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Pulmonology > Physiology > Flashcards

Physiology Flashcards

1
Q

parietal pleural membrane

A

outer membrane of the lung that is against the inner surface of the thoracic cavity

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2
Q

visceral pleural membrane

A

membrane that covers the surface of each lung

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3
Q

pleural cavity

A

space between the parietal and visceral membranes

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4
Q

What is the order of branching in the respiratory tree from largest to smallest?

A
  • trachea
  • main bronchus
  • lobar bronchus
  • segmental bronchus
  • conducting bronchiole
  • terminal bronchiole
  • respiratory bronchiole
  • alveolar duct
  • alveolar sac
  • alveolus
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5
Q

Conducting zone vs. respiratory zone

A

conducting zone:
-trachea to terminal bronchiole

respiratory zone:

  • respiratory bronchiole
  • alveolar duct and sac
  • alveolus
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6
Q

What functions are greatly decreased in the respiratory zone?

A
  • smooth muscle

- ability to constrict passages

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7
Q

respiratory epithelium in the nasal cavity

A

mucous cells and mucus escalator

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8
Q

respiratory epithelium in the pharynx

A

stratified squamous for protection from abrasion and chemical attack

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9
Q

respiratory epithelium in the conducting portion of respiratory tract

A

typical respiratory mucosa

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10
Q

respiratory epithelium in the bronchioles

A

becomes cuboidal

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11
Q

respiratory epithelium in the gas exchange surfaces

A

delicate simple squamous epithelium

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12
Q

pneymocytes (3)

A
  • Type I alveolar cells
  • Type II alveolar cells
  • Alveolar macrophages
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13
Q

type I alveolar cells

A

form the alveolar wall

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14
Q

type II alveolar cells

A
  • secrete surfactant
  • allows membranes to separate
  • continuously released by exocytosis
  • aqueous protein-containing hypophase and overlying phospholipid film composed primaryily of dipalmitoyl phosphatidylcholine
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15
Q

purpose of surfactant

A

lower surface tension

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16
Q

alveolar macrophages

A

phagocytize foreign material such as bacteria

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17
Q

pulmonary circulation of low oxygen blood

A
  • returned from systemic circulation to RA
  • RV to pulmonary artery
  • to capillaries in lungs
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18
Q

pulmonary circulation of oxygenated blood

A
  • from lungs to pulmonary veins to LA

- LV to aorta to systemic circ

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19
Q

atmospheric pressure at sea level

A

760 mmHg

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20
Q

intrapulmonary pressure

  • where
  • how does it change
A
  • within alveoli

- changes w/ volumes

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21
Q

intrapleural pressure

  • where
  • relation w/ atmospheric pressure
A
  • within pleural cavity

- about -4 from atmospheric pressure

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22
Q

What are the 3 factors that hold the lungs to the thorax?

A
  1. surface tension of pleural fluid
    -holds membranes together
  2. positive pressure in lungs
    -always higher than
    intrapleural
    -net outward pressure
  3. atmospheric pressure
    -exterior force
    -higher than subatm. P of intrapleural space
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23
Q

What are the 2 factors that pull lungs from thorax?

A
  1. recoil tendency
    - elastic nature of lungs
    - always seek smallest size
  2. alveolar surface tension
    - draws the alveolus in
    - maintaining air in this space prevents collapses
    - also fluid from type II cells
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24
Q

What is the most important factor in holding the lungs to the thorax?

A

negative pressure of the intraplueral space (positive pressure in lungs)

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25
Q

atelectasis

A

collapse/closure of the lung

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26
Q

Boyle’s Law

A

pressure of a gas varies inversely with its volume

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27
Q

effects of increasing thoracic volume in all direction

A
  • lowers pressure interiorly
  • air rushes in through trachea down its pressure gradient
  • results in inspiration
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28
Q

effects of relaxation of the thorax

A
  • compresses air inside
  • air flows out from this area of increased pressure
  • results in expiration
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29
Q

Sequence of events in inspiration (5)

