient quantities of blood, or severe stress, which may induce spasm of the smooth muscle in the walls of the vessel.
In the case of acute MI, there is often sudden pain beneath the sternum (retrosternal pain) called angina pectoris, often radiating down the left arm in males but not in female patients. Until this anomaly between the sexes was discovered, many female patients suffering MIs were misdiagnosed and sent home. In addition, patients typically present with difficulty breathing and shortness of breath (dyspnoea), irregular heartbeat (palpations), nausea and vomiting, sweating (diaphoresis), anxiety and fainting (syncope), although not all of these symptoms may be present. Many of the symptoms are shared with other medical conditions, including anxiety attacks and simple indigestion, so differential diagnosis is critical. It is estimated that between 22 and 64 percent of MIs present without any symptoms.
An MI can be confirmed by examining the patient’s ECG, which frequently reveals alterations in the ST and Q components. Some classification schemes of MI are referred to as ST-elevated MI (STEMI) and non-elevated MI (non-STEMI). In addition, echocardiography or cardiac magnetic resonance imaging may be employed. Common blood tests indicating an MI include elevated levels of creatine kinase MB (an enzyme that catalyses the conversion of creatine to phosphocreatine, consuming ATP) and cardiac troponin (the regulatory protein for muscle contraction), both of which are released by damaged cardiac muscle cells.
Immediate treatments for MI are essential and include administering supplemental oxygen, aspirin that helps to break up clots, and nitroglycerine administered sublingually (under the tongue) to facilitate its absorption. Despite its unquestioned success in treatments and use since the 1880s, the mechanism of nitroglycerine is still incompletely understood but is believed to involve the release of nitric oxide, a known vasodilator, and endothelium-derived releasing factor, which also relaxes the smooth muscle in the tunica media of coronary vessels. Longer-term treatments include injections of thrombolytic agents such as streptokinase that dissolve the clot, the anticoagulant heparin, balloon angioplasty and stents to open blocked vessels, and bypass surgery to allow blood to pass around the site of blockage. If the damage is extensive, coronary replacement with a donor heart or coronary assist device, a sophisticated mechanical device that supplements the pumping activity of the heart, may be employed. Despite the attention, development of artificial hearts to augment the severely limited supply of heart donors has proven less than satisfactory but will likely improve in the future.
MIs may trigger cardiac arrest, but the two are not synonymous. Important risk factors for MI include cardiovascular disease, age, smoking, high blood levels of the low-density lipoprotein (LDL, often referred to as “bad” cholesterol), low levels of high-density lipoprotein (HDL, or “good” cholesterol), hypertension, diabetes mellitus, obesity, lack of physical exercise, chronic kidney disease, excessive alcohol consumption, and use of illegal drugs.
Coronary Veins
Coronary veins drain the heart and generally parallel the large surface arteries (see Figure 6.1.14). The great cardiac vein can be seen initially on the surface of the heart following the interventricular sulcus, but it eventually flows along the coronary sulcus into the coronary sinus on the posterior surface. The great cardiac vein initially parallels the anterior interventricular artery and drains the areas supplied by this vessel. It receives several major branches, including the posterior cardiac vein, the middle cardiac vein, and the small cardiac vein. The posterior cardiac vein parallels and drains the areas supplied by the marginal artery branch of the circumflex artery. The middle cardiac vein parallels and drains the areas supplied by the posterior interventricular artery. The small cardiac vein parallels the right coronary artery and drains the blood from the posterior surfaces of the right atrium and ventricle. The coronary sinus is a large, thin-walled vein on the posterior surface of the heart lying within the atrioventricular sulcus and emptying directly into the right atrium. The anterior cardiac veins parallel the small cardiac arteries and drain the anterior surface of the right ventricle. Unlike these other cardiac veins, it bypasses the coronary sinus and drains directly into the right atrium.
Diseases of the Heart: Coronary Artery Disease
Coronary artery disease is the leading cause of death worldwide. It occurs when the build-up of plaque—a fatty material including cholesterol, connective tissue, white blood cells, and some smooth muscle cells—within the walls of the arteries obstructs the flow of blood and decreases the flexibility or compliance of the vessels. This condition is called atherosclerosis, a hardening of the arteries that involves the accumulation of plaque. As the coronary blood vessels become occluded, the flow of blood to the tissues will be restricted, a condition called ischaemia that causes the cells to receive insufficient amounts of oxygen, called hypoxia. Figure 6.1.15 shows the blockage of coronary arteries highlighted by the injection of dye. Some individuals with coronary artery disease report pain radiating from the chest called angina pectoris, but others remain asymptomatic. If untreated, coronary artery disease can lead to MI or a heart attack.
The disease progresses slowly and often begins in children and can be seen as fatty “streaks” in the vessels. It then gradually progresses throughout life. Well-documented risk factors include smoking, family history, hypertension, obesity, diabetes, high alcohol consumption, lack of exercise, stress, and hyperlipidaemia or high circulating levels of lipids in the blood. Treatments may include medication, changes to diet and exercise, angioplasty with a balloon catheter, insertion of a stent, or coronary bypass procedure.
