Question

In lungs, the air is separated from the venous blood through

• A. transitional epithelium + tunica externa of blood vessel
• B. squamous epithelium + endothelium of blood vessel
• C. squamous epithelium + tunica media of blood vessel
• D. none of these.

Answer 1

Answer: (B)

squamous epithelium + endothelium of blood vessel

The wall of the alveoli is very thin and has a rich network of blood capillaries. The alveolar capillary membrane consists mainly of squamous epithelium, epithelial basement membrane, a thin interstitial space, capillary basement membrane and capillary endothelium.