GENERAL HISTOLOGY

Detailed explanation-1: -The capillary wall is a one-layer tissue so thin that gas and other items (eg oxygen, water, proteins and fats) can pass through them driven by pressure differences. Waste items such as carbon dioxide and urea can move back into the blood to be carried away for removal from the body.

Detailed explanation-2: -Fenestrated capillaries These are found in some tissues where there is extensive molecular exchange with the blood such as the small intestine, endocrine glands and the kidney. The ‘fenestrations’ are pores that will allow larger molecules though. These capillaries are more permeable than continuous capillaries.