Angioplasty is a procedure in which the occlusion is mechanically widened with a balloon. A specialised catheter with an expandable tip is inserted into a superficial vessel, normally in the leg, and then directed to the site of the occlusion. At this point, the balloon is inflated to compress the plaque material and to open the vessel to increase blood flow. Then, the balloon is deflated and retracted. A stent consisting of a specialised mesh is typically inserted at the site of occlusion to reinforce the weakened and damaged walls. Stent insertions have been routine in cardiology for more than 40 years.
Coronary bypass surgery may also be performed. This surgical procedure grafts a replacement vessel obtained from another, less vital portion of the body to bypass the occluded area. This procedure is clearly effective in treating patients experiencing a MI, but overall does not increase longevity. Nor does it seem advisable in patients with stable although diminished cardiac capacity since frequently loss of mental acuity occurs following the procedure. Long-term changes to behaviour, emphasising diet and exercise plus a medicine regime tailored to lower blood pressure, lower cholesterol and lipids, and reduce clotting are equally as effective.
Section Review
The heart resides within the pericardial sac and is located in the mediastinal space within the thoracic cavity. The pericardial sac consists of two fused layers: an outer fibrous capsule and an inner parietal pericardium lined with a serous membrane. Between the pericardial sac and the heart is the pericardial cavity, which is filled with lubricating serous fluid. The walls of the heart are composed of an outer epicardium, a thick myocardium, and an inner lining layer of endocardium. The human heart consists of a pair of atria, which receive blood and pump it into a pair of ventricles, which pump blood into the vessels. The right atrium receives systemic blood relatively low in oxygen and pumps it into the right ventricle, which pumps it into the pulmonary circuit. Exchange of oxygen and carbon dioxide occurs in the lungs, and blood high in oxygen returns to the left atrium, which pumps blood into the left ventricle, which in turn pumps blood into the aorta and the remainder of the systemic circuit. The septa are the partitions that separate the chambers of the heart. They include the interatrial septum, the interventricular septum, and the atrioventricular septum. Two of these openings are guarded by the atrioventricular valves, the right tricuspid valve and the left mitral valve, which prevent the backflow of blood. Each is attached to chordae tendineae that extend to the papillary muscles, which are extensions of the myocardium, to prevent the valves from being blown back into the atria. The pulmonary valve is located at the base of the pulmonary trunk, and the left semilunar valve is located at the base of the aorta. The right and left coronary arteries are the first to branch off the aorta and arise from two of the three sinuses located near the base of the aorta and are generally located in the sulci. Cardiac veins parallel the small cardiac arteries and generally drain into the coronary sinus.
Review Questions
Critical Thinking Questions
Click the drop down below to review the terms learned from this chapter.


2
OER can be integrated into classes as either a primary textbook or supplemental material. As noted earlier in the book, OER represent a wide range of materials, including videos, textbooks, and course assignments. Open Textbooks are exactly like traditional textbooks except that they offer free access to students. These textbooks may also include a CCL. An example of an open textbook is OpenStax’s Psychology book. This is an introductory psychology textbook aimed at undergraduate students. The text also includes some ancillary materials for instructors, like a test bank and PowerPoint slides. The textbook is licensed under a Creative Commons Attribution License which allows instructors to remix, share, transform, and copy as needed. In the current open education landscape, open textbooks are a growing commodity that is generating a lot of research and interest, especially in higher education.
In addition to open textbook options, primary sources are materials that may be considered OER. For example, Project Gutenberg houses thousands of books that fall within the public domain. Image-based primary sources can be discovered and used via the Creative Commons CC Search. Items that fall in the public domain or use CCL allow for certain uses. For more information on these licenses, please see Chapter 3.
The advantage of OER is that it allows instructors to truly mix resources and media to create a customized text or set of resources for their class. And, this is only the first step in open education. The next steps include incorporating more open pedagogy into classes. While open pedagogy is complex, one part of it includes creating assignments for students that build something rather than a “disposable assignment” (Wiley, 2013). In “What is Open Pedagogy”, David Wiley (2013) provides the example of students creating tutorials for future classes as an example of open pedagogy in the classroom. Students learn the class material by creating the tutorials, these can be used in the future by other students. While open pedagogy is a logical next step in higher education, it will take faculty extra time to create this type of assignment.
Quotable Quotes
The Importance of Open
“One of the main motivations behind our involvement in the creation and distribution of OER is to ensure educational materials are accessible to all students. The rising cost of textbooks creates a substantial barrier to learning for many students, locally and in developing regions (BC Campus, n.d.).”
Did you know?
As of 2016, there are over 306 Millions Creative Commons licensed photographs available (Fact File, 2016). That number continues to rise.
Additional OER Resources
R campus, OER Assessment Rubric
https://www.rcampus.com/rubricshowc.cfm?code=L9WC6X&sp=yes
OER Evaluation Checklist
http://guides.library.illinois.edu/ld.php?content_id=9830689
A Guide to Teaching with Open Educational Resources (OER)
https://cer.jhu.edu/files/guide-to-open-education-resources.pdf
Idaho Training Clearinghouse: OER
https://idahotc.com/Topics/N-Z/Open-Educational-Resources#10769
References
1.BC Campus. (n.d.) Open education advocacy. Retrieved from https://bccampus.ca/topics-of-practice/open-education/advocacy/.
2. Fact File. (2016). 10 facts about Creative Commons. Retrieved from https://factfile.org/10-facts-about-creative-commons.
