Question

Blood capillaries are made up of
A) Endothelium and the thin coat of connective tissues
B) Endothelium and the thin coat of muscle fibres
C) Endothelium and the thin coat of connective tissues and muscle fibres
D) Only Endothelium

Answer 1

Hint: The endothelium is a thin membrane covering the interior of the blood vessels and the heart. Endothelial cells discharge substances which control relaxation and contraction in the vascular cells.

Complete Answer:
- Capillaries are the tiniest blood vessel in the body. They're interested in transporting oxygen and other nutrients from the bloodstream to other body tissues. They also extract waste products and fluids from carbon dioxide to get back into the veins.
- Capillaries connect the branches of arteries with tiny veins, called arterioles. The capillary is ultimately the centre of internal or cellular respiration. It is responsible for the tissue's absorption of oxygen and for the transportation of carbon dioxide as waste to the veins for lung removal.
- The capillary wall is very small, it has several minute pores and consists only of the endothelium. The exchange of material transfer occurs between blood and tissue fluid through active diffusion, using the capillary endothelial membrane.
- Although Connective tissue is one of four essential animal tissue types, along with epithelial tissue, muscle tissue, and nervous tissue.
- Similarly, a mechanism known as myogenesis produces muscle fibres, or muscle cells, through the fusion of embryonic myoblasts. Muscle fibres are cylindrical and have several nuclei.

So the answer is D, Only Endothelium.

Note: Capillaries are very small, around 5 micrometres in diameter, and consist of just two cell layers; an inner layer of endothelial cells; and an outer layer of epithelial cells.