BIO 203 Lecture Notes - Lecture 19: United States Navy Seals, Partial Pressure, Freediving Blackout
18 Aug 2018
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Document Summary
Very sensitive - important for regulation of respiration in mammals and other air-breathing vertebrates. Stimulated by a decrease in the ph (increase of [h+]) of cerebral spinal fluid (csf) Multiple groups of cells that are important to regulate respiration. Medulla generate the rhythm, alternating inspiration and expiration. Neurons are chemosensitive (cid:1543) they respond to changes in carbon dioxide. Neurons project down to the motor neurons located in the spiral cord (cid:1543) (ex. motor neurons that innervate the diaphragm and the intercostal muscles) Receive input specifically from pons, but different places. Co2 interacts with water, forming carbonic acid, dissociate into bicarbonate and hydrogen ions. Anytime there is elevated carbon dioxide, there is elevated hydrogen ions. Increased carbon dioxide, increase in hydrogen ion, decrease in ph. Hydrogen ion does not cross the blood brain barrier (bbb), does not directly influence chemoreceptors in the brain cell. Carbon dioxide can go right across the bbb.
