Physiology 3120 Lecture Notes - Lecture 5: Central Chemoreceptors, Respiratory Center, Extracellular Fluid

• School: Western University
• Department: Physiology
• Course: Physiology 3120
• Professor: Tom Stavraky

Document Summary

Spontaneous respiration is produced by rhythmic discharges from the motor neurons that innervate the respiratory muscles. These discharges are totally dependent on nerve impulses from the brain. Brain -> motor neurons -> inspiratory muscles -> inspiration. Breathing stops if spinal cord is transected above the origin of the phrenic nerves (phrenic nerves originate from cervical segments 3, 4 and 5) The motor neurons supplying the expiratory muscles are inhibited when those supplying the inspiratory muscles are active. The motor neurons supplying the inspiratory muscles are inhibited when those supplying the expiratory muscles are active. When you want, you can change your breathing pattern (e. g. : hold breath, speaking, hyperventilate or hypoventilate to such an extent that derangement in blood pco2, po2 and ph can occur. The neural pathway for voluntary control passes directly from the cerebral cortex downward through the corticospinal tract to the spinal neurons that drive the respiratory muscles.