1.3 Chemical Control of Breathing

Bolingurrr

chemical regulatory mechanisms adjust ventilation to keep the _____ constant

alveolar partial pressure of CO2 (pCO2)

the link between metabolism and ventilation is…

CO2

True or false:

the link between ventilation and metabolism is O2

false

diabetes mellitus causes accumulation of acidic ketone bodies in the circulation (metabolic acidosis) which leads to…

respiratory stimulation (kussmaul breathing)

kussmual breathing (hyperventilation) leads to a decrease in…

alveolar pCO2 and blood H+ concentrations

kussmual breathing (hyperventilation) leads to a _____ in alveolar pCO2 and blood H conc

decrease

vomiting can lead to…

metabolic alkalosis

metabolic alkalosis leads to decreased _____

ventilation

metabolic alkalosis leads to an increase in…

arterial pCO2 and H conc

metabolic alkalosis leads to a _____ in arterial pCO2

increase

metabolic alkalosis leads to raising the ____ to normal

H concentration

arterial pCO2 is maintained at…

40 mm Hg

arterial pCO2 rises due to

increased tissue metabolism

when arterial pCO2 rises as a result of increased tissue metabolism ____ is stimulated

ventilation

when arterial pCO2 rises the rate of ____ increases until arterial pCO2 is normal

pulmonary excretion of CO2

when CO2 is inhaled ___ rises

alveolar pCO2

when CO2 is inhaled, alveolar CO2…

rises

when CO2 is inhaled, the alveolar pCO2 rises which in turn leads to elevating the ___

arterial pCO2

when arterial pCO2 is elevated, ____ is stimulated

ventilation

CO2 elimination is increased when ____ is stimulated

ventilation

when pCO2 of inspired gas is close to the alveolar pCO2…

elimination of CO2 becomes difficult

when CO2 content of inspired gas is more than 7%, the alveolar and arterial pCO2 begins to…

rise

when CO2 content of inspired gas is more than ____, the alveolar and arterial pCO2 begins to rise

7%

hypercapnia

accumulation of CO2 in the body

hypercapnia leads to what side effects

depression of the central nervous system, respiratory center, produces headaches, confusion, and eventually coma

when the O2 content of the inspired air decreases ____ is increased

respiration/breathing/ventilation

respiratory stimulation is slight until pO2 drops to less than…

60 mm Hg

why is it that respiratory stimulation is slight until pO2 drops to less than 60 mmHg

there is a slight decrease in H conc of the arterial blood when the arterial pO2 falls, which inhibits respiration AND increases in ventilation lowers the alveolar pCO2 which inhibits respiration

stimulatory effects of hypoxia on ventilation do not manifest until

they become strong enough to override the counterbalancing inhibitory effects of the decline in arterial H conc and pCO2

breaking point

the point where a person can no longer voluntarily inhibit holding their breath

what causes the breaking point

rise in arterial pCO2 and fall in pO2

breathing in 100% oxygen before breath holding leads to…

raised alveolar pO2 so the breaking point can be delayed

breaking point can be influenced by

reflex, psychological, and mechanical factors