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Flashcards in respiration 3 Deck (57)
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1
Q

what percent of oxygen is dissolved in the blood

A

2%(3ml/L;2mmol; 40mg)

2
Q

what O2 in the blood is capable of diffusing

A

DIssolved O2

3
Q

what is the resting O2 consumption

A

250ml/min

4
Q

can dissolved O2 alone support basal metabolism

A

No(only can do 10%)

5
Q

how much O2 is carried by hemoglobin

A

98% of O2

6
Q

how much hemoglobin is found in the erythrocyte

A

250-280 million Hb for cell

7
Q

how is hemoglobin designed

A

as a tettrameric molecule

8
Q

what is hemoglobin made of

A

4 protein subunits
each with heme goup
+1 iron atom per heme

9
Q

how much O2 can bind to one hemoglobin

A

4 O2’s

10
Q

what is total O2 in blood a function of

A

PO2

Hb in blood

11
Q

when is carrying capacity of the blood reached

A

when maximum HbO2% saturation = % of Hb in HbO2

12
Q

what kind of binding does Hb exhibit to O2

A

cooperative binding

13
Q

what else can bind to Hb to change its affinity to O2

A

binding of 2,3 DPG reduced Hb binding to O2

14
Q

what is the plateua region of the Oxygen hemoglobin dissociation cuves

A

Loading phase

15
Q

what is the steep region of the oxygen hb disociation curve

A

Unloading phase

16
Q

what is O2 binding to Hb a function of

A

PO2

17
Q

what is P50 on the oxygen-Hb dissociation curve

A

when half the Hb is saturated

18
Q

does the amount of dissolved O2 change a lot as Po2 increases

A

No

19
Q

why is it important to keep a high pool of dissolved O2 in the blood

A

Supply mitochondrial demand

20
Q

does Po2 increase or decrease as it goes from ambient air to the mitochondira

A

decreases

21
Q

can O2 bound to Hb diffuse

A

No, but is relasesd from Hb into the dissolved pool as PO2 falls

22
Q

what does Hb do to help get O2 into blood

A

maintains Po2 gradient until Hb is saturated

23
Q

what does an increase in Hb affinity for O2 do to the HB-OX binding curve

A

shifts it to the left

24
Q

what does a decrease in Hb affinity for O2 do to the Hb-ox binding curve

A

shift curve to the right

25
Q

what factors at the tissue tend to decrease Hb affinity for O2

A

metabolic activity

  • increased temp (to right)
  • increase CO2 (to the right)
  • increased acidity (to the right)
  • increase 2,3 diphosphoglycerate
26
Q

what is the Bohr effect

A

increase in CO2 decreases Hb affinity for O2 when CO2 binds tot he Globin part of Hb (allosteric)

27
Q

where does H bind to in Hb

A

binds to the globin part of Hb with allosteric affect

28
Q

what does 2,3 Diphosphoglycerate come from

A

Glycolysis in erythrocytes

29
Q

how does 2,3 DPG work

A

allosteric modulation

30
Q

does the fetus or adult bind Hb better

A

fetus

31
Q

why does fetal Hb bind O2 better than adult Hb

A

because a lower PO2 in the fetus

32
Q

what makes fetal Hb different than adult Hb

A

subunits of fetal Hb are from different genes than postnatal/adult Hb

33
Q

what are the amounts of Hb and O2 in the blood`

A

15g Hb and 20ml O2/100ml blood

34
Q

what is anemia

A

fewer erythrocytes due to blood loss, reduced erythropoiesis, volume overload

35
Q

how does the hematocrit change as Hb get lower per ml

A

Low hematocrit

36
Q

does less Hb per ml of blood affect PO2, Hb saturation, or total O2 content

A

does no affect PO2 or Hb saturation

total O2 content though is reduced

37
Q

how much greater does Hb have affinity for Co than O2`

A

200 times

38
Q

how does .1% CO in air affect arterial PO2 and total O2

A

no change in PO2

50% drop of O2 in blood

39
Q

what does CO do to the HB-O2 dissociation curve

A

moves it to the left (greater affinity for O2)

40
Q

what are the ways CO2 is transported

A

dissolved (7%)
Bound to Hb (about 23%)
as HCO3 (70%)

41
Q

does CO2 or O2 dissolve in plasma more

A

CO2 more

42
Q

what is CO2 bound to hemoglobin

A

Carbaminohemoglobin

43
Q

does CO2 compete with O2 binding

A

No, because CO2 binds to globin and O2 binds to heme

44
Q

how does an increase in PCO2 change Hb affinity for CO2

A

increases affinity

45
Q

what is the haldane effect

A

decreaseing PO2 increases Hb affinity (why CO2 binds in veins and not in arteries

46
Q

what turns CO2 and H2O into HCO3 (carbonic acid)

A

carbonic anhydrase

47
Q

where is carbonic anhydrase found

A

in the erythrocytes (not plasma)

48
Q

how does HCO3 leave the Erythrocyte into the plasma

A

there is a HCO3/CL transporter in the erythrocyte

49
Q

what does the transformation of CO2-> HCO3 do to the pH of the plasma

A

acifies the plasma

50
Q

where do H+ bind in the hemeoglobin

A

binds to histine restidine

51
Q

what does the affinity of H+ to hemoglobin depend on

A

PO2

52
Q

oxygenated Hb affinity for H+ is high or low and why

A

high, because need to minimize the effect of HCO3 on pH

53
Q

what buffers the H+ produced by the CA reaction

A

Hb

54
Q

is there a large difference in pH of arteries and veins

A

No

55
Q

what happens to H+ in the lungs

A

released from Hb and the CA reaction is reversed to create CO2

56
Q

what does Hypoventilation do to blood pH

A

acidosis( increased PCO2-> increased H+)

57
Q

what does hyperventilation do to blood pH

A

alkalosis ( decreased PCO2-> decreased H+)