CSB346H1 Lecture Notes - Lecture 5: Central Chemoreceptors, Raphe Nuclei, Chemoreceptor
28 Apr 2016
School
Department
Course
Professor
Document Summary
Experiment: when co2 was removed from the body of a lamb, the lamb"s breathing slowed and stopped. Suggests that co2 is the driving force that causes breathing. A decrease in pco2 caused by hyperventilation can also cause apnea. Response depends on the state of consciousness (hyperventilation doesn"t usually cause apnea during waking) In waking, hypocapnia only caused a slight pause in breathing, while in sleep, this pause is prolonged. These results show that central and peripheral chemoreceptors are important in monitoring co2 levels and producing respiratory drive. An increase in pco2 caused by inhaling co2 is a powerful stimulus. Ventilation usually doubles for a 2 mmhg rise in. Steeper slope for lower oxygen, shallower slope for sleep. During hypercapnia, virtually all brainstem neurons are stimulated co2 is an alerting stimulus. There are 2 distinct thresholds to breathing one is due to peripheral chemoreceptors and the other is due to central chemoreceptors. Measured ventilation in response to co2 in intact dog.
