To be precise, a normal person s blood circulation is composed of several parts, three parts, or fou

To be precise, the blood circulation of a normal person is made up of three parts.

The human circulatory system consists of blood, blood vessels, and the heart. The constant beating of the heart and the power that provides the blood to circulate in it provide various cells of the body with substances for survival, including nutrients and oxygen, and also take away carbon dioxide, the product of cell metabolism.

Blood circulation:

Circulation begins in the left ventricle. Blood beats out of the left ventricle and flows through the aorta and several arterial branches derived from it, sending blood to the corresponding organs. The artery then branches several times, the diameter of the tube gradually narrows, the number of blood vessels gradually increases, and finally reaches the capillaries, where the intercellular fluid is exchanged with the tissue cells.

Oxygen and nutrients in the blood are absorbed by the tissues, and carbon dioxide and other metabolites in the tissues enter the bloodstream, turning arterial blood into venous blood. The veins gradually thicken and decrease in number until all the veins collect into the superior and inferior vena cava, from which blood returns to the right atrium and from the right atrium to the right ventricle, thus completing the systemic circulation.

The above content refers to Encyclopedia - Blood Circulation.

The blood circulation of a normal person is a dual circulation composed of two pathways, the systemic circulation and the pulmonary circulation, that is, it is composed of two parts.

The circulatory process of pulmonary circulation is as follows: blood is ejected from the right ventricle, passes through the pulmonary artery to the pulmonary capillaries, exchanges with the gas in the alveoli, and then flows back to the left atrium from the pulmonary vein, and flows into the left ventricle.

The circulatory process of systemic circulation is as follows: blood is ejected from the left ventricle, passes through the aorta, and then flows to the organs and tissues of the whole body through the medium and small arteries, reaches the capillaries, exchanges substances with the histiocytes, and finally flows back to the right atrium through the superior and inferior vena cava, and flows into the right ventricle.

"Dual circulation" discovery process

The Spanish physician Servette found that blood flowed from the right ventricle into the lungs, and after air purification, from the lungs into the left ventricle, refuting Galen's thesis that "the heart septum has a ethmoid hole". What Servet discovered was the pulmonary circulation.

Shortly after Servette's death, another person who made a decisive contribution to blood circulation was born: Harvey. In mid-April 1616, Harvey gave a lecture in the school near St. Paul's Church on Knights Street, where he first developed his theory of blood circulation. In 1628, he published The Treatise on the Movement of the Heart, which systematically expounded his theory.

In 1661, the mystery of the connection between blood vessels was unraveled by the Italian scientist Marbiqui. He used a microscope to observe the capillaries between the arteries and veins of the frog's lungs, and it was these microvessels that connected the arteries and veins into a sealed tube in which blood circulated, thus proving Harvey's correct inference.

The above content reference: Popular Science China - The Secret of Blood Circulation.

Blood circulation is divided into systemic circulation and pulmonary circulation.

Pulmonary circulation: right ventricle - pulmonary artery - capillary network in the lungs - pulmonary vein - left atrium.

Systemic circulation: left atrium - aorta - capillary network throughout the body--- superior and inferior vena cava - right atrium.

Blood circulation route: left ventricle (arterial blood in this case) aorta arteries at all levels Capillary (material exchange) (becomes venous blood after substance exchange) Veins at all levels Superior and inferior vena cava Right atrium Right ventricle Pulmonary artery Pulmonary capillaries (material exchange) (Arterial blood after material exchange) Pulmonary veins Left atrium Finally, it returns to the left ventricle and starts a new cycle.

Among them, the period from the left ventricle to the right atrium is called blood circulation, and the beginning of the right ventricle to the left atrium is called blood circulation.

Discovery of blood circulation.

As early as more than 1800 years ago, the ancient Roman physician Galen (129 199) proposed that the flow of blood in the blood vessels rushed to the surroundings like a tide, and disappeared naturally after reaching the four corners of the body. Since Galen was the highest authority in the medical profession at the time, it was considered unquestionable.

It wasn't until the middle of the 16th century that doubts arose about it. Keep an eye on the dust chain.

At the beginning of the 17th century, the English physician Harvey (1578-1657) conducted such an experiment: after dissecting a snake, Kaisun dissected it, clamped the major artery with tweezers, and found that the blood vessels below the tweezers quickly deflated, while the blood vessels between the tweezers and the heart and the heart itself became more and more swollen and almost burst. Harvey quickly removed the tweezers, and the heart and arteries returned to normal.

Harvey then clamped the large vein, and found that the vein between the tweezers and the heart was immediately deflated, and at the same time, the heart became smaller and lighter in color. Harvey removed the tweezers again, and his heart and veins returned to normal.