A
  1. inspiratory muscles contract
  2. thoracic cavity volume increases
  3. lungs are stretched; intrapulmonary volume increases
  4. intrapulmonary pressure drops
  5. air flows into lungs down pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric)
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30
Q

Sequence of events in expiration (5)

A
  1. inspiratory muscles relax
  2. thoracic cavity volume decreases
  3. elastic lungs recoil passively; intrapulmonary volume decreases
  4. intrapulmonary pressure rises
  5. air flows out of lungs down pressure gradient until intrapulmonary pressure is 0
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31
Q

Resistance

A

the opposition to airflow

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32
Q

resistance depends on what?

A
  • diameter of tube
  • type of flow: turbinate; laminar
  • viscosity of gas (humidity)
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33
Q

airflow equation

A

V = deltaP / R

airflow = pressure gradient / resistance

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34
Q

physical factors influencing ventilation through airway resistance

A
  • obstruction
  • bronchoconstriction: smooth muscle contraction, parasympathetic control, irritants, RAD
  • bronchodilation: smooth muscle relaxation, sympathetic control
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35
Q

lung compliance

A
  • ease w/ which lungs can be distended or stretched

- a measure of the change in lung volume that occurs w/ a change in the intrapulmonary pressure

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36
Q

compliance equation

A

C = delta V / delta P

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37
Q

hysteresis

A

gap between input and output

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38
Q

where is airway resistance the highest?

A

the medium sized bronchi of the conducting zone

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39
Q

lung compliance is dependent on what?

A

elasticity of tissues

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40
Q

lung compliance decreases with what? (4)

A
  • decreased lung elasticity such as fibrosis
  • obstruction
  • alveolar film changes
  • impaired thoracic cage flexibility
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41
Q

factors influencing ventilation through lung elasticity

A
  • ability of tissues to recoil
  • essential to expiration
  • COPD reduces recoil d/t deterioration of alveolar walls
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42
Q

surface tension

A
  • occurs at fluid-air interface
  • liquid molecules are more attracted to each other
  • creates tension across liquid surface
  • water has high surface tension
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43
Q

surfactant

A
  • alveolar film
  • secreted from type II alveolar cells
  • lipoprotein
  • disrupts cohesiveness of water molecules
  • decreases surface tension
  • prevents alveolar collapse
  • reduces energy required to overcome surface tension
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44
Q

infant respiratory distress syndrome

A
  • insufficient surfactant in neonate
  • incidence decreases w/ increasing gestational age
  • 50% in babies born at 26-28 wks; 25% at 30-31 wks
  • high HR, RR, cyanosis
  • tx: surfactant spray and positive pressure ventilation
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45
Q

spirometry

A
  • measuring of breath
  • most common PFT
  • measures lung function
  • specifically the amount (vol.) and/or speed (flow) of air that can be inhaled and exhaled
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46
Q

tidal volume (TV)

A

quiet eupnea

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47
Q

inspiratory reserve volume (IRV)

A

air forced in above TV

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48
Q

expiratory reserve volume (ERV)

A

forced out after exp

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49
Q

residual volume (RV)

A
  • remains after forced expiration

- maintains alveolar patency and prevents lung collapse

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50
Q

inspiratory capacity (IC)

A
  • total amount that can be inhaled after tidal expiration

- TV + IRV

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51
Q

Have a general understanding of the amount of air in each pulmonary capacity

A
  • IRV: 3100 ml
  • TV: 500 ml
  • ERV: 1200 ml
  • RV: 1200
  • IC: 3600
  • FRC: 2400
  • VC: 4800
  • TLC: 6000
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52
Q

functional reserve capacity (FRC)

A
  • amount of air remaining in lungs after tidal expiration

- ERV + RV

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53
Q

vital capacity (VC)

A
  • total amount of exchangeable air

- TV + IRV + ERV

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54
Q

total lung capacity (TLC

A

sum of all

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55
Q

dead space

A

air which enters the pulmonary space but cannot be used

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56
Q

anatomical dead space

A
  • conducting zone

- 150 ml of tidal volume

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57
Q

physiological dead space

A
  • nonfunctioning alveolus

- d/t mucus or blood flow

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58
Q

pulmonary function tests (PFT)

