Pulm

Question 1

upper airway

Answer 1

nose
pharynx
glottis
vocal cords

Question 2

2 subdivisions of lower airway and their generations+ volume

Answer 2

conducting- 16 gen, 150 mL

respiratory unit- 7 gen, 2.5 L

Question 3

types of airflow and where it occurs

Answer 3

upper airway- turbulent
treachea through conducting- laminar
respiratory units - diffusion

Question 4

what does the volume in the conducting airways represent and what do you use to measure it?

Answer 4

anatomic dead space; Fowler method (single breath nitrogen washout)

Question 5

how do you measure residual volume?

Answer 5

1) Helium dilution (how deeply you breath in dilutes He in monitor)
2) body plethysmography

Question 6

main muscle of inspiration + what its innervated by

Answer 6

diaphragm (phrenic, C3-C5)

Question 7

4 lung volumes

Answer 7

tidal volume
expiratory reserve volume
inspiratory reserve volume
residual volume

Question 8

4 lung capacities

Answer 8

TLC
FRC
IC
Vital capacity

Question 9

why does air go into lung?

Answer 9

boyle’s law- P proportional to 1/v

Question 10

what determines the volume of air in the lung?

Answer 10

1) lung compliance- delta v/delta p

2) interaction between lung (pulling in) and chest wall (pulling out)

Question 11

what is special about the inflation compliance curve?

Answer 11

exhibits hysteresis due to high surface tension of alveoli at small volumes

Question 12

trans-lung pressure

Answer 12

PL= Palveolar (0) - Ppleural (-5) = 5

pressure that keeps alveoli open

Question 13

wall pressure

Answer 13

Pw= Ppleural (-5) - Pbarometric (0)= -5

Question 14

respiratory pressure

Answer 14

Pr= alvolar pressure- barometric pressure= 0

Question 15

at what point on the relaxation pressure curve are the pressures balanced?

Answer 15

at FRC- chest pull out equals lung pull in

Question 16

describe the process of inspiration in terms of lung pressures

Answer 16

• diaphragm contracts
• pleural pressure (Ppl) becomes more negative (pulling air in)
• trans-lung pressure (Pa-Ppl) become more positive
• alveolar pressure becomes more negative, alveoli want to expand and pull air in

Question 17

During quiet breathing, pleural pressure is always positive/negative

Answer 17

negative (-5 to -8)

Question 18

Take away from the Hagen-Poiseuille equation explaining laminar flow & resistance

Answer 18

• resistance directly proportional to airway length/gas viscosity
• resistance inversely proportional to airway radius to the fourth power

Question 19

four factors influencing airway resistance

Answer 19

decreased AWR with increased

1) lung volume
2) sympathetic stimulation

increased AWR with increased

1) vagal stimulation
2) mucus/edema/infection/smooth muscle contraction

Question 20

what is flow limitation?

Answer 20

• at equal pressure point (abnormally outside cartilage), the pressure outside the airway (pleural) is greater than the pressure inside, can cause airway compression
• airflow becomes independent of total driving pressure (aka is FORCE INDEPENDENT)
• look at Palveolar-Ppleural (Plung)
• occurs with emphysema
• increase pressure in airways using purse lipped breathing

Question 21

what does a dynamic lung function test measure? what do you want it to be?

Answer 21

FEV1/FVC

normal - >75%

Question 22

what dynamic lung function result is low in asthma? what do you test?

Answer 22

low FEV1/FVC ratio

test if albuterol (beta 2 agonist) helps

Question 23

how does pulmonary vascular resistance change with changes in pressure and why?

Answer 23

pulmonary vascular resistance decreases with increases in pressure b/c of

1) recruitment (more capillaries open up) and
2) distension (vessels are thin, can easily be expanded)

Question 24

when is pulmonary vascular resistance lowest with respect to lung volume? what is it a balance between?

Answer 24

at FRC

• balance between alveolar and extra-alveolar vessels
• extra-alveolar vessels behave like lung tissue, expand with inhalation

Question 25

intrapleural pressure is less negative at the bottom/top of the lung; alveoli at this point have a smaller/larger translung pressure (Pa-Ppl), how do they compensate?

Answer 25

bottom (more surface area, gravity) - alveoli at base have smaller translung pressure, are smaller BUT have *higher* compliance, recieve more of the ventilation in lung

Question 26

what does breathing at a smaller volume benefit?

