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Bioscience 2 > Pulmonary Physiology > Flashcards

Pulmonary Physiology Flashcards

1
Q

Major functions of the pulmonary system?

A
  • Gas exchange (O2 delivery, CO2 removal)

- Maintenance of acid base balance (CO2 is the major source of hydrogen ions in the blood).

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2
Q

How many lobes are in the left lung?

A

2, upper and lower

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3
Q

How many lobes are in the right lung?

A

3, upper, middle and lower.

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4
Q

What is the ventilatory capacity of the L and R lung, respectively?

A

45%, 55%

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5
Q

What are the functions of the conducting airways?

A
  • Warm air to body temp
  • Humidify air
  • Filter air via mucus and cilia
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6
Q

How is ventilation distributed?

A

Not uniform, smooth muscle directs inhaled air to well perfused regions.

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7
Q

Define: acinus

A

The functional unit of the lung: a respiratory bronchiole and all its associated alveolar ducts and sacs.

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8
Q

Describe the structure of alveoli

A
  • Large surface area to volume ratio for gas exchange.

- Structures are not totally separated, moire like bubbles than grapes.

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9
Q

What are the two types of pneumocytes?

A

Type 1: squamous epithelium

Type 2: surfactant producers

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10
Q

What is the relationship between circulatory system and airways?

A

-Capillaries and lymphatics are closely intertwined with alveoli, allowing for very short diffusion distances.

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11
Q

What is the energy expenditure at rest for a healthy person?

A

3-4%

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12
Q

What is the energy expenditure for a healthy person at heavy exercise intensity?

A

15-18%

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13
Q

How high can energy expenditure at exercise be for individuals with a pulmonary pathology?

A

25%. Goal of PT: Decrease this.

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14
Q

T/F: Intrapleural pressure is usually negative.

A

True. This keeps alveoli inflated.

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15
Q

What is the transmural pressure?

A

P-alv - P ip

This is the pressure difference across the alveolar wall.

Determines alveolar size.

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16
Q

How does alveolar pressure change during a normal respiratory cycle?

A

Negative during inspiration, positive during expiration. Very small (1->2 mmHg) changes.

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17
Q

What is the normal intrapleural pressure and how does it change during the respiratory cycle?

A
  • Normally -4mmHg

- Becomes more negative (-6) during inspiration which increases their volume. Returns to -4 during expiration.

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18
Q

What are the main inspiratory muscles?

A

-Diaphragm, external intercostals.

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19
Q

What are the main expiratory muscles?

A

None, passive. Relaxed inspiratory muscles allow for expiration.

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20
Q

What is the role of surfactant in the alveoli?

A

Decreases the surface tension on the alveolar surface, requires less work to change volume of alveoli.

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21
Q

What does surface tension do to breathing?

A

Increases the work required, makes it more difficult. Inserts itself between water molecules. Lowers surface tension drastically in smaller alveoli to keep the pressures very similar across all alveoli.

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22
Q

What is surfactant?

A

An amphipathic phospholipoprotein synthesized and secreted by type II alveolar cells.

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23
Q

What is dynamic compression?

A
  • during forced expiration, abs and internal intercostals contract which increases intra-abdominal and intra-thoracic pressure.
  • Pip becomes positive
  • As Pip approaches or exceeds airway pressure, (Palv), there is a collapse of the airways which limits expiratory flow.
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24
Q

What is compliance?

A

Stretchability. Lung tissue has a ton of this.

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25
Q

What is the formula for compliance?

A

change in volume/change in pressure

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26
Q

What can decrease compliance?

A

Scarring and fibrosis. This results in more pressure change/muscle action being needed to breathe.

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27
Q

What is elasticity?

A

The ability to recoil when stretched.

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28
Q

What is the formula for elasticity?

A

Change in pressure / change in volume

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29
Q

How does lung volume impact surfactant concentration?

A

-At high lung volume, surfactant molecules are spread out and have a low concentration, increasing surface tension. The inverse applies.

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30
Q

What controls pulmonary perfusion?

A

Bronchiolar and arteriolar smooth muscle responding to PO2 concentrations.

High PO2 leads to arteriole dilation and perfusion.

Low PO2 leads to arteriole constriction.

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31
Q

What is a lung capacity?

A

The sum of two or more lung volumes.

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32
Q

What is TV?

A

Tidal volume. Normally inhaled.

33
Q

What is IRV?

A

Inspiratory reserve volume. Additional air that can be forcibly inhaled after a normal inhalation.

34
Q

What is inspiratory capacity?

A

TV + IRV

35
Q

What is expiratory reserve volume?

A

Air remaining in the lung after you normally exhale. Can be forced out.

36
Q

What is the residual volume?

A

Air left in the lung after forcible exhale

37
Q

What is the vital capacity?

A

ERV + TV + IRV

38
Q

What is the Total lung capacity?

A

IRV + TV + ERV +RV

39
Q

What is the functional residual capacity?

A

ERV + RV; buffer volume that helps maintain gas composition in alveoli.

40
Q

What is a flow volume loop?

A

Way of visualizing pulmonary function. Flow rate on vertical axis, lung volume on horizontal axis.

