Respiratory Physiology Intro Flashcards

1
Q

What are the four purposes of pulmonary system?

A

supply O2/remove CO2
maintain acid/base
phonation
pulmonary defence

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2
Q

Partial pressure of gases at 1 atmosphere

A

O2: 160 mmHg
N2: 600 mmHg
CO2: 0.3 mmHg
H2O: 3 mmHg

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3
Q

What does anaerobic metabolism yield?

A

2 ATP, pyruvate, and lactic acid

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4
Q

Where does anaerobic metabolism occur?

A

glycolysis occurs in the cytoplasm

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5
Q

Where does aerobic metabolism occur?

A

The mitochondria

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6
Q

What does aerobic metabolism yield?

A

38 ATP, CO2, water, heat

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7
Q

What innervates the cricothyroid muscle?

A

SEM (SLN external motor)

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8
Q

What innervates the majority of the larynx motor?

A

RLN

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9
Q

What innervates the sensory (VC and above)

A

SLN (internal)

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10
Q

What innervates the sensory (VC and below)

A

RLN

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11
Q

Abduction of vocal cords

A

Posterior CricoArytenoid (please come apart)

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12
Q

Adduction of vocal cords

A

Lateral CricoArytenoid (let’s close airway)

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13
Q

Relaxation vocal cords

A

ThyroaRytenoid (they relax)

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14
Q

Tension of vocal cords

A

CricoThyroid (cords tense)

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15
Q

What is the degree of angle for right bronchus?

A

25

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16
Q

What is the degree of angle for the left bronchus?

A

45

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17
Q

What % of TLC is the right lung?

A

55% and it is 3 lobes

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18
Q

What % of TLC is the left lung?

A

45% and it is 2 lobes

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19
Q

How many generations do the lungs have?

A

20-25 generations (bifurcations) with 10 bronchopulmonary segments

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20
Q

What is the conducting zone?

A

Generation 0 - 16
Trachea –> Bronchi –> Bronchioles –> Terminal Bronchiol
NO GAS EXCHANGE
Goblet cells here

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21
Q

What is the respiratory/transitional zones?

A

Respiratory bronchioles –> Ducts –> Sacs

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22
Q

Phrenic nerve innervation

A

C3, C4, C5 nerve roots bilaterally

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23
Q

Muscles for inspiration

A

Diaphragm, external IC (forced)

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24
Q

Muscles for expiration

A

passive

forced: internal IC, abdominal muscles

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25
Q

What are the three types of pneumocytes?

A

Type I: structural
Type II: surfactant producing
Type III: Macrophages (alveolar) monocyte that moved into tissue conducting airways

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26
Q

How many alveoli do humans have? What is their surface area?

A

300 million; 60 - 80 m^2

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27
Q

What is the distance from the front incisors to the carina?

A

26 cm (13 from teeth to larynx; 13 from larynx to carina)

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28
Q

What are the type of cells in the conducting zone?

A

Pseudostratified ciliated epithelium –> ciliated columnar epithelium –> cuboidal epithelium
*mucus-secreting goblet cells are also present

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29
Q

What is the blood supply in the conducting zone?

A

thyroid, bronchial, internal thoracic arteries (systemic circulation)

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30
Q

What is the size of the terminal bronchioles? What do they lack?

A

1 mm

Lack cartilaginous plates

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31
Q

What makes up anatomic dead space?

A

The conducting zone!!

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32
Q

How do you measure anatomic dead space?

A

150 mL
1/3 the Vt
1 mL/lb or 2 mL/lb (IBW)

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33
Q

What are the cells of the respiratory zone?

A

cuboidal –> squamous

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34
Q

What is the blood supply to the respiratory zone?

A

Pulmonary.. duh

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35
Q

What is the size of the respiratory bronchioles?

A

0.5 mm; flow moves by diffusion at this point

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36
Q

Name the accessory muscles for inspiration

A

sternocleidomastoid & scalene

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37
Q

Name the accessory muscles for expiration

A

rectus, internal/external obliques, transverse abdominus

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38
Q

Transpulmonary pressure

A

the difference between the intrapleural and intra alveolar pressures; it determines the size of the lungs. a higher transpulmonary pressure corresponds to a large lung

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39
Q

What are the components of WOB?

A

Elastive

Resistive

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40
Q

Discuss the medulla’s control over breathing

A

DRG: pacemaker for breathing; stimulates inspiration
VRG: stimulates inspiration/expiration (forced)

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41
Q

Discuss the pon’s control over breathing

A

Modifies the medulla output.

  • Pneumotaxic: decreases Vt for fine control (located high in the pons)
  • Apneustic: increases Vt for long, deep breathing (located lower in the pons)
    * output limited by baroreflex, pneumotaxic*
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42
Q

How do central chemoreceptors work?

A

respond to H+ ions

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43
Q

How do peripheral chemoreceptors work?

