Respiratory Physiology

Question 0

Tidal volume

Answer 0

Normal inspiration and expiration volumes

Relaxed breathing

Question 1

Inspiratory reserve volume

Answer 1

Additional volume that can be inspired above tidal volume

Question 2

Inspiratory capacity

Answer 2

Tidal volume + IRV

Question 3

Expiratory reserve volume

Answer 3

Volume of air that can be expired beyond tidal volume

Question 4

Residual volume

Answer 4

Amount of air left in the lungs after forced expiration

Question 5

Functional reserve capacity

Answer 5

ERV + residual volume

Question 6

Vital capacity

Answer 6

Inspiratory capacity + ERV

volume that can be expired after maximal inspiration

Question 7

Total lung capacity

Answer 7

Vital capacity plus residual volume

Question 8

Forced vital capacity

Answer 8

Total volume that can be forcibly expired following maximal inspiration (FVC)

Question 9

FEV

Answer 9

Forced expiratory volume

Measured @1,2 and 3 seconds (fev1,2,3)

Changes in FEV/FVC ratio are indicative of different diseases

Question 10

Fibrosis (or restrictive lung disease) and FEV/FVC ratio

Answer 10

Both fev1 and FVC go down but FVC goes down to a greater extent than fev1, the ratio goes up

Question 11

Obstruction (asthma) and FEV/FVC ratio

Answer 11

FEV1 and FVC both go down but FEV1 to greater extent so ratio goes down

Normal fev1 is around .8- 80% of the FVC is expired in the first second

Question 12

BTPS

Answer 12

Body temperature, ambient pressure, and gas saturated with water vapor

Question 13

STPD

Answer 13

Standard temp., standard pressure, and dry gas

Question 14

Henry’s law

Answer 14

For a given partial pressure, the higher the solubility of the gas the greater the concentration of the gas in solution

This only refers to gas dissolved in solution not gas bound to protein or gas that has been chemically modified.

Question 15

Physiologic shunt

Answer 15

Accounts for the discrepancy wherein arterial PO2 is less than alviolar. The some of the blood that courses through the pulmonary capillaries aren’t oxygenated and thus dilute the oxygen slightly.

Question 16

Perfusion limited gas exchange

Answer 16

Differences in partial pressure in the capillary and alveoli make the diffusion gradient

If a gas doesn’t bind proteins and dissolves in solution it is perfusion limited as blood in the capillary will equilibrate and diffusion will stop if flow is not increased

Question 17

Diffusion limited gas exchange

Answer 17

Differences in partial pressure in the capillary and alveoli make the diffusion gradient

If a gas binds to plasma proteins then it will continue to maintain the gradient and diffusion of a given gas is limited by the diffusion gradient

Question 18

Positive cooperativity

Answer 18

Refers to how binding of one molecule of O2 increases the affinity of binding of the second molecule of O2 and so on to hemoglobin

Question 19

P50

Answer 19

Partial pressure of O2 where hemoglobin is 50% saturated. Increase is a decrease in affinity And a decrease is an increase in affinity

Question 20

Erythropoietin

Answer 20

A growth factor synthesized in the kidneys and to a lesser extent in the liver

Kidney senses decrease in Po2 and releases epo

Causes differentiation if erythroblastosis to rbc

Question 21

Alveolar ventilation (VA)

Answer 21

The total air exchanged by alveoli per minute

Question 22

Minute ventilation (VE) (E is subscript)

Answer 22

Total air volume exchange by entire lung per minute

Question 23

Breathing patterns and VA

Answer 23

Alveolar ventilation increases and decreases with slow-deep and rapid-shallow breathing respectively

Question 24

Physiologic dead space VDP (DP are subscript)

Answer 24

Non conduction pathway dead space such as alveoli that do not contribute to gas exchange but contain air

Question 25

Hypercapnia

Answer 25

Acidosis where [CO2] is increased