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Flashcards in respiration 5 Deck (20)
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1
Q

Solution to the high cellular demand of oxygen

A

98.5 % of oxygen is bound to Haemoglobin, only 1.5% is dissolved

2
Q

Oxygen can be _________ dissolved or ________ bound

A

physically

chemically

3
Q

Each iron molecule in the heme portion can combine with an oxygen molecule. How many O2 molecules per Hb molecule

A

4 O2 molecules per Hb molecule

4
Q

What drives the reduction reaction of Oxyhemoglobin [HbO2 Hb + O2]

A

Partial pressure drives the reaction

5
Q

The average hematocrit for women is ______, with plasma occupying _____
The average hematocrit for men is ______, with plasma occupying _____

A

42%
58%

45%
55%

6
Q

A hemoglobin molecule consists of _____ highly folded ________ (the globin portion) and four __________ heme groups.

A

four
polypeptide chains
iron-containing

7
Q

Percentage O2 carried when physically dissolved

A

1.5%

8
Q

Percentage O2 carried when bound to hemoglobin

A

98,5

9
Q

PO2 in resting cell (mm Hg)

A

40

- 75% saturation

10
Q

PO2 in alveoli (mm Hg)

A

100

- 97.5% saturation

11
Q

At 40 mmHg, ____% of all Hg must dissociate

A

25

12
Q

If tissue cells metabolize more actively, a small change in ______ (eg 10 mmHg) yields a ______ of O2 dissociation to meet metabolic demands

A

partial pressure

large amount

13
Q

Plateau between 60 and 100 mm/Hg:

A
  • large pressure change causes hardly any change in O2 content
  • Hb: “soaks up” the O2, keeping the partial pressure high for longer
14
Q

when does blood PO2 start falling to that of the surrounding tissue

A

Only when Hb is maximally unloaded at the given pressure gradient

15
Q

storage depot for oxygen, facilitating large net transfer by maintaining the partial pressure for longer

A

Hemoglobin

16
Q

What causes a favor in unloading?

A

increased PCO2, H+ (acid) , temperature, or 2,3-bisphosphoglycerate

17
Q

of increased PCO2, H+, temperature, and 2,3-bisphosphoglycerate causes what

A

right-shift in the curve

18
Q

Effect of increased PCO2, H+, temperature, and 2,3-bisphosphoglycerate on the O2–Hb curve

A

shift the O2–Hb curve to the right. As a result, less O2 and Hb can be combined at a given PO2 so that more O2 is unloaded from Hb for use by the tissues. Similarly, 2,3-bisphosphoglycerate, whose production is increased in red blood cells when arterial HbO2 is chronically below normal, shifts the O2–Hb curve to the right, making more of the limited O2 available at the tissue level.

19
Q

Breathing pure oxygen: can it provide more Oxygen to the tissue?

A

Very little is added

20
Q

How does carbon monoxide poisoning occur?

A

Hemoglobin: high affinity for carbon monoxide
[CO Hb affinity: 240x higher than O2]
Carboxyhemoglobin HbCO
Even small amounts of CO can make large amounts of Hb unavailable for oxygen
Odorless, colorless, tasteless, non-irritating
Not sensed: no response in ventilation
Treatment: 100% oxygen