Question

Part 1) Which of the following types of blood vessels would have the greatest resistance to flow?

                       

                        veins

                        arteries

                        venules

                        capillaries

Part 2) Which of the following blood vessels play an important role in controlling blood flow to different regions of the body through the contraction and relaxation of smooth muscles in their walls?

                       

                        capillaries

                        arterioles

                        venules

                        veins

Answer 1

Part 1 : Correct answer is arteries

Arteries have greatest resistance to flow .

The arteries are referred as resistance vessels.These vessels control where and how much blood flows to a given area by way of change in vascular smooth muscle tone. the greater the muscle tone the greater the resistance to flow and vice versa .These are also known as regulatory vessels.

Part 2 : Correct answer is arterioles

Arterioles play an important role in controlling blood flow to different regions of the body through the contraction and relaxation of smooth muscles in their walls .

Arterioles have muscular walls with one to two layers of smooth muscles .velocity of flow is increased with decrease in diameter. This is important as efficient exchange at the capillary pressure and flow need to be much lower. The greatest change in blood pressure and velocity of blood flow occurs.