Crr Week 1: Respiratory Physiology I

Front 1

Which portions of the respiratory system do not contain ciliated cells?

Back 1

Alveolar ducts and alveolar sacs

Front 2

Which portion(s) of the respiratory system do not contain smooth muscle?

Back 2

Alveolar sacs

Front 3

Which portion(s) of the respiratory system contain cartilage?

Back 3

Only the trachea and bronchi

Front 4

Which anatomical structures comprise the "conducting zone"?

Back 4

Structures from the nose to the terminal bronchioles
(nose, nasopharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles)

Front 5

What type of sympathetic and parasympathetic receptors are located in the conducting zone of the respiratory system?

Back 5

Sympathetic --> B2 adrenergic receptors (inhibitory; stimulation results in dilation)

Parasympathetic --> muscarinic cholinergic (stimulatory; activation results in constriction)

Front 6

What is the effect of isoproternol and albuterol on bronchial smooth muscle?

Back 6

Relaxation and dilation of the airways

Front 7

Which anatomical structures comprise the "respiratory zone"?

Back 7

Structures that are lined with alveoli, participating in gas exchange
(respiratory bronchioles, alveolar ducts, and alveolar sacs)

Front 8

What type of epithelial cells line the alveolar walls?

Back 8

Type I and Type II pneumocytes

Front 9

Since the alveoli have no cilia, how are dust and debris removed?

Back 9

Alveolar macrophages

Front 10

Which type of pneumocyte are responsible for gas exchange and cover a majority of the surface area?

What type of epithelial cell are these?

Back 10

Type I pneumocytes

*Squamous epithelium

Front 11

What are the functions of Type II pneumocytes?

Back 11

1. Production/secretion of surfactant
2. Replicate to replace damaged Type I pneumocytes

Front 12

What type of epithelial cells are Type II pneumocytes?

Back 12

Cuboidal

Front 13

What type of circulation supplies the conducting airways?

Back 13

Bronchial circulation

Front 14

What is the PO2 and PCO2 of blood entering the pulmonary capillaries?

Back 14

PO2 = 40 mm Hg (relatively low)

PCO2 = 46 mm Hg (relatively high)

Front 15

What is the PO2 and PCO2 of blood leaving the pulmonary capillaries?

Back 15

PO2 = 100 mm Hg (relatively high)

PCO2 = 40 mm Hg (relatively low)

Front 16

How does gravity affect pulmonary blood flow?

Back 16

Causes an uneven distribution of pulmonary blood flow:
When a person is standing, blood flow is lowest at the apex (top) of the lungs and highest at the base (bottom) of the lungs

Front 17

Describe pulmonary blood flow in terms of pressure and resistance.

Back 17

Flow is DIRECTLY proportional to the pressure gradient and INVERSELY proportional to resistance.

Front 18

Is the pulmonary circulation higher or lower in pressure and resistance than the systemic circulation?

Back 18

Much LOWER in pressure and resistance

Front 19

List the 2 sources of the physiologic shunt that result in systemic arterial blood having a slightly lower PO2 than alveolar air.

Back 19

1. Bronchial blood flow
2. Small portion of coronary venous blood that drains directly into the left ventricle

Front 20

What is a ventilation/perfusion defect?

Back 20

The defect is an increased difference between the PO2 of alveolar air and PO2 of systemic arterial blood. "A-a difference."

Front 21

What is the volume of the tidal volume?

Back 21

500 mL

Front 22

What is the volume of the inspiratory reserve volume?

Back 22

3000 mL

Front 23

What is the volume of the expiratory reserve volume?

Back 23

1200 mL

Front 24

What is the volume of the residual volume?

Back 24

1200 mL

Front 25

What is the inspiratory capacity and what is its volume?

Back 25

Tidal volume + Inspiratory reserve volume = 3500 mL

Front 26

What is the Vital capacity and what is its volume?

Back 26

Inspiratory capacity + Expiratory reserve volume
3500 + 1200 = 4700 mL

Front 27

What is the Functional residual capacity and what is its volume?