A

measurement of pulmonary function, dysfunction and efficacy of medication

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59
Q

minute respiratory volume (MRV)

A
  • total vol. moved in 1 minute
  • TV x breaths per min
  • 500 ml x 12 breaths per min. = 6000 ml/min
  • rate and depth increases w/ activity
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60
Q

forced vital capacity (FVC)

A

-deep breath and rapid forced exhalation

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61
Q

forced exiratory volume (FEV)

A
  • FVC measurements at specific intervals:
  • FEV1: volume in first second
  • FEV1 FVC ratio (normal is 80%)
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62
Q

FEV1 in obstructive diesase

A
  • low and slow

- ratio = 40%

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63
Q

FEV1 in restrictive disease

A
  • low and fast

- ratio = 88%

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64
Q

alveolar ventilation rate

A
  • better index of effective ventilation than MRV

- subtracts dead space volume

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65
Q

What are processes other than breathing that move air?

A
  • cough: forced expulsion of air from lower respiratory tract
  • sneeze: forced expulsion of air from upper airways
  • hiccup: diaphragm spasms
  • crying/laughing: emotionally induced, release of air in short expirations
  • yawns: deep inspiration w/ jaw open; ventilates all alveoli
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66
Q

Dalton’s Law

A

-total pressure exerted by a mixture of gases is the sum of the pressures of each gas

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67
Q

Henry’s Law

A
  • the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the surface of the solution
  • i.e: dissolves in proportion to its pp
  • depends also on the solubility of the gas in liquid
  • CO2 is very soluble
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68
Q

hyperbaric chamber

A
  • makes use of henry’s law
  • increase atmospheric pressure
  • increases partial pressure of O2
  • increasing diffusion into blood
  • use in CO poisoning, gas gangene, would healing, decompression sickness
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69
Q

properties of gases

A

atmospheric p. at sea level = 760 mmHg

  • N2 (78.6%) - 597
  • O2 (20.9%) - 159
  • CO2 (0.04%) - 0.3
  • H2O (0.46%) - 3.7
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70
Q

properties of alveolar gases

A
  • N2 (74.9%) - 569
  • O2 (13.7%) - 104
  • CO2 (5.2%) - 40
  • H2O (6.2%) - 47
71
Q

What is the difference in amount of gases between air and alveolar gas due to?

A
  • gas exchange
  • humidification
  • mixture of new and residual air
72
Q

diffusing capacity

A
  • diffusing capacity of the lung for a gas is indirectly proportional to the surface area of the alveolar-capillary membrane
  • it is inversely proportional to its thickness
73
Q

diffusing capacity equation

A

DLCO = V / P

74
Q

DLCO (diffusing capacity of lung to CO2)

A
  • a measure of how well oxygen and CO2 are transferred (diffused) b/w the lung and the blood
  • CO2 is generally the test gas used to measure
75
Q

When is DLCO reduced?

A

in diseases that:

  1. thicken the membrane (fibrosis)
  2. reduce the surface area of membrane (emphysema, cancer)
76
Q

external respiration

  • where
  • based on what
A
  • occurs at alveolus-capillary junction

- based on pressure gradients and solubility

77
Q

what is the surface area for diffusion in the lung?

A
  • 300 million alveoli

- 145m (size of tennis court)

78
Q

ventilation

A

(V) = air reaching alveolus

79
Q

perfusion

A

(Q) = gas reaching pulmonary capillaries

80
Q

ventilation perfusion coupling

A
  • V/Q

- ideally matched

81
Q

VQ scan

A
  • imaging
  • inhaled radiolabeled isotope
  • gold standard for PE
82
Q

in pulmonary gas exchange, what happens when alveolar O2 is inadequate?

A

pulmonary vasoconstriction occurs to send blood to more ventilated areas

83
Q

in pulmonary gas exchange, what happens when alveolar CO2 is high?

