Heller Ch. 6

Question 1

What are the units for transport rate?

Answer 1

Mass/time

Question 2

How is transport rate calculated?

Answer 2

Flow rate x concentration (Volume/time) x (mass/volume) = mass/time

Question 3

What are the four determinants to diffusion?

Answer 3

1. The concentration difference
2. The surface area of exchange
3. The diffusion distance
4. The permeability of the capillary wall to the diffusing substance

Question 4

What two types of pressure influence transcapillary fluid movement?

Answer 4

Hydrostatic pressure Osmotic pressure

Question 5

Is hydrostatic pressure higher in the interstitial or intracapillary fluid?

Answer 5

Intracapillary (25mmHg) P_c

Interstitial (0mmHg) P_i

Question 6

What is osmotic pressure?

Answer 6

Hydrostatic pressure necessary to prevent osmotic water movement

Question 7

What is Oncotic pressure?

Answer 7

Part of osmotic pressure

Particle concentration due to particles that cannot diffuse

Question 8

Is the oncotic pressure higher in the capillary or in the interstitial fluid?

Answer 8

Capillary (25mmHg) π_c

Interstital fluid (0mmHg) π_i

Question 9

What is the effect of the oncotic pressure?

Answer 9

Fluid goes back into the plasma

Question 10

What is the net filtration rate?

Answer 10

K[(Pc – Pi) – (πc – πi)]

Question 11

What is the role of the lymphatic system?

Answer 11

To remove large molecules from the interstitial space

Question 12

Why is it important to remove large molecules from the interstitial space?

Answer 12

A build up in large molecules in the interstitial space would decrease the osmotic pressure difference…fluid would build up

Question 13

What promotes lymphatic activity?

Answer 13

Increases in interstitial pressure (due to fluid accumulation or to movement to surrounding tissue)

Contractions of the lymphatic vessels…valves prevent back flow

Question 14

What is the resistance of vessels arranged in parallel?

Answer 14

(1/R_T) = (1/R₁) + (1/R₂) + … + (1/R_n)

Question 15

What is the resistance of vessels in series?

Answer 15

R_T = R₁ + R₂ + … + R_n

Question 16

How does blood flow velocity relate to the vessel’s total cross-sectional area?

Answer 16

As the total cross-sectional area increases–i.e. capillaries–the velocity goes down

Question 17

What is laminar flow?

Answer 17

Orderly, streamlined flow

Little mixing

Question 18

What causes turbulent flow?

Answer 18

Fluid being forced to move too fast through a narrow opening

Question 19

What happens as a result of turbulent flow?

Answer 19

Mixing

Sounds–cardiac murmurs, bruits, checking blood pressure

Question 20

What is the percentage of blood volume in the arteries? Arterioles? Capillaries? and Venules/Veins?

Answer 20

Arteries: 12%

Arterioles: 2%

Capillaries: 5%

Venules/Veins: 60%

Question 21

Where is the peripheral venous pool?

Answer 21

Veins of the systemic organs

Question 22

Where is the central venous pool?

Answer 22

Great veins of the thorax

Right atrium

Question 23

What happens to the blood pressure as blood goes through the different vessels?

Answer 23

Blood pressure decreases to 0 by the time it gets to veins

The vessels are in a series so the resistance increases

Question 24

What is the resistance across organs?

Answer 24

Organs are in parallel

Question 25

What is Compliance in relation to volume/pressure?

Answer 25

Compliance is the volume change in response to a pressure change

C = ΔV/ΔP

Question 26

What is arterial compliance?

Answer 26

Arteries have very little change in volume relative to change in pressure

Question 27

What is venous compliance?

Answer 27

Veins have a large change in volume relative to the change in pressure

Question 28

Why is arterial elasticity important for conserving energy?

Answer 28

Expansion during systole and contraction during diastole keeps the blood moving…without relying on the heart pumping

Question 29

What are Korotkoff sounds?

Answer 29

During auscultation for systolic/diastolic blood pressures

Rely on turbulence caused by collapsed vessels

Question 30

What is the relationship between arterial pressure, cardiac output, and total peripheral resistance?

Answer 30

P_A = CO x TPR

Question 31

How is mean arterial pressure determined from systolic and diastolic pressures?

Answer 31

P_A = P_D + 1/3(P_S – P_D)

Question 32

What is the relationship between pulse pressure, stroke volume, and arterial compliance?

Answer 32

P_P = P_S – P_D = SV/CA

Question 33

How does arterial compliance change with age?

Answer 33

Older arteries have a higher pressure change for a given volume changes

Question 34

What is the effect of constricting venous smooth muscles on venous volume?

Answer 34

There will be a lower volume for a given pressure