A

respond to CO2, pH, and hypoxemia

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44
Q

What carries the aortic arch and lung stretch signals?

A

Vagus (X) carries it to the DRG

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45
Q

What carries the carotid body signals?

A

Glossopharyngeal (IX) carries it to the DRG

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46
Q

Parasympathetic control over the airway

A
From vagus (X)
Causes: mucous secretion, increased vascular permeability, vasodilation, bronchospasm, bronchoconstriction (greatest in upper airway)
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47
Q

Sympathetic control over the airway

A

intrinsically, small effect –> inhibit mediator release from mast cells, increase mucociliary clearance

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48
Q

What is the Vt of a patient?

A

usually 6-8 ml/kg IBW

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49
Q

Inspiratory capacity

A

IRV + Vt

50
Q

VC

A

IRV + Vt + ERV

51
Q

FRC

A

ERV + residiual volume; 2L

52
Q

What does a normal tidal breath bring into the respiratory zone?

A

350 mL inspiration (21% O2)

350 mL expiration (5-6% CO2)

53
Q

Per minute, how much oxygen & co2 diffuse at alveolar/capillary membrane

A

250 mL of O2, 200 mL of CO2

respiratory quotient

54
Q

What are some reasons for decreased static compliance? (7)

A

fibrosis, obesity, edema, vascular engorgement, ARDS, external compression, atelectasis

55
Q

How do you calculate static compliance?

A

= Vt/ (Pplat - PEEP)

normal = 60 - 100 ml / cmH2O

56
Q

How do you calculate dynamic compliance?

A

= Vt/ (PIP - PEEP)

normal = 50 - 100 mL / cm H2O

57
Q

Reasons for decreased dynamic compliance

A

bronchospasm, tube kinking, mucous plugs, increased RR

58
Q

Laminar flow

A

small airways ( < 2000)

59
Q

Turbulent flow

A

large airways (greatest resistance in medium sized bronchi) (> 4000)

60
Q

Reynold’s Number

A
Re = pvd/n
p= density
v = velocity
d = diameter
n= viscosity
61
Q

Poiseuille’s Law

A

R = 8nl/r^4

62
Q

Zone 1

A

alveolar > arterial > venous

v/q > 1
no blood flow

63
Q

Zone 2

A

arterial > alveolar > venous

v/q = 1
intermittent blood flow

64
Q

Zone 3

A

arterial > venous > alveolar

v/q = 0.8 yay
alveolar compliance and perfusion are the greatest
i am where blood pools

65
Q

Zone 4

A

arterial > IS > venous > alveolar

v/q < 1 (disease)

66
Q

Alveolar concentrations of gas

A
O2 = 100
CO2 = 40
H2O = 47
N2 = 575
67
Q

Expired concentrations of gas

A
O2 = 116
CO2 = 32
H2O = 47
N2 = 565
68
Q

Arterial concentrations of gas

A
O2 = 95
CO2 = 40
H2O = 47
N2 = 575
69
Q

Capillaries concentrations of gas

A
O2 = 40
CO2 = 46
H2O = 47
N2 = 575
70
Q

Venous concentrations of gas

A
O2 = 40
CO2 = 46
H2O = 47
N2 = 575
71
Q

What is closing volume

A

the volume above residual volume where small airways close

72
Q

What is closing capacity

A

the absolute volume of gas when small airways close (CV + RV)

increases from 30% (age 20) of TLC to 55% of TLC (age 55)

increased by: supine, obesity, pregnancy, copd, chf, aging

73
Q

what does hemoglobin consist of?

A

4 protein subunits (2 alpha, 2 beta)
4 heme subunits
Iron

each gram of hgb binds to 1.34 mL of oxygen

74
Q

left shift of oxyhemoglobin curve

A

loves - higher affinity

-low temp, low CO2, high pH, low DPG

75
Q

right shift of oxyhemoglobin curve

A

releases - lower affinity

-high temp, high CO2, low pH, high DPG

76
Q

haldane effect

A

oxygenation of blood displaces CO2 from hgb; curve shifts up and left when PO2 decreases

occurs at A/C membrane

77
Q

bohr effect

A

hgb affinity for O2 is inversely r/t CO2 levels

occurs at tissue level

78
Q

what is the p50

A

PaO2 at which 50% of hgb is saturated

26 - 28 mmHg

79
Q

70% saO2

A

40 mm Hg PAO2

80
Q

90% saO2

A

60 mm Hg PAO2

81
Q

DLCO

A

tests the lungs diffusing capacity for carbon monoxide

normal > 75%
mild: 60%
moderate: 40 - 60%
severe < 40%

82
Q

How is CO2 transported in the blood?

