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Human physiology > Chapter 17: Mechanics of Breathing > Flashcards

Chapter 17: Mechanics of Breathing Flashcards

1
Q

what are the respiratory system functions?

A
  1. Exchange of gases between the atmosphere and the blood
  2. Contributing to the regulation of acid-base balance in the blood
  3. Vocalization
  4. Defense against pathogens and foreign particles in the airways
  5. Route for water and heat loss
  6. Enhancing venous return (respiratory pump)
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2
Q

what does internal respiration involve?

A

oxidative phosphorylation

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3
Q

what are the four processes of external respiration?

A
  1. Pulmonary ventilation
  2. Exchange between lungs and blood
  3. Transportation in blood
  4. Exchange between blood and body tissues
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4
Q
  • *airways from pharynx to lungs
    • conducting zone
    • respiratory zone
A

respiratory tract

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5
Q
  • consists of:
    • larynx
    • trachea
    • bronchi
    • secondary bronchi
    • tertiary bronchi
    • bronchioles
    • terminal bronchioles
A

conducting zone

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6
Q

consists of glottis and epiglottis

A

larynx

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7
Q
  • 2.5 cm diameter
  • 10 cm long
  • 15-20 C shaped bands of cartilage
A

trachea

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8
Q
  • Three on right side to three lobes of right lung

- Two on left side to two lobes of left lung

A

secondary bronchi

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9
Q

20–23 orders of branching

A

tertiary bronchi

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10
Q

less than 1 mm in diameter

A

bronchioles

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11
Q
  • Air passageway: 150 mL in volume (dead space)
  • Increases air temperature to body temperature
  • Humidifies air
A

functions of conducting zone

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12
Q

consists of goblet cells and ciliated cells

A

epithelium of conducting zone

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13
Q

secrete mucus

A

goblet cells

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14
Q
  • Cilia move particles toward mouth

- Mucus escalator

A

ciliated cells

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15
Q

secrete saline and mucus

A

Epithelial cells lining the airways and submucosal

glands

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16
Q

move the mucus layer toward the pharynx, removing trapped

pathogens and particulate matter

A

cilia

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17
Q

creates 80 million bronchiooles

A

branching of airways

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18
Q
  • Exchange of gases between air and blood

- Mechanism of action: diffusion

A

function of respiratory zone

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19
Q

what are the structures of the respiratory zone?

A
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli
  • Alveolar sacs
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20
Q

surrounded by elastic fibers and a network of capillaries`

A

each cluster of alveoli

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21
Q
  • Respiratory membrane
    • Epithelial cell layer of alveoli
    • Endothelial cell layer of capillaries
A

epithelium of respiratory zone

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22
Q
  • site of gas exchange
  • 300 million in the lungs
  • rich blood supply from capillary sheet
A

alveoli

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23
Q

what are the types of alveoli?

A
  • alveolar pores
  • type I alveolar cells
  • type II alveolar cells
  • alveolar macrophages
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24
Q
  • make up wall of alveoli
  • single layer of epithelial cells
  • for gas exchange
A

type I alveolar cells

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25
Q

secrete surfactant

A

type II alveolar cells

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26
Q

ingests foreign material

A

alveolar macrophage

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27
Q
  • airtight, protects lungs
  • consists of:
    • rib cage
    • sternum
    • thoracic vertebrae
    • muscles (internal and external intercostals, diaphragm)
A

chest wall

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28
Q
  • membrane lining of lungs and chest wall

- sac around each lung

A

pleura

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29
Q
  • filled with intrapleural fluid

- volume = 15 mL

A

intrapleural space

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30
Q

how does air move in and out of the lungs?

A

bulk flow

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31
Q

what drives the flow of air?

A

pressure gradient

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32
Q

in what direction does air move?

A

from high to low pressure

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33
Q

pressure in lungs less than atmospheric pressure

A

inspiration

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34
Q

pressure in lungs greater than atmospheric pressure

A

expiration

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35
Q

Atmospheric pressure=

A

Patm

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36
Q
  • Pressure of air in alveoli

- Palv

A

intra-alveolar pressure

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37
Q
  • pressure inside pleural sac

- Pip

A

intrapleural pressure

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38
Q

what are the pulmonary pressures?