A

vasodilation occurs to allow for greater CO2 diffusion from blood

84
Q

internal respiration occurs between ?

A

between blood and tissues

85
Q

What solves the poor solubility of O2?

A

hemoglobin

86
Q

At what partial pressure is Hgb saturated?

A

70 mmHg

87
Q

purpose of the venous reserve

A
  • it can deliver O2 rapidly to tissues in need w/o changing RR or HR
  • about 20-25% O2 is unloaded in 1 venous circuit
88
Q

What effect does temp have on hgb affinity for O2?

A
  • as temp increases, affinity for O2 decreases (not linear)

- decreasing affinity relates to O2 unloading which is desirable in areas of high metabolic activity

89
Q

Bohr effect

A
  • As [H+] increases, pH decreases
  • low pH decreases affinity for O2
  • metabolically active tissues release more CO2 and H+
  • so O2 unloading occurs at active tissues needing it
90
Q

DPG

A
  • diphosphoglycerate
  • intermediate of glycolysis in RBCs
  • binds Hgb and decreases its affinity for O2
91
Q

as DPG increases, what is the result?

A

more O2 is available to the tissues

92
Q

hormones that increase RBC activity

A
  • thyroxine
  • testosterone
  • growth hormone
  • catecholamines (epi norepi)
93
Q

what does a left shift indicate in the O2 dissociation curve?

A

high O2 affinity

94
Q

what does a right shift indicate in the O2 dissociation curve?

A

lower O2 affinity

95
Q

oxygen saturation

A
  • SaO2
  • pulse ox measures peripheral O2 sat as an estimate of percentage of O2 bound to Hgb
  • healthy: 96-99%
  • <90% is hypoxemia
96
Q

partial pressure oxygen

A
  • PaO2
  • low oxygen pressure Hgb tends to be unsaturated
  • in cells= 40mmHg
  • in blood = 75-100mmHg
97
Q

PaO2 in the oxygen dissociation curve

A
  • at low PaO2, Hgb becomes rapidly saturated w/ O2

- levels off w/ increasing partial pressures of O2

98
Q

Hgb binding to CO

A

-Hgb binds CO 200-250 times more radily than with O2
-Hgb completely dissociates the oxygen molecules for the more favorable CO, yeilding HbCO
= hypoxia (w/o cyanosis), HA, confusion, respiratory distress, coma, death

99
Q

Hgb CO reaction equation

A

HbO2 + CO HbCO + O2

100
Q

what is the source of carbon dioxide?

A
  • cellular respiration

- 200 mL produced per min

101
Q

3 forms of CO2 transport

A
  • dissolved in plasma (7-10%)
  • carbaminohemoglobin (20-30%)
  • bicarbonate ion (60-70%)
102
Q

carbaminohemoglobin

A
  • hgb can bind to 4 CO2 molecules
  • in absence of O2, unbound hgb molecules have greater chance of becoming carbaminohemoglobin
  • distinctive blue color contributes to dark red color of low O2 in venous blood
103
Q

bicarbonate ion forms d/t what?

A

enzymatic activity of carbonic anhydrase

104
Q

equation yielding bicarb

A

CO2 + H2O H2CO3 HCO3- + H+

carbon dioxide + water carbonic acid bicarb + hydrogen

105
Q

Bohr efffect

A

generation of H+ enhances O2 unloading

106
Q

Haldane effect

A
  • deoxygenation of Hgb increases its ability to bind CO2
  • Hgb uptakes protons
  • buffering pH in the RBC
107
Q

pH blood values

A
  • normal: 7.35-7.45
  • acidosis: <7.35
  • alkalosis: >7.45
108
Q

acid base disorders are changes in what? (3)

A
  • blood pH
  • arterial pCO2
  • blood HCO3
109
Q

actual changes in pH depend on what?