3. Wiley, D. (2013). What is open pedagogy. Retrieved from https://opencontent.org/blog/archives/2975.


Healthcare Systems
Learning Outcomes
- Explain healthcare in the United States, including healthcare reform (Affordable Care Act)
- Compare the healthcare system of the United States with that of other countries
There are broad, structural differences among the healthcare systems of different countries. In core nations, those differences might arise in the administration of healthcare, while the care itself is similar. In peripheral and semi-peripheral countries, a lack of basic healthcare administration can be the defining feature of the system. Most countries rely on some combination of modern and traditional medicine. In core countries with large investments in technology, research, and equipment, the focus is usually on modern medicine, with traditional (also called alternative or complementary) medicine playing a secondary role. In the United States, for instance, the American Medical Association (AMA) resolved to support the incorporation of complementary and alternative medicine in medical education. In developing countries, even quickly modernizing ones like China, traditional medicine (often understood as “complementary” by the western world) may still play a larger role.
U.S. Healthcare
Healthcare coverage can broadly be divided into two main categories: public healthcare (government-funded) and >private healthcare> (privately-funded).
In the United States, the healthcare system is more complex than what is found in other countries—there is no uniform health system nor universal healthcare coverage provided (Citation P), and it is more of a hybrid system that what is found in other developed nations. In 2014, 48% of healthcare spending came from private funds, both from businesses and individuals, 28% came from the federal government, and 17% came from state and local governments (Citation P). Political changes have also resulted in drastic policy changes regarding healthcare.[1]
The two main public, government funded healthcare programs are Medicare, which provides health services to people over sixty-five years old as well as people who meet certain standards for disability, and Medicaid, which provides services to people with very low incomes who meet other eligibility requirements. Other government-funded programs include service agencies focused on Native Americans (the Indian Health Service), Veterans (the Veterans Health Administration), and children (the Children’s Health Insurance Program).
The most recent U.S. census (2011) divides private insurance into employment-based insurance and direct-purchase insurance. Employment-based insurance is health plan coverage that is provided in whole or in part by an employer or union; it can cover just the employee, or the employee and their family. Direct purchase insurance is coverage that an individual buys directly from a private company.
With all these insurance options, ranging from government-provided to employee-provided and individual-provided, insurance coverage must be almost universal, right? Unfortunately, the U.S. Census Current Population Survey of 2013 showed that 18 percent of people in the United States had no health insurance at all. Equally alarming, a study by the Commonwealth Fund showed that in 2010, 81 million adults were either uninsured or underinsured; that is, people who pay at least 10 percent of their income on healthcare costs not covered by insurance or, for low-income adults, those whose medical expenses or deductibles are at least 5 percent of their income (Schoen, Doty, Robertson, and Collins 2011). The Commonwealth study further reported that while underinsurance had historically been an issue that low-income families faced, today it is affecting middle-income families more and more.
Why were so many people uninsured or underinsured? Skyrocketing healthcare costs were part of the issue. Many people cannot afford private health insurance, but their income level is not low enough to meet eligibility standards for government supported insurance. Further, even for those who are eligible for Medicaid, the program is less than perfect. Many physicians refuse to accept Medicaid patients, citing low payments and extensive paperwork (Washington University Center for Health Policy, n.d.).
Healthcare in the United States looks different today than it did just a few years ago—a result of changes in policy, such as the Affordable Care Act (PPACA or ACA or “ObamaCare”). You’ve probably heard of ObamaCare at some point—but what did it seek to do? ObamaCare expanded eligibility to programs like Medicaid and CHIP, helped guarantee insurance coverage for people with pre-existing conditions, and established regulations to make sure that the premium funds collected by insurers and care providers go directly to medical care. It also included an individual mandate, which required everyone to have insurance coverage by 2014 or pay a penalty in their taxes. A series of provisions, including significant subsidies, were intended to address the discrepancies in income that are currently contributing to high rates of uninsurance and underinsurance.
While the program has been controversial and something of a flashpoint for strongly partisan politics, in 2012 the U.S. Supreme Court upheld the constitutionality of the PPACA’s individual mandate. According to Blumenthal (2014), by 2014, 20 million people in the United States had gained health insurance under PPACA. This lowered the number of uninsured people to 13 percent. Three years later, by 2017, healthcare reform had lowered the number of uninsured people to the lowest it has ever been in the United States. In 2017, less than 9% of the population was uninsured at some point during the year[2]—a drastic drop relative to the alarming 18% in the early 2010’s. Over half of the population was insured by an employer, over one third was covered by government-funded programs, and the rest were either covered by direct-purchase or by military funding.
The PPACA remains contentious and at the forefront of political debates. The Supreme Court ruled in the case of National Federation of Independent Businesses v. Sebelius in 2012, that states cannot be forced to participate in the PPACA’s Medicaid expansion. This ruling has opened the door to challenges to the PPACA in Congress and the Federal courts, in some state governments, and among conservative groups and independent businesses.
WATCH IT
Still confused about the healthcare system in the United States? Watch this video for clarification.
