Posted In: Biology

The circulatory system allows blood to circulate in our body. This important system supplies nutrients and oxygen to and carries the waste material from the blood cells in the body. The circulatory system consists of two systems - the cardiovascular system and the lymphatic system. Let us look at each of them.

The cardiovascular system consists of blood, heart and blood vessels and its job is to  distribute the blood in the body.
The lymphatic system consists of the lymph, lymph nodes and lymph vessels and its job is to circulate the lymph in the body.

Circulatory System | Image source:

Components of the circulatory system
The main parts of the cardiovascular system are as follows:

There are three types of blood vessels - arteries, veins and capillaries.

The main artery is the aorta which is a massive and thick walled artery. The aorta is responsible for providing blood to the upper part of the body. It also descends and supplies blood to the abdomen, pelvis and lower limbs.

The two major veins are the superior vena cava which drains blood from the area above the heart and the inferior vena cava which drains blood from the area below the heart.

Did you know: There are four pulmonary veins - two from each lung.

The arteries branch into capillaries that supply blood to the venous system. The venous system refers to the veins that drain blood into the right atrium of the heart.

Coronary vessels
The coronary system supplies blood to the heart muscle.

Portal veins
The main portal vein is the hepatic portal vein that combines capillaries from the gut. This is where the blood absorbs the products of the digestive system .

The heart is the most important organ of the circulatory system. It pumps oxygenated blood to the body. It also pumps deoxygenated blood to the lungs. It is the pulmonary artery that pumps the deoxygenated blood to the lungs for re-oxygenation and removal of Carbon Dioxide.

Heart | Image Source:

The system pumps the deoxygenated blood away from the heart to the lungs. Gas exchange happens in the lungs where oxygen is taken in and carbon dioxide is given out.
The lymphatic system
The main function of the lymphatic system is to carry lymph - a colourless fluid containing white blood cells. It drains and returns the interstitial fluid back to the heart.

How the circulatory system works with the other systems
The circulatory system works with the respiratory system, the urinary system and the digestive system.

  • As discussed earlier, the connection between the circulatory system and the respiratory system is the lungs. The air we breathe in goes to the blood vessels filled with deoxygenated blood. The carbon dioxide from the blood cells goes out and the oxygen is taken in. In this way exchange of gases happens in the lungs.
  • In the urinary system the blood goes to the kidneys and the kidneys filter the blood and send it back to the heart.
  • In the digestive system, nutrients are absorbed by the blood and transported to the rest of the body.

This is how the circulatory system work with the other systems and plays an important role in their functioning.



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