CVS 1.1 - intro Flashcards

1
Q

Where does gas exchange take place in the cvs?

A

The capillaries

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2
Q

What is used as a transporter in the cvs?

A

Blood

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3
Q

What is used to control the perfusion rate and how is this achieved?

A
  • Arterioles and pre-capillary sphincters

- Add resistance to flow by decreasing the diameter of the lumen therefore making it harder to flow through

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4
Q

How do O2 and CO2 diffuse through the capillary wall?

A

Both are lipid soluble so move through by simple diffusion

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5
Q

How do molecules such as glucose or amino acids move through the capillary wall?

A

Both are hydrophilic so diffuse through specific pores by facilitated diffusion

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6
Q

What are the three factors that affect the rate of diffusion? Which is the most limiting?

A
  • Area (not usually limiting)
  • Resistance (not usually limiting)
  • Concentration gradient (not usually limiting)
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7
Q

How does the area of a diffusion surface affect the rate?

A
  • Smaller diffusion area = lower rate of diffusion

- Higher capillary density = higher rate of diffusion

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8
Q

Where are the most likely areas of high capillary density?

A

Areas that have high metabolic activity

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9
Q

What are the three factors that affect the resistance to diffusion?

A
  • Molecule type e.g. Lipophilic? Hydrophilic? Size?
  • Barrier type e.g. Size of pore, number of pores for hydrophilic substances
  • Path length e.g. Capillary density, increased path length = lower rate of diffusion
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10
Q

How does the concentration gradient affect the rate of diffusion?

A

Higher concentration gradient = higher rate of diffusion

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11
Q

Where is the affect of a concentration gradient most significant?

A

Between the blood and the capillaries

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12
Q

Why do concentration gradients need to be maintained?

A

So that supply can meet demand otherwise the gradients will disappear

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13
Q

What is the typical cardiac output for a 70kg male? What can this increase to in order to maintain perfusion rates to vital organs?

A
  • 5.0 lmin-1

- 24.5-25 lmin-1

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14
Q

What is the typical perfusion rate to the brain? Describe it

A

0.5 ml.min-1g-1

High and constant

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15
Q

What is the typical perfusion rate to the heart? Describe it

A

0.9 - 3.6 ml.min-1g-1

Rest - high when exercising

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16
Q

What is the typical perfusion rate to the kidneys? Describe it

A

3.5 ml.min-1g-1

High, constant

17
Q

What is the distribution of blood within the cardiovascular system?

A
  • Veins = 67%
  • Arteries and Arterioles = 11%
  • Capillaries = 5%
  • Heart and lungs = 17%
18
Q

Why does the total flow of blood need to be able to change?

A

So that the blood can return to the heart at a different rate to which it leaves at

19
Q

How can veins act as a variable reservoir of blood?

A

Have thin walls that can distend and recoil (capacitance)

20
Q

What is the distribution system of the cvs?

A

Blood vessels and blood