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36 terms

19 Circulatory System

What are the 2 components of blood and what produces it?
1. Plasma: water, plasma proteins
2. Formed Elements: erythrocytes, leukocytes, platelets
(formed by hemopoietic tissue)
What are the 3 types of Blood Vessels and their functions?
1. Arteries/Arterioles: blood away from heart
2. Veins/Venules: blood to the heart
3. Capillaries: gas, nutrient, water, ion, heat exchange
What is the Tunica Interna, Media, Externa?
1. Interna: inner lining, endothelium continuous with endocardial lining of heart
2. Media: Muscular/connective tissue layer, smooth muscle regulates diameter or lumen
3. Externa: elastic/collagen fibers
What is vasconstriction and vasodilation?
1. vasoconstriction: decrease in lumen (tunica media constricts)
2. vasodialation: increase in lumen (tunica media dilates)
What are 4 regulatory aspects of micro-circulation?
1. metarteriole has precapillary sphincter (monitors blood flow into capillary)
2. sympathetic innervation & local chemical mediators alter diameter (blood flow resistance)
3. Resistance vessles (opposition to blood flow)
4. Vasconstriction (raise blood pressure)
Describe Blood Distrubution in the body
1. largest amount at rest= veins and venules
2. smallest= systemic capillaries and heart
What is venoconstriction?
reduces volume of blood in reservoirs and allows greater blood volume to flow where needed in the body
What is Hemodynamics?
The flow patterns and pressure of circulating blood through the blood vessels
What are the 2 types of blood pressure?
1. low= venous side
2. high= arterial side
What is Systolic and Diastolic pressure?
systolic= heart contraction: removing blood
diastolic= heart relaxation: filling with blood
Which blood vessel has the greatest resistance to flow?
What are the 2 flow factors in hemodynamics?
1. Velocity (how fast is blood moving)
2. Area (what size area is blood moving thru)
What type of circulatory system do mammals have? How does it operate?
Closed system -that uses heart as a pump. recieves blood at low hydrostatic pressure and increases pressure to drive blood thru the system
Where is the heart located in mammals? how are it's surfaces genreally named?
-Located in the mediastinum (extends from sternum to vertebral column, the first rib and between the lungs)
-apex=tip of left ventricle
-base= posterior surface
What are the 3 layers of the heart wall?
1. Epicardium (external layer): visceral layer of serous pericardium, allows heart to beat without friction
2. Myocardium (muscle layer): 95% is cardiac muscle
3. Endocardium (inner layer): smooth lining for chambers of heart, valves, continuous with lining of large blood vessels
What is the pericardium? What are the 2 types of pericardium?
-membrane surrounding and protecting the heart
1. fibrous pericardium (tough inelastic dense connective tissue/ prevents overstretching/ anchors heart)
2. Serous pericardium (thin delicate membrane/ parietal fused to fibrous pericardium & visceral called epicardium)
What are the 4 chambers of the heart?
1. 2 Atria (receiving chambers/ auricles increase capacity)
2. 2 Ventricles (pumping chambers)
What are Sulci? What do they contain? What are 3 major ones?
1. Grooves in the heart
2. Contain coronary blood vessels
3. Coronary Sulcus, Anterior Interventricular Sulcus, Posterior interventricular Sulcus
What are the 3 places the heart receives blood from?
1. Superior/ Cranial Vena Cava
2. Inferior/Caudal Vena Cava
3. Coronary Sinus
What is the Fossa Ovalis? Where is it located
1. Remnant of foramen ovale (fetal blood flow)
2. located in interatrial septum
Describe blood flow starting in right atrium
Right atrium -tricuspid valve-right ventricle- pulmonary semilunar valve -pulmonary trunk -right or left pulmonary artery
What is Chordae Tendinae?
tendons connected to the tricuspid or bicuspid valve and pappilary muscles
Describe blood flow starting in left atrium
Left Atrium -bicuspid (mitral) valve - left ventricle - Aortic semilunar valve -ascending aorta
What is the Ductus Arteriosus? What is it called as an adult?
-During fetal life, ductus arteriosus shunts blood from pulmonary trunk to aorta.
-Called ligamentum arteriosum
Describe the atrioventricular valve when: Atria contracts/ventricule relaxed
Atria relaxed/ ventricle contracts
1. atria contracts/ventricle relaxed: AV valve opens, projects into ventricle/ papillary muscle relaxed and chordae tendinae slack
2. Atria relaxed/ventricle contracts: pressure drives valve closed/ papillary muscle contracts tightening chordae tendinae
How are blood cells and vessels differentiated?
-Groups of mesoderm (mesenchyme) form blood islands
-mesenchyme differentiates into blood cells and vessels
How are blood vessels developed? What vessels specifically do they form?
1. In the splanchnic layer of lateral plate mesoderm adjacent to the yolk sac
2. vitelline/subintestinal veins that extend forward beneath developing pharynx
What are the 4 chambers of the embryonic heart?
1. Sinus Venosus
2. Atrium
3. Ventricle
4. Bulbus Cordis
What does the ventral aorta extending from the heart give rise to?
-paired aortic arches that extend dorsally through branchiomeres to the dorsal aorta
What do the paired dorsal aorta unite to form?
-single aorta
-first branch is vitelline artery
-second branch umbilical artery
What does the liver develop from?
-ventral outgrowth of the archenteron and expansion around the vitelline veins (this also forms hepatic sinusoids)
What do the hepatic sinusoids drain into?
-hepatic veins that differentiate from anterior vitelline veins leading to the heart
Describe the following primitive plan: ventral aorta, aortic arches, external carotids, internal carotids, dorsal aorta, sublcavian artery, iliac artery, renal artery.
-Ventral aorta: blood leaving heart
-Aortic arches: pass dorsally thru branchial arches and enter paired dorsal aorta
-External Carotids: carries blood from ventral aorta to ventral head region
-Internal Carotids: carries blood from dorsal aorta to brain
-Dorsal Aorta: unite and form single aorta (distribute blood to posterior part of body) ends in caudal artery
-Subclavian artery: supply anterior appendages
-Iliac artery: supply posterior appendages
-Renal artery: supply kidneys
What are the 3 visceral branches of the aorta?
-celiac: supplies liver, spleen, stomach
-anterior mesenteric: supplies sm. intestine
-posterior mesenteric: supplies lg. intestine
What are the 2 branches of the common cardinal vein?
-anterior cardinal vein: drains anterior body
-posterior cardinal vein: drains posterior body (subclavian vein-drains anterior appendages & lateral abdominal vein-drains lateral body and posterior appendages)
How many arches develop in gnathostomes and tetrapods?
6 *primitive animals may have more -lamprey 8