Quiz 5 Transport of O2 and CO2 Flashcards

1
Q

Rate of CO2 production by cells

A

200 mL/min

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2
Q

Metabolic arteriovenous CO2 difference

A

40 mL/L

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3
Q

Metabolic arteriovenous O2 difference

A

50 mL/L

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4
Q

Rate of O2 use by cells

A

250 mL/min

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5
Q

Tissue PCO2

A

> 50 mmHg

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6
Q

Tissue PO2

A

> 10 mmHg

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7
Q

hypoxic hypoxia

A

inadequate O2 uptake in lungs

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8
Q

stagnant (ischemic) hypoxia

A

inadequate blood flow to an organ (arteriosclerosis, PVD, stroke, MI, bowel infarct)

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9
Q

anemic hypoxia

A

inadequate blood o2 carrying capacity

inactivated hemoglobin

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10
Q

histotoxic hypoxia

A

interference with mitochondrial respiration (like cyanide poisoning)

tissues have O2, but can’t use it

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11
Q

Normal Hb concentration?

A

15 g/dL

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12
Q

RBC carry ___ times more O2 than plasma

A

65

97% carried via Hbg
3% carried in plasma

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13
Q

How many subunits (or heme groups) does Hb have?

A

4 subunits= α2β2

4 subunits = 2 alpha + 2 beta

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14
Q

Amount of oxygen each gm of Hb can carry?

A

1.31 mL O2*

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15
Q

What shape is the HbO2 curve?

A

sigmoid

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16
Q

The ratio of O2 bound to Hb compared to total amount that can be bound is

A

Oxygen Saturation

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17
Q

Maximal amt of O2 bound to Hb is

A

Oxygen Capacity

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18
Q

***What is the Hb P50 point?

A

PaO2 is 27 when sat is 50!!!

reference point for when hemoglobin is 50% saturated

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19
Q

What is your PaO2 when the sat is 90

A

60

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20
Q

What is your PaO2 when the sat is 50?

A

27!

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21
Q

Rough rule for PaO2 to sat

A

40,50,60 for sat 70,80,90

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22
Q

The higher the affinity, the ___ the saturation

A

higher

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23
Q

The top of the curve represents

A

Oxygenated blood leaving the lungs

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24
Q

The middle of the curve represents

A

Capillaries

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25
Q

The starting point of the curve represents

A

Reduced blood returning from tissues

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26
Q

The x axis on curve

A

PaO2= pressure of oxygen in blood (mmHg)

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27
Q

The y axis on curve

A

Hb saturation % (SaO2)

28
Q

Carbon Monoxide has ___ times the affinity for Hb than O2

A

250

pt in fire

29
Q

Nitric Oxide binds to Hb _____ times more strongly than O2

A

200,000

binds irreversibly

30
Q

What is NO used for

A

to treat pulmonary hypertension

31
Q

As PaO2 in the tissues decreases, the __ affinity Hb has for it, so…

A

less, so O2 is dumped in the tissues

32
Q

Left shift =

A

lock on/ hold on
↑ affinity for O2
↑ sat, but O2 bound

33
Q

Right shift =

A

release
↓ affinity for O2
↓ sat, but tissues receive more O2

34
Q

which way does alkalosis shift the curve

A

left

35
Q

which way does acidosis shift the curve

A

right

36
Q

which way does hyperthermia shift the curve

A

right

37
Q

which way does hypothermia shift the curve

A

left

38
Q

which way does increased 2,3, DPG shift the curve

A

right

39
Q

Which way does carboxyhemoglobin and methemoglobin shift the curve?

A

left = ↑ affinity

40
Q

which way does increased H+ shift the curve

A

right

41
Q

which way does increased PCO2 shift the curve

A

right

42
Q

Bohr effect

A

Shift to the Right and Down:

↑CO2 in blood=> O2 Hb displacement= ↓O2 affinity = ↑ O2 transport to tissues

It’s the cells way of asking Hb to release O2 to support aerobic metabolism like in tissues

43
Q

PRBC’s in the package shift the curve

A

left… because cold and ↓ 2,3 DPG (a salt that releases O2 from Hb)

44
Q

Myoglobin has ___ affinity for O2, and this causes a shift to the ____

What is myoglobin?

A

increased, left

Myoglobin is found in skeletal muscle cells to store O2 temporarily

45
Q

Fetal blood causes a shift

A

left

46
Q

O2 content in blood (CaO2) is the sum of

A

O2 carried on Hb and dissolved in plasma

mL/dL

47
Q

Shift up is caused by

A

↑ O2 capacity

48
Q

Shift down is caused by

A

↓ O2 capacity - anemia or something binding Hb up

49
Q

What are the 3 ways CO2 is transported by blood

A

1) Dissolved directly in blood
2) Bicarb-/ H+ & Carbonic acid
3) Bound to Hb and plasma proteins

50
Q

What is the MAIN way CO2 is transported?

A

HCO3-bicarb! = 70%

the bicarbonate buffer system

51
Q

Venous blood transports ___ CO2 than arterial blood

A

more

52
Q

Haldane effect

A

↑O2 Hb binding => CO2 displacement => ↑CO2 transport to lungs

53
Q

The reaction that converts CO2 to HCO3- and H+ ions requires

A

the enzyme carbonic anhydrase

54
Q

Mixed venous blood in pulm artery sat and pa02

A

75% PaO2 40

55
Q

Venous Hb affinity shift

A

PO2 of 70 mmHg = Shift to the Right =↓ O2 affinity

Bohr effect = ↑ in H+ = ↓ Hb’s affinity for O2 = ↑ delivery of O2 to tissues

56
Q

CaO2 formula

A

(SO2 x Hb x 1.31) + (PO2 x 0.003)

57
Q

DO2 (oxygen delivery)=

A

=CaO2 x CO

58
Q

Ability to bind with CO2 is ___ in deoxygenated Hb

A

increased

59
Q

The presence of HB in normal arterial blood increase its oxygen concentration approx how many times?

A

70

60
Q

severe anemia with normal lugs, you’d expect

A

↓ oxygen concentration of mixed venous blood

61
Q

In carbon monoxide poisoning you’d expect

A
  • ↓ oxygen concentration of mixed venous blood because carbon monoxide has 250 X affinity for Hg
  • could have a normal SpO2 (just means Hb is saturated with x % of molecules, does not mean it’s oxygen)
62
Q

How much O2 is carried in the plasma?

A

0.003mL O2 per 100mL plasma*

3% in plasma
other 97% is carried via hemoglobin

63
Q

What is methemoglobinemia and is there an antidote?

A

Blood disorder where an abnormal amount of methemoglobin is produced and reduces Hg’s ability to release oxygen to tissues

Antidote= Methylene blue

64
Q

What causes methemoglobinemia?

A
  • Antibiotics: dapsone
  • Anesthetics: benzocaine, lidocaine, procaine, prilocaine
  • Analgesic: Tylenol
  • Antimalarials
  • Anticancer drugs
  • Nitroglycerin, nitroprusside

and more..

65
Q

Dissolved CO2 in plasma

A

0.76 mmol per 1L whole blood