1. CV Review Flashcards Preview

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Flashcards in 1. CV Review Deck (29):
1

What is the basic function of the circulatory system?

Support cell metabolism by:

-delivering O2 and nutrients to cells

-removing CO2 and wastes from cells

2

By what mechanism are nutrients delivered by the circulatory system?

Diffusion

3

Over what distances is diffusion timely? Why?

Timely only over tiny distances (over large distances, diffusion is too slow to keep up w/ cells' metabolic rates)

4

How is diffusion maximized?

-Larger surface area

-Minimal distance and membrane thickness

-Large concentration gradient

5

What is Fick's Law of Diffusion?

Qx = rate of diffusion of X

D = diffusion coefficient

As = surface area for exchange

Δ[X] = concentration gradient

ΔL = diffusion distance

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6

What drives transcapillary solute movement?

Diffusion

7

How do capillaries affect Fick's Law of Diffusion?

-Increases surface area for exchange

-Minimizes diffusion distance

8

How are capillaries made to maximize diffusion?

-Huge CSA

-Thin membrane wall

-Small diameter

-Large number throughout body

9

How are CSA and speed of flow in the CV system related?

Inversely:

-large CSA = slower flow

-small CSA = rapid flow

10

Why is it important for CSA and speed of flow in the CV system to have an inverse relationship?

Large CSA --> velocity slows --> allows more time for nutrient exchange

11

What is the basic function of the heart?

Develops the pressure gradient that creates flow of blood w/in the circulatory system

12

Over what distances is convection (bulk flow) timely?

Timely over large distances

13

Why is bulk flow (convection) important?

-Maintains the driving force for diffusion, so nutrients are coming in at a rate proportional to their leaving

-Shortens time b/t capillary beds --> speeds up diffusion

14

Define convection.

Bulk flow of blood around the circulatory system

15

How could one increase the delivery rate of a substance?

-Increase blood flow rate

-Increase concentration of substance in blood

16

Equation for delivery rate

X = Q[X]

X = rate of delivery of x (mass/time)

Q = blood flow rate (volume/time)

[X] = concentration of X in blood (mass/volume)

17

What is the Fick Principle?

  • Xtc = transcapillary efflux of X
  • Q = blood flow rate
  • [X]a = concentration of X in arterial blood
  • [X]v = concentration of X in venous blood

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18

What is the equation for convective flow?

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19

What are the 2 ways to alter how quickly blood flows to an organ?

-Change the pressure difference across its vascular bed

-Change its vascular resistance

20

What are the resistance vessels controlling the radius?

Arterioles

21

What does arterial dilation promote?

Filtration (fluid exit across the capillaries)

-Less of the oncoming pressure from heart is resisted out --> capillaries leak a lot

22

What does arterial constriction promote?

Reabsorption (fluid movement back into the capillaries)

-Arterioles resist out most of the pressure, so the actual pressure entering the capillaries is much lower --> capillaries leak less

23

What drives transcapillary fluid movement?

Convection

24

What governs fluid movement into and out of the circulation?

4 starling forces (pressures) in the blood and tissue compartments

25

What are the 4 starling forces?

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26

Which starling forces push fluid into circulation? Out of circulation?

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27

What occurs on the arterial end of a capillary?

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28

What occurs on the venous end of a capillary?

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29

Transcapillary solute movement vs. transcapillary fluid movement

-Solute: has to do w/ rate of diffusion of solute/gas from the capillary to the cell

-Fluid: has to do w/ volume distribution b/t plasma in capillaries and interstitial space