Lecture 27 Flashcards

Gas Transport

1
Q

Why is partial pressure equal but concentration is not?

A

CO2 is 20X more soluble than O2 in plasma

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2
Q

How is O2 transported?

A

it binds to hemoglobin inside the red blood cell
4 binds to hemoglobin at a time

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3
Q

When oxygen is bonded to hemoglobin, what is it called?

A

Oxyhemoglobin

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4
Q

How does hemoglobin increase O2 carrying capacity?

A

Since the partial pressure of the alveoli and the capillaries are the same, only 2 percent of the oxygen dissolves into plasma. the hemoglobin allows 98% of the oxygen to be in the blood

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5
Q

Where is O2-Hb binding saturation plateau?

A

At the lungs (60-100mm Hg)

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6
Q

where is the O2-Hb binding saturation steep?

A

at the tissues (0-40mm Hg)

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7
Q

Why is the O2-HB dissociation curve sigmoidal?

A

hemoglobin is cooperative, the more O2 binds, the greater the affinity for O2 grows

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8
Q

when the dissociation curve moves to the right, it means..

A

Affinity decreases (P50 increases meaning it takes longer and more O2 to reach 50%)

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9
Q

when the dissociation curve moves to the left, it means..

A

Affinity increases (P50 decreases meaning it takes shorter and less O2 to reach 50%)

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10
Q

an increase of acidity…

A

decreases the affinity of hemoglobin cause it makes it go into the T state therefore increasing the P50

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11
Q

an increase of PCO2…

A

decreases affinity cuz it increases the acidity therefore increases the P50

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12
Q

2 ways of O2 Transport

A

98%- Oxyhemoglobin
2% - dissolved O2 in plasma

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13
Q

3 ways of CO2 transport

A
  • 7% transported as dissolved gas in plasma
  • 23% transported as HbCO2
  • 70% transported as bicarbonate dissolved in plasma
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14
Q

What is the bicarbonate equation?

A

CO2 + H2O ——-> H2CO3 ——> H+ + HCO3-

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15
Q

where does carbonic anhydrase fit in the equation?

A

to turn CO2 + H20 to carbonic acid

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16
Q

What happens when there’s too much H+ in the blood

A

acidosis

17
Q

How does CO2 get transported out of tissues

A

The CO2 diffuses into he plasma and into the red blood where it binds to Hb
More CO2 and binds to water beaconing carbonic acid with the help of Carbonic anhydrase. It then turns into bicarbonate and the H+ binds to the Hb

18
Q

How does CO2 get transported out of the lungs

A

the dissolved CO2 diffuse out (7%)
the 23% bonded to the Hb diffuse out
this makes the opposite reaction occur and more bicarbonate goes into the blood to drive the production of CO2 (70%)

19
Q

how is ventilation regulated?

A

medulla oblongata receives input from the
- medullary chemoreceptors
- carotid & aortic chemoreceptors
- limbic system

20
Q

How is CO2 levels detected

A

medulla chemoreceptors

21
Q

how is O2 and pH levels detected?

A

the carotid and aortic chemoreceptors

22
Q

What type of feedback is regulation of ventilation

A

negative feedback loop

23
Q

What system controls the medulla receptors

A

central nervous

24
Q

what system controls the aortic and carotid arch

A

peripheral nervous