respiration and gaseous exchange

by pleural membranes

acts as lubrication so surfaces of lungs dont stick to inside of chest wall

mucus is secreted to trap bacteria and dirt cilia beat backward and forward sweeping mucus out

moving air in and out of lungs

diaphragm muscles relax becoming dome shaped intercostal ms contract pulling ribs down and in volume of thorax dec vice versa during inhalation

2 test tubes one long tube and one short in each same vol of limewater in each test tube connecter between test tubes seal with bung person breathes in and out gently through test tube limewater in exhaled test tube will turn milky clean tube to prevent infection

spirometer

vol of air breathed in and out with one normal breath

diff between max breath in and max breath out

vol of air left even after a person has breathed out

max total vol of lungs

large bell jar is marked to 6dm3 placed open end downward in a large bucket rubber bung is removed position of bell jar is adjusted until water mark is at 0 bung is then replaced person wearing nose clip breaths in as deeply as possible through piece of rubber tubing second person supports weight of bell jar and slowly moves it up so water levels inside and outside stays the same when person is finished exhaling new vol on scale is noted repeats

medulla in brain aorta and carotid arteries leading to heart

smoke destroys cilia so mucus builds up with trapped bacteria causing infections and bronchitis damages walls of alveoli causing them to break down which dec SA for gas exchange and emphysema carcinogens which cause cells to divide uncontrollably causing tumours and lung cancer nicotine is addictive carbon monoxide combines with Hb forming carboxyhb and less O2 binds with Hb