ABG lecture (extras from csi)

Question 1

what is pulmonary transit time

Answer 1

the time for which the epithelial membrane in alveolus is in contact with an erythrocyte (0.75s)

Question 2

How much does the acidity of the blood vary?

Answer 2

tightly regulated window: 0.1ph ESPECIALLY in arterioles

Question 3

what kind of molecule is a base and why

Answer 3

its an anionic molecule and as a result is capable of reversibly binding protons to reduce the amount that are free.

Question 4

what kind of equlibrium is this: H2O + CO2 <-> H2CO3

Answer 4

enzymatic equilibrium

Question 5

what kind of equillibrium is H2CO3 <-> H+ + HCO3-

Answer 5

dynamic equilibrium

Question 6

why is the ph in the blood tightly regulated?

Answer 6

because marked changes in ph will alter the 3d structure of proteins (enzymes, hormones, protein channels)

Question 7

The body produces significant amounts of acid that needs clearing, but what proportion of this is respiratory acid, and how much is metabolic acid?

Answer 7

99%

Question 8

how much co2 in mls is released in blood per deciliter of blood perfusiong that tissue

Answer 8

4 ml

Question 9

how much co2 is released in blood from total tissues per minute

Answer 9

200 mls

Question 10

why did the dog in experiment not die after injected with extremely acidic solution 14 molar acid? (which qualities of blood)

Answer 10

bc of enormous buffering capacity of blood - very fast

Question 11

example of mixed aetiology of imbalance

Answer 11

in a copd patient that has resp acidosis anyways, permanently bc of copd, if he gets kidney failure, hco3 will stop being reabsorbed and h+ stop being secreted so ph lowered even more- this is 2 causes of resp acidosis= mixed resp acid

Question 12

how can you tell from abg if uncompensated, partial or total compensation

Answer 12

from ph. in uncompensated the ph is wrong and only one resp or metabol is wrong and the latter hasnt compensated in partial you see compensation but ph stll not totally normal and in total compansation both reps and met are weird levels but ph normal

Question 13

what is base excess

Answer 13

its a mathematical categorization of bicarb levels
its : expected hco3 (depending on -CO2 value)- observed hco3

below -2 theres base excess, too much hco3

above +2 theres too little hco3