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Respiratory - Physiology Flashcards

1
Q

What are the effects of surfactant secretion in the lungs?

A

Decreased alveolar surface tension, increased compliance, and decreased work of inspiration

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2
Q

Name five important molecules produced by the lungs.

A

Surfactant, prostaglandins, histamine, angiotensin-converting enzyme, and kallikrein

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3
Q

In addition to inactivating bradykinin, what other reaction does angiotensin-converting enzyme catalyze?

A

The conversion of angiotensin I to angiotensin II

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4
Q

Angiotensin-converting enzyme inhibitors increase bradykinin, which leads to which two common adverse effects?

A

Cough and angioedema

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5
Q

A deficiency of surfactant leads to what neonatal condition?

A

Respiratory distress syndrome

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6
Q

Give the equation for calculating collapsing pressure.

A

Collapsing pressure = 2 × tension / radius

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7
Q

What is the effect of histamine on the airways in the lung?

A

Increases bronchoconstriction

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8
Q

In the lung, _____ (angiotensin-converting enzyme/kallikrein) inactivates bradykinin, _____ (angiotensin-converting enzyme/kallikrein) activates bradykinin.

A

Angiotensive converting enzyme; kallikrein

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9
Q

What is the term for the volume of air in the lungs after maximal expiration?

A

Residual volume

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10
Q

What is the term for the volume of air that can still be breathed out after normal expiration?

A

Expiratory reserve volume

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11
Q

What is the term for the volume of air that moves into the lungs with each quiet inspiration?

A

Tidal volume

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12
Q

How much is the typical tidal volume?

A

500 mL

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13
Q

What is the term for the volume of air in excess of tidal volume that moves into the lung on maximum inspiration?

A

Inspiratory reserve volume

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14
Q

What is the term for the maximum volume of air that can be inhaled and exhaled?

A

Vital capacity

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15
Q

Vital capacity equals the sum of what three lung volumes?

A

Tidal volume, inspiratory reserve volume, and expiratory reserve volume

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16
Q

The residual volume plus the expiratory reserve volume equals what?

A

The functional reserve capacity

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17
Q

Describe the functional reserve capacity.

A

The volume left in the lungs after normal expiration

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18
Q

The inspiratory reserve volume plus the tidal volume equals what?

A

Inspiratory capacity

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19
Q

The inspiratory reserve volume plus the tidal volume plus the expiratory reserve volume plus the residual volume equals what?

A

Total lung capacity

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20
Q

What is the term for the lung volume that includes all capacity except the residual volume?

A

Vital capacity

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21
Q

Which lung volume cannot be measured on spirometry: inspiratory reserve volume, tidal volume, expiratory reserve volume, or residual volume?

A

Residual volume

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22
Q

What is the formula for calculating dead space volume given an arterial blood gas and a measurement of exhaled carbon dioxide?

A

Dead space volume = tidal volume × [(partial arterial pressure of carbon dioxide - partial expiratory pressure of carbon dioxide) / partial arterial pressure of carbon dioxide]

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23
Q

Physiological dead space includes the anatomical dead space of the _____ (conducting/respiratory) airways plus the functional dead space in _____ (alveoli/bronchioles).

A

Conducting; alveoli

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24
Q

Which section of the healthy lung contributes more to functional dead space: the apex or the base?

A

The apex

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25
Q

Describe the natural tendency of movement of the lung and chest wall.

A

The lungs tend to collapse inward and chest wall springs outward

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26
Q

At the point of functional residual capacity (i.e., at the end of a normal expiration), what is the value of the air pressure within the lungs?

A

At functional residual capacity, the pressure within the lungs is equal to atmospheric pressure

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27
Q

What balances the inward elastic pull of the lung at the point of functional residual capacity (i.e. at the end of a normal expiration)?

A

The outward pull of the chest wall

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28
Q

How many polypeptide subunits make up hemoglobin?

A

Four

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29
Q

Adult hemoglobin is formed from two _____ subunits and two _____ subunits.

A

α; β

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30
Q

What are the two conformational forms of hemoglobin?

A

Relaxed and taut

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31
Q

Which form of hemoglobin has a low affinity for oxygen, relaxed or taut?

A

Taut

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32
Q

Which form of hemoglobin has a high affinity for oxygen, relaxed or taut?

A

Relaxed

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33
Q

Fetal hemoglobin is composed of two ____ subunits and two ____ subunits.

A

α; γ

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34
Q

Does hemoglobin have positive or negative cooperativity with respect to oxygen binding and affinity?

