IMMUNOLOGY

Detailed explanation-1: -When the left ventricle contracts, it forces blood through the aortic semilunar valve and into the aorta. The aorta and its branches carries the blood to all the body’s tissues.

Detailed explanation-2: -The first phase is called systole (SISS-tuh-lee). This is when the ventricles contract and pump blood into the aorta and pulmonary artery. During systole, the atrioventricular valves close, creating the first sound (the lub) of a heartbeat.

Detailed explanation-3: -When the left ventricle contracts, the mitral valve closes and the aortic valve opens. This is so blood flows into the aorta and out to the rest of the body. While the left ventricle is relaxing, the right ventricle also relaxes. This causes the pulmonary valve to close and the tricuspid valve to open.

Detailed explanation-4: -This is called circulation. Your heart, blood and blood vessels together make up your cardiovascular system (or heart and circulatory system). The right side of the heart receives blood that is low in oxygen because most has been used up by the brain and body.