Try It
Healthcare Elsewhere
Other Developed Areas
Clearly, healthcare in the United States has some areas for improvement. But how does it compare to healthcare in other countries? Many people in the United States are fond of saying that this country has the best healthcare in the world, and while it is true that the United States has a higher quality of care available than many peripheral or semi-peripheral nations, it is not necessarily the “best in the world.” In a report on how U.S. healthcare compares to that of other countries, researchers found that the United States does “relatively well in some areas—such as cancer care—and less well in others—such as mortality from conditions amenable to prevention and treatment” (Docteur and Berenson 2009). A 2016 study on global healthcare ranked the United States at 29th,[3] an improvement from its ranking of 37th by The World Health Organization in 2000.[4]
One critique of the Patient Protection and Affordable Care Act is that it will create a system of socialized medicine, a term that for many people in the United States has negative connotations lingering from the Cold War era and earlier. Under a socialized medicine system, the government owns and runs the system. It employs the doctors, nurses, and other staff, and it owns and runs the hospitals (Klein 2009). The best example of socialized medicine is in Great Britain, where the National Health System (NHS) gives free healthcare to all its residents. And despite some U.S. citizens’ knee-jerk reaction to any healthcare changes that hint of socialism, the United States has one socialized system in the form of the Veterans Health Administration.
It is important to distinguish between socialized medicine, in which the government owns the healthcare system, and universal healthcare, which is simply a system that guarantees healthcare coverage for everyone. Germany, Singapore, and Canada all have universal healthcare. People often look to Canada’s universal healthcare system, Medicare, as a model for the system. In Canada, healthcare is publicly funded and is administered by the separate provincial and territorial governments. However, the care itself comes from private providers as opposed to government providers, and is therefore not a socialized medicine system. This is the main difference between universal healthcare and socialized medicine. The Canada Health Act of 1970 required that all health insurance plans must be “available to all eligible Canadian residents, comprehensive in coverage, accessible, portable among provinces, and publicly administered” (International Health Systems Canada 2010).
Underdeveloped and Undeveloped Regions
Heated discussions about socialization of medicine and managed-care options seem frivolous when compared with the issues of healthcare systems in developing or underdeveloped countries. In many countries, per capita income is so low, and governments are so fractured, that healthcare as we know it is virtually non-existent. Care that people in developed countries take for granted—like hospitals, healthcare workers, immunizations, antibiotics and other medications, and even sanitary water for drinking and washing—are unavailable to much of the population. Organizations like Doctors Without Borders, UNICEF, and the World Health Organization have played an important role in helping these countries get their most basic health needs met.
WHO, which is the health arm of the United Nations, set eight Millennium Development Goals (MDGs) in 2000 with the aim of reaching these goals by 2015. Some of the goals dealt more broadly with the socioeconomic factors that influence health, but MDGs 4, 5, and 6 all related specifically to large-scale health concerns, the likes of which most people in the United States will never contemplate. MDG 4 was to reduce child mortality, MDG 5 aimed to improve maternal health, and MDG 6 strived to combat HIV/AIDS, malaria, and other diseases. The goals may not seem particularly dramatic, but the numbers behind them show how serious they are. In 2015, these goals were revised and were turned into the UN’s Sustainable Development Goals—one of which is focused specifically on Good Health and Well-Being, another which is focused on Clean Water and Sanitation, and a myriad of other goals that would support the implementation and improvement of healthcare systems (Citation S). These goals seek to show tangible results by 2030.
The fact that these goals, some of which are closely related to healthcare, remain at the forefront of the United Nations’ agenda suggests that preventable deaths and medical conditions continue to be an international issue. Maternal mortality has fallen by 37% since 2000, yet the maternal mortality ratio in developing countries is 14 times higher in developing regions relative to mothers in developed regions (Citation R). 37 million people globally were living with HIV in 2017, with tuberculosis being the leading cause of death among people living with HIV, accounting for roughly one third of deaths. Malaria incidence rates have dropped, as have mortality rates, but millions are still affected.[5] Access to healthcare would lower these numbers and improve the lives of individuals around the world.
An important component of disease prevention and control is epidemiology, or the study of the incidence, distribution, and possible control of diseases. Fear of Ebola contamination, primarily in Western Africa but also to a smaller degree in the United States, became national news in the summer and fall of 2014 and again in 2018, and Zika virus outbreaks in the Pacific Islands as well as in South America, now spreading to Central and North America, have been alarming. Countries might have their own healthcare systems, but we live in an increasingly globalized and interconnected world, and the consequences of one system of healthcare do not stop at the country’s borders.
WATCH IT
In 2018, the World Health Organization launched a pilot program for universal healthcare in a county in Kenya. Watch the video to learn more about it.
Further Research
Project Mosquito Net says that mosquito nets sprayed with insecticide can reduce childhood malaria deaths by half.
Think It Over
- What do you think are the best and worst parts of the PPACA? Why?
