Intro

Question 1

Type of cells at respiratory epithelium?

Answer 1

Pseudostratefied columnar epithelium

Question 2

Goblet cells

Answer 2

Make mucus

Question 3

Type II pneumocytes

Answer 3

Divide to become type II pneumocytes, but also make surfactant

Question 4

Difference between bronchus histology and bronchiole histology

Answer 4

Bronchus is cartilagenous.

Bronchiole is noncartilagenous

Question 5

Blood air barrier

Answer 5

Fused basement membranes of alveolus and capillary.

Question 6

Interstitium

Answer 6

Space between epithelial basement membrane and vascular basement membrane.

Question 7

Type I pneumocytes

Answer 7

Cover 95% of the surface area but only represent 40% of the cells. Cannot divide

Question 8

Type II pneumocytes

Answer 8

Cover 5% of the surface area but account for 60% of the cells

Question 9

Pulmonary vasculature

Answer 9

Is dual:

Pulm arteries: low pressure, has capacitance, gas exchange

bronchial arteries: systemic pressure, supply nutrients to parenchyma.

Question 10

Structure of pulmonary arteries

Answer 10

Thinner and wider than systemic counterparts due to low pressure

Question 11

How does size of particulate matter from environmental exposure matter?

Answer 11

Greater than 10 microns get filtered in nose/nasopharynx

5-10 microns get trapped in mucous coating in airways

<2 microns can reach alveolar air spaces.

Question 12

Minute respiration = ?

Answer 12

Tidal volume * RR

Vt * RR

Question 13

Normal tidal volume?

Answer 13

450-500 ml

Normal RR is 12-14 breaths/minute

Question 14

Normal minute ventilation

Answer 14

~6 liters/min

Question 15

Alveolar respiration = ?

Answer 15

Minute ventilation - dead space ventilation
or
Va = (Vt-Vd) * RR

Question 16

Physiologic dead space?

Answer 16

The total volume of lungs that does not participate in gas exchange.

Equals anatomic dead space (structures north of respiratory bronchioles) and functional dead space (any alveoli that arent participating in gas exchange)

Normally physiologic dead space = anatomic dead space.

Question 17

How to measure dead space?

Answer 17

Assuming that arterial CO2 is equal to alveolar CO2…

Vd = Vt * [(PaCO2-PeCO2)/PaCO2]

Question 18

Relationship between alveolar ventilation and alveolar CO2 content assuming production of CO2 is constant.

Answer 18

Inverse relationship of alveolar ventilation and alveolar CO2 content.

Breathe more, alveolar CO2 decreases. Breathe less, alveolar CO2 increases

Question 19

Equation for relating alveolar ventilation to partial pressure of alveolar CO2

Answer 19

Va = (VCO2 * K) /PACO2

Question 20

What happens if the production of CO2 doubles?

Answer 20

Ventilation will increase to maintain PACO2

Question 21

What does the alveolar gas equation describe?

Answer 21

Describes the relationship between alveolar PCO2 and PO2

Question 22

Alveolar Gas Equation

Answer 22

PAO2 = PIO2 - (PACO2/R)

R=0.8

Question 23

Why is R=.8 in the alveolar gas euqation

Answer 23

Because rate of CO2 production is only 80% the rate of O2 consumption

Question 24

How to determine alveolar concentration of CO2?

Answer 24

Assume its equal to the partial pressure of CO2 in the arterioles.

Question 25

Regional differences in ventilation?

Answer 25

Lungs are more compliant at bottom and can utilize the weight of the lungs to squeeze more air out. Least ventilation ot that top

Question 26

Regional differences in perfusion

Answer 26

At top of lungs Palveoli>Parterioles>Pveins, so decrease in perfusion.

Middle Parterioles>Palveoli>Pveins so slight increase in perfusion

Bottom Parterioles>Pveins>Palveoli because gravity.

Question 27

Regional differences in V/Q

Answer 27

V/Q highest at top because Q is so low
V/Q lowest at bottom because Q is so high.

The slopes of the lines are different. Regional variations in perfusion are huge.

Question 28

In what zone is PaO2 highest?

Answer 28

Zone 1. PaCO2 is opposite to PaO2.

Question 29

Overall V/Q ratio for lung?

Answer 29

0.8. Alveolar ventilation is 80% of pulmonary blood flow.

Question 30

High V/Q ratio means

Answer 30

More ventilation relative to perfusion. There is a blockage (DEAD SPACE). Ventilation w/o perfusion ie PE. V/Q can be infinity. Air coming from this area will have high O2 content.

Question 31

Low V/Q means

Answer 31

High perfusion relative to ventilation. This can be caused by an airway obstruction or a cardiac shunt. Blood coming from this area will have a low O2 and a high CO2.

Question 32

PIO2 =

Answer 32

(Pb-PH2O) * Concentration of O2 in inspired air.

Question 33

Alveolar air o2 and co2 content

Answer 33

O2 = 100

Co2=40

Question 34

Mixed venous blood o2 and co2 content

Answer 34

O2=40

Co2=46

Question 35

Systemic arterial blood o2 and co2 content

Answer 35

100

40

Question 36

Fick’s law of diffusion

Answer 36

Rate of transfer of a gas by diffusion is proportional to the driving force (partial pressure), diffusion coefficient, surface area available. All of this divided by thickness of the membrane barrier.

Question 37

Perfusion limited gas exchange

Answer 37

total amount of gas transported is limited by the amount of blood coming through because it diffuses rapidly. Partial pressure gradient won’t be maintained because of rapid equilibration, so need to bring more deoxygenated blood to drive diffusion.

Question 38

Gases that are perfusion limited

Answer 38

O2, CO2. Pressure equilibrates in first 1/3 of capillary.

Question 39

How does the pressure gradient diminish for O2?

Answer 39

Even though O2 is binding to hemoglobin, Hb can be saturated, so O2 goes into solution. When blood PaO2 reaches PAO2, transfer stops.

Question 40

Diffusion limited gas exchange

Answer 40

Total amount of gas transported across barrier is limited by diffusion process. Pressure gradient is always maintained. For example, CO, immediately picked up by hemoglobin, doesn’t dissolve in blood.

Question 41

What is diffusion limited

Answer 41

CO

O2 during exercise (because CO increases and brings a lot more hemoglobin).

Question 42

Concentration of O2 in blood=

Answer 42

C = Po2 * solubility

Solubility of blood is 0.003

Question 43

How much total O2 content is bound by Hb

Answer 43

98%