Respiratory Phys

Question 1

Describe the vital capacity

Answer 1

tidal volume + expiratory reserve + inspiratory reserve

Question 2

What 5 things determine diffusion?

Answer 2

1 Pressure
2 area
3 1/thickness
4 1/molecular wt. 
5 solubility

Question 3

Which gases are diffusion limited? perfusion limited?

Answer 3

diffusion: CO, O2 if pulmonary disease (increased thickness)
perfusion: N2O, O2, CO2

Question 4

What conditions decrease Hb affinity for O2 (shift the O2 binding curve right)?

Answer 4

increased: temp, 2,3-BPG, CO2, H+
decreased: pH

Question 5

How much O2 is dissolve in plasma? carried by Hb?

Answer 5

blood = 0.3 ml O2 /100 mL blood 
Hb = 20 ml O2 /100 mL blood

Question 6

What are four things that cause hypoxia?

Answer 6

1 decreased ventilation
2 decreased diffusion
3 shunt
4 ventilation-perfusion mismatch

Question 7

Describe PAO2 and PACO2 in a ventilation perfusion mismatch due to decreased ventilation?

Answer 7

like a PTX or obstruction

O2= 40, CO2= 46 (concentrations similar to venous blood)

Question 8

Compare intrapleural pressures at the base and apex? PO2? PCO2? pH?

Answer 8

Pressures: less negative (greater pressure) at the base
more negative (smaller pressure) at the apex
PO2 and pH higher at apex (better perfusion at base)
PCO2 higher at base

Question 9

What are three adaptations to high altitude?

Answer 9

1 hyperventilation
2 polycythemia (slow)
3 hypoxia drives ventilation (instead of CO2)

Question 10

What is normally the main day-to-day driver of ventilation?

Answer 10

CO2

detected pH of medullary CSF at medullary central chemoreceptor

Question 11

Describe the peripheral chemoreceptors

Answer 11

aortic arch- increased CO2

carotid body- increased CO2, decreased pH, decreased O2

Question 12

What effects do obstructive respiratory diseases have on FEV1/FVC?

Answer 12

decreased FEV1, normal FVC –> decreased FEV1/FVC