Exchange surfaces and breathing

Page 58 Fact recall1a) Oxygen and nutrientsb) Carbon dioxide and urea2) Large diffusion distance, small SA:V

Page 61 Application1) It will receive less oxygenated blood supply, decreasing the concentration gradient for diffusion of gases = slower diffusion rate2) Less oxygen reaching alveoli = decreases concentration gradient = slow rate of diffusion between alveoli and capillaries3a) Alveoli are larger in the diseased lung tissueb) Loss of elasticity in alveoli, larger alveoli gives small surface area for gas exchange, so rate of diffusion of oxygen would be slower

Page 62 Fact recall1) Oxygen goes into alveoli air space, diffused out of alveoli, across alveolar epithelium and capillary endothelium and into capillaries, taken up by haemoglobin in the blood2) Contain many alveoli - large surface area, thin diffusion distance, good blood supply = increasing rate of diffusion3a) To secrete mucus to trap microorganisms and dust particles, preventing them from reaching alveolib) To waft mucus up airways to be swallowed4) Function - Stretch and recoil to prevent alveoli bursting, stretch and recoil in airways to help push air out of lungs5) Trachea and bronchi

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