Question

The mammalian heart has no valves to control blood entering the atria but does have valves for blood exiting the ventricles. Explain why this adaptation makes sense for efficient circulation.

Answer 1

We all know that the mammalian heart is the most advanced and advantageous heart which is consists of 4 chambers. Where 2 auricles and 2 ventricles. The most important and significant feature is Valve, the mammalian heart has 4 valves where two are atrioventricular (AV) valves and others are semilunar valve. There are two types of AV valves the valve on the right side called right av valve or tricuspid valve and the valve on the left side called the left av valve or bicuspid valve or mitral valve. The semilunar valve is also two types of the aortic valve and pulmonary valve

The function of the AV valve: To control the post ventricle blood flow by allowing the direction to the downward

The function of the Semilunar valve: To control the blood from the mixed up between auricle and ventricle.

There is no valve for controlling the blood which is entering the auricle because auricle has a thin wall and it created for collecting blood and in the case of ventricle it behaves like a pump by sending the purify blood. But in case of auricle here no as such pressure to send blood, it has rooms to store blood. That's why when a superior and inferior store the blood in the auricles there is no valve.

But in case of ventricle valve is much more important because after purifying the pureblood stores in the ventricle, and if the valve is not present then the blood will be mixed up, as a result, polluted blood becomes mixed with pure blood more specifically oxygen-enriched blood will be mixed with carbon dioxide enriched blood which causes a huge problem. This is the problem which faces reptile amphibian and other heart.

In the case of an amphibian and reptile heart, it consists of three-chamber two auricles and one ventricle as a result In the ventricle deoxygenated and oxygenated blood are mixed before being pumped out of the heart.

But mammalian hearts do not face this problem due to 4 chambers and the presence of valves. For this reason, adaptation makes sense for efficient circulation.