A

the degree of physiologic compensation

110
Q

respiratory causes of acid-base balance disorders

A
  • inadequacy of respiratory function

- usually pCO2 imbalance

111
Q

metabolic cause of acid-base balance disorders

A

any abnormalities resulting in pH changes except those caused by pCO2 imbalance

112
Q

compensation mechanisms

A
  • respiratory changes
  • buffering systems in blood and tissues
  • kidney absorption and secretion
113
Q

metabolic acidosis can be d/t: (4)

A
  • increased acid production
  • acid ingestion
  • decreased renal acid secretion
  • GI or renal HCO3 loss
114
Q

metabolic alkalosis causes: (2)

A
  • acid loss

- HCO3 retention

115
Q

respiratory acidosis

A
  • blood pH <7.35
  • pCO2 > 45mmHg (hypercapnia)
  • CO2 accumulated in blood d/t hypoventilation
  • pneumonia, CF, emphysema, overdose, brainstem dysfunction
116
Q

compensation of respiratory acidosis (respiration and renal)

A
  • respiration: increases to allow CO2 ventilation
  • kidney:
  • renal tubule cells have carbonic anhydrase
  • retain bicarb
  • eliminate H+
117
Q

respiratory alkalosis

A
  • blood pH >7.45
  • pCO2 <35 (hypocapnia)
  • CO2 decreased in blood d/t hyperventilation
  • pneumonia, reactive airway dz, high altitude, anxiety, brain stem injury
118
Q

compensation of respiratory alkalosis (respiration and renal)

A
  • respiration: decreases to allow CO2 accumulation
  • kidney:
  • retain H+
  • eliminate bicarb
119
Q

hypoxia

A

oxygen deficit at tissue level

120
Q

most common types of hypoxia

A
  • hypoxemia: low arterial O2; pneumonia, high altitude;
  • anemic hypoxia: adequate O2, low Hbg
  • ischemic hypoxia: slowed circulation, heart failure, shock
  • histotoxic hypoxia: poisoning i.e cyanide
121
Q

hypoxemia S/S

A
  • SOB, dyspnea
  • HA
  • fatigue/lethargy
  • severe mood changes or irritability
  • cyanosis
  • digital clubbing (chronic)
122
Q

causes of hypoxemia (decreased arterial pO2)

A
  • ARDS
  • asthma
  • CO poisoning
  • congenital heart disease
  • COPD
  • high altitude
  • interstitial lung disease
  • meds
  • pneumonia
  • pneumothorax
  • pulmonary edema
  • PE
  • pulmonary fibrosis
  • sleep apnea
123
Q

high altitude causing hypoxemia

A
  • composition of gases is unchanged by atm pressure but partial pressures are decreased
  • as pO2 falls, ventilation increases, pCO2 falls and respiratory alkalosis can occur
124
Q

altitude sickness

A
  • irritability
  • mental status change
  • N/V
  • HA
  • LOC
  • coma
  • death
125
Q

acclimatization to high altitude

A
  • DPG increases resulting in O2 unloading
  • ventilatory response decreases after about 4 d
  • EPO secretion increases RBC
126
Q

hypoxemia d/t venous to arterial shunts

A
  • cardiovascular abnormalities
  • ie. interseptal defect
  • large amount of low O2 blood shunts from RV to LV bypassing pulmonary oxygenation
  • chronic hypoxemia and cyanosis
  • O2 administration has little effect
127
Q

what is the most common cause of hypoxemia?

A

ventilation/perfusion imbalance

128
Q

ventilation/perfusion imbalance causing hypoxemia

A
  • defects in ventilation (low V/Q ratio): chronic bronchitis, RAD, acute pulmonary edema, hepatopulmonary syndrome of liver failure
  • defects in perfusion (high V/Q ratio): PE, emphysema
129
Q

anemic hypoxia

A
  • decreased Hg
  • compensated by increased DPG production
  • shifts dissociation curve to right
130
Q

