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Mitrol of Respiralion

RESPIRATORY PHYSIOLOGY

Chemical Control of Respiration (Fcedback Mcchanism)

Cilossopharyngeal (IX) nerve

Vagus|X)nerve

2. ^owered Po₂

m biood affects ^emoreceptors a carotid and aortic bodies h arc also

■«f5ponsive to c^Mrred pH)

l hadequate —-aiation for

needs may *pressPo₂ and or ełevate of biood . ated PC0₂ **ads to lower pH>

Alveolar capillary

Diaphragm

7. Accelerated respiration improves ventilation and thus tends to normałize Po₂, Pco₂, and pH ot blood

4.    Impulses from carotid and aortic bodies reach respiratory center via glosso-pharyngeal and vagus nerves

*

5.    Impulses from central chemo receptors reach respiratory center

6. Impulses from respiratory centers descend in spinał cord lo reach diaphragm via phrenic nerves and intercostal musełes via intercostal nerves to inerease ratę and amplitudę of respiration

rcuRE 5.22 Control of Respiration-

"V en trał chemoreceptors respond to changes in arterial Pco„ but -*-r artcrial Po., or pi 1. Flevated Pro., of arterial blood stimulates central * anstem chemoreceptors via changes in the pH of the cerebrospinal r>r twain inlerstitial fluid. The incrcased Pco₂ results in a decrease in and this in lurn intreases iłu* ratę and amplitudę of respiration. ^-Tiberal chemoreceptors (carotid and aortic bodies) sense changes in the arterial blood Pro.. Po... and pH, and send signals via the glos-sopharyngeal and vagus nerves to the brainstem respiratory centers. Ihe inerease in respiratory ratę and amplitudę seen with a decrease in arterial Po, <hvpoxiai or a decrease in arterial pH is mediated by the pcripheral chemoreceptors.

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