Pulmonary Physiology Flashcards Preview

Cardio Pulm > Pulmonary Physiology > Flashcards

Flashcards in Pulmonary Physiology Deck (55):
1

Parasympathetic NS

-Causes bronchoconstriction
-(Ach & muscarinic receptors)

2

Sympathetic NS

-causes bronchodilation
-NE, Epinephrine & beta-2 receptors

3

Anatomical Dead Space

-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

2 Reasons for Physiological Dead Space

-area ventilated but not perfused
-area perfused but not ventilated

5

Dead Space Types

-anatomical dead space
-physiological dead space

6

Physiological dead Space

-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

Example of Ventilated but not Perfused

-poor circulation, pulmonary embolism
-V/Q=4/0=infinity

8

Air distribution in lungs

-R lung bigger=more air to it
-dependent alveoli are more compliant and get more air
-air goes where gravity pulls it

9

Example of perfused but not ventilated

-bronchospasm, obstructions, secretions, (CF, pneumonia, Asthma)
-V/Q=0/5=0

10

Normal V/Q

4/5=0.8

11

3-Zone Model

-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

Gravity & Blood Flow

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

13

Right Ventricular Stroke Volume

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

14

Pulmonary Vascular Resistance

-increased PVR=decreased perfusion

15

Elastic Recoil

-ability of lungs to return to original shape after having been stretched
-due to elastin

16

V/Q

-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

Compliance

-the ease with which the lungs expand during inspiration

18

low compliance=

greater pressure needed to get the same change in volume

19

Large compliance=

greater increase in volume for small change in pressure

20

Example that Increases Compliance

-Age & Emphysema

21

Increased Fluid in Lungs=

decreased compliance

22

RDS

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

(Surfactant mature @ 35 weeks)

23

Surfactant

-produced by type II alveolar cells
-decreases H2O tension
-decrease amount of Mm tension needed to expand lungs

24

3 Factors Affecting Airway Distribution

-Airway obstruction
-Abnormal Lung or Chest wall Compliance
-Respiratory Mm weakness

25

Examples that Decrease compliance

-fibrosis
-alveolar edema
-(inspiratory Mm must work harder)

26

C=

C=change in volume/change in pressure

27

WOB

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

with pathology=25% VC

28

5 Factors Affecting WOB

-Airway resistance
-Lung compliance
-Alveolar surface tension
-Dead space volume
-Respiratory Rate

29

Airway Resistance

-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

Bronchiole Mm Control

-respond to local changes
-increased CO2 in alveolus causes vasodilatoin to increase airflow

31

Increased WOB=

-decreased tidal volume and RR-->decreased alveolar ventilation

-->less O2 to blood and body

32

Assessment of Perfusion

-IV injection of technetium labeled human albumin
-will lodge in pulmonary capillaries in proportion to perfusion
-gamma cameras detect

33

Control mechanisms during disease

-O2 levels decreased and CO2 levels increase or stay same
-peripheral chemoreceptors fire in response to low O2 levels--><60PaO2 mmHg

34

Cold Spots

areas not ventilated or perfused

35

Assessment of Ventilation

-pt inhales radioactive xenon
-gamma camera detects location of gas in lungs

36

Diabetes

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

37

Slow-Wave Sleep

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

38

2 kinds of sleep apnea

-central
-obstructive

39

Eupnea

-normal rate and rhytm
-12-20breaths/min

40

Tachypnea

-increased rate with normal rhythm
>20breaths/min

41

Hyperventilation

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

42

Apnea

-no breathing

43

Bradypnea

-decreased rate with normal rhythm
-<12 breaths/min

44

hypoventilation

shallow inspirations, often irregular

45

Kussmaul's Respiration

-deeper and faster respirations
-to compensate for metabolic/ketoacidosis (blow off excess acid/CO2)

46

Glossopharyngeal Breathing

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

47

Central Sleep Apnea

-failure of respiratory center
-from encephalitis, brain stem infarction, bulbar polio
-idiopathic: Odine's curse-->use conscious effort to control ventilation

48

REM Sleep

-irregular breathing
-decreased Mm activity-->sleep obstructive apnea

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

49

Airway Receptors

-in nose, nasopharynx, larynx and trachea
-respond to increased airway pressure or irritants
-results in sneezing, coughing, bronchospasm or laryngospasm

50

3 respiratory reflexes

-Hering-Breuer Reflex
-Juxtacapillary (J) Receptors
-Airway receptors

51

Hering-Breuer Reflex

-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

Juxtacapillary Receptors

-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

Cheyne-Stokes Respiration

-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

Obstructive Sleep Apnea

-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

Biot's Respiration

-faster and deeper respirations with abrupt pause
-often due to increased ICP