Respiration 4

Question 1

explain what happens when decrease inspired PO2

Answer 1

lower amount of O2 in the alveoli and blood–>peripheral chemoreceptors fire–>tells medulla there is a problem–>increase respiratory muscle contraction–>increase ventilation–>alveolar and arterial PO2 can return toward normal

Question 2

explain what happens when breathing in a lot of CO2

Answer 2

increase PCO2 in alveoli and arteries–>increase [H+] in arteries and increase PCO2 and [H+] in brain extracellular fluid (CO2 is only thing that crosses blood brain barrier but the CO2 forms H+ in the extracellular fluid)–>increase in peripherial and central chemoreceptors–>sends signal to medulla–>increase contractions of respiratory muscles–>increase ventilation–>return of alveolar and arterial PCO2 toward normal–>eventually causes the [H+] to return to normal in the arterioles and brain