Back 27

Expiratory reserve volume + Residual volume
1200 + 1200 = 2400 mL

Front 28

Which lung volume cannot be measured by spirometry?

Back 28

Residual volume

Front 29

Which lung volume includes the volume of air that fills the alveoli PLUS the volume of air that fills the airways?

Back 29

Tidal volume

Front 30

How are static volumes of the lung measured?

Back 30

Spirometry

Front 31

Which type of lung capacity can be thought of as the equilibrium volume of the lungs?

Back 31

Functional residual capacity

Front 32

What is the difference between the symbols "A" and "a"?

Back 32

"A" = alveolar gas

"a" = arteriol blood

Front 33

What is the PO2 of dry inspired air?

Back 33

160 mm Hg

Front 34

What is the PCO2 in dry inspired air?

Back 34

0 mm Hg

Front 35

What is the PO2 in alveolar air?

Back 35

100 mm Hg

Front 36

What is the PCO2 in alveolar air?

Back 36

40 mm Hg

Front 37

What is the average breaths/minute?

Back 37

15 breaths/min

Front 38

What is the constant atmospheric pressure (at sea level)?

Back 38

760 mm Hg

Front 39

What is the constant water vapor pressure?

Back 39

47 mm Hg (37 *C)

Front 40

What is the standard temperature, pressure, dry (STPD)?

Back 40

273 K, 760 mm Hg

Front 41

What is the constant body temperature, pressure, saturated (BTPS)?

Back 41

310 K, 760 mm Hg, 47 mm Hg

Front 42

What is the hemoglobin concentration?

Back 42

15g/100 mL blood

Front 43

Which lung capacity is mainly determined by the balance between the forces of the lung and chest wall?

Back 43

Functional residual capacity

Front 44

How is FRC changed in the cases of emphysema and fibrosis?

Back 44

Emphysema --> FRC increased

Fibrosis --> FRC decreased

Front 45

Which 3 tests can be used to determine the residual volume?

Back 45

1. Nitrogen washout
2. Helium dilution
3. Body plethysmography

Front 46

What is a common method for measuring FRC?

Back 46

Helium dilation

Front 47

What is dead space?

What is anatomic dead space and what is its value?

Back 47

The volume of air in the lungs that does not participate in gas exchange.

Anatomic dead space = volume of air in conduction airways (150 mL)

Front 48

What term is used to describe the ventilated alveoli that are not perfused by pulmonary capillary blood?

Back 48

Functional dead space

Front 49

What does physiologic dead space include?

Back 49

Both anatomic and functional dead space
(Total volume of the lungs that does no participate in gas exchange).

Front 50

What volume of air during passive breathing actually participates in gas exchange?

Back 50

350 mL

(500 mL tidal volume - 150 mL anatomic dead space)

Front 51

What is the relationship between alveolar ventilation and alveolar PCO2?

Back 51

Inverse relationship
(As alveolar ventilation increases, PCO2 decreases)

Front 52

What is the normal value for the respiratory exchange ratio?

Back 52

0.8

(CO2 production / O2 consumption)

Front 53

The volume of air that can be forcibly expired in the first second is called _______.

Back 53

FEV1

Front 54

In a normal person, the FEV1/FVC is approximately what value?

What does this mean?

Back 54

0.8

80% of the vital capacity can be expired in the first second of forced expiration

Front 55

What is the effect of asthma on FEV1 and FVC?

Back 55

Both are decreased
FEV1/FVC < 80%

Front 56

What is the effect of fibrosis on FEV1 and FVC?

Back 56

Both are decreased, but FEV1/FVC is >80%.

Front 57

Which muscles are used during inspiration?

Back 57

1. Diaphragm
2. External intercostals
3. Accessory muscles

Front 58

Which muscles are used during expiration?

Back 58

Normally a passive process, but during forced expiration:

1. Abdominal muscles
2. Internal intercostals

Front 59

By convention, how is transmural pressure calculated?

What is the result of positive transmural pressure?