A
  • Atmospheric pressure
  • intra-alveolar pressure
  • intrapleural pressure
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39
Q
  • 760 mm Hg at sea level
  • Decreases as altitude increases
  • Increases under water
A

atmospheric pressure

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40
Q

are given relative to atmospheric pressure (set Patm= 0mmHg)

A

other lung pressures

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41
Q
  • pressure of air in alveoli
  • given relative to atmospheric pressure
  • varies with phase of respiration
A

intra-alveolar pressure

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42
Q

when is intra-alveolar pressure negative (less than atmospheric)?

A

during inspiration

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43
Q

when is intra-alveolar pressure positive (more than atmospheric)?

A

during expiration

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44
Q

drives ventilation

A

Difference between Palv and Patm

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45
Q
  • pressure inside pleural sac

- varies with phase of respiration

A

intrapleural pressure

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46
Q
  • Always negative under normal conditions

- Always less than Palv

A

pressure inside pleural sac

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47
Q

what is the intrapleural pressure at rest?

A

-4mm Hg (vacuum)

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48
Q

prevents wall and lungs from pulling apart

A

surface tension of intrapleural fluid

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49
Q

keeps the lung adhered to the chest wall, in a normal lung at rest

A

pleural fluid

50
Q

creates an inward pull

A

elastic recoil

51
Q

tries to pull the chest wall outward

A

elastic recoil of the chest wall

52
Q

-If the sealed pleural cavity is opened to the
atmosphere, air flows in. –The bond holding the lung to the chest
wall is broken, and the lung collapses
-air in thorax

A

pneumothorax

53
Q

what is movement of air in and out of the lungs due to?

A

pressure gradients

54
Q

describes mechanisms for creating pressure gradients

A

mechanics of breathing

55
Q

force for flow=

A

pressure gradient (mechanics of breathing)

56
Q

remains constant during breathing cycle

A

atmospheric pressure

57
Q

do alveolar pressure changes affect gradients?

A

yes

58
Q

pressure is inversely related to volume

A

Boyle’s law

59
Q

related to airway radius and mucus

A

resistance to air flow (R)

60
Q

flow =

mechanics of breathing

A

Patm-Palv/R

61
Q

how can you change alveolar pressure?

A

by changing its volume

62
Q

V=1/P

A

relationship says that if the volume of gas increases, the pressure decreases and vice versa

63
Q

PV=nRT

A

ideal gas equation

64
Q

P1V1=P2V2

A

boyle’s law expresses the inverse relationship between pressure and volume

65
Q

what are the determinants of intra-alveolar pressure?

A
  • factors determining intra-alveolar pressure
  • lungs expand-alveolar volume increases
  • lungs recoil-alveolar volume decreases
66
Q

what are the factors determining intra-alveolar pressure?

A
  • quantity of air in alveoli

- volume of alveoli

67
Q
  • alveolar volume increases
  • Palv decreases
  • pressure gradient drives air into lungs
A

lungs expand

68
Q
  • alveolar volume decreases
  • Palv increases
  • pressure gradient drives air out of lungs
A

lungs recoil

69
Q

moves

sternum upward and outward

A

expansion of ribs during inspiration

70
Q

when does the diaphragm and external intercostals contract?

A

during inspiration

71
Q

when do the chest wall and lungs expand?

A

during inspiration

72
Q

when do the external intercostals and diaphragm relax?

A

expiration

73
Q

when do the internal intercostals and abdominals contract?

A

only for active expiration

74
Q

when do the chest cavity and lungs contract?

A

during expiration

75
Q

when do the ribs and sternum depress?

A

during expiration

76
Q

what are the factors affecting pulmonary ventilation?

A
  • lung compliance

- airway resistance

77
Q

-Change of volume (V) that results from a given force or pressure (P) exerted on the lung
=ΔV/ΔP
-ease with which lungs can be stretched

A

lung compliance

78
Q

when is it easier to inspire?

A

when there is a larger lung compliance

79
Q

requires more force from inspiratory muscles to stretch

A

low compliance lung

80
Q

what are the factors affecting lung compliance?

A
  • elastance (elastic recoil)

- surface tension of lungs

81
Q
  • Low elastance → high compliance

- Balloon vs plastic bag

A

elastance

82
Q
  • Thin layer of fluid lines alveoli
  • arises due to attractions between water molecules
  • Greater tension → less compliant
A

surface tension of lungs

83
Q

how can surface tension be overcome?

A

-surfactant secreted from type II cells

84
Q
  • detergent that decreases surface tension
  • more concentrated in smaller alveoli
  • increases lung compliance, makes inspiration easier
A

surfactant

85
Q

what happens when airways get smaller in diameter?

