Lecture 11

Question 1

Vascular Distensibility

Answer 1

Increase in volume/increase in pressure*original volume

Question 2

Vascular Compliance

Answer 2

Increase in volume/increase in pressure; also equal to distensibility*volume

Question 3

Relationship between capacitance and volume and capacitance and pressure

Answer 3

Capacitance is directly proportional to volume and inversely proportional to pressure; much greater in veins than in arteries; capacitance of arteries decreases with age

Question 4

What happens to the compliance as the amount of elastic tissue increases?

Answer 4

Compliance decreases

Question 5

What is compliance measuring?

Answer 5

Measure of the ease with which a hollow viscus may be distended (the volume change resulting from the application of a unit pressure differential between the inside and outside of the viscus; reciprocal of elastance

Question 6

Elastance

Answer 6

Measure of the tendency of a hollow viscus to recoil toward its original dimensions upon removal of a distending or collapsing force

Question 7

Pulse Pressure

Answer 7

Stroke volume/arterial compliance

Question 8

Factors that affect pulse pressure

Answer 8

Stroke volume output of the heart (most important determinant) and compliance of the arterial tree

Question 9

Conditions causing abnormal contours of the pressure pulse wave

Answer 9

Aortic valve stenosis, arteriosclerosis, patent ductus arteriosus, or aortic regurgitation

Question 10

Aortic Valve Stenosis

Answer 10

Diameter of the aortic valve opening is reduced significantly, and the aortic pressure pulse is decreased significantly

Question 11

Arteriosclerosis

Answer 11

Hardening of arterial walls

Question 12

Patent Ductus Arteriosus

Answer 12

Half or more of the cardiac output flows back into the pulmonary artery and lung blood vessels

Question 13

Aortic Regurgitation

Answer 13

Aortic valve is absent or will not close completely; pressure may fall all the way to 0 between heartbeats

Question 14

Mean Arterial Pressure

Answer 14

Average arterial pressure with respect to time; not simple average of systole and diastole because a larger fraction of the cardiac cycle is spent in diastole than systole; calculated by adding diastolic pressure and 1/3 of the pulse pressure

Question 15

Central Venous Pressure

Answer 15

Pressure in the right atrium; regulated by ability of heart to pump blood out of the right atrium or ventricle and tendency of blood to flow into the right atrium

Question 16

Factors that increase venous return (which increases right atrial pressure)

Answer 16

Increased blood volume, increased peripheral venous pressures due to increased large vessel tone, and dilation of arterioles

Question 17

Varicose Veins

Answer 17

Defects of the valves of the veins, commonly in the legs

Question 18

Arterioles

Answer 18

Control blood flow to each tissue; local conditions in tissues control diameters of arterioles; highly muscular until it is lost in metarterioles

Question 19

Capillaries

Answer 19

Smooth muscle fiber encircles capillary at point where it originates from a metarteriole (referred to as a precapillary sphincter); capillaries in the liver, GI tract, and kidneys have pores

Question 20

Capillary Wall

Answer 20

Unicellular layer of endothelial cells; thin basement membrane; total wall thickness is .5 micrometers; internal capillary diameter is 4-9 micrometers

Question 21

Slit Pores

Answer 21

Allow for rapid diffusion of water, water-soluble ions, and small solutes

Question 22

Plasmalemmal Vesicles

Answer 22

Formed from caveolins; play a role in endocytosis and transcytosis

Question 23

Most Important Factor in Regulating Vasomotion

Answer 23

Concentration of oxygen in the tissues

Question 24

Diffusion and Capillary Exchange

Answer 24

Review Slides 40-42 in Lecture 11

Question 25

Starling Forces

Answer 25

Determine direction of diffusion into or out of a capillary

Question 26

Factors that Increase Lymph Flow and Interstitial Fluid Pressure

Answer 26

Elevated capillary hydrostatic pressure
Decreased plasma colloid osmotic pressure
Increased interstitial fluid colloid osmotic pressure
Increased permeability of capillaries

Question 27

Rate of Lymph Flow

Answer 27

Interstitial fluid pressure*activity of lymphatic pump