Pulmonary Physiology Flashcards Preview

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Flashcards in Pulmonary Physiology Deck (55)
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1
Q

Parasympathetic NS

A
  • Causes bronchoconstriction

- (Ach & muscarinic receptors)

2
Q

Sympathetic NS

A
  • causes bronchodilation

- NE, Epinephrine & beta-2 receptors

3
Q

Anatomical Dead Space

A
  • portion of tidal volue contained in conducting airways
  • doesn’t participate in gas exchange
  • reflects size of conducting airways

(approx = to body weight [108lbs=108ml)

4
Q

2 Reasons for Physiological Dead Space

A
  • area ventilated but not perfused

- area perfused but not ventilated

5
Q

Dead Space Types

A
  • anatomical dead space

- physiological dead space

6
Q

Physiological dead Space

A

-the anatomic dead space plus any other areas that don’t exchange gases (that should)=alveolar dead space

=~30% of tidal volume and should be equal to anatomical dead space

7
Q

Example of Ventilated but not Perfused

A
  • poor circulation, pulmonary embolism

- V/Q=4/0=infinity

8
Q

Air distribution in lungs

A
  • R lung bigger=more air to it
  • dependent alveoli are more compliant and get more air
  • air goes where gravity pulls it
9
Q

Example of perfused but not ventilated

A
  • bronchospasm, obstructions, secretions, (CF, pneumonia, Asthma)
  • V/Q=0/5=0
10
Q

Normal V/Q

A

4/5=0.8

11
Q

3-Zone Model

A
  • Zone 1: least gravity dependent; gets little blood
  • Zone 2: Intermediate zone (intermittant flow based on pulmonary arterial & alveolar pressures
  • Zone 3: most gravity dependent & gets the most blood
12
Q

Gravity & Blood Flow

A
  • blood flow is gravity dependent

- blood flow ~6x greater at bases of lungs than apices

13
Q

Right Ventricular Stroke Volume

A

-increased SV=increased pulmonary artery pressure & cause zone 3 to extend farther upward in each lung

14
Q

Pulmonary Vascular Resistance

A

-increased PVR=decreased perfusion

15
Q

Elastic Recoil

A
  • ability of lungs to return to original shape after having been stretched
  • due to elastin
16
Q

V/Q

A
  • ventilation-perfusion ratio
  • relationship between factors affecting alveolar gas flow and capillary blood flow
  • not perfectly matched: V/Q=4L/min/5L/min=0.8
17
Q

Compliance

A

-the ease with which the lungs expand during inspiration

18
Q

low compliance=

A

greater pressure needed to get the same change in volume

19
Q

Large compliance=

A

greater increase in volume for small change in pressure

20
Q

Example that Increases Compliance

A

-Age & Emphysema

21
Q

Increased Fluid in Lungs=

A

decreased compliance

22
Q

RDS

A
  • in premature infants born before 26-28 weeks old
  • before surfactant ready

(Surfactant mature @ 35 weeks)

23
Q

Surfactant

A
  • produced by type II alveolar cells
  • decreases H2O tension
  • decrease amount of Mm tension needed to expand lungs
24
Q

3 Factors Affecting Airway Distribution

A
  • Airway obstruction
  • Abnormal Lung or Chest wall Compliance
  • Respiratory Mm weakness
25
Q

Examples that Decrease compliance

A
  • fibrosis
  • alveolar edema
  • (inspiratory Mm must work harder)
26
Q

C=

A

C=change in volume/change in pressure

27
Q

WOB

A

-amount of muscular effort needed for ventilation
-=~5% total Vo2
=~10%VC

with pathology=25% VC

28
Q

5 Factors Affecting WOB

A
  • Airway resistance
  • Lung compliance
  • Alveolar surface tension
  • Dead space volume
  • Respiratory Rate
29
Q

Airway Resistance

A
  • Q(flow of air)=change in pressure/Resistance
  • airflow due to pressure gradient and airway resistance
  • radius of airway biggest control of airway resistance
30
Q

