Respiratory Physiology Lecture Powerpoint Flashcards

1
Q

Respiratory system functions (5)

A
  • Gas exchange
  • Regulation of pH
  • voice production
  • olfaction (smell and taste)
  • protective against infection
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2
Q

Conducting zone vs respiratory zone of the respiratory system

A

Conducting is down to terminal bronchioles, respiratory zone begins at respiratory bronchioles, and extends to alveolar ducts and alveoli

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3
Q

2 major functions of the conducting zone of the respiratory system

A
  • warms and moistens air

- removal of microbes and toxins thru macrophages and mucociliary escalator

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4
Q

Respiratory membrane and its 4 layers

A
  • The thickness that the gas has to move thru to be exchanged between the vasculature and the alveoli
  • cell membrane of RBC, interstitial space, alveolar membrane, and fluid/content within the alveoli
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5
Q

Pleural membranes and their 2 functions

A
  • Visceral and parietal adherant double layered serosa filled in potential space cavity with lubricating fluid
  • functions to reduce friction when breathing, creates a slightly negative pressure gradient to promote inflation of the lungs
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6
Q

Stages of respiration (5)

A

1) ventilation - movement of air into and out of lungs
2) external respiration - gas exchange between air in lungs and blood
3) respiratory gas transport - movement of o2 and co2 throughout circulation
4) internal respiration - gas exchange between blood and tissues in the body
5) cellular respiration - usage of o2 and production of co2 from cells

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7
Q

Boyle’s law

A

States pressure of any given quantity of gas is inversely proportional to its volume assuming constant temperature

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8
Q

Dalton’s law

A

Total pressure of gas mixture is equal to the sum of its partial pressures of individual gases

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9
Q

Henry’s law

A

At the air water interface, the amount of gas dissolves in water is determined by its solubility in water (coefficient, property of the chemical) and its partial pressure in the air assuming constant temp

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10
Q

Atmospheric pressure value at sea level

A

1atm or 760mmHg

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11
Q

Air enters lungs when…

Air exits lungs when….

A

…alveolar pressure is less than atmospheric

….alveolar pressure is greater than atmospheric

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12
Q

Poiseuille’s law and importance

A
  • States R=8n(viscosity)*l/pi r^4

- Small changes in the diameter of the bronchioles greatly impacts resistance of airflow

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13
Q

Pulmonary compliance, what dz states decrease and increase it?

A
  • Refers to distensibility of lungs, change in lung volume relative to given change in transpulmonary pressure
  • decreased with disease states such as pulmonary fibrosis and increased in diseases such as emphysema or copd (harder to get air out of lungs)
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14
Q

Triggers of bronchoconstriction (4)

A
  • airborne irritants
  • cold air
  • paraysmpathetic stimulation
  • histamine
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15
Q

Triggers of bronchodilation (2)

A

Sympathetic nerves, epi (or a b-2 agonist such as albuterol)

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16
Q

Most common causes of increased airway resistance (3)

A
  • swelling (laryngedema)
  • obstruction (mucus plugging)
  • spasm of smooth muscle (asthma attack)
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17
Q

Muscles involved in inspiration and how do they move? (3)

A
  • diaphragm (flattens and increases superior inferior aspect of chest cavity)
  • external intercostals (elevate ribs moving the thoracic cavity up and out)
  • pec minors, sternocleidomastoid, erector spinae muscles (accessory use for deep inspiration only)
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18
Q

Intrapleural pressure at rest vs during inspiration

A

Intrapleural pressure becomes even more neg (decreases***) going from -756mmHg at rest (creating the adherence of the pleura to each other) to -754mmHg on inspiration

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19
Q

Intrapulmonary (intraalveolar) pressure at rest vs. during inspiration

A

Pressure drops from resting value of 760mmHg to 757mmHg (subatmospheric)

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20
Q

Transpulmonary pressure at rest vs during inspiration

A

Rises from resting value of 0mmHg to 3-4mmHg due to gradient difference between atmosphere and intrapulmonary pressure, causes airflow inward

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21
Q

Passive expiration and what does it do to intrapulmonary pressure, intrapleural pressure, and transpulmonary pressure?