- Compare and contrast the healthcare system of the United States with the WHO’s Sustainable Development Goals
Try It
Glossary
- individual mandate:
- a government rule that requires everyone to have insurance coverage or they will have to pay a penalty
- private healthcare::
- health insurance that a person buys from a private company; private healthcare can either be employer-sponsored or direct-purchase
- public healthcare:
- health insurance that is funded or provided by the government
- socialized medicine:
- when the government owns and runs the entire healthcare system
- underinsured:
- people who spend at least 10 percent of their income on healthcare costs that are not covered by insurance
- universal healthcare:
- a system that guarantees healthcare coverage for everyone
<a style="margin-left: 16px;" target="_blank" href="https://docs.google.com/document/d/1vy-T6DtTF-BbMfpVEI7VP_R7w2A4anzYZLXR8Pk4Fu4"
- Department for Professional Employees. (2016) The U.S. Health Care System: An International Perspective. Retrieved from https://dpeaflcio.org/programs-publications/issue-fact-sheets/the-u-s-health-care-system-an-international-perspective/. ↵
- Berchick, Edward R. and Emily Hood and Jessica C. Barnett. (2018) Health Insurance Coverage in the United States: 2017. Retrieved from https://www.census.gov/library/publications/2018/demo/p60-264.html. ↵
- GBD 2016 Healthcare Access and Quality Collaborators (May 2018). Measuring performance on the Healthcare Access and Quality Index for 195 countries and territories and selected subnational locations: a systematic analysis from the Global Burden of Disease Study 2016. The Lancet. Volume 391, issue 10136, p2236-2271. Retrieved from https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)30994-2/fulltext#seccestitle190. ↵
- The World Health Report (2000). Retrieved from https://www.who.int/whr/2000/en/whr00_en.pdf?ua=1. ↵
- UN Sustainable Development Goals (n.d.). Goal 3: Ensure healthy lives and promote well-being for all at all ages. Retrieved from https://www.un.org/sustainabledevelopment/health/. ↵


90 Extra Credit Assignments
Extra Credit Primary Source Assignment
Pick one of the online primary sources assigned from the past two modules (Growing Pains: The New Republic, 1790-1820 and Industrial Transformation in the North: 1800-1850). Remember, primary sources are sources from the time we are studying — not stuff written about it later.
Answer the question about it, following the procedure provided, and using quoted evidence from the source. You may supplement your answer with evidence from other primary sources, or with information from our textbook.
Write a long paragraph/short page about your source (250 words):
Question: What does your chosen source demonstrate about the time period when it was produced?
In order to answer this question, you will probably want to do the following:
- Explain and analyze what you can determine about the author, the author’s point of view.
- Explain and analyze what you can determine about document’s likely audience, and their point of view.
- Summarize and explain the author’s message. What do they want to convince their audience to do or think? How do they go about this?
- Explain and analyze what you can determine about the context in which the document was produced.
If you wish to do this assignment more than once, you may. (Email me for details.)
Points from this assignment will be added to your final grade.
Extra Credit Movie Assignment
Pick one of the following films relevant to the past few weeks’ material:
- One or more episodes of the John Adams TV series from HBO (2008)
- Amistad (1997)
- Twelve Years a Slave (2013)
You’ll need to obtain them yourself (Netflix or a library, or something).
Watch the film. In a long paragraph/short page (250 words) consider how the film-maker depicted the past and what decisions he or she made.
In order to answer this question, you will probably want to do the following:
- Explain and analyze what you can determine about the film’s creator and the film-maker’s point of view.
- Explain and analyze what you can determine about film’s likely audience, and their point of view.
- Summarize and explain the film-maker’s message. What do they want to convince their audience to do or think? How do they go about this?
- Explain and analyze what you can determine about the context in which the objects were produced.
You may do this assignment more than once. Email me for further details.
Points from this assignment will be added to your final grade.


22
Melissa Cooper
Twitter: @LOL1librarian
Osaka International School
Abstract
Twitter is a powerful social media tool for educators. As more educators contribute, the stronger this community becomes since the users will build a nest of a thriving community of practice (Lave & Wenger, 1991 as cited by Xing & Gao, 2018). As connectivists (Siemens, 2004), educators can find ways to support knowledge construction (Steward, 2015) and create a social culture of collaboration (Xing & Gao, 2018) that will support their development of a stronger curriculum to establish a students acquisition of 21st-century skills. A willingness to find the time and acknowledge the validity of the resources and information available is critical to using Twitter successfully. Reputable tweeters have given sound advice in order to curate resources. Although further study needs to be completed, there is evidence that the resources teachers find on Twitter can support professional and curriculum development.
Keywords: professional development, professional learning, Twitter, social media, community of practice, 21st-century learning, connectivism
Introduction
Social media is becoming more pervasive in our society and it has the potential to play a positive role in educators professional and curriculum development. Through Twitters’ connections, an educator can construct knowledge and be engaged in a culture of collaboration in order to build a community of practice (Lave & Wenger, 1991 as cited by Xing & Gao, 2018). This community requires an active presence to be beneficial and educators need to learn how to avoid some pitfall. Educators need to be flexible and try to find time in their schedule in order to engage meaningfully since Twitter requires careful curation and participation. There’s a range of resources available, including ‘just in time’ resources (Greenhalgh & Koehler, 2017) that can support educators during a time of tragedy. Twitter can offer not only resources but provide educators a platform to share their epistemology. As a result of this supportive community of practice, educators can further develop their curriculum. Curriculum enhancement through a combination of an educator’s media savvy, critical thinking skills and technology tools is needed to support 21st-century learning. However, using social media to improve a user’s professional learning and development comes with some words of caution; due to the volume and the lack of neutrality in the information provided. By striking a solid balance, the power of tweeting will be revealed.
 Moving along the avenue of ‘knowledge construction’ (Stewart, 2015), Twitter provides educators a couple of different paths to follow. Establishing your tribe on Twitter will allow a user to develop a ‘culture of collaboration’. Social media is here to stay so why not make those connections or connectivism (Siemens, 2004) work for you?