CO poisoning hypoxia

A
  • decreases O2 sat

- fatal is >70% COHgb

131
Q

ischemic hypoxia

A
  • slowed circulation therefore poor delivery
  • shock
  • heart failure
  • ARDS
132
Q

histotoxic hypoxia

A
  • decrease in oxidative processes
  • i.e: toxin like cyanide
  • treat w/ methylene blue
  • binds Hgb then cyanide to form cyanomethemoglobin which is non toxic
133
Q

decompression sickness

A
  • result of increases pressure esp when diving
  • inert gases (N2) will dissolve in plasma
  • forms gas bubbles on ascent
  • decompress on ascent to allow gases to be unloaded by lungs
134
Q

Henry’s law

A

-increased pressure increases partial pressures (think decompression sickness)

135
Q

onset of decompression sickness symptoms

A
  • w/i 1 hr: 42%
  • w/i 3 hrs: 60%
  • w/i 8 hrs: 83%
  • w/i 24 hrs: 98%

although onset of DCS can occur rapidly, in more than 1/2 cases they don’t occur for at least an hour

136
Q

top 3 most common symptoms of decompression sickness?

A
  1. local joint pain
  2. arm symptoms
  3. leg symptoms

others: dizziness, paralysis, SOB, extreme fatigue, collapse/unconsciousness

137
Q

hyperoxia

A
  • oxygen toxicity

- O2 at pressures above normal

138
Q

3 settings for hyperoxia

A
  1. underwater diving
  2. hyperbaric O2 therapy
  3. provision of supplemental O2 (particularly to premature infants)
139
Q

effects of hyperoxia

A
  • CNS: convulsions followed by LOC
  • Pulmonary: SOB, dyspnea
  • Ocular: myopia, retinal detachment, damage
140
Q

hypercapnia

A
  • retention of CO2
  • usually d/t hypoventilation
  • stimulates respiration to blow off CO2
  • respiratory acidosis
141
Q

S/S and causes of hypercapnia

A

S/S: confusion, decreased sensory acuity, respiratory depression and coma
causes: heart failure, sleep apnea, LOC

142
Q

hypocapnia

A
  • depletion of CO2
  • secondary to hyperventilation
  • respiratory alkalosis
143
Q

S/S and causes of hypocapnia

A
  • S/S:
  • cerebral vasoconstriction leads to ligh headedness, numbness and tingling
  • tetany
  • Cvostek sign d/t increases plasma Ca2+
  • Causes: hyperventilating; brainstem dysfunction
144
Q

What controls the regulation of respiration?

A

-two separate neural control centers; voluntary and involuntary

145
Q

voluntary system control center

A

cerebral cortex to respiratory motor nerves via the corticospinal tracts

146
Q

involuntary system control center

A
  • medulla and pons of brain stem
  • sets pace
  • appropriating responses to sensory info from chemoreceptors and mechanoreceptors
147
Q

what is found within the medullary center?

A
  • VRG

- DRG

148
Q

ventral respiratory group (VRG)

A
  • contains both inspiratory and expiratory neurons
  • secondarily responsible for initiation of inspiratory activity after the DRG
  • pre-botzinger complex
  • expiratory respiratory group
149
Q

pre-botzinger complex

A
  • in VRG of medulla
  • pacemaker of breathing
  • neurons send rythmic signals
  • results in expansion of rib cage, air enters
  • cycles 12-18 times per min
  • inspiration 2 sec
  • expiration 3 sec
150
Q

neuron signals from the pre-botzinger complex (3)

A
  • phrenic nerve: contraction of diaphragm
  • intercostal nerve: external intercostals
  • hypoglossal nerve: tongue
151
Q

expiratory respiratory group

A
  • located in the VRG of medulla
  • maintains tone
  • increases contraction of inner intercostals and abs for forced exhalation
152
Q

dorsal respiratory group (DRG)

A
  • primarily responsible for the generation of inspiration
  • stimulated via the apneustic center in the lower pons and is also a part of the solitary tract (responsible for appropriating responses to sensory info from chemo and mechanoreceptors)
153
Q

DRG is inhibited by ?

A

pneumotaxic center

154
Q

pontine control centers

A
  • appear to modulate medullary centers
  • if medullary-pontine connection is transected, breathing is rhythmic by occurring in gasps
  • responsible for transition b/w inhalation and exhalation
155
Q

What are the 2 pontine control centers?