A

Refers to how during quiet breathing expiration is achieved by the elasticity of the lungs and thoracic cage creating a intrapulmonary pressure of approx 763mmHg, intrapleural pressure increase back to 756mmHg, and transpulmonary pressure to reverse to begin flow outward

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22
Q

Forced expiration

A

Use of internal intercostal muscles that lie underneath external intercostal muscles and function to contract rib cage down and inward decreasing size of thoracic cavity, alongside abdominal muscles contracting increasing intra-abdominal pressure forcing diaphragm upward and increasing pressure on thoracic cavity to improve force of expiration

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23
Q

Pneumothorax

A

Loss of negative intrapleural pressure due to air in pleural cavity causing lungs to recoil and collapse (atelectasis)

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24
Q

Elasticity of lungs

A

Ability of lungs to return to normal shape after being distended, function of elastin protein content within lungs

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25
Q

Surface tension

A

Collapsing pressure resulting from attractive forces between molecules of liquid lining the alveoli (pulmonary surfactant decreases it naturally), the greater the surface tension the more difficult to expand the alveoli and the transpulmonary pressure needed to be generated

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26
Q

When lung compliance is abnormally high, lungs are prone to ____, often seen in the dz state ____, due to _____

A

collapse, emphysema, elastin protein loss

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27
Q

Respiratory distress syndrome of premature infants and its 3 treatment options

A
  • Occurs often in premature born infants before production of surfactant has occurred at approx 8 months
  • Can be treated with corticosteroids to mother, provision of synthetic surfactant, or placement on positive pressure airway
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28
Q

Surfactant allows for alveoli size to….

A

….be smaller without increased tendency to collapse

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29
Q

5 facts about pulmonary surfactant

A
  • contains mix of phospholipids and protein
  • type II alveolar cells secrete it
  • lowers surface tension making lungs easier to expand
  • deep breath increases secretion
  • not produced until late gestation (>8months)
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30
Q

Anatomic dead space

A

150mL of respiratory tract in the conducting division of the airway that does not participate in gas exchange

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31
Q

Physiologic dead space

A

Sum of anatomic dead space and any pathological alveolar dead space where lungs are damaged from dz state

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32
Q

Alveolar ventilation

A

Volume of air actually reaching the alveoli, equals tidal volume (500mL)- anatomic dead space (150mL) = 350mL

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33
Q

Minute respiratory volume and its approx value at rest

A

total volume of air taken in 1 minute, =RR x tidal volume, at rest 6000mL but can increase significantly in exercise

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34
Q

Alveolar ventilation rate

A

Air that actually ventilates alveoli (Tidal volume - dead space volume) x the respiratory rate, directly relevant to body’s ability to exchange gases

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35
Q

Partial pressure of a gas =

A

vol%of that gas x total pressure

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36
Q

Composition of atmospheric air and their partial pressures at sea level (760mmHg) (4)

A
  • 79% nitrogen (600mmHg at sea level)
  • 21% oxygen (160mmHg at sea level)
  • water presence depending on humidity
  • trace amounts carbon dioxide and others (.23 mmHg at sea level)
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37
Q

Gases move ____ a partial pressure gradient

A

down

38
Q

PO2 and PCO2 in alveoli

A

104 mmHg, 40mmHg

39
Q

PO2 and PCO2 in oxygenated blood

A

104 mmHg, 40mmHg

40
Q

PO2 and PCO2 in cells

A

40mmHg, 45mmHg

41
Q

PO2 and PCO2 in deoxygenated blood

A

40mmHg, 45mmHg

42
Q

O2 is ____ in water/plasma, while CO2 is ____ by ___x more

A

not very soluble, highly soluble, 24

43
Q

Nitrogen narcosis

A

Excessive nitrogen buildup in the tissues often seen in patients at elevated pressures such as divers due to henry’s law where nitrogen increases in solubility because of its increased partial pressure, causing individuals to experience an intoxication due to the exposure

44
Q

Decompression sickness

A

Nitrogen gas bubble build up in tissue causing deep pain and obstruction in the body from sudden drops in pressure such as ascending too quickly during a dive where because nitrogens partial pressure has decreased due to atmospheric pressure decrease, the solubility of it in the tissues decreases creating symptoms

45
Q

Time required for gases to equilibrate in alveolar gas exchange vs time for RBC to pass the alveoli at rest and exercise

A

.25 sec, .75 at rest and .3 sec during exercise

46
Q

At high altitudes, how is the partial pressures of gas affected?

