oxygen transport

Question 1

at alveoli, how are o2 and co2 exchanged?

Answer 1

rapid simple diffusion (high to low [])

Question 2

partial pressure

Answer 2

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

Question 3

atm air is a mixture of

Answer 3

79% nitrogen 21% oxygen .04% co2

Question 4

henrys law for gases in solution…

Answer 4

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

Question 5

gas diffusion rate is inversely proportional to

Answer 5

mol weight of gas diffusion distance

Question 6

gas diffusion rate is directly proportional to

Answer 6

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

Question 7

solubility coefficient for O2

Answer 7

.024

Question 8

SOLUBILITY COEFFICIENT FOR co2

Answer 8

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

Question 9

Hb allows

Answer 9

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

Question 10

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

Answer 10

Hb - 97% dissolved - 3%

Question 11

Hb structure

Answer 11

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

Question 12

cooperativity

Answer 12

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

Question 13

bohr effect

Answer 13

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

Question 14

when do you see bohr effect?

Answer 14

exercise

Question 15

Hb oxygen binding is inversely related to

Answer 15

acidity and [co2]

Question 16

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

Answer 16

increase them all

Question 17

chloride shift

Answer 17

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

Question 18

haldane effect

Answer 18

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

Question 19

henderson hasselbach eq

Answer 19

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

Question 20

carbonic anhydrase

Answer 20

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

Question 21

resp. acidosis vs alkalosis

Answer 21

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

Question 22

what compensates for respiratory pH changes?

Answer 22

renal function

Question 23

how does renal system compensate in acidosis? alkalosis?

Answer 23

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

Question 24

bicarbonate buffer system

Answer 24

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