BLOOD VESSELS -
1. Tunica Externa - Made up of connective tissue, collagen fibres present.
2. Tunica media - Thick, made up of smooth muscles arranged in circular way.
3. Tunica interna - Inner most layer. Outerly made up of yellow elastin fibre. Inner layer is of endothelial cells.
Carry blood away from heart
Pure blood flows
(in pulmonary artery impure blood flows)
Blood flows with jerk
Blood flows with more pressure
Walls are thick
Lumen is narrow
Not collapse after death
Impure blood flows
(In pulmonary vein pure blood flows)
Present to check back flow