A

-Atmospheric PO2 decreases, (not the number of O2 molecules, big difference) causing less oxygen to diffuse into the blood and perfuse the tissues (compensated over time with increased erythropoietin production), common causing high altitude sickness

47
Q

How does decreased membrane surface area affect gas exchange?

A

Decreases rate of external respiration, requiring more respiration to achieve the equivalent perfusion

48
Q

Opioid impact on respiratory rate

A

Slows respiratory center in medulla that can eventually cause hypoperfusion of tissue

49
Q

V/Q matching

A

Required to adequately oxygenate blood, must match air moved into and out of lungs (V) with amount of blood flow thru the lungs (Q)

50
Q

When standing, blood flow is increased in this zone and decreased in this one

A

Zone 3, zone 1

51
Q

Standing patient alveolar, arterial, and venous pressure relationships in zones 1-3

A

Zone 1 - pAlveolar >parterial >pvenous
Zone 2 - parterial>pAlveolar>pvenous
Zone 3 - parterial>pvenous>pAlveolar

52
Q

Normal V/Q ratio in healthy lungs

A

.8, perfusion exceeds ventilation under normal conditions

53
Q

Causes of poor ventilation with continued perfusion (5)

A

Airway obstruction, mucus, edema, restrictive disease, atelectasis

54
Q

Causes of poor perfusion with continued ventilation (1)

A

Pulmonary emboli secondary to DVT

55
Q

Causes of impaired diffusion with continued perfusion and ventilation (2)

A

Pulmonary edema or pulmonary fibrosis that create a barrier to diffusion across the alveolar membrane

56
Q

Positioning for lung dysfunction to max V/Q matching

A

Refers to trying to maximize the greatest pulmonary flow using gravity and positioning in coordination to ensure adequate blood flows past the good lung to maintain a good V/Q

57
Q

Perfusion adjustment to match ventilation mech of action

A

-increased airflow
-causes elevated PO2 in blood vessels
-this causes vasodilation of pulmonary vessels
-increased blood flow occurs
-blood flow matches up to airflow
(works vise versa too)

58
Q

Ventilation adjustment to match perfusion mech of action

A

-decreased blood flow
-reduced PCO2 in alveoli
-constriction of bronchioles decreases airflow
-airflow matches blood flow
(works vise versa as well)

59
Q

At rest, only ___% of available o2 in oxygenated blood enters tissue, in exercise, ___%

A

25, 75

60
Q

In 100mL of blood, __% of O2 is dissolved in plasma, and ___% is bound to hemoglobin

A

1.5, 98.5

61
Q

How many O2 molecules can bind hemoglobin?

A

4, each one being EASIER than the last

62
Q

Law of mass action

A

Refers to positive cooperativity where more oxygen binds to hemoglobin results in increased capacity to bind more o2 till all 4 slots fully saturated

63
Q

As PO2 levels drop, what happens to hemoglobin saturation?

A

Hemoglobin saturation decreases

64
Q

Venous blood is ___% saturated with O2 while arterial is normally ___%

A

75, 96-98

65
Q

What factors cause the hemoglobin dissociation curve to shift to the right (improve O2 unloading)? (5)

A
  • Decreased PO2 in metabolically active tissue
  • temp increase in metabolically active tissue
  • Bohr effect (active tissue has increased CO2 which raises H+ and lowers pH facilitating O2 release)
  • Carbamino effect (Decreased affinity of HbCO2 for O2)
  • DPG metabolite conc. increases facilitating O2 release by binding Hb
66
Q

What factors cause the hemoglobin dissociation curve to shift to the left (improve O2 loading) (5)

A
  • Increased PO2 conc. in metabolically inactive tissue
  • temp decrease in metabolically inactive tissue
  • Bohr effect (inactive tissue has decreased CO2 which lowers H+ and raises pH facilitating O2 loading)
  • carbamino effect (decreased affinity of oxygen in HbCO2, which there is not a lot of HbCO2)
  • DPG metabolite conc. decreases facilitating O2 binding to Hb
67
Q

Carbon monoxide

A

Deadly gas that is undetectable by sense, has 200x greater affinity for hemoglobin than oxygen and thus prevents o2 from binding hemoglobin, can cause rapid loss in 50% of functional hemoglobin from just .5mmHg of partial pressure presence and thus leads to poisoning at low levels of exposure

68
Q

Carbon dioxide 3 different transport mechanisms in circulation and what % travels in that form