Connectivism
At the heart of the realm of Twitter is a sense of connection, and Siemens work on connectivism in 2004 highlights how the knowledge is connected, and how it cycles around the network. Twitter does require one to curate followers and to follow others in order to maintain connections and for a learner to be self-directed. The quality of what can be learned on Twitter depends on the diversity of the people you are following as well as the hashtags you explore. Does the realm of Twitter prove that learning can reside in non-human machines?
Knowledge Construction
How in the world is it possible to construct knowledge within such a limited number of characters? People utilize this brevity quite well since you can ask questions, state opinions, have a flurry of ideas exchanged, share resources and pump up your colleagues by acknowledging content they have shared (Prestridge, 2019). All critical thinking skills can be utilized and critical thinking skills are an essential component of a robust curriculum. It’s been found by Lupton (2014, as cited by Stewart, 2015) that 90% out of 711 academics use Twitter for professional purposes like networking, promoting, developing research and offering support. For some there can be an element of competitiveness, if you allow yourself to be sucked into the vortex of the number following you and your followers. Balance can be struck in different ways such as only following people you met in the real physical world (Xing & Gao, 2018) or by reviewing profiles and their associated blogs (Stewart, 2015). Within a limited space you can find construct knowledge with your fluttering followers. With input from fellow tweeters, educators can further develop their curriculum to include a wider range of skills and resources. All you need to build your tribe is a healthy sense of curiosity!
Culture of Collaboration
In terms of user-friendly space, most professional Twitter hashtags and tweeters participate positively and build a wonderful collective intelligence that will add to a teacher’s sense of self-efficacy (Prestridge, 2019). Through these language-based social interactions, which build upon each other, you can modify interpretation and eventually your understanding will change (Xing & Gao, 2018). As one continues to tweet and interact, your sense of capacity grows exponentially as you realize that you are able to positively contribute to a global conversation (Stewart, 2015). Hopefully, over time this professional learning will evolve into professional development where you can see a change in practice.
Applications: Tweeting to Learn and Develop Curriculum
Twitter has been around for over a decade and how the platform has been utilized on a professional level is continually evolving. In order to ascertain educators views of social media on their professional learning a survey was conducted using a Google form and shared via Facebook groups (International School Teachers, Int’l School Library Connection and Future Ready Librarians), Twitter (#EDUC5303G, #inTLchat, #educhat, #digitalcitizen), Google Group forum (Singapore’s International School Library Network) and email (Canadian International School email). There’s some diversity in responses, of the 129 participants there are 24 different countries represented; although the majority are Singapore or Canada based. Unfortunately, the majority of the participants responded via social media which makes generalizations more challenging but there are a few trends in responses.
Flexibility and Accessibility
At this point in Twitters decade plus lifetime, it seems that educators are still getting on board. Considering educators views on flexibility and accessibility through the lens of Davis’ (1989) Technology Acceptance Model (TAM) is helpful since two major factors seem to be perceived ease of use in terms of time to work on the platform and the perceptions of its usefulness.
According to Prestige (2019), since Twitter is available anytime and anywhere it should suit everyone. Slowly many educators and other professionals viewpoints are changing and they are acknowledging that the ideas on Twitter do have value in comparison to concepts taught in the more traditional professional development workshop model. Since many workshops are dictated by an administration, many people like Twitter since it is self-directed. According to this survey, 63% of educators find it challenging to find the time to sit down and build a community. There is a disconnect between the perceived ease of use in order to sift through information to find a nugget of worth (Davis, 1989).
Community of Practice
A Twitter tribe is built by the user to suit their own needs, it is an individually curated community of practice (Lave & Wenger 1991 as cited by Xing & Gao, 2018). As pointed out by Xing and Gao (2018), users will not benefit from the community if they leave it so users need to be active participants who engage in cognitive and interactive ways in order to learn. In terms of time, they recommend checking in a couple of times a week to search for new ideas, ask questions and react to others. Figure 1 shows that many people who read posts will attempt to implement some ideas. Twitter’s community of educators is growing and more and more users are not just trolling for information but cognitively interact with the community as seen in Figure 2. As educators, modeling 21st-century skills and collaborating with colleagues in the Tweetosphere will support the development of an innovative curriculum. Educators who apply these skills are more likely to see their value and importance in a strong technology skill-based curriculum. Basically, if you interact at a deeper cognitive level and conscientiously use critical thinking skills then the more you will get out of the experience.
A study of academics who use Twitter for their professional learning done by Stewart (2015) had a number of useful tips. If you do not want to end up overwhelmed by useless news in your feed you should have a set of criteria to use when selecting people to follow: look at their blog link and see if their epistemology aligns with your own, scan the quality of tweets they have posted and review the hashtags they use. To continue to build your following, you can look at who they follow and Twitter will post recommendation based on hashtags or people you have in common. Twitter, as a platform, is working to be a smart user-friendly platform that supports a community of practice.
Through this ‘self-generating professional learning’ (Prestridge, 2019) teachers engage in authentic learning that leads to professional and curriculum development. In turn, this professional development can then be shared with a user’s real-world academic community and update their curriculum to include more technology-based skills.
In this survey, 70% of participants felt that social media played a role in developing their practice. An interesting aspect is that Twitter offers what Greenhalgh and Koehler (2017) call ‘just in time’ professional development. Tragedies are broadcast quickly and can have a great impact on our students, equators grapple to find information that is age-level appropriate and interesting in order to facilitate discussions. In their study, they examined the quality of the tweets used by educators following a hashtag that was created just after the terrorist attacks in Paris in November 2015. What they found was that educators were sharing rich and relevant resources and building a dialogue of support. The concept of ‘just in time’ resources for professional development is new and it will be interesting to watch its evolution.