Answer 26

alveoli at the top of the lung- have a negative translung pressure, are not collapsed like the ones at the bottom, sit at better part of compliance curve

Question 27

where does most of the blood flow in the lungs go to?

Answer 27

the base- zone 3- alveolar dead space | Parterial>Pvenous>Palveolar

Question 28

in what zone do you see the waterfall effect? what does this mean?

Answer 28

zone 2 Parterial>Palveolar>Pvenous | flow determined by difference between alveolar and arterial pressure

Question 29

when does the ventilation-perfusion (V/Q) ratio equal 0?

Answer 29

- shunt alveolus - aka you have blood flowing but no air - you have a HIGH PCO2 in alveolus - PO2 is very low in alveolus

Question 30

when does the ventilation-perfusion (V/Q) ratio approach infinity?

Answer 30

- dead space alveolus - aka you have air but no blood - have HIGH PO2 in alveolus - PCO2 is almost 0

Question 31

what are the units for V/Q?

Answer 31

mL O2/mL blood

Question 32

differences in V/Q ratio based on where you are in the lung?

Answer 32

apex: V/Q > 1 - more air than blood

Question 33

The majority of oxygenated blood leaving the lung comes from the ____? what does this cause?

Answer 33

base | - have lower PO2 in arterial blood than in alveolar air

Question 34

take away from ficks principle of diffusion

Answer 34

diffusion directly proportional to area, inversely proportional to thickness

Question 35

what gas is diffusion limited, and what does that mean?

Answer 35

- soluble gases like CO - quickly binds Hb, causes little change in partial pressure - will never saturate blood, just depends how quickly it can get out of alveolus

Question 36

what gas is perfusion limited, and what does that mean?

Answer 36

- insoluble gases such as NO (and to some extent O2 and CO2) - equilibrate rapidly - gas transfer is limited by the amount of blood

Question 37

how do you measure the diffusion capacity of the lung?

Answer 37

* single breath CO test* - patients breaths dilute CO gas from residual volume to TLC - holds breath for 10 seconds, exhale - 1st part of exhaled gas is discarded b/c its dead space - measure how much CO is diluted down in alveoli

Question 38

what is the alveolar gas equation?

Answer 38

PAO2= (Patm-Ph20)xFiO2 - (PACO2/R) where at 37*C, Patm= 760, Ph2O= 47 , FiO2= 0.21, R=0.8

Question 39

what does the alveolar partial pressure of CO2 depend on?

Answer 39

1) directly proportional to metabolism (production) | 2) inversely proportional to ventilation (elimination)

Question 40

describe the Bohr effect

Answer 40

``` a decreased p50 or increased affinity for O2 to Hb is caused by: decreased: Temp PCO2 2,3 DPG H+ ```

Question 41

O2 capacity

Answer 41

1 gm Hb binds 1.34 mL O2 normal blood= 15 g Hb/100mL or 20.1 mL O2/100 mL blood

Question 42

T/F An anemic patient has a lower venous SaO2

Answer 42

true- need to extract more O2 because you have less circulating Hb

Question 43

4 causes for hypoxemia (PaO2

Answer 43

1. hypoventilation- increase in pCO2, Aa difference is normal, PO2 would go up with O2, 2. diffusion limitation 3. shunt 4. V-Q inequality

Question 44

only form of hypoxemia that doesn't respond to 100% O2

Answer 44

SHUNT (PaO2= 55mmHg)

Question 45

how is CO2 transported in blood?

Answer 45

10% dissolved 20-30% carbamino 60-70% HCO3-

Question 46

what regions generate breathing pattern?

Answer 46

DRG (inhalation) & | VRG (expiration) of medulla

Question 47

what regions control breathing pattern?

Answer 47

apneustic (excites DRG) | pneumotaxic (inhibits DRG)

Question 48

what do medullary chemoreceptors do

Answer 48

decreased pH and increased CO2

Question 49

where are peripheral cehmoreceptors and what do they do?

Answer 49

carotid body and aortic arch respond to low O2

Question 50

three components of mucociliary clearance system?

Answer 50

mucus, periciliary fluid, cilia (beat upwards to mouth) | * no cilia in alveoli (removed via macrophages)