A
  • Bicarbonate ion HCO3- + H+ (70%)
  • carbaminohemoglobin (binds hemoglobin in diff place than o2 making HbCO2 - 23%)
  • dissolved gas in plasma (7%)
69
Q

Carbonic anhydrase

A

Enzyme that converts carbon dioxide picked up at the tissue and water into carbonic acid in the a RBC in circulation which then dissociates into H+ and HCO3- ions which then leave the cell in exchange for a Cl- ion uptake (the reverse process undergoes upon the cell reaching the lungs

70
Q

Haldane effect

A

Refers to how o2 bound with hemoglobin decreases affinity of hemoglobin for carbon dioxide, beneficial in venous blood flow upon the unloading of O2

71
Q

Unconscious breathing control (quiet respiration) is facilitated by…

A

…neurons in medulla oblongata and pons

72
Q

Voluntary breathing control is facilitated by…

What nerve groups (2) are these?

A

…Motor cortex inspiratory neurons which fire during inspiration to skeletal muscles of inspiration and expiratory neurons which fire during forced expiration to skeletal muscles of forced expiration

The phrenic nerve and intercostal nerves

73
Q

Inspiratory center/dorsal respiratory group

A

1 of 2 respiratory nuclei in medulla oblongata that with more frequent firing cause more deep inhalation

74
Q

Expiratory center/ventral respiratory group

A

1 of 2 respiratory nuclei in medulla oblongata that is involved with forced expiration

75
Q

Pneumotaxic center

A

Part of pons that inhibits apneustic and inspiratory center/dorsal respiratory group to prevent overinflation of lungs during inspiration

76
Q

Apneustic center

A

Part of pons that encourages and prolongs inspiration, continually active but overridden by pneumotaxic center to prevent overinflation

77
Q

The apneustic and pneumotaxic centers do not ____ rhythms, but act as…

A

generate, …modifiers of established rhythm by the medullary centers (dorsal and ventral respiratory groups)

78
Q

Respiratory control center mech of action

A
  • Inspiratory center becomes active increasing AP’s to respiratory muscles and to pneumotaxic center
  • After short delay, pneumotaxic center is stimulated to inhibit inspiratory and apneustic center
  • inspiration ends and expiration begins
  • pneumotaxic center activity declines back to baseline
  • apneustic center and inspiratory center generate drive to begin the cycle anew
79
Q

Irritant receptors of the lungs function

A

Lung receptors tat respond to inhaled irritants to result in bronchoconstriction or coughing by stimulating vagal afferents to medulla

80
Q

Hering breur reflex (stretch receptors) function

A

Lung receptors that prevent excessive inflation by being triggered upon stretch to cease inspiration

81
Q

J receptors function

A

Juxtapulmonary capillary receptors located near capillaries in alveolar septa, sensitive to increased pulmonary capillary pressure stimulates them to initiate rapid shallow breathing

82
Q

Perpiheral chemoreceptors that monitor pH, PCO2 and PO2 of body fluids (2)

A

The aortic and carotid bodies that signal to the medulla via the vagus and glossopharyngeal nerves respectively

83
Q

Central chemoreceptors function

A

Located on the surface of the medulla and primarily monitor the pH of CSF (and indirectly CO2 because of the relationship between CO2 levels and pH)

84
Q

Increase in CO2 is related to a ___ in pH

A

Drop

85
Q

In a patient with COPD with chronic elevated CO2 levels, peripheral chemoreceptors become…
Why is this clinically relevant?

A

…more sensitive to decreased O2 pressures

-don’t want to give positive pressure O2 to stop their respiration

86
Q

Most important cause of pulmonary artery constriction is….

A

….low alveolar PO2 (hypoxia), to not waste blood in areas of the lung where gas exchange is not occurring but to shunt it and increase pressure to better ventilated areas

87
Q

Why does emphysema lead to right sided heart failure?

A

Emphysema raises peripheral resistance to high levels and rises afterload of right side of heart causing failure

88
Q

Primary control over resistance to airflow

A

Bronchiolar diameter

89
Q

Valsalva maneuver

A

Involves contraciton of abdominal muscles while holding breath causing increased pressure in abdominal cavity to expel urine, feces, or aid in childbirth

90
Q

State that shifts the oxyhemoglobin dissociation curve to the right

A

Exercise