Physiology: hypoxic drive & H+ drive in respiration

Question 1

what effect does hypoxia and severe hypoxia have on ventialtion

Answer 1

hypoxia = increased ventilation

severe hypoxia = decreased ventilation

Question 2

what chemoreceptor is hypoxic drive effect via

Answer 2

peripheral chemoreceptor

Question 3

when is the peripheral chemoreceptor stimulated in hypoxia

Answer 3

when arterial Po2 falls <8kPa

Question 4

hypoxic drive is not important in normal people, when may it become important

Answer 4

in patients with chronic CO2 retention(e.g. COPD)

at high altitudes

Question 5

what causes hypoxia at high altitudes

Answer 5

decreased partial pressure of inspired O2(PiO2)

Question 6

what are the acute responses to hypoxia

Answer 6

hyperventilation + increased CO

Question 7

what are some chronic responses to hypoxia (3)

Answer 7

increased RBC production
increased no. of capillaries
increased no. of mitochindria

Question 8

what chemoreceptor is the effect of H+ drive via

Answer 8

peripheral chemoreceptor

Question 9

what does a rise in arterial H+ conc., stimulating peripheral chemoreceptors cause

Answer 9

hyperventilation and increased elimination of CO2 from body(to decrease CO2 generated H+)

Question 10

where is the H+ drive important

Answer 10

in acid-base balance