Central chemoreceptors in the medulla also recognize chemical variations in H +.
2.
Inputs to this neuron come from the peripheral chemoreceptors, carotid body, aortic body, and central chemoreceptors.
3.
Peripheral chemoreceptors ( carotid and aortic bodies ) and central chemoreceptors ( medullary neurons ) primarily function to regulate respiratory activity.
4.
Commonly, in various pressor reflexes, the central chemoreceptors, which transform chemical signals into action potentials, and the baroreceptors, which sense pressure changes, of the carotid sinuses work together to increase or decrease blood pressure.
5.
This response does not control ventilation rate at normal p, but below normal the activity of neurons innervating these receptors increases dramatically, so much so to override the signals from central chemoreceptors in the hypothalamus, increasing p despite a falling p
6.
Normal respiration is driven mostly by the levels of carbon dioxide in the arteries, which are detected indirectly by central chemoreceptors when carbon dioxide crosses the blood brain barrier, forming detectable Hydrogen ions, and directly by peripheral chemoreceptors, and very little by the oxygen levels.
7.
However, a change in plasma pH alone will not stimulate central chemoreceptors as H + are not able to diffuse across the blood brain barrier into the CSF . Only CO 2 levels affect this as it can diffuse across, reacting with H 2 O to form carbonic acid and thus decrease pH . Central chemoreception remains, in this way, distinct from peripheral chemoreceptors.
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