BIO-0014 Lecture Notes - Lecture 25: Ideal Gas Law, Carbonic Anhydrase, Carotid Body
Document Summary
Air is not dense or viscous- very little frictional resistance. Only important in pathological situations like: asthma, emphysema. Carotid body (glonus cells): contains cells which are sensitive to changes in o2. If o2 levels fall (from change in elevation) Glonus cells become excited, releases chemical to excite afferent neurons to brainstem, medulla causes respiratory center to become excited, stimulate efferent neurons controlling diaphragm and external intercostals. Cerebrospinal fluid: carbonic anhydrase catalyzes co2 to h+ Co2 increases in blood, more of the gas diffuses into brain tissue, increased levels of co2 lead to production of more carbonic acid- more h+, Air breathers: co2 is more powerful gas in causing change in respiration. Co2 increases, ph falls, reduces ability of enzymes. Water breathers: o2 is more powerful gas in causing change in respiration. Do not have an abundance of o2 in water. Diffusion- works at lungs and at tissues (capillaries) due to small distance for diffusion of gases and other molecules.