gas exchange and acid base regulation Flashcards

1
Q

this law states that the rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of the gas and the difference in the partial pressure of the gas on the two sides of the tissue and is inversely proportional to the thickness

A

ricks law of diffusion

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2
Q

partial pressure can be determined by

A

the specific % of fractional content of the gas in the gas mixture x the absolute barometric pressure

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3
Q

the total pressure is equal to the sum of the arptial pressures of the gases is known as

A

Dalton’s law

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4
Q

air is composed of

A

oxygen, carbon diode and nitrogen

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5
Q

calculation of partial pressure

A

Pair = PO2 + PCO2 + PN2

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6
Q

T or F: when we say there is less oxygen at higher altitudes, what we really mean is that the air is less dense

A

true - the percentage of each gas is the same but the concentration of the gases is less

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7
Q

what happens if another gas was added to the atmosphere?

A

the absolute barometric pressure would not change - the partial pressure of each gas would decrease but the absolute barometric pressure would not change

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8
Q

The rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of the gas, and the difference in the partial pressure of the gas on the two sides of the tissue, and inversely proportional to the thickness.

A

ricks law of diffusion

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9
Q

v gas =

A

rate of diffusion

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10
Q

v gas =

A

A/T x D x (change of P)

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11
Q

a ]

A

tissue area

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12
Q

T =

A

tissue thickness

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13
Q

D=

A

diffusion coefficient of gas

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14
Q

P1 - P2 =

A

difference in partial pressure

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15
Q

the rate of diffusion of O2 and CO2 is proportional to the

A

pressure gradient, surface area

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16
Q

diffusion constant relationship is inversely proportional to the

A

thickness of the membrane

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17
Q

the diffusion constant is influenced by the

A

solubility of the gas

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18
Q

the greater the solubility of a gas, what happens to the pressure gradient?

A

the lower the pressure gradient needed for the gas to diffuse across a membrane

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19
Q

T or F: the membrane solubility of CO2 is 20x greater than O2

A

true

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20
Q

T or F: the pressure gradient needed for CO2 is much less than the pressure gradient needed for O2 to diffuse across the respiratory membrane

A

true

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21
Q

blood flow to the lungs is described in terms of

A

zones

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22
Q

zone 1

A

capillary pressure < alveolar pressure

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23
Q

zone 2

A

capillary pressure is intermittently > alveolar pressure

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24
Q

zone 3

A

capillary pressures is > alveolar pressure

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25
Q

pressure in the capillaries is affected by

A

hydrostatic pressure

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26
Q

pulmonary circuit

A

-same rate of flow as systemic circuit
-lower pressure

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27
Q

ventilation/perfusion ration (V/Q)

A

-indicates matching of blood flow to ventilation
- ideal = 1.0 or above if blood flow is high

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28
Q

apex of lung (standing at rest)

A
  • under perfused (V/Q ratio >1.0)
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29
Q

base of lung (standing rest)

A
  • overperfused (V/Q ration < 1)
    -gravitational force
  • zone 3
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30
Q

during upright exercise, blood flow will?

A

increase to top of lung (apex)

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31
Q

light to moderate exercise will _____ V/Q ration

A

improve

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32
Q

exercise converts all areas of the lungs to zone

A

zone 3 perfusion

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33
Q

heavy exercise may result in V/q

A

inequality

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34
Q

each gram of hemoblgobbin binds to

A

four 4 molelecues of oxygen

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35
Q

what happens to O2 transport in the blood

A
  • bounds to hemoglobin >98% of total
  • dissolved in the blood. < 2% of total
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36
Q

binds how many O2 molecule per heme group

A

1

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37
Q

___ hemp groups per Hb

A

4

38
Q

Ox + Hb <–>

A

HbO2

39
Q

normal Hb concentrations for men and women

A

14-18 g/100ml blood
12-16 g/100ml blood

40
Q

oxyhemoblobin

A

Hb bound to O2

41
Q

Deoxyhemoglobin

A

Hb not bound to O2

42
Q

each gram of Hb has the capacity to bind how many O2 molecules

A

4 O2 molecules

43
Q

when full saturated )o is

A

1.34 mL O2

44
Q

content of O2 in the blood depends on

A
  • amount of Hb in the blood
  • amount of O2 bounds to Hb
45
Q

low grams of O2 could result

A

shortness of breath

46
Q

CO2 transport in the blood by

A
  • dissolved in plasma (10%)
  • bound to Hb (20%)
  • Bicarbonate (70%)
47
Q

CO2 has a greater solulbity than Oz leading to

A

greater transport by this mechanism

48
Q

hemoglobin + CO2 =

A

carbaminohemoglobin

49
Q

Binding of carbaminohemoglobin depends on

A

PO2

50
Q

Tor F: when PO2 is low, the affinity of CO2 for Hb is high

A

true

51
Q

muscle bicarbonate ions -

A

CO2 + H2O –> Carbonic anhydrase -> carbonic acid -> Hydrogenn ion + Bicarbonate

52
Q

gas transport key points

A
  • O2 is transported in the blood primarily bound to Hb
  • Hb unloading of O2 in tissues is enhanced by: decrease PO2, decreased pH, increased temp
53
Q