A

-they increase in number, keeping overall resistance low

86
Q

what does an increase in resistance result in?

A
  • make it harder to breath
  • contraction activity of smooth muscle
  • mucus secretion
87
Q

what is the role of bronchiolar smooth muscle in airway resistance?

A
  • bronchoconstriction
  • bronchodilation
  • contractile state of bronchiolar smooth muscle under extrinsic and intrinsic controls
88
Q

smooth muscle contracts, causing radius to decrease

A

Bronchoconstriction

89
Q

smooth muscle relaxes, causing radius to increase

A

Bronchodilation

90
Q

what is involved in the extrinsic control of the bronchiole radius?

A
  • autonomic nervous system

- hormonal control

91
Q

-parasympathetic
-contraction of smooth
muscle
-bronchoconstriction

A

autonomic nervous systems

92
Q
  • epinephrine
    • relaxation of smooth muscle
    • bronchodilation
A

hormonal control

93
Q

what is involved in the intrinsic control of the bronchiole radius?

A
  • CO2: bronchodilation

- histamine: bronchoconstriction

94
Q
  • Released during asthma and allergies

- Also increases mucus secretion

A

Histamine: bronchoconstriction

95
Q

what is involved in total lung capacity?

A
  • tidal volume
  • inspiratory reserve volume
  • expiratory reserve volume
  • residual volume
96
Q
  • 500 mL

- single,unforced breath

A

tidal volume (Vt)

97
Q
  • 3000mL

- after breathing in, volume you can still inspire

A

inspiratory reserve volume (IRV)

98
Q
  • 1000mL

- after breathing out, volume you can still expire

A

expiratory reserve volume (ERV)

99
Q
  • 1200 mL

- volume left after ERV

A

residual volume (RV)

100
Q

= VT + IRV = 3500 mL

A

Inspiratory capacity (IC)

101
Q
  • maximum volume expired after maximum inspiration

- VC = VT + IRV + ERV = 4500 mL

A

vital capacity

102
Q

= volume remaining after resting tidal volume

-FRC = ERV + RV = 2200 mL

A

functional residual capacity

103
Q
  • volume air in lungs after maximum inspiration

- TLC = VT + IRV + ERV + RV = 5700 mL

A

total lung capacity

104
Q
  • difficulty expelling air
  • associated with increased airway resistance
  • residual volume increases (making it more difficult to expire)
  • vital capacity decreases
A

obstructive pulmonary diseases

105
Q

what are some major obstructive pulmonary diseases?

A
  • COPD (chronic bronchitis and emphysema)

- asthma

106
Q
  • difficulty expanding lungs

- involve structural damage to the lungs

A

restrictive pulmonary diseases

107
Q

what happens when the lungs are damaged structurally due to restrictive pulmonary diseases?

A
  • decrease in lung compliance
    • total lung capacity decreases
    • vital capacity decreases
  • pulmonary fibrosis (fibrous scar tissue)
    • asbestos
108
Q

maximum-volume inhalation followed by exhalation as fast as possible

A

forced vital capacity (FVC)

109
Q

what does a low FVC indicate?

A

restrictive pulmonary disease

110
Q

percentage of FVC that can be exhaled within certain time frame

A

forced expiratory volume (FEV)

111
Q

percentage of FVC that can be exhaled within 1 second

A

FEV1

112
Q

what is a normal FEV1?

A

80%

113
Q

what does a FEV <80% indicate?

A

obstructive pulmonary disease

114
Q

total volume of air entering and leaving the respiratory system each minute

A

minute ventilation

115
Q

= VT × RR

A

minute ventilation

116
Q

Normal respiration rate =

A

12 breaths/minute

117
Q

Normal VT =

A

500 mL

118
Q

Normal minute ventilation =

A

500mL x 12 breaths/min= 6000 mL/min

119
Q

Air in conducting zone does not participate in gas exchange

A

anatomical dead space

120
Q
  • equals the anatomical dead space

- about 150 mL

A

conducting zone

121
Q

-Volume of fresh air reaching the gas exchange areas per minute

=(VT × RR) – (DSV × RR)

-normal is 4200 mL/min

A

alveolar ventilation

122
Q

why are the conducting airways known as anatomic dead space?

A

because they don’t exchange gases with the blood

Human physiology (17 decks)

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