Respiratory Physiology Exam 2/18/11

Front 1

What is the difference between gas exchange and breathing?

Back 1

gas exchange involves moving O2 into blood and CO2 out of blood, while breathing only refers to moving air in and out of the lung

Front 2

What are the requirements for good gas exchange?

Back 2

large volumes of gases and blood
limit space
reserve for exercise or fright
efficient for getting O2 to tissues so they can make energy
sterility - lung is the only organ in contact with the outside

Front 3

Where are alveoli located?

Back 3

ends of terminal bronchioles

Front 4

What is the site of gas exchange?

Back 4

alveolar-capillary membrane

Front 5

What can an alveoli be described as?

Back 5

small bubbles of air surrounded by tissue and blood

Front 6

Based on the Fick equation, what is Vgas directly proportional to?

Back 6

membrane area
diffusion constant
pressure gradient

Front 7

Based on the Fick equation, what is Vgas inversely proportional to?

Back 7

membrane thickness

Front 8

How does the size of the airway change as it branches?

Back 8

shorter, narrow, and more numerous

Front 9

How many alveoli are in a human lung?

Back 9

2^23 (>8,000,000)

Front 10

How does the amount of cartilage in the airway change as it approaches the lung?

Back 10

decreases

Front 11

How does the amount of smooth muscle in the airway change as it approached the lung?

Back 11

increases

Front 12

True or False: There is no cartilage in lungs?

Back 12

True

Front 13

How can asthma be treated?

Back 13

relaxing smooth muscle

Front 14

What happens in an asthma attack?

Back 14

A stimulus causes mast cell degranulation, which releases histamine and other substances that contract smooth muscle and secrete mucus. This causes decreased caliber and air flow, making it harder to breathe.

Front 15

Why does the respiratory zone appear pink in color?

Back 15

red blood cells

Front 16

What makes up the alveolar/capillary membrane?

Back 16

projection from an endothelial cell and a type I epithelial cell

Front 17

What is important about type I epithelial cells?

Back 17

make up part of the alveolar/capillary membrane

Front 18

What is important about type II epithelial cells?

Back 18

they are loaded with lipids that produce surfactant

Front 19

Which type of epithelial cells produce surfactant?

Back 19

type II - they begin to develop and mature at about 8 months of fetal life

Front 20

What is the diameter of a capillary?

Back 20

10 um

Front 21

Is pressure higher in the aorta or pulmonary artery?

Back 21

aorta

Front 22

Is pressure lower in the aorta or pulmonary artery?

Back 22

pulmonary artery

Front 23

What can high pressure in the pulmonary artery cause?

Back 23

physical damage and pulmonary edema

Front 24

Does the pulmonary artery contain oxygenated or deoxygenated blood?

Back 24

deoxygenated

Front 25

Does the pulmonary vein contain oxygenated or deoxygenated blood?

Back 25

oxygenated

Front 26

Is pulmonary circulation a high pressure or low pressure system?

Back 26

low pressure

Front 27

What can macrophages not kill or detoxify?

Back 27

HIV, TB, asbestos

Front 28

Where in the respiratory system are macrophages found?

Back 28

lungs (both zones)

Front 29

What is the top tacky layer of the mucocilliary escalator that contains antibodies and enzymes?

Back 29

gel layer

Front 30

What is the bottom watery, ciliated layer of the mucocilliary escalator?

Back 30

sol layer

Front 31

What does the gel layer of the mucocilliary contain?

Back 31

antibodies and enzymes

Front 32

What does the sol layer of the mucocilliary escalator contain?

Back 32

cilia

Front 33

What happens in cystic fibrosis?

Back 33

too much mucus

Front 34

What is Tidal Volume?

Back 34

air moved in a normal breath

Front 35

What is Vital Capacity?

Back 35

air moved in a maximum inspiration/expiration

Front 36

What is Total Lung Capacity?

Back 36

vital capacity + residual volume

Front 37

What is Functional Residual Volume?

Back 37

air remaining after a normal breath

Front 38

What is Residual Volume?

Back 38

air remaining after a maximum inspiration/expiration

Front 39

True or False: The lungs never completely empty.

Back 39

True

Front 40

What is the term for the air that is moved in a normal breath?

Back 40

Tidal Volume

Front 41

What is the term for the air that is moved in a maximum inspiration/expiration?

Back 41

Vital Capacity

Front 42

What is the term for the air remaining after a normal breath?

