L19 - Blod gas transport

Question 1

what is partial pressure

Answer 1

the pressure exerted by each gas

directly proportional to its % in total gas mixture

Question 2

atm pressure at sea level

Answer 2

760mmHg

Question 3

what % of atm is O2

Answer 3

20.9%

so 20.9% x 760mmHg
= 159mmHg

Question 4

what is Henrys law

Answer 4

amount of gas that dissolves in water is determined by its solubility in water and its partial pressure in air

Question 5

if partial pressure of solution is directly proportional to partial pressure in the gas,
then why is there much less O2 in solution compared to CO2 (despite O2 having a larger partial pressure)

Answer 5

O2 is not very soluble
this also plays a big role

CO2 much more soluble
so higher amount is dissolved in solution

Question 6

whats the protein and non protein subunits in Hb

Answer 6

protein = globin and
non protein = haem

Question 7

what’s the name of the ring structure that Hb forms

Answer 7

porphyrin ring

Question 8

if 97% O2 carried in HB, where’s the rest

Answer 8

dissolved in plasma

Question 9

how is uptake of O2 considered positive feedback

Answer 9

after binding w/ O2 it changes shape to facilitate more uptake

Question 10

bohr shift

Answer 10

increase in CO2
CO2 binds with H2O
to make H2CO3 (carbonic acid)
which dissociates into H+ and bicarbonate
(aka chloride shift, cuz Cl- moves into the cell)

increase in H+ makes it acidic
curve shifts to right
better unloading

Question 11

increase in temp effect on affinity

Answer 11

decreases affinity
cuz usually associated with active tissues
so more O2 needed in tissue
curve shifts right

Question 12

carboxyhaemoglobin

Answer 12

carbon monoxide
binds tighter than O2
reduces ability of O2 to bind to Hb

Question 13

methaemoglobin

Answer 13

use of drugs
means Fe2+ to Fe3+
so unable to carry O2

Question 14

fetal Hb

Answer 14

has 2 gamma subunits instead of beta
higher affinity to O2
allows better transfer of O2 from mum to fetus
shift to left

Question 15

most common way CO2 is transported in blood

Answer 15

70% coverted to carbonic acid and transported as BICARBONATE ion HCO3-

Question 16

2nd most common way for CO2 to be carried in blod

Answer 16

carbaminohaemoglobin
on a diff binding site so it doesnt compete with O2
23%

Question 17

what happens the the remaining 7% of CO2

Answer 17

dissolved in plasma

Question 18

CO2 yields H+ when it becomes bicarbonate, how does the blood not become rly acidic?

Answer 18

histidine residues in haemoglobin are good buffers
and
deoxygenated Hb has strong affinity for H+

Question 19

haldane effect

Answer 19

helps unload CO2

when Hb gets oxygenated, it has less affinity for H+
so Hb decreases in its buffering power
and H+ released and therefore CO2 released

also works vice versa in tissues
Hb gets deoxygenated
and inc affinity for H+
so CO2 also taken up