A

Positive; the more oxygen molecules bind, the more affinity hemoglobin has for additional oxygen molecules

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35
Q

Does fetal hemoglobin have a higher or lower affinity for oxygen compared with adult hemoglobin?

A

Higher; as a result, fetal blood can draw oxygen across the placenta

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36
Q

Does fetal hemoglobin have a higher or lower affinity for 2,3-biphosphoglycerate compared with adult hemoglobin and what is the result?

A

Lower; increased affinity for oxygen

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37
Q

An increase in which five factors will favor the taut form of hemoglobin over the relaxed form and decrease affinity for oxygen?

A

Chloride, hydron, carbon dioxide, 2,3-bisphosphoglycerate, and temperature

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38
Q

Which form of hemoglobin will lead to decreased oxygen unloading?

A

The relaxed form (remember: “When you’re Relaxed, you do your job better [carry oxygen]”)

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39
Q

With respect to cooperativity and affinity for oxygen, what are the differences between hemoglobin and myoglobin?

A

Myoglobin has high affinity for oxygen but does not display cooperativity of oxygen binding because it has only a single subunit

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40
Q

Does hemoglobin contain iron in the oxidized state or in the reduced state; Fe2+ or Fe3+; ferric iron or ferrous iron?

A

The reduced state; Fe2+; ferrous iron

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41
Q

Does methemoglobin contain iron in the oxidized state or the reduced state; Fe2+ or Fe3+; ferric iron or ferrous iron?

A

The oxidized state; Fe3+; ferric iron

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42
Q

Hemoglobin contains _____ (ferric/ferrous) iron, whereas methemoglobin contains _____ (ferric/ferrous) iron.

A

Ferrous; ferric

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43
Q

What are the mechanisms of action of nitrites and thiosulfate in the treatment of cyanide poisoning?

A

Nitrites oxidize the iron in hemoglobin to form methemoglobin; methemoglobin then binds to cyanide ions, which in turn allows cytochrome oxidase to function; after administering nitrites, thiosulfate is used to bind to the cyanide-methemoglobin complexes, to form thiocyanate, which is renally excreted

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44
Q

When another molecule, such as CO, binds to hemoglobin in place of oxygen, what are the systemic effects?

A

This leads to tissue hypoxia from decreased oxygen saturation and decreased oxygen content in the blood

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45
Q

Which has a higher affinity for oxygen, hemoglobin or methemoglobin?

A

Hemoglobin

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46
Q

What is the treatment for toxic levels of methemoglobin?

A

Methylene blue (remember: METHemoglobinemia can be treated with METHylene blue)

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47
Q

Which has a higher affinity for cyanide, hemoglobin or methemoglobin?

A

Methemoglobin

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48
Q

What is the name of a form of hemoglobin in which carbon monoxide is bound instead of oxygen?

A

Carboxyhemoglobin

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49
Q

In treating cyanide poisoning, ______ is the compound used to bind cyanide, forming _____ which is a renally excretable compound.

A

Thiosulfate; thiocyanate

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50
Q

What is the treatment for cyanide poisoning?

A

Nitrites, and subsequently thiosulfate

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51
Q

Does carbon monoxide or oxygen have a greater affinity for hemoglobin?

A

Carbon monoxide has 200 times the affinity of oxygen

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52
Q

What is the shape of the oxygen-hemoglobin dissociation curve?

A

Sigmoidal

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53
Q

When the oxygen-hemoglobin dissociation curve shifts to the right, what happens to the affinity of hemoglobin for oxygen?

A

A right shift decreases the affinity of hemoglobin for oxygen

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54
Q

When the oxygen-hemoglobin dissociation curve shifts to the right, what happens to the P50?

A

A right shift increases the P50, indicating that higher oxygen pressure is required to saturate hemoglobin

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55
Q

A shift of the oxygen-hemoglobin dissociation curve to the right facilitates what process in tissue?

A

The unloading of oxygen to tissue

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56
Q

When the oxygen-hemoglobin dissociation curve shifts to the left, what happens to the affinity of hemoglobin for oxygen?

A

A left shift increases the affinity of hemoglobin for oxygen

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57
Q

When the oxygen-hemoglobin dissociation curve shifts to the left, what happens to the P50?

A

A left shift decreases the P50; hemoglobin is saturated at lower pressures of oxygen

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58
Q

A decrease in the partial pressure of carbon dioxide causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Left

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59
Q

A decrease in temperature causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Left

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60
Q

A decrease in pH causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Right

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61
Q

A decrease in 2,3-diphosphoglycerate causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Left

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62
Q

The oxygen-hemoglobin dissociation curve for fetal hemoglobin is shifted in what direction?