Back 42

Functional Residual Capacity

Front 43

What is the term for the air remaining after a maximum inspiration/expiration?

Back 43

Residual Volume

Front 44

What is the term for the air moved in a maximum inspiration/expiration PLUS the air remaining in the lung?

Back 44

Total Lung Capacity

Front 45

What is the normal tendency of the lungs?

Back 45

to collapse

Front 46

What is required for inspiration?

Back 46

contraction of the diaphragm to increase the volume of the chest cavity

Front 47

True of False: Lungs are not attached to the chest wall or diaphragm.

Back 47

True

Front 48

What is the intrapleural space?

Back 48

space between pleura and chest wall

Front 49

How does intrapleural pressure change when the chest expands and what is the result of this change?

Back 49

IPP becomes more negative, which creates pressure gradient from mouth to alveoli

Front 50

What is IPP when the chest expands?

Back 50

-15 cm H2O

Front 51

What is the pressure at the mouth?

Back 51

0 cm H2O

Front 52

What is the significance of functional reserve capacity (FRC)?

Back 52

keeps lung partially inflated so it's on the high compliance part of the V/P curve

Front 53

What is compliance?

Back 53

measure of the ability to deform a system (slope of tangent to V/P curve)

Front 54

What happens in emphysema?

Back 54

it's very easy to inflate lungs, but expiration is difficult

Front 55

At residual volume (RV), is compliance high or low?

Back 55

low

Front 56

At functional residual capacity (FRC), is compliance high or low?

Back 56

high

Front 57

After a normal inspiration, is compliance high or low?

Back 57

low

Front 58

What factors affect compliance?

Back 58

elastic recoil
surface tension

Front 59

In general, is pressure greater in a large bubble or a small bubble?

Back 59

small

Front 60

What is the La Place Law state?

Back 60

pressure is inversely proportional to radius

Front 61

In lungs, is pressure greater in a large bubble or a small bubble?

Back 61

large

Front 62

What is the driving force for air flow in a rigid tube?

Back 62

pressure gradient

Front 63

How is resistance related to radius?

Back 63

R is inversely proportional for r^4

Front 64

What factors affect resistance?

Back 64

smooth muscle (asthma/bronchi)
infections, mucus, foreign particles

Front 65

Describe CNS control regulating ventilation.

Back 65

poorly defined groups (no discrete nuclei) in pons and medulla regulate depth and frequency

Front 66

Is the response to CO2 or O2 more important in regulating ventilation?

Back 66

CO2

Front 67

Where are the two types of chemoreceptors located?

Back 67

central in pons and medulla
peripheral in aortic arch

Front 68

What do peripheral chemoreceptors sense and what do they do?

Back 68

sense increased pCO2, which lowers pH
cause increased ventilation

Front 69

Wheat do central chemoreceptors sense and what do they do?

Back 69

sense increased CO2
CO2 reacts with H2O to form H2CO3
carbonic acid separates to H+ and HCO3-

Front 70

What reaction is catalyzed by carbonic anhydrase?

Back 70

CO2 + H2O --> H2CO3

Front 71

True or False: H+ can cross the blood-brain barrier.

Back 71

False

Front 72

What is the CNS response to a blow to the head?

Back 72

- ventilation decreases, which causes increased pCO2 and [H+]
- chemoreceptors send positive signal to CNS, which leads to increased ventilation
- decreased pCO2 and [H+] causes chemoreceptors to send negative signal to CNS

Front 73

How can oxygen delivery be increased?

Back 73

increase cardiac output

Front 74

Normally, how long are RBCs in a capillary?

Back 74

0.75s

Front 75

Normally, how long does it take for a RBC to become fully saturated with oxygen?

Back 75

0.25s

Front 76

How is oxygen uptake changed during exercise?

Back 76

cardiac output is increased, so RBC transit time through capillaries decreases to 0.25s and RBCs are still fully saturated with oxygen

Front 77

Is carbon dioxide or oxygen more soluble, and how much more soluble is it?

Back 77

carbon dioxide 21x more soluble than oxygen

Front 78

How can you calculate the volume of each breath?

Back 78

volume in conducting zone + volume in respiratory zone

Front 79

How can you calculate tital volume?

Back 79

Vt = V(dead space) + V(alveolar)

Front 80

What is the % composition of O2 in air?

Back 80

21%

Front 81

What is partial pressure a function of?

Back 81

barometric pressure and % composition

Front 82

What is the atmospheric pressure at sea level?