Back 59

Alveolar pressure minus intrapleural pressure

(+) transmural pressure = expanding pressure is exerted in the lung, resulting in expiration

Front 60

How is compliance of the lungs and chest wall related with the elastic properties or elastance?

Back 60

INVERSELY correlated

Front 61

Is compliance higher during inspiration or expiration?

Back 61

Expiration

Front 62

What equation is used to describe compliance?

Back 62

C = Change in volume / change in pressure

Front 63

What is the effect of surfactant on lung compliance?

Back 63

Increases lung compliance
(decreases surface tension)

Front 64

What is the effect of pneumothorax on the lungs and chest wall?

Back 64

Lungs collapse and chest wall springs out

Front 65

What is the effect of fibrosis on lung compliance?

Back 65

Decreased compliance

Front 66

What are the advantages and disadvantages of small alveoli?

What is the role of surfactant?

Back 66

Small alveoli have a greater tendency to collapse due to increased surface tension and collapsing pressure.

However, since small alveoli have an increased relative surface area, they are more efficient at gas exchange.

*Surfactant serves to reduce the surface tension of alveoli to prevent collapse and increase lung compliance (can withhold more air volume)

(Intermolecular repelling forces between the phospholipid molecules break up the attracting forces between liquid molecules lining the alveoli)

Front 67

According to Poiseuille's law, which factors affect resistance of airflow?

Back 67

1. Viscosity of inspired air (directly proportional)
2. Length of airway (directly proportional)
3. Radius of aiway (inversely proportional)

Front 68

Why do the smallest bronchi not have the highest resistance?

Back 68

Despite the inverse relationship between radius and resistance, small airways do not have the greatest resistance due to their parallel arrangement.

Medium-sized bronchi actually have the greatest resistance

Front 69

What is the effect of muscarine or carbachol on airway resistance?

Back 69

Increase resistance

(Muscarine and carbachol are muscarinic agonists, increasing constriction and decreasing the radius of airways).

Front 70

At rest, is intramural pressure positive or negative?

Does this keep the lungs inflated or deflated?

Back 70

Negative (-5 cm H2O)

This means that the transmural pressure across the lungs at rest is POSITIVE (+5 cm H2O).

*This keeps the lungs inflated

Front 71

Give the same temperature, does water saturated gas create a higher or lower pressure than the same amount of dry gas?

Back 71

Higher pressure

Front 72

Which law states that at a given pressure, the relationship between temperature and gas volume is directly proportional?

Back 72

Charles' law.

Front 73

Which law states that at a given temperature, the product of pressure times volume for a gas is constant?

Back 73

Boyle's Law
(P1 x V1 = P2 x V2)

Front 74

The general gas law is based on what equation?

Back 74

PV = nRT

Front 75

Which law states that the partial pressure of a gas is the total pressure multiplied by the fractional concentration of dry gas?

Back 75

Dalton's law

Front 76

Which law describes the concept that if alveolar air has a PO2 of 100 mm Hg, thene the capillary blood that equilibrates with alveolar air also will have a PO2 of 100 mm Hg?

Back 76

Henry's law

At equilibrium, the partial pressure of a gas in the liquid phase equals the partial pressure in the gas phase

Front 77

Which law is used to convert the partial PRESSURE of gas in the liquid phase to the CONCENTRATION of gas in the liquid phase?

Back 77

Henry's law.

Convert partial pressure of gas in gas phase to partial pressure of gas in liquid phase. Then calculate the concentration of gas in liquid phase.

Front 78

Fick's law is used to describe the rate of transfer by diffusion.
Describe the variables that contribute to the rate of diffusion

Back 78

1. Driving force (partial pressure difference of gas)
2. Diffusion coefficient
3. Thickness of the membrane (inversely proportional)

Front 79

Which has a higher diffusion coefficient-- CO2 or O2?

Back 79

CO2 diffusion coefficient is about 20 times higher than that of O2.

Front 80

What is used as the test gas to measure lung diffusing capacity?

Back 80

CO
(subject breathes low concentration of CO; the rate of disappearance of CO from gas mixture is proportional to the lung diffusing capacity).