A

Left; fetal hemoglobin has higher affinity for oxygen than adult hemoglobin

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63
Q

An increase in the partial pressure of carbon dioxide causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Right

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64
Q

An increase in temperature causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Right

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65
Q

An increase in pH causes a ______ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Left

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66
Q

High altitude induces what change in the oxygen-hemoglobin dissociation curve?

A

A right shift

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67
Q

An increase in 2,3-diphosphoglycerate causes a _____ (left/right) shift in the oxygen-hemoglobin dissociation curve.

A

Right

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68
Q

In the oxygen-hemoglobin dissociation curve, what values are represented by the x and y axes?

A

The partial pressure of oxygen represents the x axis, while hemoglobin saturation represents the y-axis

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69
Q

Hemoglobin can bind four oxygen molecules and has a higher affinity for each subsequent oxygen molecule bound. What is the term for this phenomenon?

A

Positive cooperativity

70
Q

An increase in the amounts of which six factors causes a right shift of the oxygen-hemoglobin dissociation curve?

A

CO2, hydrogen ions (therefore acidity), altitude, 2,3-DPG, metabolic needs (eg, exercise), and temperature

(remember: CADET face right: CO2, Acid/Altitude, DPG [2,3-DPG], Exercise, Temperature)

71
Q

Normally, pulmonary circulation is a _____ (high/low) resistance, _____ (high/low) compliance system.

A

Low; high

72
Q

Within the lungs, a decrease in the partial pressure of oxygen in arterial blood causes what process to occur within the vasculature in the area?

A

Hypoxic vasoconstriction; in the rest of the body hypoxia causes vasodilation

73
Q

Within the lungs, hypoxic vasoconstriction serves what physiologic function?

A

It shifts blood away from the poorly ventilated regions of the lung to the well-ventilated regions of the lung

74
Q

Under normal, healthy conditions, is oxygen a perfusion-limited gas or a diffusion-limited gas?

A

Perfusion-limited gas

75
Q

Is carbon dioxide a perfusion-limited gas or a diffusion-limited gas?

A

Perfusion-limited gas

76
Q

Is nitrous oxide a perfusion-limited gas or a diffusion-limited gas?

A

Perfusion-limited gas

77
Q

Is carbon monoxide a perfusion-limited gas or a diffusion-limited gas?

A

Diffusion-limited gas

78
Q

Under conditions of strenuous exercise, is oxygen a perfusion-limited gas or a diffusion-limited gas?

A

Diffusion-limited gas

79
Q

Under perfusion-limited conditions, where along the length of the pulmonary capillary do the partial pressures of a gas equilibrate?

A

Early; gas exchange is not limited by its ability to cross the membrane, only by the supply of blood

80
Q

Under perfusion-limited conditions, how can gas exchange be increased?

A

By increasing blood flow

81
Q

Under what three conditions is oxygen a diffusion-limited gas?

A

Exercise, emphysema, and fibrosis

82
Q

Under diffusion-limited conditions, where along the length of the pulmonary capillary does the gas equilibrate?

A

It does not equilibrate; the characteristics of the gas cause it to diffuse slowly across the alveolar membrane

83
Q

What are the cardiac complications of pulmonary hypertension?

A

Cor pulmonale and right ventricular failure

84
Q

What are three signs of right ventricular heart failure due to cor pulmonale?

A

Jugular venous distention, edema, and hepatomegaly

85
Q

What is the equation for diffusion of a gas across a membrane?

A

Vgas = A/T × Dk(P1- P2), where A = area, T = thickness, and Dk(P1 - P2) = difference in partial pressures

86
Q

In the equation for gas diffusion, which variable is affected by emphysema and how?

A

Area of membranes available for gas transfer is decreased in emphysema, causing a decrease in diffusion

87
Q

In the equation for gas diffusion, which variable is affected by pulmonary fibrosis and how?

A

Thickness of the membrane is increased in pulmonary fibrosis, causing a decrease in diffusion

88
Q

What is normal pulmonary arterial pressure?

A

10-14 mm Hg

89
Q

What pulmonary artery pressures define pulmonary hypertension?

A

25 mm Hg or greater during rest and >35 mm Hg during exercise

90
Q

Primary pulmonary hypertension is caused by what?

