Circulatory system: main function

2021-05-31 04:21 PM

As blood flows through the tissue, it immediately returns to the heart via the venous system. The heart responds automatically to an increase in incoming blood by pumping blood back into the arteries.

The function of the circulatory system is to supply blood needed for tissues - transport nutrients to organ tissues, and transport substances and hormones from some organs in the body to other places. The concentration of substances in the homeostasis in the body helps cells survive and perform their functions well.

Three main points about circulatory system function.

Blood flow to tissues is regulated according to the needs of the tissues

When tissues are active, they increase their need for nutrients, so more blood comes in when the tissue is at rest, about 20-30 times more at rest. Furthermore, the normal heart cannot increase its rate to more than 4-7 times its resting rate. Therefore, it cannot increase blood flow to any tissue in the body when the tissue's demand increases. Instead, the micro vascularity of each tissue continuously monitors tissue needs, such as the availability of oxygen and nutrients, and the accumulation of carbon dioxide and tissue metabolism products that stimulate these small forces, in turn, These vessels directly activate the forces in the tissue, dilating or constricting the blood vessels in order to regulate the exact amount of blood to the amount required for the functioning of the tissue. At the same time, the control nerve of the circulatory system from the central nervous system and hormones also contribute to the regulation of blood to tissues.

Cardiac output is the sum of all blood flows to the tissues

As blood flows through the tissue, it immediately returns to the heart via the venous system. The heart responds automatically to an increase in incoming blood by pumping blood back into the arteries. Thus, the heart acts as an automaton in response to the demands of the tissues.

However, the heart often needs help from specific nerve signals to get it to pump.

The regulation of arterial blood pressure depends on the regulation of blood flow to the tissues or the regulation of cardiac output

The systemic circulation is provided with a layering system to regulate arterial blood pressure. Accordingly, whenever blood pressure drops below the normal range of about 100 mmHg. Within seconds, the nerve impulse in response to it activates a series of changes in the circulatory system that raise blood pressure back to normal. Special nerve impulses (a) increase heart rate, (b) constrict large veins to bring blood back to the heart, (c) vasoconstriction to many tissues, from which blood concentrates into large arteries to raise blood pressure. After that, the process lasts more than a few hours or a few days, the kidneys will work to play a key role in regulating blood pressure by secreting hormones that regulate blood pressure and change blood volume.

Thus, the needs of individual tissues are specifically met by the circulatory system. In the rest of the circulatory system, we will talk about the basics of tissue perfusion, cardiac output, and arterial pressure.