01:377:370 Lecture Notes - Lecture 26: Peripheral Chemoreceptors, Hyperpnea, Carotid Body
17 Sep 2019
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This can actually cause alveolar po2 to rise above resting (very slight) Temperature has little influence on respiratory rate during exercise. There is really not one single mechanism that explains increases in ventilation (hyperpnea) due to exercise- appears to be combined (and maybe simultaneous) effects of several stimuli. Apnea: not breathing; dyspnea: irregular breathing; hyperpnea: increased breathing. Phase i (beginning of exercise): neurogenic stimuli from cortex (plus feedback from active limbs) increase respiration. Phase ii: after about 20 sec ventilation rises exponentially to reach steady state. Central command: brain telling what to expect in terms of work. Phase iii: fine tuning of steady-state ventilation through peripheral sensory feedback mechanisms (e. g. co2, h+) If you"re doing non steady state, you will not fully hit phase iii. An abrupt decline in ventilation reflects removal of central command and input from receptors in active muscle. Slower recovery phase from gradual metabolic, thermal, and chemical adjustments.