Front 81

In solution (blood), the total gas concentration is the sum of what forms of gas?

Back 81

1. Free dissolved gas
2. Bound gas
3. Chemically modified gas

Front 82

In solution, only _______ gas molecules contribute to the partial pressure.

Back 82

Dissolved gas molecules

Front 83

Give an example of a diffusion-limited gas.

Back 83

CO

Front 84

At normal resting conditions, is O2 transfer determined by perfusion-limited or diffusion-limited O2 transport?

Back 84

Perfusion-limited
(pulmonary blood flow determines net O2 transfer)

*Diffusion-limited O2 transport occurs under pathologic conditions such as fibrosis

Front 85

What is the solubility of oxygen in blood?

Back 85

0.003 mL/ 100 ML blood/mm Hg
(very, very small portion)

Front 86

For the subunits to bind O2, iron in the heme moieties must be in which state?

Back 86

Ferrous state (Fe2+)

Front 87

List 2 causes of methemoglobinemia.

Back 87

1. Oxidation of Fe2+ to Fe3+ by nitrites and sulfonamides
2. Deficiency in methemoglobin reductase

Front 88

Hemoglobin can be ____% saturated at a PaO2 of 100 mm Hg.

Back 88

98%

Front 89

1 g of hemoglobin can bind ___ mL of O2.

Back 89

1.34 mL O2.

Front 90

What is the O2-binding capacity of hemoglobin?

Back 90

20.1 mL O2/ 100 mL blood

Front 91

In tissues, PVO2 is approximately 40 mm Hg and hemoglobin is only ____% saturated.

Back 91

75%

Front 92

List 3 causes for a right shift in the O2-Hb dissociation curve.

Back 92

1. Bohr effect (increased CO2 or decreased pH result in decreased O2 affinity)
2. Increased temperature
3. Increased 2,3-DPG

Front 93

What is the effect of CO on the O2-Hb dissociation curve?

Back 93

Shifts to the left
(causes increased O2 affinity due to positive cooperativity)

Front 94

What happens to the FEV1/FVC ration in COPD patients?

Back 94

FEV1/FVC is INCREASED
(Both are separately decreased, but FEV1 is decreased less than FVC, increasing the ratio)

Front 95

COPD is the co-occurence of which respiratory conditions?

Back 95

1. Chronic bronchitis
2. Emphysema
3. Asthma

*Airways become narrowed

Front 96

In restrictive lung diseases such as fibrosis and neuromuscular diseases, what happens to the FEV1/FVC ratio?

Back 96

The ratio is normal or increased

Front 97

What is the defining feature of COPD?

Back 97

Irreversible airflow limitation during forced expiration

Front 98

When is O2 supplementation therapy recommended?

Back 98

1. Resting PO2 less than 55 mmHg
2. Oxygen saturation less than 88%

Front 99

Why might patients with chronic high PCO2 do WORSE with supplemental O2?

Back 99

These patients may be relying on peripheral chemoreceptors to drive their respiration.
(Peripheral chemoreceptors detect PO2 levels lower than 60 mmHg and stimulate the inspiratory center to increase respiration rate).

*Supplying these patients with O2 may cause them to lose their respiratory drive

Front 100

What are some treatments for COPD?

Back 100

1. Supplemental O2
2. Bronchodilators (albuterol inhaler)
3. Anticholinergic agents (reduce constriction)
4. Inhaled glucocorticoids (reduce inflammation)
5. Pneumococcal vaccine
6. Pulmonary rehabilitation
7. Surgery

Front 101

List 3 reasons why V/Q ratio may increase in COPD.

Back 101

(Either increased ventilation or decreased perfusion)

1. Hyperventilation (due to PO2 < 60 mmHg activating peripheral chemoreceptors which stimulate inspiratory center)
2. Loss of blood flow due to alveolar wall destruction
3. Hypoxic vasoconstriction due to PO2 < 70 mmHg

Front 102

What would cause the V/Q ratio to decrease in COPD?

Back 102

Reduced ventilation secondary to mechanical airway obstruction