Respiratory

Question 1

Atmosphere pressure?

Answer 1

760mmHg

Question 2

Water vapour pressure?

Answer 2

47mmHg

Question 3

pO2 in alveolar? & oxygenated blood leaving lungs?

Answer 3

100mmHg

Question 4

pCO2 in alveolar? & oxygenated blood leaving lungs?

Answer 4

40mmHg

Question 5

Venous blood pO2 & pCO2?

Answer 5

pO2 = 40mmHg

pCO2 = 46mmHg

Question 6

What causes the Hb dissociation curve to shift to Right?

Answer 6

C - CO2 increase
A - acidosis
D - DPG (slow) produced in RBCs to help adjust to low O2
E - exercise
T -temperature

Question 7

What causes the Hb dissociation curve to shift to LEFT?

Answer 7

CO - carbon monoxide CO has high affinity for Hb. Hb’s affinity for O2 greatly increases also, so it holds onto the O2, and less released in periphery tissue where needed. No O2 available to act as electron acceptor in ETC, backs up TCA cycle, pyruvate moves to lactate, lactate = acidosis.

Question 8

CO₂ in blood…

Answer 8

CO₂ + H₂0 –> H₂CO₃ –> H⁺ + HCO₃^-

90% of CO₂ transported in blood as bicarb ions.

When O2 binds to Hb at alveolar, H⁺ dissociates from the Hb, as it goes into blood solution, drives the eqn to release CO2 from HCO₃^-

Question 9

How is breathing controlled?

Answer 9

Peripheral chemoreceptors:

carotid & aortic bodies

low pH, high pCO₂, very low pO₂

medullary chemoreceptors detect H⁺ ions