Review Questions

DIRECTIONS: Each of the numbered items or incomplete statements in this section is followed by answers or completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.

1. The vessels most responsible for both controlling systemic vascular resistance and regulating blood flow to a particular organ are the

(A) Small arteries

(B) Arterioles

(C) Capillaries

(D) Venules

(E) Lymphatic vessels

2. The structures between adjacent capillary endothelial cells that primarily determine what size water-soluble molecules can enter the tissue are the

(A) Fiber matrices at the blood side of endothelial pores

(B) Molecular-sized openings within the tight junctions

(C) Basement membrane structures of the capillary

(D) Plasma proteins trapped in the spaces between cells

(E) Rare, large defects found between adjacent endothelial cells

3. The major pressures that determine filtration and absorption of fluid by capillaries are the

(A) Capillary hydrostatic pressure and plasma colloid osmotic pressure

(B) Plasma colloid osmotic pressure and interstitial hydrostatic pressure

(C) Interstitial hydrostatic pressure and tissue colloid osmotic pressure

(D) Capillary hydrostatic pressure and tissue colloid osmotic pressure

(E) Plasma colloid osmotic pressure and tissue colloid osmotic pressure

4. Myogenic vascular regulation is a cellular response initiated by

(A) A lack of oxygen in the tissue

(B) Nitric oxide release by vascular muscle cells

(C) Stretch or tension on vascular muscle cells

(D) Shear stress on the endothelial cells

(E) An accumulation of metabolites in the tissue

5. The most important function of the microcirculation is

(A) The exchange of nutrients and wastes between blood and tissue

(B) The filtration of water through capillaries

(C) The regulation of vascular resistance

(D) The autoregulation of blood flow

(E) Its role as a blood reservoir

6. When lipid-soluble molecules pass through a capillary wall, they primarily cross through

(A) The lipid component of cell membranes

(B) The water-filled spaces between cells

(C) The specialized transport proteins of the cell membranes

(D) The pinocytotic-exocytotic vesicles formed by endothelial cells

(E) Filtration through the capillary wall

7. Venules function to collect blood from the tissue and

(A) Act as a substantial source of resistance to regulate blood flow

(B) Serve as a reservoir for blood in the cardiovascular system

(C) Are virtually impermeable to both large and small molecules

(D) Are about the same diameter as arterioles

(E) Exchange a large amount of oxygen with the tissue.

8. The interstitial space can best be described as a

(A) Water-filled space with a low plasma protein concentration

(B) Viscous space with a high plasma protein concentration

(C) Space with alternating gel and liquid areas with a low plasma protein concentration

(D) Space primarily filled with gel-like material and a small amount of liquid

(E) Major barrier to the diffusion of water and lipid-soluble molecules

9. An arteriole with a damaged endothelial cell layer will not

(A) Constrict when intravascular pressure is increased

(B) Dilate when adenosine is applied to the vessel wall

(C) Constrict in response to norepinephrine

(D) Dilate in response to adenosine diphosphate (ADP) or acetylcholine

(E) Dilate when blood flow is reduced

10. The first step for lymphatic vessels to remove excess fluid from interstitial tissue spaces is by

(A) Generating a lower intravascular than tissue hydrostatic pressure

(B) Contracting and forcing lymph into larger lymphatics

(C) Opening and closing one-way valves in the lymph vessels

(D) Lowering the colloid osmotic pressure inside the lymph vessel

(E) Closing the opening between adjacent lymphatic endothelial cells

11. When the sympathetic nervous system is activated,

(A) Norepinephrine is released by the vascular smooth muscle cells

(B) Acetylcholine is released onto vascular smooth muscle cells

(C) Norepinephrine is released from axons onto the arteriolar wall

(D) The arterioles constrict because nitric oxide production is suppressed

(E) The endothelial cells induce vascular smooth muscle cells to constrict

12.At a constant blood flow, an increase in the number of perfused capillaries improves the exchange between blood and tissue because of

(A) Greater surface area for the diffusion of molecules

(B) Faster flow velocity of plasma and red blood cells in capillaries

(C) Increased permeability of the microvasculature

(D) Decreased concentration of chemicals in the capillary blood

(E) Increased distances between the capillaries

13. For an arterial blood content of 20 mL oxygen per 100 mL blood and venous blood content of 15 mL oxygen per 100 mL of blood, how much oxygen is transferred from blood to tissue if the blood flow is 200 mL/min?

14. Assume plasma proteins have a reflection coefficient of 0.9, plasma colloid osmotic pressure is 24 mm Hg, and tissue colloid osmotic pressure is 4 mm Hg. What is the net pressure available for filtration or absorption of fluid if capillary hydrostatic pressure is 23 mm Hg and tissue hydrostatic pressure is 1 mm Hg?

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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