A

An inactivating mutation in the BMPR2 gene, which normally functions to inhibit vascular smooth muscle proliferation

91
Q

What is the prognosis for a patient diagnosed with primary pulmonary hypertension?

A

Very poor; the disease is progressive and fatal

92
Q

What are some of the potential causes of secondary pulmonary hypertension?

A

Chronic obstructive pulmonary disease, left-to-right shunt, mitral stenosis, recurrent thromboemboli, autoimmune disease (ie, systemic sclerosis), sleep apnea, or living at high altitudes

93
Q

What are three pathological changes in the vasculature are caused by pulmonary hypertension?

A

Atherosclerosis, medial hypertrophy, and intimal fibrosis of the pulmonary arteries

94
Q

How does chronic obstructive pulmonary disease cause pulmonary hypertension?

A

By the destruction of lung parenchyma and subsequent vasoconstriction due to hypoxia

95
Q

How does mitral stenosis cause pulmonary hypertension?

A

By increasing resistance to blood flow in the left heart; thus causing a build-up of pressure starting in the left atrium and backing up to the pulmonary vasculature

96
Q

How do recurrent thromboemboli cause pulmonary hypertension?

A

By decreasing the total cross-sectional area of the pulmonary vascular bed

97
Q

How can autoimmune disease cause pulmonary hypertension?

A

Processes such as systemic sclerosis lead to inflammation, then to intimal fibrosis, which in turn leads to medial hypertrophy in the pulmonary vasculature

98
Q

How does left-to-right shunt cause pulmonary hypertension?

A

By causing increased shear stress (due to increased blood volume in the pulmonary vasculature) and thus endothelial injury

99
Q

How do sleep apnea or living at high altitudes cause pulmonary hypertension?

A

Sleep apnea and living at high altitudes cause hypoxia, which in turn causes pulmonary vasoconstriction

100
Q

What are the sequelae of pulmonary hypertension if left untreated?

A

Severe respiratory distress, causing right ventricular hypertrophy and cyanosis . This results in decompensated cor pulmonale which leads to death

101
Q

How is pulmonary vascular resistance calculated?

A

Pulmonary vascular resistance = (pressure in the pulmonary artery minus pressure in the left atrium) divided by the cardiac output

102
Q

How is left atrial pressure measured?

A

It is approximated by wedge pressure

103
Q

Pulmonary vascular resistance is _____ (directly/inversely) related to vessel length and _____ (directly/inversely) related to vessel radius.

A

Directly; inversely

104
Q

What is the equation for resistance, given vessel length, diameter, and blood viscosity?

A

R = (8ηl) / (πr4), where η = viscosity of blood, l = vessel length, and r = vessel radius

105
Q

How is the oxygen content of the blood calculated?

A

Oxygen content of the blood = (oxygen-binding capacity × percent saturation) + dissolved oxygen

106
Q

How much oxygen can 1 g of hemoglobin bind?

A

1.34 mL

107
Q

What is the average amount of hemoglobin in normal blood?

A

Approximately 15 g/dL

108
Q

What is the normal oxygen-binding capacity of the blood?

A

Approximately 20.1 mL oxygen/dL of blood

109
Q

When the hemoglobin level rises, the oxygen content of the blood _____ (rises/falls).

A

Rises, because oxygen-binding capacity depends on the total amount of hemoglobin

110
Q

When the hemoglobin level falls, the percent oxygen saturation of the blood ______ (rises/falls/remains stable).

A

Remains stable; the blood can still be 100% saturated but there will be less oxygen-binding capacity and therefore lower total oxygen content

111
Q

A decrease in hemoglobin will have what effect on partial oxygen pressure: decrease, increase, or no change?

A

No change

112
Q

Visible cyanosis typically results when deoxygenated hemoglobin is at what level?

A

> 5 g/dL

113
Q

Why does arterial partial pressure of oxygen decrease with chronic lung disease?

A

Physiologic shunt decreases the oxygen extraction ratio

114
Q

What is the formula for oxygen delivery to tissues?

A

Oxygen delivery to tissues = cardiac output × oxygen content of blood

115
Q

Will a patient with anemia become cyanotic at a higher or lower oxygen saturation than a normal patient?

A

An anemic patient will have a lower oxygen saturation by the time she appears cyanotic; the blue coloration of cyanosis is proportional to the concentration of deoxyhemoglobin, which is lower in anemic patients (as are the concentrations of all types of hemoglobin)

116
Q

What is the alveolar gas equation?