A
  • apneustic center

- pneumotaxic center

156
Q

apneustic center

A
  • excitatory to medullary inspiratory center (DRG)
  • creates inspiratory drive
  • prolongs inspiratory phase
  • receives inhibitory signals from pneumotaxic center
157
Q

pneumotaxic center

A
  • location superior to apneustic
  • inhibitory to apneustic center
  • inhibitory to DRG medullary center
  • prevents over inflation
158
Q

factors influencing rate and depth of breathing

A
  • irritant reflexes
  • hering-breuer reflex (inflation and deflation)
  • medullary chemoreceptors (central receptors)
  • carotid and aortic bodies
159
Q

irritant reflexes

A
  • particles such as debris, dust, lint, fumes
  • stimulate release of histamine by granulocytes in airway -stimulate irritant receptors
  • vagus mediated response: sneeze, cough, bronchocontricition
160
Q

Hering-Breuer reflex

A
  • mechano or stretch receptors in vesceral pleura and airways
  • inflation reflex
  • deflation reflex
161
Q

inflation hering-breuer reflex

A
  • prevents over-inflation of lung
  • receptors respond to excessive stretching of lung during large inspirations
  • action potential through vagus n. to inspiratory area in the medulla
162
Q

deflation hering-breuer reflex

A
  • shorten exhalation when the lung is deflated
  • by stimulation of stretch receptors or stimulation of proprioceptors activated by lung deflation
  • impulses travel afferently via Vagus and pneumotaxic centers of pons
163
Q

medullary chemoreceptors i.e central receptors

A
  • located on ventral surface of medulla, bathed in CSF
  • sensitive to pH
  • CO2 diffuses into CSF, carbonic anhydrase releases H+ and HCO3
  • hypercapnia
  • hypocapnia
164
Q

carotid and aortic bodies

A
  • perpherial receptors
  • sensitive to pO2 <60mmHg
  • aortic impulses ascend afferent vagal nerves to medulla
  • carotid impulses ascend afferent hypoglassal fibers
  • result is medullary stimulated ventilation to increase O2
165
Q

there is an increase in ventilation during exercise d/t:

A
  • physic stimulation
  • stimulation of cortical motor activation of skeletal muscle and respiratory centers
  • proprioceptors in muscles, tendons, and joints send excitatory impulses to respiratory center
166
Q

ventilation plateaus during exercise d/y:

A
  • central stimulatory effects of rising body temp
  • sympathetic nervous system stimulation
  • decreased activity shuts down respiratory stimulation
167
Q

skeletal muscle energy/oxygenation

A
  • skeletal muscle has myoglobin (hold 1 O2)
  • muscle cell energy needs to exceed ability to oxidatively phosphorylate ADP
  • anaerobic respiration ensues
168
Q

fatigue and exhaustion during exercise

A
  • consumption of resources
  • increased neural inputs to brain
  • lactate increase
  • temp increase
  • dyspnea
  • pain
169
Q

breathing pattern imbalances

A
  • Cheyne Stokes
  • Kussmaul breathing
  • sleep apnea
170
Q

cheyne stokes

A
  • rapid breathing d/t hypoxia followed by apnea d/y hypercapnia
  • seen in CHF, uremia, bain dysfunction
171
Q

Kussmaul breathing

A
  • deep and labored breathing pattern
  • often associated w/ severe metabolic acidosis, particularly DKA but also kidney failure
  • form of hyperventilation
  • in metabolic acidosis: first breathing is rapid and shallow, then gets deep and labored and gasping
172
Q

sleep apnea

A
  • obstructive most common, can be central
  • pharyngeal muscles relax or genioglossus pulls tongue foward
  • during REM, muscles are most tonic
  • airway obstruction and reduced effort awaken pt
  • fatigue, HA, snoring, reduced learning
  • tx: CPAP
173
Q

sleep apnea is associated with:

A
  • HTN
  • obesity
  • ETOH/drug use

Pulmonology (11 decks)

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