CO2 is primarily transported as

A

bicarbonate ion in the blood

54
Q

key point - - Hb is 98% saturated with oxygen, and O2 carrying capacity typically does not limit performance: true or false

A

true

55
Q

direction of reactions for oxyhemoglobin dissociation curve depends on

A
  • PO2 of the blood
  • affinity between Hb and O2
56
Q

At the the lung, High PO2 results

A

formation of oxyhemoglobin

57
Q

at the tissues, low PO2 results in

A

release of O2 to tissues

58
Q

what does steep decline in Hb-O2 from PO2 of 40 to 0 mmHg indicate

A

this all unloading of O2 to working tissues

59
Q

indication of the flat portion of the curve from a Po2 of 90 - 100 mmHg

A

serves as a buffer

60
Q

A decrease in blood pH (increased acidity) results a

A

decreased bond between O2 and Hb

61
Q

three factors effect on O2-Hb dissociation curve?

A

pH level, temp, 2-3 DPG

62
Q

AS pH decreases

A

affinity of O2 for Hb decrease
(bohr effect)

63
Q

Affinity of )2 for Hb decreases causes

A
  • increases unloading of O2
  • rightward shift in the oxyhemoglobin curve
64
Q

as temperature increases

A

affinity of O2 for Hb decreases

65
Q

as 2,3 DPG increases

A

affinity of O2 for Hb decreases

66
Q

decrease of pH causes a right shift of the

A

oxygen hemoglobin dissociation curve

67
Q

increase temp cause a right shift to the

A

oxygen hemoglobin dissociation curve

68
Q

myoglobin (Mb) serves as

A

an O2 binding protein in skeletal muscle

69
Q

Myoglobin shuttles

A

O2 from the cell membrane to the mitochondria

70
Q

Mb has a higher affinity of O2 than hemoglobin

A
  • binds O2 at very Low PO2
  • allows Mb to store O2
  • O2 reseve for muscle
  • Buffers muscle O2 needs at onset of exercise until cardiopulmonary system increases O2 delivery to muscle
71
Q

lactic acid is a strong

A

acid

72
Q

bicarbonate is a strong

A

base

73
Q

lower than 7.4 pH is

A

acidosis

74
Q

higher than 7.4 pH is

A

alkalosis

75
Q

how do you lose acid

A

vomitting

76
Q

increase of concentration of H+ would decreas pH =

A

acidosis

77
Q

decrease concentration of H+ would increase pH =

A

alkalosis

78
Q

loss of acids and accumulation of bases =

A

decrease concentration of hydrogen ions

79
Q

production of carbon dioxide

A
  • end product of oxidative phosphorylation
  • CO2 + H2) <-> H+ + HCO3
80
Q

production of lactic acid

A

glucose metabolism via glycolysis

81
Q

Sources of H+ - ATP breakdown during muscle contraction

A
  • results in release of H+
  • ATP + H2) <-> ADP + HPO4 + H+
82
Q

high intensity exercise results in production of lactic and

A

increased hydrogen ions in muscle fibers and blood

83
Q

increased hydrogen ions can impair performance by

A
  • inhibits glycolytic and TCA enzyme activity (ATP production)
  • H+ can impairs muscle contraction by competing with Ca+2 for binding sites on troponin
84
Q

release H+ ions when

A

pH is high

85
Q

Accept H+ ions when

A

pH is low

86
Q

intracellular buffers

A
  • carnosine (histidine-dipeptides0
    -proteins
    -phosphate groups
  • bicarbonate
87
Q

extracellular buffers

A
  • bicarbonate
  • hemoglobin
  • blood proteins
88
Q

major extracellular buffers

A

bicarbonate

89
Q

which have a higher buffering capacity? type 1 or type 2

A

type 2 have a higher buffering capacity - they are producing more

90
Q

how does high intensity exercise improves muscle buffering capacity ?

A

increases of carnosine and hydrogen ion transporters in the trained muscle fibers

91
Q

carbonic acid dissociation equation

A

CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3−.

92
Q

when Ph decreases H+ increase. therefore, the reaction moves?
- what is removed?
- what is eliminated?
- what happens to pH?

A
  • reaction moves to the left
  • CO2 is removed by the lungs
  • Eliminating H
  • increasing pH