Back 82

760 mm Hg

Front 83

How does an increase in pCO2 affect alveolar ventilation?

Back 83

decreases it

Front 84

How does an increase in alveolar ventilation affect arterial pCO2?

Back 84

decreases it

Front 85

What regulates arterial pO2?

Back 85

alveolar pCO2 regulates alveolar pO2, which regulates arterial pO2

Front 86

How do you calculate alveolar pO2?

Back 86

alveolar pO2 = PIO2 - (alveolar pCO2/RQ)
RQ = 0.8

Front 87

What is the vapor pressure of water?

Back 87

47 mm Hg

Front 88

What is PIO2 the same as?

Back 88

pO2 in conducting zone

Front 89

What is the value for PIO2 at sea level?

Back 89

150 mm Hg

Front 90

Is alveolar pO2 or alterial pO2 greater?

Back 90

alveolar pO2

Front 91

How does alveolar ventilation change as you move up the lung?

Back 91

decreases

Front 92

How does alveolar ventilation change as you move down the lung?

Back 92

increases

Front 93

How do you calculate pulmonary vascular resistance (PVR)?

Back 93

R = ΔP/V

Front 94

Does an increase in arterial/venous pressure cause an increase or decrease in pulmonary vascular resistance (PVR)?

Back 94

decrease

Front 95

Does an increase in arterial/venous pressure cause an increase or decrease in systemic vascular resistance (SVR)?

Back 95

increase

Front 96

What are the two mechmisms for dealing with increased vascular resistance?

Back 96

recruitment: all vessels are perfused
distension: vessels that were already being perfused are expanded

Front 97

How does blood flow volume change as you move up the lung?

Back 97

flow initially increases a little, then decreases

Front 98

What is blood flow proportional to?

Back 98

pulmonary arterial pressure - left atrial pressure

Front 99

How does pulmonary arterial pressure change as you move up the lung?

Back 99

decreases

Front 100

How does pulmonary arterial pressure change as you move down the lung?

Back 100

increases

Front 101

What happens in hypoxic vasoconstriction?

Back 101

local mediators cause local decrease in pO2, which leads to local constriction of smooth muscle in blood vessels

Front 102

How does pulmonary vascular resistance (PVR) change with a newborn?

Back 102

PVR initially high, alveolar pO2 change at first breath causes a decrease in PVR

Front 103

What percentage of total blood O2 is bound to hemoglobin?

Back 103

98%

Front 104

What percentage of total blood O2 is dissolved in plasma?

Back 104

2%

Front 105

True or False: O2 dissolves in plasma before entering red blood cells.

Back 105

True

Front 106

What does Henry's Law part I state?

Back 106

at equilibrium, partial pressure of a gas is the same as partial pressure of a liquid

Front 107

What does Henry's Law part 2 state?

Back 107

concentration is proportional to solubility constant and partial pressure

Front 108

True or False: O2 only binds to unreduced iron.

Back 108

False

Front 109

What is O2 binding capacity proportional to?

Back 109

[Hb]

Front 110

What is the normal concentration of hemoglobin?

Back 110

15 g Hb/100 ml blood

Front 111

What is the normal O2 binding capacity of hemoglobin?

Back 111

1.39 ml O2/g Hb

Front 112

What is the maximum bound O2 concentration in blood?

Back 112

20.8 ml O2/100 ml blood

Front 113

What is the actual bound O2 concentration in blood?

Back 113

20.2 ml O2/100 ml blood

Front 114

What is the normal concentration of dissolved oxygen in blood?

Back 114

0.3 ml/100 ml blood

Front 115

What is the normal total O2 concentration in blood?

Back 115

20.5 ml O2/100 ml blood

Front 116

How do you calculate how much O2 is delivered to tissues?

Back 116

total O2 concentration x cardiac output

Front 117

How much O2 is normally delivered to tissues per minute?

Back 117

2,050 ml O2/min

Front 118

In the "lung part" of the oxyhemoglobin dissociation curve, what do big changes in pO2 cause in [O2]?

Back 118

small changes in [O2]
this maximizes Hb loading with O2

Front 119

In the steep part of the oxyhemoglobin dissociation curve, what do big changes in [O2] cause in pO2?

Back 119

small changes in pO2

Front 120

The Bohr Effect describes changes in what?

Back 120

Hb affinity for O2

Front 121

In which direction does fetal hemoglobin shift the oxygen saturation curve?

