ch.20 quiz

Capillary beds have precapillary sphincters at the junction of capillaries and the metarteriole. Constriction of these sphincters _________ the blood flow into true capillaries.

decreases

Vasodilation

increases blood flow and decreases blood pressure.

If a patient's systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg, what is the patient's pulse pressure?

40 mm Hg

If a patient's systolic pressure is 110 mm Hg and diastolic pressure is 80 mm Hg, what is the patient's mean arterial pressure (MAP)?

90 mm Hg

Which vessel drains blood from a capillary bed?

Postcapillary venule

Place the blood vessel tunics in order from most external to most internal.

__3__Tunica intima __1__Tunica externa __2__Tunica media

Precapillary sphincters will

all of the answers are correct

In a capillary bed, the direction of movement of substances in or out of the blood is dependent upon the net pressure of two opposing forces : hydrostatic pressure and colloid osmotic pressure. Which of the following is a measure of the blood pressure within capillaries, and is greatest at the arterial end of a capillary bed?

blood hydrostatic pressure (HPb)

Gas, nutrient, and waste exchange occur between the __________ and the tissues of the body.

capillaries

Valves in veins

cause venous blood flow to go in only one direction.

Upon dissection of a capillary, it is found to contain no pores, openings or gaps in the vessel wall. This is probably a __________ capillary.

continuous

The largest arteries of the body are classified as

elastic arteries.

The tunica intima is the innermost blood vessel tunic, and contains predominantly smooth muscle cells supported by elastic fibers

false

The tunica intima is the innermost blood vessel tunic, and contains predominantly smooth muscle cells supported by elastic fibers.

false

Bulk flow refers to the movement of large amounts of fluids and their dissolved substances in one direction down a pressure gradient. There are two types of bulk flow in a capillary bed: filtration and reabsorption. Which type of bulk flow occurs at the arterial end of the capillary bed and involves movement of fluid out of the blood and into the surrounding tissues?

filtration

The function of capillaries is

to allow for the exchange of substances between the blood and the surrounding tissues.

The contraction of skeletal muscles plays an important role in the movement of blood in the veins.

true

The ________ is composed of an endothelium and a subendothelial layer made up of a thin layer of areolar connective tissue.

tunica intima

The ________ is composed of circularly arranged layers of smooth muscle cells.

tunica media

In arteries, the thickest layer of the wall is the

tunica media.

Contraction of smooth muscle in the tunica media results in ______, or narrowing of the blood vessel lumen. Relaxation of the smooth muscle causes ______, or widening of the blood vessel lumen.

vasoconstriction, vasodilation