Ch 21 Blood Vessels and Circulation

Venous valves are responsible for -preventing blood from re-entering a ventricle. -regulating blood pressure in veins. -channeling blood away from the heart. -channeling blood toward the heart. -preventing anterograde flow.

channeling blood toward the heart.

The blood colloid osmotic pressure mostly depends on the -concentration of plasma proteins. -concentration of plasma glucose. -concentration of plasma sodium ions. -number of red blood cells. -concentration of plasma waste products.

concentration of plasma proteins.

Capillaries that have a complete lining are called vasa vasorum. continuous capillaries. fenestrated capillaries. sinusoidal capillaries. sinusoids.

continuous capillaries.

Arteries have a structure in their middle and internal vessel walls that veins lack, called a/an __________. elastic membrane endothelium adventitia smooth muscle

elastic membrane

The muscular layer in the wall of a blood vessel is the tunica interna. externa. media. intima. adventitia.

media.

Blood flow through a capillary is controlled by the plexus. thoroughfare channel. vasa vasorum. venule. precapillary sphincter.

precapillary sphincter.

Each of the following will lead to a decrease in blood pressure except -decrease in blood volume. -increased levels of ANP (atrial natriuretic peptide). -decreased peripheral resistance. -decreased levels of aldosterone. -release of renin.

release of renin.

Which part of the blood vessel wall is dominated by smooth muscle? the tunica media the tunica intima the tunica externa the endothelium

the tunica media

Which of the following is normally the greatest source acting against blood flow? turbulence venous pressure vascular resistance viscosity of blood vessel length

vascular resistance

Each of the following factors would increase peripheral resistance except -irregularities in the vessel walls caused by plaques. -increased sympathetic stimulation. -vasodilation. -elevated hematocrit. -elevated levels of epinephrine.

vasodilation.

What vessels hold the largest percentage of the blood supply? veins arterioles capillaries arteries venules

veins

These vessels may be continuous or fenestrated. arteries venules arterioles veins capillaries

capillaries

Exchange between a blood vessel and the cells that surround it can occur only in arteries. veins. arterioles. capillaries. venules.

capillaries.

Elevated levels of the natriuretic peptide hormones ANP and BNP will produce increased -sodium ion levels in blood. -blood pressure. -salt and water loss through the kidneys. -venous return and preload. -blood volume.

-salt and water loss through the kidneys.

Hemorrhage triggers all of these responses EXCEPT __________. -an increase in erythropoiesis -an increase in heart rate -release of the venous reserve -an increase in urine production

an increase in urine production

When renin is released from the kidney, -angiotensin I is converted to angiotensin II. -blood flow to the kidneys decreases. -angiotensin I increases salt reabsorption at the kidneys. -angiotensinogen is converted into angiotensin I. -blood pressure goes down.

angiotensinogen is converted into angiotensin I.

Compared to arteries, veins -have a pleated endothelium. -have more smooth muscle in their tunica media. -have thinner walls. -are more elastic. -hold their shape better when cut.

are more elastic.

Each of the following will cause an increase in blood pressure except -increased levels of angiotensin II. -increased levels of ANP (atrial natriuretic peptide). -increased levels of ADH (antidiuretic hormone). -increased levels of aldosterone. -increased blood volume.

increased levels of ANP (atrial natriuretic peptide).