List major mammals heart valves and their locations
While mammals have four-chambered hearts, they do not possess specific heart valves like humans do. However, they do have different structures that function similarly to valves. Here are the major structures in mammals that act as valves:
1. Tricuspid Valve: Present in the right atrioventricular (AV) opening of the heart, it consists of three cusps or flaps that prevent backflow of blood from the right ventricle into the right atrium.
2. Bicuspid (Mitral) Valve: Located in the left AV opening, it also has two cusps and prevents the blood from flowing back into the left atrium when the left ventricle contracts.
3. Pulmonary Valve: Positioned at the entrance of the pulmonary artery, this semilunar valve prevents blood from flowing back into the right ventricle after it is pumped out of the heart towards the lungs.
4. Aortic Valve: Found at the opening of the aorta, this semilunar valve regulates the blood flow from the left ventricle to the aorta. It prevents the blood from flowing back into the left ventricle when the heart relaxes.
These structures play crucial roles in directing the flow of blood through the mammalian heart, ensuring the unidirectional circulation of oxygenated and deoxygenated blood.