What are the components of the transport system in human beings? What are the functions of these components?
Answer
The transport system in humans is called the ‘ Circulatory System ’. The various organs of the circulatory system are Heart , Arteries , Veins and Capillaries .
- The heart acts like a pump, which pumps out oxygenated and deoxygenated blood .
- Arteries , Veins and capillaries are the tubes through which the blood flows .
- Blood flows from the heart to the body in Arteries .
- Veins carry blood from the body back to the heart .
- Capillaries are small blood vessels with thin walls that allow oxygen and nutrients to diffuse through to the organs and cells , and waste diffuses back to the capillaries which combine to become veins.
Human Heart :
- Human heart is a four chambered structure having 2 atria (left and right) and 2 ventricles (left and right)
- It is a double pump , which pumps blood around our body.
- The left side of the heart (left atrium and left ventricle ) acts as one pump which pumps blood to the body , except the lungs.
- The right side of the heart ( right atrium and right ventricle )only pumps blood into the lungs.
- The left side of the heart is separated from the right side, by a partition called septum.
- This separation is important to avoid mixing the oxygenated blood on the left side with the deoxygenated blood on the right.
Blood Vessels:
The blood vessels are of three types :
Arteries :
- They carry blood from the heart to all parts of the body.
- Since they receive the blood directly from the heart which has a very high pressure , they are thick walled.
- The main artery is called Aorta , carries oxygenated blood from the left ventricle to all parts of the body .
- The Pulmonary artery is connected to the right ventricle , which carries deoxygenated blood from the right ventricle to the lungs .
Veins :
- These blood vessels carry blood (deoxygenated) from the body back to the heart.
- They are thin walled because of the low pressure of the blood which flows in them
- These have valves present in them which prevents backflow of blood.
- The main vein , called Vena Cava, is connected to the right atrium and carries deoxygenated blood from all parts, back to the heart .
- The pulmonary vein carries oxygenated blood from the lungs back to the heart.
Capillaries :
- These are thin walled, extremely narrow tubes which connect arteries to veins .
- The various dissolved substances like oxygen, food etc. present in blood pass through the capillaries.
- At the same time, the waste materials also enter the capillaries . Thus, an exchange takes place.
