Question

Which of the choices below is the closest to the lumen of a blood vessel?
A. endothelium B. collagen fibers C. smooth muscle

Answer 1

Answer:

A, endothelium is closest to the lumen of blood vessel

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Answer 2

Endothelium is closest to the "lumen of a blood vessel".

Answer - (Option A)

Explanation:

• They are the innermost layer of a 'blood vessel' covering the lumen and are in "direct contact with the blood".
• The endothelial cells together with the elastic lamina, forms the 'tunica intima layer' of the blood vessels.
• Since the endothelium is 'closest to the lumen' of the blood vessel and is in 'direct contact' with the blood, the properties of endothelium like high permeability, haemostatic control, immune response, and angiogenesis play a vital role in the functioning, growth and maintenance of the blood vessels.