Cardiovascular System and Types, The cardiovascular system is sometimes called the blood-vascular, or simply the circulatory, system. It consists of the heart, which is a muscular pumping device, and a closed system of vessels called arteries, veins, and capillaries. As the name implies, blood contained in the circulatory system is pumped by the heart around a closed circle or circuit of vessels as it passes again and again through the various “circulations” of the body. Source
Cardiovascular system consists of 3 major components, they are;
- A pumping organ (i.e. the heart),
- A set of interconnected tubes (i.e. the blood vessels),
- A circulatory fluid (i.e. the blood).
Types of circulation:
There are 2 types of circulation, they are given as follows;
- Pulmonary circulation:
Pulmonary circulation is the transport of deoxygenated blood towards lungs for oxygenation and transport of the oxygenated blood towards the heart. The heart then pumps it to the whole body. Circulation consists 16% of the blood.
As we know, the human heart consists of four chambers that is; 4 auricles/ atriums and 2 ventricles. The blood from the right ventricle is pumped into pulmonary trunk, which bifurcates (divides) into two pulmonary arteries. Each pulmonary artery leads to a single lung. Inside the lungs, this pulmonary arteries divide into smaller and smaller branches called capillary, where the exchange of gases take place by diffusion. When we inhale oxygen from the ai, it goes into alveoli. Blood has low level of oxygen and by diffusion, exchange of gases occur. The oxygenated blood is carried through pulmonary veins to the heart for oxygenation. There are 4 pulmonary veins, meaning 2 pulmonary veins arise from each lung.
- Systemic circulation.
Systemic circulation is the transport of blood towards all organs of the body except lungs. It consists 84% of the blood.
The deoxygenated blood from various parts of the body then travel through different veins (with a gradual increase in width), unify into two large veins when going towards the heart. These two veins are superior vena cava and inferior vena cava.
The superior vena cava brings deoxygenated blood from all the upper part of the body to the heart for oxygenation and similarly the inferior vena cava do so for the lower parts of the body, that is; the abdominal area. Both these vena cava enter the blood through right auricle. This blood will then enter the right ventricle and then lungs for oxygenation.
This oxygenated blood goes from lungs to the left atrium and then left ventricle. The oxygenated blood from the left ventricle is pumped by the heart and goes to the full body through arteries, arterioles and capillaries, where exchange of material between the blood and tissue.
This exchange occurs so that the waste materials are get picked up by the capillaries and the nutrients are delivered to the tissues by the capillaries (this is the start of venous system). From the capillaries, this deoxygenated blood will travel to venules and from the venules to veins and then to superior and inferior vena cava. Then the blood will go to the right atrium of the heart.
Capillaries and venules all together make the micro circulation.
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