Bronchiole Mm Control

A
  • respond to local changes

- increased CO2 in alveolus causes vasodilatoin to increase airflow

31
Q

Increased WOB=

A

-decreased tidal volume and RR–>decreased alveolar ventilation

–>less O2 to blood and body

32
Q

Assessment of Perfusion

A
  • IV injection of technetium labeled human albumin
  • will lodge in pulmonary capillaries in proportion to perfusion
  • gamma cameras detect
33
Q

Control mechanisms during disease

A
  • O2 levels decreased and CO2 levels increase or stay same

- peripheral chemoreceptors fire in response to low O2 levels–><60PaO2 mmHg

34
Q

Cold Spots

A

areas not ventilated or perfused

35
Q

Assessment of Ventilation

A
  • pt inhales radioactive xenon

- gamma camera detects location of gas in lungs

36
Q

Diabetes

A

-diabetic ketoacidosis–>decreased pH (increased H+) –>firing of peripheral chemoreceptors–>increased ventilation to blow off excess acid

37
Q

Slow-Wave Sleep

A
  • decreased sensory stimulation
  • decreased central control mechanisms
  • decreased alveolar ventilation
  • PaCO2 2-3mmHg higher than waking
38
Q

2 kinds of sleep apnea

A
  • central

- obstructive

39
Q

Eupnea

A
  • normal rate and rhytm

- 12-20breaths/min

40
Q

Tachypnea

A

-increased rate with normal rhythm

>20breaths/min

41
Q

Hyperventilation

A
  • increased rate/depth

- commonly from anxiety due to signals from cortex/limbic system that modify normal breathing

42
Q

Apnea

A

-no breathing

43
Q

Bradypnea

A
  • decreased rate with normal rhythm

- <12 breaths/min

44
Q

hypoventilation

A

shallow inspirations, often irregular

45
Q

Kussmaul’s Respiration

A
  • deeper and faster respirations

- to compensate for metabolic/ketoacidosis (blow off excess acid/CO2)

46
Q

Glossopharyngeal Breathing

A
  • frog breathing

- used by high SCI injury pt to force air into lungs using tongue and palate

47
Q

Central Sleep Apnea

A
  • failure of respiratory center
  • from encephalitis, brain stem infarction, bulbar polio
  • idiopathic: Odine’s curse–>use conscious effort to control ventilation
48
Q

REM Sleep

A
  • irregular breathing
  • decreased Mm activity–>sleep obstructive apnea

-wakes person up with high PaCO2 or low O2 stimulate carotid chemoreceptors

49
Q

Airway Receptors

A
  • in nose, nasopharynx, larynx and trachea
  • respond to increased airway pressure or irritants
  • results in sneezing, coughing, bronchospasm or laryngospasm
50
Q

3 respiratory reflexes

A
  • Hering-Breuer Reflex
  • Juxtacapillary (J) Receptors
  • Airway receptors
51
Q

Hering-Breuer Reflex

A
  • protective receptors in smooth Mm of airways from trachea to bronchioles
  • when stimulated via vagus nerve to DRG to shut off inspiration
  • respond to lung over expansion
  • Tidal volume of 1.5 liter before firing
52
Q

Juxtacapillary Receptors

A
  • within alveolar walls near pulmonary capillaries
  • sense increased fluid pressure w/n caps or interstitial space
  • signal via vagus nerve to cause rapid shallow breathing
  • may be in pts with pulm edema
53
Q

Cheyne-Stokes Respiration

A
  • gradual increased rate and depth then slower with alternate periods of apnea
  • usually due t slow blood flow from heart to brain or change in feed back sensitivity to CSF
  • pt with cardiac failure, head injury (sign of impeding death)
54
Q

Obstructive Sleep Apnea

A
  • results from collapse/closure of pharynx, glottis or larynx
  • associated w/ obesity, hypersomnolence, hypoxemia, R heart failure, collapse of throat
  • most common: older men
  • Pickwickian Syndrome
55
Q

Biot’s Respiration

A
  • faster and deeper respirations with abrupt pause

- often due to increased ICP