BMS 420 Lecture Notes - Group C Nerve Fiber, Atelectasis, Bronchoconstriction
Document Summary
Inputs come to medulla (ph, blood gas amounts, temperature, stretch receptors in lungs, &c. ) affect muscles of respiration. The peripheral chemoreceptors (carotid bodies in carotid arteries or aortic bodies in the aortic arch) are more often studied than the central chemoreceptors because of their accessibility for study. The carotid and aortic bodies respond to decreases in pao2, but not oxygen content, and to increases in paco2 and decreases in ph. The peripheral chemoreceptors are far less of the ventilatory response than the central chemoreceptors as a result of an increase in carbon dioxide. The type i cells (glomus) contain a rich supply of the neurotransmitter dopamine and are the cells which sense changes in partial pressure of oxygen and carbon dioxide as well as in the ph. Action potentials from these cells are transmitted to the medullary respiratory centers to affect a change in ventilation.
