Blood Vessels

 Introduction : Blood vessels are tube like structure and composition of circulation system that transport blood throughout the human body.

The vessels transport blood calls nutrients and Oxygen to the tissue of the body and take waste and Carbon dioxide always from the tissue.

Types of blood vessels

Arteries

Veins 

Capillaries

1. Arteries : They carry oxygenated blood  away from the heart through large aorta.

Aorta break in to branches arteries than arterioles.

The large arteries are more elastic tissue and less smooth muscle in their walls arteries are more thicker than veins 

2. Capillaries : The arterioles break up into a minute vessels called capillaries which connect arterioles with the venules.

Capillaries is the site of exchange of substance between the blood and the tissue fluid.

Note : Capillaries are replaced by sinusoids in certain organ Like- Liver , Spleen.

Sinusoids allow fast exchange of substance between blood and tissue.

3. Veins :  It carries blood from organs to the heart.

All the veins carry impure blood except pulmonary vein which carries pure blood.

In the vein blood flow with a low pressure and speed.