does anyone know what the role of this is? i have been searching for days and i only come up with sino atrial node. please help i need this for my as level biology presentation on the heart, just this left!
2007-11-25 07:13:24 · 3 answers · asked by topher 2 in Science & Mathematics ➔ Biology
You can see it in frog. It prevents the reentry of deoxygenated blood from right atrium to the sinus venosus.
2007-11-28 22:49:38 · answer #1 · answered by Ishan26 7 · 0⤊ 0⤋
there isn't a sinoatrial valve in the human heart. There are 2 AV (atrioventricular) valves, and 2 semilunar valves, which are the aortic valve, and pulmonary valve. The AV valve seperate the atrium (on top) and ventricle (on bottom). Blood flows down from the atrium, to the ventricle, and then the AV valve closes to keep blood from going back into the atrium. While the valve is closed, the ventricle contracts, which send blood up through, the aorta ( left side) or the pulmonary trunk(right side). The semilunar valves seperate the ventricles from the aorta and the pulmonary trunk.
2007-11-25 15:33:42 · answer #2 · answered by Matt 2 · 0⤊ 0⤋
... if, however, you are asking about the sinoatrial node, it is the heart's primary "pacemaker". it generates the impulse which triggers a heartbeat.
It has a natural "rhythm" of 60 to 90 beats per minute. This rate can be adjusted by hormones and/or nerve impulses from the brain.
The SA node starts the heartbeat, the second part of the heartbeat comes from the atrioventricular node (AV node) which is also triggered by the SA node, with a slight time delay.
John H
2007-11-26 03:48:03 · answer #3 · answered by Anonymous · 0⤊ 0⤋