The steps in running order.Eg:From which part of the heart to which part...... Thanks
2006-12-09 05:27:43 · 4 answers · asked by brandon s 1 in Science & Mathematics ➔ Biology
Its pretty simple, blood is pumped by out of the left ventricle by left ventricular contraction, where it is ejected into the aorta. Blood leaves the aorta into several large arteries, and its then carried by arterioles, where most of flow regulation takes place by smooth muscle contraction and relaxation. From the arterioles, the blood enters capillaries, where exchange of gases (O2 and CO2) and nutrients occurs between blood and tissue. From the capillaries, the blood, travels into venules, and then into veins. Veins are very "compliant" meaning they stretch a lot to accomodate a lot of blood, and the body stores a lot of its blood in the venous system. The veins feed into the superior and inferior vena cava (SVC, IVC), and the blood is returned to the beart.
Blood from the SVC and IVC enters the heart into the right atrium, where it is contained by the tricuspid valve until enough blood builds up so that the pressure forces the valve to open, and the blood fills up in the right ventricle. Contraction of the right ventricle leads to the opening of the pulmonary valve, and blood is ejected into the pulmonary circulation, where it goes toward the lungs in the pulmonary artery, becomes oxygenated, and returns from the lung in the pulmonary vein. The pulmonary vein deposits the blood into the left atrium, where it builds up until the pressure is enough to open the mitral valve, and then the blood pools in the left ventricle, and the left ventricle contracts, opens the aortic valve, and the blood is once again ejected into the aorta completing the cycle.
Note that the valves are in place to prevent backward flow.
2006-12-09 05:41:31 · answer #1 · answered by Brian B 4 · 0⤊ 0⤋
i know the flow but then i cannot expalin without a diagram
try this link below maybe it can be useful for u to understand more about the circulatory system
2006-12-09 13:33:37 · answer #2 · answered by f1fanz 2 · 0⤊ 0⤋
Quick answer,pressure, and the veins have one way valves.
2006-12-09 14:15:51 · answer #3 · answered by solara 437 6 · 0⤊ 0⤋
check this out
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcircSYS.html#The%20Heart
2006-12-09 13:38:43 · answer #4 · answered by hellokitty_uu 2 · 0⤊ 0⤋