Question

1.

What characteristic of arterioles makes it possible for them to control flow into capillary beds via vasodilation and vasoconstriction?

		valves
		smooth muscle walls
		large lumens
		high pressure

2.

What is a special characteristicof capillaries in the brain?

		Tight junctions are complete, forming the blood-brain barrier.
		They're fenestrated, forming the blood-brain barrier.
		They're highly permeable sinusoidal capillaries.
		They're the only capillaries with tight junctions
		More than one answer is correct.

Answer 1

Hi Answer:

Q. 1. What characteristic of arterioles makes it possible for them to control flow into capillary beds via vasodilation and vasoconstriction?

Answer: Option B [Smooth muscle walls]

Arterioles have smooth muscle walls and elastic fibers which are responsible for the vasodilation and vasoconstriction of blood vessels.

Q.2. What is a special characteristic of capillaries in the brain?

Answer: Option E [More than one answer is correct]

In the above-given options, the option A and D are correct because the tight junction is the characteristic of brain capillaries and these capillaries are continuous in nature and forming tight junctions and create blood-brain barrier which allows only small molecules, some gases, and fat-soluble molecules to pass freely the capillary walls and into the brain cells. Whereas the brain capillaries are non-fenestrated in nature so they allow only limited molecules across them.