A

Alveolar partial pressure of oxygen (in mm Hg) = the partial pressure of oxygen in inspired air minus (alveolar partial carbon dioxide pressure divided by the respiratory quotient); or, PAO2 = PIO2 - (PACO2/R)

117
Q

How can the alveolar gas equation be simplified and approximated (assuming that the patient is breathing ambient air)?

A

Alveolar partial pressure of oxygen = 150 - (arterial partial pressure of carbon dioxide / 0.8)

118
Q

By using the alveolar gas equation, what important measure of pulmonary function can be determined?

A

The alveolar-arterial gradient (the A-a gradient)

119
Q

What is the normal alveolar-arterial gradient?

A

10-15 mmHg

120
Q

What three pathological processes can lead to increased A-a gradient?

A

Shunting, ventilation/perfusion mismatch, and fibrosis of the lungs

121
Q

Name five processes that can lead to hypoxemia (ie, decreased arterial oxygen).

A

High altitude, hypoventilation, ventilation/perfusion mismatch, diffusion limitation, and right-to-left shunt

122
Q

Name five processes that can lead to hypoxia (ie, decreased oxygen delivery to tissue).

A

Decreased cardiac output, hypoxemia, anemia, cyanide poisoning, and carbon monoxide poisoning

123
Q

Name two processes that can lead to ischemia (i.e. loss of blood flow).

A

Impeded arterial flow, and reduced venous drainage

124
Q

What is the difference between hypoxemia and hypoxia?

A

Hypoxemia refers to decreased arterial partial pressure of oxygen and can lead to hypoxia, which is defined as decreased oxygen delivery to tissue

125
Q

Which 2 processes lead to hypoxemia with a normal A-a gradient?

A

High altitude and hypoventilation

126
Q

Which 3 processes can lead to hypoxemia with an increased A-a gradient?

A

Ventilation/perfusion mismatch, diffusion limitation, and right-to-left shunt

127
Q

What is the ideal ratio of ventilation to perfusion to maximize gas exchange?

A

1 to 1

128
Q

Within what part of the lung does ventilation/perfusion equal approximately 3?

A

The apex of the lung

129
Q

In the apex of the lung, there is wasted _____ (perfusion/ventilation).

A

Ventilation

130
Q

Within what part of the lung does ventilation/perfusion equal approximately 0.6?

A

The base of the lung

131
Q

In the base of the lung, there is wasted _____ (perfusion/ventilation).

A

Perfusion

132
Q

Is ventilation greater at the base of the lung or the apex of the lung?

A

The base of the lung

133
Q

Is perfusion greater at the base of the lung or the apex of the lung?

A

The base of the lung

134
Q

The vasodilation of the apical capillaries of the lung that occurs with exercise results in what change to the ventilation/perfusion ratio?

A

The ventilation/perfusion ratio approaches 1, maximizing gas exchange to meet the metabolic demands of exercise

135
Q

Microorganisms that thrive in high-oxygen environments, such as tuberculosis, flourish in which part of the lungs?

A

The apex

136
Q

A ventilation/perfusion ratio that approaches 0 for a given area of lung indicates that what is occurring in that area?

A

Airway obstruction, creating a shunt of blood flow that does not participate in gas exchange

137
Q

What is the name for the process whereby airway obstruction leads to perfusion with no ventilation within an area of the lungs?

A

Shunt

138
Q

A ventilation/perfusion ratio that approaches infinity for a given area of lung indicates that what is occurring in that area?

A

Blood flow obstruction (ie, pulmonary embolus)

139
Q

When blood flow (but not airflow) into an area of the lungs is obstructed such that the ventilation/perfusion ratio approaches infinity, the area can be considered what type of space?

A

Physiologic dead space

140
Q

Which zone of the lung is associated with wasted ventilation?

A

Zone 1

141
Q

Which zone of the lung is associated with wasted perfusion?

A

Zone 3

142
Q

In hypoxia due to _____ (dead space/shunting), 100% oxygen does not improve the partial pressure of oxygen in the blood; while in hypoxia due to increased _____ (dead space/shunting), there is an improvement in the partial pressure of oxygen in the blood.

A

Shunting; dead space

143
Q

In the lung apex (zone 1), arrange the following in order of increasing pressure: artery, vein, alveolus.

A

Vein < artery< alveolus

144
Q

In zone 2 of the lung, arrange the following in order of increasing pressure: artery, vein , alveolus.

A

Vein < alveolus < artery

145
Q

In the lung base (zone 3), arrange the following in order of increasing pressure: artery, vein, alveolus.

