Introduction

Welcome to my blog. In this writeup, parts of the human heart, blood vessels and distintive features of the arteries, veins and capillaries will be discussed.

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The Circulatory System

The circulatory system consisting of the heart and the blood vessels passes amino acids, gases, hormones and blood to and from the cells in the body to help fight diseases and stabilize the body temperature. It is also known as the blood distribution network.

Source

The heart is the pumping organ and its function is to pump blood to all parts of the body. The blood vessels that is arteries, veins and capillaries form a system of tubes which allow the movement of blood and other life-supporting materials to all parts of the body. Blood makes it possible for materials to be transported through the circulatory system.

The human circulatory system consists of the heart, the blood, and the blood vessels.

Source Red blood cells

Structure of the heart

The heart is slightly tilted towards the left. The heartbeat is felt strongly towards the left.

Source Cross section of the heart

• The heart is covered by a sheet call the pericardium.
• The heart is made up of muscles that have the capability of beating from the time it was formed even before Birth till death. The muscles have never tired.
• The heart have four Chambers. The two Upper chambers are the receiving Chambers called auricles. The lower chambers are the distributing Chambers called ventricles.
• The left side of the heart is filled with blood carrying oxygen.
• The right side of the heart has blood without oxygen.
• The auricles and the ventricles are connected by valves.
• The left and the right sides are separated by thick muscular walls.
• Blood from all parts of the body is brought to the right auricle by the vena cava.
• The left auricle is connected to the pulmonary vein.
• The right ventricle has the pulmonary artery coming out of it and going to the lungs.
• The aorta comes out of the left ventricle. It gives blood flow to the muscles of the heart as they are working non-stop and need a lot of energy.

The heart functions as a pump

1. When the heart relaxes, blood from all parts of the body enters the right auricle. This blood does not contain oxygen. It is deoxygenated blood.
   At the same time blood comes from the lungs to the left auricle. This blood contains oxygen. It is oxygenated blood.
2. The auricles contact. The auricles that are now filled with blood send all the blood to the ventricles so the valves.
3. The ventricles contract. The right ventricle sends blood without oxygen to the lungs. Here the blood is with the oxygen that has been breathed in.
4. This cycle is repeated

Blood vessels

In the human body, blood travels through pipes called blood vessels. Let's now consider the different kinds of blood vessels in the body.

Source Blood vessel

a) Arteries: Arteries carry blood away from the heart into the other organs of the body. It has oxygenated blood, except the pulmonary artery.

The arteries have thick muscular walls with a narrow lumen. The walls are thick and a elastic to enable them to withstand the high-pressure with which blood arterioles direct blood into the body organs.

b) Veins: The veins carry blood from the capillaries towards the heart.
Veins have thin, muscular, but in elastic walls with a wide lumen.

Source A cross sectikn of an artery, vein and capillaries

c) Capillaries: The capillaries are found inside the organ. They connect the arteries with the veins. They have very thin walled.

All substances like food and oxygen come out of the capillaries into the cells and they collect all waste from the body cells.

Functions of blood

1. Blood carries carbon dioxide from the cells to the lungs for elimination.
2. Blood carries food from the small intestine to all the cells of the body.
3. Blood carries wastes from all the cells to the kidneys for removal.
4. Blood helps to cool the body.
5. Blood carries other important substances, like hormones which perform many functions, from one part of the body to another.

Conclusion

The three types of blood vessels we have discussed in this writeup are arteries, veins and capillaries. The heart beat from the time humans were form that is before birth till death.