Further Study & Conclusion
Will the use of social media platforms for professional learning become the norm? Many teachers are still very cautionary in the role of social media in their professional lives, as can be seen in the comments from the survey in Appendix A. People are justifiably concerned about the volume of information and its validity.
Robson (2016) is critical of what is found on social media. He questions many components: how information is linked to profiles, the lack of neutrality in the technology itself and the power of dominant discourse. Since information and resources are shared via profile, he expresses the concern the only reason why people share is to stroke their own ego, rather than positively contributing to a community. Although there are some valid concerns in the nest of dominance interaction, but this happens in the physical world as well where it is the nature of some individuals to lead the discussion and others will be hesitant to join in a debate or critic colleagues contributions. Instead of viewing this as a fault of social media, is it not a fault of human nature?
Twitter can be a powerful tool to support educators in developing a community of practice that will support their professional learning and curriculum development. Viewing the use of Twitter through the lens of connectivism (Siemens, 2004) and a community of practice realms (Lave & Wenger, 1991 as cited by Xing & Gao, 2018) educators can socialize and engage in a manner that will promote the use of critical thinking skills and improve their curriculum. There are some words of caution, time needs to be taken to curate as well as actively participate in order for an educator to truly benefit from Twitter. Educators should embrace social media and leap into the Twitter nest!
References
Davis, F. (1989). Perceived usefulness, perceived ease of use, and user acceptance of information technology. MIS Quarterly, 13(3), 319-339.
Greenhalgh, S. P., & Koehler, M. J. (2017). 28 Days Later: Twitter Hashtags as “Just in Time” Teacher Professional Development. TechTrends: Linking Research and Practice to Improve Learning, 61(3), 273–281. http://search.ebscohost.com/login.aspxdirect=true&db=eric&AN=EJ1138470&site=ehost-live
Prestridge, S. (2019). Categorising teachers’ use of social media for their professional learning: A self-generating professional learning paradigm. Computers & Education, 129, 143-158. doi:10.1016/j.compedu.2018.11.003
Robson, James (2016). Engagement in structured social space: an investigation of teachers’ online peer-to-peer interaction. Learning, Media and Technology, 41(1), 119-139, DOI: 10.1080/17439884.2015.1102743
Rosell-Aguilar, F. 2018. Twitter: A Professional Development and Community of Practice Tool for Teachers. Journal of Interactive Media in Education, 2018, 1(6), 1–12. Retrieved from http://search.ebscohost.com/login.aspx?direct=true&db=eric&AN=EJ1180366&site=ehost-live
Siemens, George. (2004). Connectivism: A Learning Theory for the Digital Age. International Journal of Instructional Technology and Distance Learning, 2, 3-10. Retrieved from http://elearnspace.org/Articles/connectivism.htm
Stewart, B. (2015). Open to influence: What counts as academic influence in scholarly networked Twitter participation. Learning, Media and Technology, 40(3), 287-309. doi:10.1080/17439884.2015.1015547
Xing, W., & Gao, F. (2018). Exploring the relationship between online discourse and commitment in Twitter professional learning communities. Computers & Education, 126, 388-398. doi:10.1016/j.compedu.2018.08.010
Appendix A: Comments on Social Media and Professional Learning
The survey conducted included a comment box in order to provide educators the opportunity to share their opinions on social media and their professional learning.
Listed below are the unedited comments recorded by participants.
Love the wealth of ideas that flow but I do try to be mindful of making time to deep dive the research rather than always wading in the more shallow, practical end.
Wanted or not we do live in a platform society. Social media is where connection, collaboration, learning and sharing happens. If you are not part of this society yet, be a risk taker, join online PLN’s and enjoy the benefits. You might like it. Don’t forget, social media is also the place where our users are. That is another reason to be there.
I’m active (read: I use a lot of ideas from others’ posts but don’t post so much myself) on Facebook groups. I don’t use Twitter or instagram.
A great way of developing as an educator – finding new ideas and connecting with others!
I am active on Facebook and am learning online, but have yet to embrace Twitter or instagram
Social media sharing is becoming just as useful as our state library email listserv.
Depends on the source:
Twitter–superficial conversations, folks trying to develop their personal branding, lack of nuance.
Facebook: I may be in the wrong groups, but I have noted folks asking questions that could be answered with a Google search. I rarely see folks sharing stuff of import. It happens though. It is just that there is SO MUCH of the other stuff. And you can’t tag for quality. It is discovered based on luck.
Ultimately, I’m bothered by the lack of research-based practices bandied about.
I learn more from collaborating with local people than I do from social media.
Disseminating this through social media channels isn’t ironic. It is a threat to validity.
I use Twitter for my PLN and FB for private connections on Insta I have both a personal and professional account
Using social media platforms has allowed me to connect better with teachers in my own school, my country and around the world!!
I don’t use Instragam, just Twitter and Facebook
I wish I had more time in the day to absorb and choose what to implement. I can’t keep up with my amazing PLN. I also feel some responsibility to share and offer ideas to others, and this is another area where I’m having trouble keeping up!