Back 121

left

Front 122

Does carbon dioxide or oxygen bind more tightly to hemoglobin, and how much more tightly does it bind?

Back 122

carbon monoxide binds times more tightly than oxygen

Front 123

In which direction does carbon monoxide shift the oxygen saturation curve?

Back 123

down (makes person enemic)

Front 124

What percentage of expired CO2 is dissolved?

Back 124

5-10%

Front 125

What percentage of expired CO2 is in bicarbonate?

Back 125

60-70%

Front 126

What percentage of expired CO2 is in carbamino compunds?

Back 126

30%

Front 127

True or False: The CO2 concentration vs. pressure curve becomes saturated.

Back 127

False

Front 128

True or False: The O2 concentration vs. pressure curve becomes saturated.

Back 128

True

Front 129

Which organs regulate [HCO3]?

Back 129

kindeys

Front 130

Which organs regulate pCO2?

Back 130

lungs

Front 131

What is the pKa of carbonic acid?

Back 131

6.1

Front 132

What is the [HCO3-]/pCO2 ratio equal to when the pH is 7.4?

Back 132

20

Front 133

What is the Henderson-Hasselback equation?

Back 133

pH = pKa + log([HCO3-]/(.03 x pCO2))

Front 134

What is hypoxemia?

Back 134

decreased pO2 or decreased [O2] in blood

Front 135

How does the body compensate for hypoxia?

Back 135

increases cardiac output

Front 136

What are the mechanisms of hypoxemia?

Back 136

hypoventilation
diffusion defect
shunted blood
ventilation/perfusion mismatch

Front 137

How does hypoventilation affect alveolar pCO2?

Back 137

decreased alveolar ventilation increases arterial pCO2, which increases alveolar pOC2

Front 138

How does hypoventilation affect arterial pO2?

Back 138

decreased alveolar ventilation decreases alveolar pO2, which decreases arterial pO2

Front 139

Is arterial pCO2 directly or inversely proportional to alveolar ventilation?

Back 139

inversely proportional

Front 140

What conditions cause an increase in membrane thickness?

Back 140

fibrosis
edema

Front 141

What conditions cause a decrease in surface are of the membrane?

Back 141

cancer
infection
blood clot

Front 142

What conditions cause a decrease in pressure gradient?

Back 142

high altitude (P1 decreases)

Front 143

What is shunted blood?

Back 143

blood that does not contact air or deal with gas exchange

Front 144

What are the two types of shunts?

Back 144

anatomical - natural
physiological - bad, ex.) patent ductus arteriosis or foramen ovale

Front 145

What is the treatment for a physiological shunt defect?

Back 145

surgery

Front 146

What is the pO2 gradient from air to the mitochondria?

Back 146

160 mm Hg in air
5 mm Hg in mitochondria

Front 147

What is dye concentration equal to?

Back 147

O2 concentration in blood leaving the lungs (g/L)

Front 148

If alveolar ventilation is constant, what is dye concentration related to?

Back 148

inversely proportional to flow

Front 149

If flow is constant, what is dye concentration related to?

Back 149

directly proportional to ventilation

Front 150

If alveolar concentration and flow are variable, what is dye concentration proportional to?

Back 150

V/Q

Front 151

Is (Va/Q) ratio greater at the top of the lung or at the bottom, and how many times greater is it?

Back 151

3.5 times greater at the top of the lung than at the bottom

Front 152

Does flow increase or decrease as you move up the lung?

Back 152

decrease

Front 153

Is pO2 greater at the top of the lung or at the bottom?

Back 153

top

Front 154

Is pCO2 greater at the top of the lung or at the bottom?

Back 154

bottom

Front 155

What is the (Va/Q) ratio equal to when there is great gas exchange?

Back 155

1

Front 156

What is the (Va/Q) ratio equal to when there is no gas exchange?

Back 156

0

Front 157

What is the (Va/Q) ratio equal to when there is wasted ventilation?

Back 157

infinity

Front 158

True or False: Q can compensate for decreased alveolar ventilation.

Back 158

True, up to a point

Front 159

True of False: Alveolar ventilation can compensate for decreased flow.

Back 159

False

Front 160

What is O2 delivery equal to when (Va/Q) = 1?

Back 160

1,950 ml O2/min

Front 161

What is O2 delivery equal to when (Va/Q) = 0.1?

Back 161

1,650 ml O2/min

Front 162

What is O2 delivery equal to when (Va/Q) = 10?

Back 162

200 ml O2/min