Res Physiology

Question 1

Oxygen consumption and CO2 production and RQ changes during GA?

Answer 1

They both decreased and therefore RQ kept unchanged

Question 2

How much decrease in pulmonary function after interscalne induced diaphragmatic paralysis ?

Answer 2

25% loss of function

Since diaphragm accounts 75% of chest volume -> half lost would be ~ 25%

The accessory muscles or respiration unaffected and patient’s do ok except if they have sever e.g. COPD then the 25% reduction will cause ventilatory insufficiency

Question 3

What prevents alveoli from becoming too small or too big?

Answer 3

because Laplace law

Alveolar pressure = 2x surface tension/ radius

When the radius of alveolar is small -> more surfactant needed to decrease surface tension.

Where if radius is larger then it has less surfactant, surface tension reduced less.

Question 4

FRC is

Answer 4

The lung volume left at the end of a Normal Vt

FRC=ERV + RV

Question 5

Factors decrease/increase FRC

Answer 5

RLD, obesity, pregnancy, supine/prone

Increased by Tall ppl and Male gender

Question 6

Things that leads to obstruction during expiration is a product of …. process

Answer 6

Increasing closing capacity like any disease process in the lung (asthma, COPD ..)

Where processes outside lung like obesity or pregnancy have no effect on closing capacity

Question 7

Closing capacity =

Answer 7

RV + closing volume

Question 8

Airway resistance for laminar flow

Airway resistance for turbulent flow

Answer 8

(8x length x viscosity of gas) / radius to 4th power)
Laminar like ketchup (the thicker u make it the more resistance so directly related to viscosity)

(Viscosity x diameter x density)/ viscosity -> high Reynolds’s # > 2000 is consistent with pure turbulent flow

Turbulent is like ping pong ball, the more u add balls the more they bump to each other so directly related to density.