As well as professional learning, I buy many books for the school libraries that I find out about on social media
It’s hard to keep up with the multitude of ideas and resources. Picking and choosing what is useful takes a lot of time.
Using social media for professional learning allows me to connect with people all over the world. It gives me the chance to see what other educators are doing, and hear other perspectives that I wouldn’t otherwise encounter in my daily life. Social media allows you to find your ‘tribe’.
I am have such limited time with classes that many of the wonderful ideas won’t work or would take resources I don’t have. I still value the insights and ideas shared by others.
Very tricky in China with all the blocking
Useful, practical, current, and of varying quality. There’s too much, like everything else on social media, but so worth it and you can pick and choose. It’s some of the best, cheapest and quickest PD I get. It’s an example of how social media can make a positive impact.
Twitter is one of my favourite social media platforms to use for sharing educational resources. It’s a plus that people are generally supportive.
The only downside is the GDPR which is making it increasingly difficult in Europe
LinkedIn is the only relevant or useful social platform as far as I’m concerned. I have no use for any of the others, which I find a) juvenile and b) a complete waste of time, both professionally and personally.
Sometimes it’s a lot of information and links people are posting to rise up in Admin and get noticed, not necessarily something they practice/believe
While social media is a good platform to reach out to friends, family members and also to the public, it is not always ideal and it’s not vetted for reliable use in education.
I find Twitter is one of the best PLC platforms.
It’s all about sharing ideas globally to build the educational community.
I mostly use Pinterest for ideas.
Some of the best PD for me happens this way!
I would like to use Twitter more frequently for teaching
I don’t find Twitter user friendly
Mostly Twitter for me.
Twitter tends to be more thought provoking and professional than other platforms, especially if you follow the right people. I also find that the character limit makes people really think about what they will say and how they will say it.
It is helpful but too time consuming.
Used to be much more engaged online, especially Twitter. However now find time is limited (kids! haha)
I know many of my colleagues use social media especially Pinterest very often! I believe it’s an excellent source for professional learning.
I wish I had more time to use social media — I have so many ideas, but not much time to curate my own platforms or to really look deeply at those of others.
If we make better use of social media then I feel every educator can upgrade their knowledge and can stay connected as one IB education
I don’t know where I would be without it.
Follow various librarians (and others) on Twitter and re-post using hashtags such as #tlchat and #iamalibrarian. Follow about six groups on FB, one of which is an international school librarians group. Everyone is so open in their sharing and supportive in their responses. It does take time and I go in waves insofar and being on and being active but the good thing is you can always go back and catch up on posts.
Easy to look and adapt ideas for my students/country/culture but I must admit I never put my ideas up – I should ! If I had the time!
Many people have tried to get me to use SM but repeatedly all I find are inanities.
I think sometimes its a great way to share practice and ideas with each other.
Great tool to explore during subject-specific PD
It’s quick and easy. I can learn something new everyday without it be a saga. Most importantly it’s relevant.
Sometimes I find social media intrusive on my life, but there are so many wonderful librarians happy to connect when I leap in.
I love the connectedness of social media. It really helps me feel less isolated and more part of a peer group.
I find that apart from resources it is a great way to hear other trends / ways to approach similar issues I encounter in my work.
I am not very interested to be honest. I rarely only use Facebook, mainly to ask friends to sign petitions
I am concerned about the amount of time people (and I) spend on social media. Added to this there are so many well-made, professional resources on the internet that I have never felt the need to use social media for work purposes.
If the answer to “Do you read and use ideas and resources from social media platforms?” is never, then rest don’t make sense.
Social media is the most convenient way to keep updated – it just takes a while to see who is good to follow (scoopit/Twitter/goodreads) and what pages (fb) I want notifications from or how often I should scan posts.
I think social media is excellent in closed groups. I really like using interacting with other professionals (i.e. librarians in a librarian group).
I often follow but don’t post. However I find it really useful to know what other librarians are doing.
I wish I had more time to engage in professional uses of social media
There are a lot of great resources and sharing out there but there are only so many hours in the day! For a single teacher who doesn’t have a family I can see they have the time to interact with social media a lot more than me. I worry that ‘the post’ becomes more important than the lesson and teachers might prioritise catching things on camera rather than truly engaging with students. Of course this is at the extreme end, and I do think there is a definite value in sharing and celebrating what happens in the classroom.


3 Historical Perspectives on Violence Against Women
Three great bodies of thought have influenced western society’s views and treatment of women: Judeo-Christian religious ideas, Greek philosophy and the Common Law legal code. All three traditions have, by and large, assumed patriarchy as natural – that is male domination stemming from the view of male superiority. As part of the culture perpetuated by these ideologies, violence towards women was seen as a natural expression of male dominance. This paper contains three main themes. The first establishes patriarchy as an early pattern of military societies and the subsequent emergence of the Judeo-Christian, Greek and legal cultural paradigm as ideological justification. The second provides evidence as to how the above attitudes were interwoven in European and American values. The third theme analyzes the new 18th century cultural paradigm of liberalism which rejected male dominance, lessened the manifestation of patriarchy, without removing its cultural memory, thereby, allowing violence towards women to remain.
Fox, Vivian C. (2002) “Historical Perspectives on Violence Against Women,” Journal of International Women’s Studies: Vol. 4: Iss. 1, Article 2.
Available at: https://vc.bridgew.edu/jiws/vol4/iss1/2