General Features Of Blood Vessels | MANISH MEVADA

👉 NEET Biology Examination 

👉 NEET Biology Tips

👉 NEET Biology Study Material

👉 UGC Net Study Material

General Features Of Blood Vessels 

• Arteries and veins are main blood vessels . Arteries carry blood from the heart to different body parts.
• Veins bring blood from different body parts to the heart.
• The veins have valves to prevent backward flow of blood . In the organs both arteries and veins divide to form arterioles and venules respectively.
• The arterioles and venules further divide into the thin walled vessels called capillaries.
• The capillaries of arteries and veins are united. The nutrients, hormones, gases, etc. can diffuse into the tissue cells through the walls of the capillaries and vice versa.
• Thus arteries, arterioles, capillaries, venules and veins are blood vessels.

• The wall of an artery and a vein consists of three coats :

• Tunica externa. It is the outermost coat which is formed of connective tissues . Tunica externa is also called tunica adventitia.
• Tunica media. It is a middle coat which is chiefly formed of elastic connective tissue and smooth muscle fibres. It is thicker in artery.
• Tunica interna ( = tunica intima ). It is the innermost coat which is made up of two parts :
• Elastic membrane . This membrane is made up of elastic tissue of yellow fibres . It is thicker in artery.
• Endothelium. It is made up of flattened squamous epithelial cells lining the lumen. Its cells are more elongated in artery. Blood capillaries consist of endothelium only.

Different Between Arteries and Veins

Arteries

• Arteries distribute blood from the heart to the different parts of the body .
• Tunica media is thick , having more muscle fibres.
• Tunica interna has strong elastic membrane and more elongated endothelial cells
• The walls of the arteries are thick and muscular
• Arteries are not collapsible as they have thick walls.
• Arteries have no valves.
• The flow of the blood is fast as the blood in them is under great pressure .
• Except the pulmonary arteries all the arteries carry oxygenated blood .

Veins

• Veins collect blood from different parts of the body and pour it into the heart.
• Tunica media is thin , having fewer muscle fibres.
• Tunica intema has simple , elastic membrane and elongated endothelial cells.
• The walls of the veins are thin and nonmuscular.
• Veins are collapsible because they have thin walls.
• Veins have valves which prevent backward flow of blood.
• The flow of blood in veins is not so fast because the blood in veins is under low pressure.
• Except pulmonary veins all the veins carry deoxygenated blood.

========================================

Mail- indiabiologymanishmevada@gmail.com

Connect with this mail for more knowledge of Biology

This Site helpful for UGC Net Examination 

It is also helpful for MCAT (Medical College Admission Test) united States, Australia, Canada and caribbean islands.

For Join With Me Mail Me 

Manish Mevada

M.Sc, M.Phil, B.Ed

THANK YOU.