Question

Fill in the blanks
Lining of blood vessels is made up of ________.

Answer 1

Hint:The blood vessels are conducting vessels for the circulation of blood throughout the body. The blood transports various nutrients and gases required by cells. The transport occurs by diffusion. Thus, the lining of blood vessels needs to be made up of cells having thin walls. These cells made up pavement like epithelium.

Complete answer:The blood vessels form an important circulatory unit of the body. These are thin long tubules spread throughout the body. They carry blood that is a connective transport tissue. The blood carries nutrients and oxygen from one place to another where they are required. Gaseous exchange occurs in the lungs between alveoli and blood vessels. Also, the diffusion of various substances occurs through blood vessels to various tissues.
For the diffusion purpose, the blood vessels need to have smooth and thin linings. Thus simple squamous epithelium makes up the lining of blood vessels. These are made up of cells having very thin cell walls and dense cytoplasm that allows appropriate material exchange. It is a type of simple epithelium that consists of a single layer of cells attached to a basement membrane. Squamous or flat cells form a single layer that is also called pavement epithelium. This is because cells appear to be arranged like tiles on a floor.

The cell's squamous epithelium provides a smooth surface having low-friction due to which fluid can move easily and quickly. The cells are thin that facilitates quick transfer and exchange of molecules across the vessels.
Thus, we can say that ‘Lining of blood vessels is made up of squamous epithelium’.

Note:The characteristic feature of squamous epithelium is that they provide a way for the exchange of molecules. However, it has various other functions. It provides a smooth and frictionless site at places where secretion takes place. It also protects underlying tissues from light stresses. Thus, they are present in places where transportation and absorption of molecules happen.