S3.3 Oxygen In The Blood

Question 1

Describe the main futures of myoglobin

Answer 1

A monomer present in muscle cells.
Contains one haem group
Hyperbolic curve

Question 2

Describe the main futures of haemoglobin

Answer 2

Has 2 alpha and beta subunits, 4 haem groups.
T state is when Hb has low affinity, R state has high affinity.
Dissociation curve is sigmoidal

Question 3

What will oxygen concentration be like in an anaemic patient with normal lung function?

Answer 3

pO2 normal, oxygen CONTENT much lower as cannot bind to Hb as there is less of it!

Question 4

Summarise the Bohr shift

Answer 4

Acidic conditions, high temp and 2,3-BPG shift the dissociation curve to the right (higher pO2 values), because the conditions promote the T state of Hb.
So in metabolically active tissues where pH is lower and temp high, more oxygen gets given up.

Question 5

What happens in carbon monoxide poisoning?

Answer 5

CO reacts with Hb to form COHb, increasing affinity of unaffected subunits for O2, so O2 not given up at tissues.

Question 6

What is hypoxaemia?

Answer 6

Low pO2 in arterial blood

Question 7

What is hypoxia?

Answer 7

Low oxygen levels in body or tissues

Question 8

What is cyanosis?

Answer 8

Bluish discolouration due to raised unsaturated haemoglobin