Question

Чому кров у серці рухається тільки в одному напрямі: із передсердь у шлуночки, і з шлуночків в артерії?

Answer 1

Ответ: По артеріях кров тече від серця до тканин. Артерії по струму крові древовидно розгалужуються на усе більш дрібні судини і, нарешті, перетворюються в артеріоли, що у свою чергу розпадаються на систему найтонших судин - капілярів

Объяснение: ^

Answer 2

Blood Flow in the Heart

The flow of blood in the heart is a complex process that involves the coordinated contraction and relaxation of different chambers and valves. The heart has four chambers: two atria (left and right) and two ventricles (left and right). Blood flows in a specific direction within the heart, from the atria to the ventricles and then out to the arteries.

Why does blood flow in only one direction within the heart?

The direction of blood flow within the heart is primarily controlled by the valves present between the chambers. These valves ensure that blood flows in one direction and prevents backflow. The two main valves responsible for directing blood flow are the atrioventricular (AV) valves and the semilunar valves.

1. Atrioventricular (AV) valves: These valves are located between the atria and ventricles. The tricuspid valve is present between the right atrium and right ventricle, while the mitral valve (or bicuspid valve) is located between the left atrium and left ventricle. These valves open when the atria contract, allowing blood to flow from the atria into the ventricles. When the ventricles contract, the AV valves close to prevent blood from flowing back into the atria.

2. Semilunar valves: These valves are located between the ventricles and the arteries. The pulmonary valve is present between the right ventricle and the pulmonary artery, while the aortic valve is located between the left ventricle and the aorta. When the ventricles contract, the semilunar valves open, allowing blood to be pumped out of the heart and into the arteries. When the ventricles relax, the semilunar valves close to prevent blood from flowing back into the ventricles.

The coordinated opening and closing of these valves ensure that blood flows in one direction within the heart, from the atria to the ventricles and then out to the arteries.