Lecture 24: CO2 Transport in Blood Flashcards
1
Q
what is the level of PCO2 in inhaled air
A
basically zero
2
Q
what is the PCO2 in pulmonary veins, arteries and alveolar (same #)
A
40 mmHg
3
Q
venous PCO2
A
46mmHg
4
Q
during exercise, what happens to tissue PCO2 levels
A
they increase due to higher metabolic rates
5
Q
CO2 that diffuses into RBCs reacts with water to form
A
carbonic acid H2CO3
6
Q
what enzyme catalyzes the reaction of CO2 to carbonic acid
A
carbonic anhydrase
7
Q
what does H2C03 rapidly dissociate into
A
bicarbonate ions (HCO3-) and hydrogen ion
8
Q
what 3 forms can CO2 be carried in
A
- as dissolved CO2
- bound to proteins
- chemically modified to HCO3- (*90%!!)
9
Q
what is the effect of the removal of O2 from Hb at tissues on CO2
A
- Hb changes shape to deoxyHb
- increases the affinity of Hb for CO2 and H+
- more CO2 and H+ are able to be removed from tissues (taken up by Hb)
10
Q
what does a decrease in pH of arterial blood cause
A
small increase in arterial CO2 or H+ which increases ventilation in order to blow off more CO2 and reduce amount of H+
