The carbon dioxide in the blood is exchanged for oxygen in the alveoli. These tiny air sacs in the lungs are only one cell thick and they are surrounded by capillaries that are also only one cell thick.
Confidence votes 1.3K. Capillaries cover the alveoli in order to maximize the area for gas exchange between the lungs and the blood. Carbon dioxide is released from the blood through the capillary walls and into the alveoli, while oxygen is picked up from the alveoli through the capillary walls and into the blood. Background. When we breathe, air enters our lungs and fills tiny airsacs called alveoli. Each air sac is surrounded by an extensive capillary bed, which is a network of tiny, thin blood vessels. In order for us to bring in oxygen and release carbon dioxide, the alveoli and capillaries must be properly aligned. Gas exchange. The air sacs (alveoli) have a very large total surface area and a very good blood supply. There is an exchange of gases between the air sacs and their surrounding capillary blood vessels. Oxygen diffuses from the air sac into the blood. Carbon dioxide diffuses from the blood into the air sac. These four features are particularly important to our lungs efficient for gas exchange.  These tiny air sacs are called alveoli. These alveoli are surrounded by capilaries tiny blood vessells. These capilaries have holes that are to small for blood cells to escape … but are big enogh for oxygen molecules to pass in to the blood stream and attach to the haemoglobin in your blood. 4 people found this useful.  There are about 300 million alveoli in a normal lung. When the air that you've just breathed in reaches these air sacs, the oxygen in the air passes through the air sac walls into the blood in the capillaries. At the same time, carbon dioxide (a waste gas) moves from the capillaries into the air sacs. This process is called gas exchange. The oxygen-rich blood in the capillaries then flows into larger veins, which carry it to the heart.  The alveoli are surrounded by tiny blood vessels, called capillaries. The alveoli and capillaries both have very thin walls, which allow the oxygen to pass from the alveoli to the blood. The capillaries then connect to larger blood vessels, called veins, which bring the oxygenated blood from the lungs to the heart. Blood capillaries allow for the rapid exchange of carbon dioxide and oxygen to occur. Carbon dioxide diffuses from the erythrocytes (red blood cells), through the capillary wa … lls, into the alveoli, and is exhaled through the mouth and nose. Carbon dioxide is released from the blood through the capillary walls and into the alveoli, while oxygen is picked up from the alveoli through the capillary walls and into the blood. The carbon dioxide in the blood is exchanged for oxygen in the alveoli. These tiny air sacs in the lungs are only one cell thick and they are surrounded by capillaries that are also only one cell thick. Blood from the heart flows through these capillaries and collects oxygen from the alveoli. The alveoli and capillaries both have very thin walls, which allow the oxygen to pass from the alveoli to the blood. The capillaries then connect to larger blood vessels, called veins, which bring the oxygenated blood from the lungs to the heart. Your bronchioles are some of the smallest airways in your lungs. Inhaled air passes through tiny ducts from the bronchioles into elastic air sacs (alveoli). The alveoli are surrounded by the alveolar-capillary membrane, which normally prevents liquid in the capillaries from entering the air sacs.  Inside the air sacs, carbon dioxide moves from the blood into the air. At the same time, oxygen moves from the air into the blood in the capillaries. The oxygen-rich blood then travels to the heart through the pulmonary vein and its branches. The heart pumps the oxygen-rich blood out to the body. The capillaries connect to a network of arteries and veins that move blood through your body. The pulmonary (PULL-mun-ary) artery and its branches deliver blood rich in carbon dioxide (and lacking in oxygen) to the capillaries that surround the air sacs.
http://www.answers.com/Q/Why_do_capillaries_cover_the_alveoli http://www.child-foundation.com/what-is-child/types-of-child/alveolar-capillary-dysplasia/ http://www.bbc.co.uk/bitesize/standard/biology/the_body_in_action/the_need_for_energy/revision/5/ http://www.answers.com/Q/What_the_capillaries_around_the_air_sacs_take_in http://www.nhlbi.nih.gov/health/health-topics/topics/ipf/lungworks http://lsa.colorado.edu/essence/texts/lungs.html http://www.answers.com/Q/Why_do_capillaries_cover_the_alveoli http://lsa.colorado.edu/essence/texts/lungs.html http://www.mayoclinic.org/airways-and-air-sacs-of-the-lungs/IMG-20008294 http://www.nhlbi.nih.gov/health/health-topics/topics/hlw/system
what do the capillaries around the air sacs do