41
Q

What is FEV1?

A

Forced expiration volume in 1 sec

42
Q

What should FEV1 be?

A

80% of FVC

43
Q

What should FEV3 be?

A

96% of FVC.

44
Q

What should FEV6 be?

A

Equal to FVC

45
Q

What is dead space?

A

Volume of gas that fills airways but doesn’t participate in gas exchange.

46
Q

Where is anatomical dead space?

A

Trachea and conducting airways

47
Q

Where is alveolar dead space?

A

Anywhere that there is ventilation without perfusion.

48
Q

What is physiologic dead space?

A

Anatomic dead space + alveolar dead space

49
Q

T/F: Inspired air is high in CO2

A

False. Very low. Negligible amounts 150mmhg of oxygen. (vs .2)

50
Q

What is the PO2 of alveolar gas?

A

100-105mmHg

51
Q

What is the PCO2 of alveolar gas?

A

40mmHg (negligible)

52
Q

Why is gas exchange effective at capillaries and alveoli?

A

Large surface area, small diffusion distance, presence of diffusion gradients

53
Q

What is the composition of veinous blood in pulmonary capillaries?

A

40mmHg PO2

46 mmHg PCO2

54
Q

What is the composition of blood in pulmonary veins?

A

PO2=100mmHg

PCO2= 40mmHg

55
Q

What impacts gas exchange at lungs?

A

Concentration difference
Surface area
Distance

56
Q

What is the ideal ventilation perfusion ratio?

A

1

57
Q

T/F: Most oxygen is bound to hemoglobin while little is free and dissolved.

A

True.

58
Q

What determines whether oxygen is bound or not?

A

O2 levels.

If O2 is readily available, it is likely to be bound. If O2 conc is low, it binds loosely and can dissolve.

59
Q

What is the PO2 and HG concentration in arterial blood?

A

95-100mmHg, 97-99%

60
Q

What is the PO2 and HG conc in veinous blood?

A

40mmHg, 75%

61
Q

What causes hemoglobin to give up O2 more readily (shift curve right)?

A
  • Increases in PCO2
  • Increased H+ conc
  • increased temp
  • Increased 2,3-DPG conc.
62
Q

What causes hemoglobin to be less likely to give up O2? (shift curve left)?

A
  • Decreased PCO2
  • Decreased H+ conc
  • Decreased temp
  • Decreased 2,3-DPG conc.
63
Q

How does anemia impact blood-oxygen?

A

-Decreases the amount of hemoglobin available to carry O2 , so overall carrying content and concentration drops, but not saturation.

64
Q

How does the majority of CO2 travel?

A
  • 90% as bicarbonate ions in blood.

- Metabolically, 60% as bicarbonate in blood, 30% bound to hemoglobin, 10% dissolved.

65
Q

What buffers hydrogen ions in veinous blood?

A

Hemoglobin (deoxy>oxy) carries HCO3. Releases H+

66
Q

What controls the normal breathing rate?

A

Brainstem, has 4 centers:

  • Dorsal Respiratory Group
  • Pneumatoxic center
  • Apneustic center
  • Ventral respiratory group
67
Q

What often impacts the four breathing centers in the brainstem?

A

-Meds. DRG is particularly easily influenced.

68
Q

What do lung receptors impact ant how?

A

Impact the DRG neurons.

  • Stretch receptors
  • Irritant receptors: limits inspiration of irritant molecules.
  • Juxtacappilary centers: sensitive to congestion as a result of fluid accumulation.
69
Q

What is the Hering-Breuer reflex?

A

Stretch during large inspiration inhibits DRG, resulting in loss of inspiration ability.

70
Q

How is ventilation chemically modulated?

A

Peripheral chemoreceptors in the aortic and carotid bodies.

-Sensitive to PO2, PCO2, pH

71
Q

What is the negative feedback loop for the chemical modulation of ventilation?

A
  • PO2 decreases, PCO2 increases, pH decreases

- Chemoreceptors stimulate respiratory centers to increase rate and depth of respiration

72
Q

Where are central chemoreceptors and how do they work?

A
  • Located near respiratory centers in brainstem.
  • Respond only to arterial CO2.
  • CO2 crosses blood-brain barrier, decreasing pH of CSF.
  • Breathing rate increases and deepens. Raises pH.
73
Q

What triggers an increased breathing rate in exercise?

A
  • Increased arterial CO2
  • Decreased pH in plasma
  • Sympathetic response
  • Muscle and joint afferents.
74
Q

What occurs up until the lactic threshold?

A
  • Linear relationship between intensity of exercise and ventilation
  • PCO2 and pH remain constant
75
Q

What happens after the lactic threshold?

A
  • pH increases

- PCO2 decreases

76
Q

What is Cheyenne-Stokes breathing?

A
  • Occurs in CNS damage, heart failure.

- Apnea followed by increasing and then decreasing respiratory pattern

77
Q

What is apneustic breathing?

A
  • Occurs with brainstem damage

- deep sigs due to excessive DRG damage

78
Q

What is sleep apnea?

A

Difficulty breathing while sleeping. Pharynx closes while breathing.

Bioscience 2 (10 decks)

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