Heart And Circulatory System (Part-I)

Contraction of the heart is also known as Systole. Systole refers to the phase of the cardiac cycle when the heart muscle contracts and pumps blood from the chambers into the arteries.

The hormone that stimulates heartbeat is Thyroxine. While several factors influence heart rate, thyroxine, produced by the thyroid gland, increases the metabolic rate of most body cells, including those of the heart, leading to an increased heart rate and contractility.

Beta Blocker is a drug that makes your heart work more slowly, used for treating high blood pressure. Beta-blockers work by blocking the effects of adrenaline and noradrenaline, slowing down the heart rate and relaxing blood vessels, thereby reducing blood pressure.

Heart attack is caused by Lack of blood supply to the heart. A heart attack, or myocardial infarction, typically occurs when blood flow to a part of the heart is blocked, usually by a blood clot in a coronary artery. This lack of oxygen rich blood causes damage or death of heart muscle.

In mammals, oxygenated blood enters the heart at the Left atrium. Oxygenated blood returns from the lungs via the pulmonary veins and enters the left atrium. From there, it passes into the left ventricle and is then pumped to the rest of the body.

The Tricuspid valve is present Between the right auricle and right ventricle. It is a crucial valve in the heart that prevents the backflow of blood from the right ventricle into the right atrium during ventricular contraction.

Sympathetic nerves increase the rate of heartbeat. The sympathetic nervous system is responsible for the "fight or flight" response, which includes increasing heart rate and contractility to prepare the body for increased activity.