A
  1. physical solution (5-10% dissolved)
  2. chemically combined w/aa or proteins (5-10% hgb)
  3. bicarbonate ions (80-90%)
83
Q

hamburger shift

A

hco2 leaves the RBCs; chloride enters to maintain electrical neutrality aka chloride shift

84
Q

hypoxic hypoxia

A

generally an issue w/lungs

low fiO2
hypoventilation
v/q mismatch
r - l shunt

supplemental O2 does help

85
Q

clinical examples of hypoxic hypoxia (8)

A
high altitudes
O2 equipment error
drug OD
COPD
pulmonary fibrosis
PE
atelectasis
CHD
86
Q

circulatory hypoxia

A

reduced CO

ex: HF, dehydrated, sepsis, SIRS

supplemental O2 does not help

87
Q

hemic hypoxia

A

reduced hgb content/function

examples: anemia, CO, methemoglobinemia (NTG, prilocaine)

supplemental O2 does not help

88
Q

histotoxic hypoxia

A

increased O2 consumption or inability to use O2

examples: fever, sz, cyanide

supplemental O2 does help

89
Q

what is HPV affected by?

A

PAo2, ph, pco2, temp

eliminated by elevated fio2, VA > 1 MAC

90
Q

MOA of HPV

A

alterations in leukotrienes and PG synthesis, inhibits NO

91
Q

deadspace V/Q mismatch

A

causes: PE, hypovolemia, cardiac arrest, shock

* anything that causes a decrease in pulmonary blood flow*

92
Q

shunt

A

causes: mucous, mainstem, atelectasis, PNA, PE

* anything that causes the alveoli to collapse*

93
Q

anatomical dead space

A

air that is present in the airway that never reaches the alveoli, therefore, never participates in gas exchange

94
Q

alveolar dead space

A

air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow

95
Q

physiologic dead space

A

anatomical + alveolar

all of the air in the respiratory system that is not being used for gas exchange

96
Q

Vd (deadspace equation (bohr))

A

Vt x (PaCO2 - PeCO2)/PaCo2

97
Q

what is PeCO2

A

is normally 2-5 mmHg less than PaCO2 d/t mixing with anatomic deadspace during exhalation

increases w V/Q mismatch

98
Q

venous admixture (3)

A

result of mixing of non-oxygenated blood w/oxygenated blood distal to the alveoli

  1. communicating between bronchial & pulmonary circulation*
  2. thebesian veins
  3. low V/Q areas
99
Q

what does PVO2 represent?

A

the overall balance between VO2 and DO2

100
Q

what decreases PVO2 (3)

A

decreased CO, increased O2 consumption, decreased Hgb

101
Q

absolute shunt

A

v/q = 0

-hypoxia unresponsive to supplemental oxygenation

102
Q

shunt-like alveoli

A

v/q < 1

-low PO2 and high PCO2

103
Q

deadspace-like alveoli

A

high v/q > 1

-high PO2 and low PCO2

104
Q

fick’s law

A

V = D * A* deltaP/T

105
Q

alveolar oxygen tension (PAO2)

A

PAO2 = (PB - H2O) x FiO2 - (PaCO2/0.8)

106
Q

alveolar arterial oxygen tension gradient

A
P(A-a)O2= PAO2 - PaO2
normal = 5 - 15
107
Q

A-a gradient increases with?

A

age, obesity, supine, heavy exercise

108
Q

A/a ratio

A

PAO2/paO2
good indicator of overall gas exchange
normal > 75%

109
Q

oxygen content

A

CaO2 = (hgb x 1.34 x saO2) + (PaO2 x 0.003)

110
Q

DO2

A

CO x CaO2
CO = 5L/m
CaO2 around 200

111
Q

VO2

A

Fick Equation
CO x (CaO2 - CvO2)
usually around 250 mL/m

112
Q

P/F Ratio

A

PaO2/FiO2
normal = 400 - 500
tells you if there is a problem, just not the etiology

113
Q

< 300 P/F Ratio

A

mild ARDS

114
Q

< 200 P/F

A

moderate ARDS

115
Q

< 100 P/F

A

severe ARDS

takes 100% O2 to yield a normal PaO2

116
Q

How is CO2 produced?

A

acetyl coA (2)
ETC (6)
kreb’s cycle (4)

117
Q

What does ETC do?

A

oxidizes NADH/FADH2, consumption of O2

118
Q

What does proton gradient do?

A

produces phosphorylation of ADP to ATP

119
Q

Normal PO2 & CO2

A
V/Q = 0.8
PAO2 = 100
PACO2 = 40
PaO2 = 100
PaCO2 =40
120
Q

TOTAL Airway obstruction PO2 & CO2

A
*shunt*
V/Q < 1 
PAO2 = 0
PACO2 = 0
PaO2 = 40
PaCO2 =46
121
Q

PULMONARY EMBOLUS PO2 & CO2

A
V/Q > 1
PAO2 = 150
PACO2 = 0
PaO2 = 
PaCO2 =