BIOLOGY 151 Lecture Notes - Lecture 34: Max Perutz, Capillary, Gas Exchange
Document Summary
Big picture: diffusion: structural adaptations are all related to making the transfer by diffusion more efficient. Lung: job: provide large surface area over which o2 and co2 can be exchanged with the blood, surface area in lung about 80x outside surface area of the body. Sa about equal to that of a tennis court: elasticity affected by. Surfactant detergent the lung secretes to reduce the surface tension in the alveoli. Important for first breath at birth: not developed until 7-8 months of gestation, if not developed, hard to draw first breath. Emphysema/copd: decreases elasticity of lungs, causes chest cavity to win the tug of war. Air pathway: resembles upside down tree (trunk=trachea, about 23 branches from trachea to an alveolus, very branchy structure, system of pipes and tubes. Diameter can change because cartilage horse shoe made into ring by a section of muscle: muscle can contract or relax. Gas exchange occurs here: unoxygenated blood carried in, oxygenated blood carried out.
