oxygen transport Flashcards Preview

CPR 2nd half > oxygen transport > Flashcards

Flashcards in oxygen transport Deck (24)
Loading flashcards...
1
Q

at alveoli, how are o2 and co2 exchanged?

A

rapid simple diffusion (high to low [])

2
Q

partial pressure

A

pressure of an individual gas in a mixture proportional to [] = %xtotal air pressure (ex % of 760 mmHG)

3
Q

atm air is a mixture of

A

79% nitrogen 21% oxygen .04% co2

4
Q

henrys law for gases in solution…

A

the higher the solubility, the less pp the gas exerts PP=[] dissolved gas/solubility

5
Q

gas diffusion rate is inversely proportional to

A

mol weight of gas diffusion distance

6
Q

gas diffusion rate is directly proportional to

A

difference in pp solubility of gas in fluid surface area of fluid T of fluid

7
Q

solubility coefficient for O2

A

.024

8
Q

SOLUBILITY COEFFICIENT FOR co2

A

.57 20x more soluble than o2 (.024)

9
Q

Hb allows

A

blood to transport 30-100x more O2 than could be carried as dissolved gas

10
Q

how much o2 is carried on Hb and how much is dissolved in blood?

A

Hb - 97% dissolved - 3%

11
Q

Hb structure

A

2 alpha and 2 beta chains, each has a heme group with a central iron that reversibly binds O2

12
Q

cooperativity

A

1 o2 atom binding increases binding affinity for additional molecules in Hb chain heme groups

13
Q

bohr effect

A

increased CO2 leads to increased H+[] leads to greater release in oxygen (less hb affinity) at peripheral tissues (occurs in exercise)

14
Q

when do you see bohr effect?

A

exercise

15
Q

Hb oxygen binding is inversely related to

A

acidity and [co2]

16
Q

to decrease oxygen affinity, -[H+] -[co2] -T -23BPG

A

increase them all

17
Q

chloride shift

A

rbc chloride content is higher in venous circulation than arterial because the bicarbonate-chloride ion echanger transports bicarbonate into blood plasma and chloride ions into rbc

18
Q

haldane effect

A

oxygen binding to Hb causes co2 to be released from blood —- reversal of bohr – allows o2 to be picked up oxygen makes hb more acidic –> Hb releases H H combines w bicarbonate to make carbonic acid –> water co2

19
Q

henderson hasselbach eq

A

determines pH of solution from pCo2 and HCO3 pH = pK + log ([HCO3]/(s x pCO2)

20
Q

carbonic anhydrase

A

rbc enzyme that catalyzes rxn of co2 and water to form bicarbonate and H - occurs in venous blood

21
Q

resp. acidosis vs alkalosis

A

acidosis - pco2 rises due to suppression of ventilation or decreased perfusion (ards and anesthetic) alk - pco2 decreases due to increased ventilation (aspirin, high altitude)

22
Q

what compensates for respiratory pH changes?

A

renal function

23
Q

how does renal system compensate in acidosis? alkalosis?

A

acidosis - increases HCO3 to return to normal pH alk - renal function decreases HCO3-

24
Q

bicarbonate buffer system

A

keeps blood plasma pH within small range (7.37venous - 7.41 arterial) despite CO2 changes acid-base homeostasis using carbonic anhydrase