Physiology

Question 1

in the R (relaxed) state, Haemoglobin has (less/more) affinity for O2
in the T (tense) state, Haemoglobin has (less/more) affinity for O2
This is useful in areas of low pH i.e. high respiration (CO2 –> H+ + HCO3-) as O2 is more readily released from Hb, and vice versa in the lungs

Answer 1

R state - high affinity for O2 - in the lungs
T state - low affinity for O2 - in lower pH, in respiring tissues

Question 2

describe the Bohr effect (related to Haemoglobin)

Answer 2

Stabilises the T state of Hb so that the more respiration a tissue is undergoing (thus the lower the pH), the more O2 is released from Hb there

Question 3

percentage of CO2 in blood carried as HCO3- ions

Answer 3

60% of all CO2 is transported through production of HCO3– ions in the red blood cell.

N.B. that by far the most important role of CO2 in the blood is to regulate the pH, not to be transported to the lungs for exhalation!

Question 4

percentage of CO2 in blood carried as carbamino compounds (including carbaminoHaemoglobin)

Answer 4

30%

CO2 diffuses into the red blood cells and is converted to H+ and HCO3– by carbonic anhydrase.
The H+ created binds to haemoglobin to produce deoxyhaemoglobin

HCO3– is transported back into the blood via an anion chloride-bicarbonate exchanger (aka anion exchanger/AE). The HCO3– can now act as a buffer against any hydrogen in the blood plasma.

Question 5

describe the Haldane effect (related to Hb)

Answer 5

high O2 reduces the CO2-affinity of Hb
so in the lungs, the Hb gets rid of CO2

High CO2 reduces the O2 affinity of Hb
so in areas of high respiration, Hb lets go of O2 and binds CO2

Question 6

percentage of CO2 in blood carried dissolved in plasma

Answer 6

10%

Question 7

What is the approximate ratio of CO2 molecules to HCO3 ions in the blood?

Answer 7

This ratio is roughly 1:20, therefore a rise of 1 CO2 requires a corresponding rise of 20 HCO3– to prevent alterations to blood pH by buffering the increase in acidity.

Question 8

name 3 anorexic (reduces appetite) hormones

Answer 8

GLP-1
PYY
Leptin

Question 9

which metabolic process produces the most energy required for uterine contraction during parturition?

Answer 9

oxidative phosphorylation by ATP synthase (according to given answers

Question 10

explain the origin of kernicterus

Answer 10

unconjugated bilirubin can cross the blood-brain barrier as it is lipid-soluble
It gets deposited in the basal ganglia

Question 11

most common cause of PMB

Answer 11

atrophy
Then HRT