Week 10: Respiratory 4 Flashcards

1
Q

How is the pressure regulated?

A

passive regulation

active regulation

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2
Q

Describe the passive regulation of pressure.

A

vessels dilate easily

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3
Q

Describe the active regulation of pressure.

A

happens in the circumstance of hypoxia and chronic respiratory insufficiency

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4
Q

What happens during hypoxia?

A

Hypoxia means not enough oxygen

causes vasoconstriction to unnecessary areas of gas exchange

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5
Q

What happens in chronic respiratory insufficiency?

A

PO2 ↓

vasoconstriction in lung vessels

pulmonary hypertension

right ventricular hypertrophy

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6
Q

What is the effect of gravity on the lung?

A
  • base of the lung has larger blood flow (more effected by gravity)
  • apex of the lung has smaller blood flow
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7
Q

Where is the volume of the alveoli smaller & less open? What is the pressure?

A

base of lung

-2 cm H20

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8
Q

Where is the volume of the alveoli larger & more open? What is the pressure?

A

apex of the lung

-10 cm H2O

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9
Q

What is the equation that tells us the diffusion of oxygen across a membrane?

A

VO2 = A•D• ΔP / T

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10
Q

What does A•D / T give us?

A

Diffusion capacity

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11
Q

What is the effect of exercise on the diffusion capacity?

A

↑ diffusion capacity

↑ surface area

↑ flow

more capillaries open

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12
Q

Does diffustion limit gas exchange in the blood?

A

NO

but in the tissues it does

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13
Q

Explain the picture

A

The partial pressure of the alveoli is equal to the partial pressure of arterial blood

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14
Q

What are the layers of which oxygen has to diffuse?

A
  1. alveolar epithelium
  2. apithelial basement membrane
  3. interstitial space
  4. capillary basement membrane
  5. capillary endothelium
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15
Q

In what direction does flow into the capillary occur?

A

from high pressure → low pressure

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16
Q

How long does it take for the actual gas exchange to occur?

A

.25 seconds

However, there is a reserve time of .75 totalseconds for gas exchange to occur in case there is a problem.

17
Q

What is the graph representing the relationship between the partial pressure of O2 and Hemoglobin saturation? What are two important values?

A

In arterial blood the PO2 is about 90 mmHg and the hemoglobin saturation is about 97%

In venous blood the PO2 is about 40 mmHg and the hemoglobin saturation is about 75%

18
Q

What is the concentratino of Hemoglobin?

A

2.3 mmol/l

19
Q

Draw the arterial and venous HgbO2 equilibrium curves.

A

* venous blood has more CO2*

20
Q

What causes a right shift of the HgbO2 equilibrium curve?

A

occurrs during exercise

(local ↑ in glycolysis occurrs)

extra amount O2 is released from Hemoglobin

  • PCO2
  • [H+] ↑
  • 2,3 BPG ↑
  • Temperature ↑
21
Q

What happens in the case of CO poisoning?

A
  • CO binds to hemoglobin with a higher affinity than oxygen
    • once bound, releases slowly
  • can bind at low concentration