BISC306 Lecture Notes - Lecture 2: Aortic Body, Skeletal Muscle, Central Pattern Generator

• School: University of Delaware
• Department: Biological Sciences
• Course: BISC306
• Professor: Cain William

Document Summary

Ventilation of mammalian lungs: du(cid:396)ing (cid:862)(cid:395)uiet(cid:863) b(cid:396)eathing, inhalation is caused by the active contraction of the diaphragm and exhalation is achieved by passive elastic recoil to return the lungs to the state labeled e above. Inhalation utilizes active contraction of the diaphragm and the eternal intercostal muscles. Active contraction of the internal intercostal muscles may assist in exhalation. Surface tension of water coating respiratory surfaces resistant expansion of alveoli: surface tension greatly increases the work of breathing, surfactants including phospholipids and proteins help reduce surface tension, surfactants also reduce resistance to blood flow in alveoli. Controlling respiration: circulation - respiratory demand by systemic tissues controls cardiac output (co) to maintain blood pressure (bp). Specifically, respiratory demand effects the tone of arteriolar smooth muscle which effects peripheral resistance (pr): respiration systemic arterial po2 & pco2 controls breath rate (and therefore alveolar ventilation rate) to meet respiratory demand. If po2 of the alveolus then vasodilation occurs in local arterioles.