Harvey pondered the results of the experiment and finally came to the conclusion that the blood in the heart must have entered the arteries after being pushed out; And the blood in the veins must flow back to the heart. The blood between the arteries and veins is connected, and the blood circulates continuously in the body.

Later, the Italian Marcello (marcello

Malpighi, 1628-1694) further validated Harvey's theory of blood circulation by observing the presence of capillaries with a microscope that connected arteries to veins.

What are the two main components of blood circulation? (c )

a.Heart and lymphatic vessels BVascular and lymphatic vessels cHeart and blood vessels DArteries and veins.

cHeart and blood vessels.

The circulatory system consists of blood, blood vessels, and the heart. If it is divided into two main parts, it is composed of blood vessels and heart. The cardiovascular system is a closed transport system composed of the heart, blood vessels, capillaries and blood.

Blood ejects from the left ventricle and flows through the aorta and its branches at all levels to the capillaries of the whole body, where it exchanges substances with interstitial fluid, supplies oxygen and nutrients to tissue cells, transports carbon dioxide and metabolites, and turns arterial blood into venous blood; It then flows back to the right atrium through the confluence of the superior and inferior vena cava at all levels, and this cycle is the systemic circulation.

Blood ejects from the right ventricle and flows through the pulmonary artery to the pulmonary capillaries, where it exchanges gas with alveolar air, absorbs oxygen and excretes carbon dioxide, and venous blood becomes arterial blood; It then flows back to the left atrium through the pulmonary veins, and this cycle is called the pulmonary circulation.

Answer] Compared with the arteries of the same level, :d has a large number of veins, thin walls, large calibers and large expandability, so its capacity is large. In the Anzen Yingkai static state, the venous system can accommodate 60% to 70% of the circulating blood volume.

When the venous caliber changes slightly, its volume can change greatly, which obviously affects the amount of blood returning to the heart, and the intravenous pressure does not change much at this time. Thus, the venous system functions as a blood bank.

The human blood circulation system includes the heart, blood vessels and lymphatic system, which is a closed continuous pipeline system in the human body, distributed in all parts of the body. The cardiovascular system is composed of the heart, arteries, veins, and capillaries connecting arteries and veins, in which there is a circulation of blood on the land. The rhythmic contraction of the heart is the driving force of blood circulation, which shoots blood into the arteries, flows through a vast network of capillaries, and then flows back to the heart through all levels of veins.

(1) systemic circulation; Pulmonary circulation.

2) [8] Lungs.

3)[1] Superior vena cava; [6] inferior vena cava; Vein.

4)[4] Right atrium; Vein.

Test question analysis: The names of the main labels in the blood circulation pattern diagram are: 1 superior vena cava, 4 right atrium, 5 right ventricle, 6 inferior vena cava, 8 pulmonary capillaries, 10 left atrium, 11 left ventricle

1) Blood circulation is divided into two parts: systemic circulation and pulmonary circulation according to the different circulatory pathways

2) After the blood passes through the pulmonary circulation, it changes from arterial blood to venous blood, and the part of the blood change is: pulmonary capillaries

3) The four chambers of the heart are connected to a certain number of blood vessels, and the blood vessels connected to the right atrium are the superior and inferior vena cava, i.e., 1 and 6 in the diagram

4) Systemic circulation refers to the circulation of blood from the left ventricle into the aorta, through the capillary network throughout the body, and finally through the superior and inferior vena cava back to the right atrium

(1) systemic circulation, pulmonary circulation, (2) 1, superior vena cava, 6 inferior vena cava, vein.

3) 10 left atrial artery.

Test question analysis: The names of the main labels in the blood circulation pattern diagram are: 1 superior vena cava, 2 pulmonary arteries, 3 aorta, 4 right atrium, 5 right ventricles, 6 inferior vena cava, 7 capillaries of the upper limbs and head, 8 capillaries of the lungs, 9 pulmonary veins, 10 left atrium, 11 left ventricles, 12 capillaries of internal organs, 13 capillaries of the lower limbs (1) Blood circulation is divided into two parts: systemic circulation and pulmonary circulation according to the different circulatory pathways (2) What blood vessels are connected to the four cavities of the heart is certain? The blood vessels connected to the right atrium are the superior and inferior vena cava, that is, [1] and [6] in the diagram, both of which flow venous blood (3) Pulmonary circulation refers to the circulation of blood from the right ventricle into the pulmonary artery, through the capillary network of 8 lungs, and finally back to the left atrium through the pulmonary veins, when the blood flows through the capillaries of the lungs, the oxygen in the alveoli diffuses into the blood, and the carbon dioxide in the blood diffuses into the alveoli, so that the blood changes from venous blood to arterial blood; Therefore, the pulmonary circulation terminates at the left atrium[10], at which point the blood becomes arterial blood