A

Alveolus < vein < artery

146
Q

What process causes the ventilation at the apex of the lungs to be considered “wasted?”

A

The high alveolar pressure at the apex causes compression of the capillaries, and thus an inability to undertake gas exchange with the blood vessels

147
Q

In which forms is carbon dioxide transported from the tissues to the lungs?

A

Three forms: (1) as bicarbonate, (2) bound to hemoglobin as carbaminohemoglobin, and (3) dissolved

148
Q

Ninety percent of the carbon dioxide transported from the tissues to the lungs is in what form?

A

Bicarbonate, the creation of which is catalyzed by carbonic anhydrase

149
Q

Other than as bicarbonate, in what two other ways is carbon dioxide transported from the tissues to the lungs?

A

Bound to hemoglobin as carbaminohemoglobin and dissolved in blood

150
Q

What percentage of carbon dioxide gets transported from the tissues to the lungs as carbaminohemoglobin; as dissolved carbon dioxide?

A

Approximately 5%; approximately 5%

151
Q

After it is inside a red blood cell, each carbon dioxide molecule combines with which molecule in a reaction catalyzed by carbonic anhydrase?

A

Water

152
Q

What enzyme catalyzes the conversion of carbon dioxide and water into carbonic acid?

A

Carbonic anhydrase

153
Q

Within a red blood cell, the carbonic acid formed from the combination of carbon dioxide and water dissociates into what two compounds?

A

Hydrogen and bicarbonate ions

154
Q

What is the fate of the bicarbonate that results from the deprotonation of carbonic acid within an red blood cell?

A

It gets exchanged out of the red blood cell for a chloride molecule that enters the red blood cell

155
Q

In the lungs, the oxygenation of hemoglobin promotes what?

A

The dissociation of a proton from hemoglobin and therefore a decrease in pH, which favors formation of carbon dioxide from bicarbonate

156
Q

What is the name for the effect in which the oxygenation of hemoglobin within the lungs promotes the dissociation of carbon dioxide from hemoglobin?

A

The Haldane effect

157
Q

Regarding carbon dioxide transport, in which direction will the lower pH of peripheral tissues (compared to the lungs) shift the oxygen dissociation curve?

A

To the right, favoring dissociation of oxygen from hemoglobin

158
Q

In peripheral tissues, the right shift of the oxygen dissociation curve that results from decreased pH causes an unloading of oxygen. What is this effect called?

A

The Bohr effect

159
Q

What happens to ventilation as a response to high altitude in acute situations; chronic situations?

A

Ventilation is increased in both cases

160
Q

What happens to erythropoietin levels as a response to high altitude?

A

Erythropoietin levels are increased as are hematocrit and hemoglobin

161
Q

What happens to the level of 2,3-diphosphoglycerate in response to high altitude?

A

The 2,3-diphosphoglycerate level increases

162
Q

What substance binds to hemoglobin so that hemoglobin releases more oxygen as a physiologic response to high altitude?

A

2,3-Diphosphoglycerate; increased concentrations shift the hemoglobin dissociation curve to the right

163
Q

What cellular changes occur in response to high altitude?

A

There is an increase in mitochondria

164
Q

Increased renal excretion of what substance occurs in response to high altitude?

A

Bicarbonate

165
Q

The increased renal excretion of bicarbonate that is seen in response to high altitude compensates for what?

A

The respiratory alkalosis that occurs as a result of increased ventilation

166
Q

The increased renal excretion of bicarbonate that is seen in response to high altitude can be augmented using what?

A

Acetazolamide; the drug is a carbonic anhydrase inhibitor that makes the urine more basic

167
Q

In response to high altitude, chronic hypoxic pulmonary vasoconstriction results in what condition?

A

Right ventricular hypertrophy

168
Q

As a result of exercise, what happens to carbon dioxide production in muscles; oxygen consumption?

A

Both are increased

169
Q

What happens to the V/Q ratio as a response to exercise?

A

It becomes more uniform from apex to base; hence gas exchange is more efficient

170
Q

What happens to pulmonary blood flow as a response to exercise?

A

It increases due to increased cardiac output

171
Q

How does the pH of the body change during strenuous exercise?

A

pH decreases during strenuous exercise due to lactic acidosis

172
Q

PaO2 and PaCO2_____ (increase/decrease/remain stable) in response to exercise, whereas venous CO2 content _____ (increases/decreases/remains stable).

A

PaO2 and PaCO2do not change in response to exercise but venous CO2content increases

piggy (83 decks)

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