1.3 Breathing PDF

1.3 - Breathing Lesson objectives Measure how much air you can push out of your lungs in one breath Learn how the muscles between your ribs and your diaphragm move air into and out of the lungs Keywords Breathing, contract, relax Breathing (or ventilation) Proc...

1.3 - Breathing Lesson objectives Measure how much air you can push out of your lungs in one breath Learn how the muscles between your ribs and your diaphragm move air into and out of the lungs Keywords Breathing, contract, relax Breathing (or ventilation) Process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. Continuous process; goes on throughout the life of an organism Process of taking in oxygen-rich air - inhalation Process of giving out air that is rich in carbon dioxide - exhalation The breathing rate of an adult is 15-18 times per minute. However, during heavy exercise, the breathing rate exceeds 25 times per minute. Inhalation Exhalation (Breathing in) (Breathing out) During breathing in, Intercostal muscles between ribs contract pulling the ribs upwards and outwards Muscles in diaphragm contract pulling the diaphragm downwards These movements make more space inside chest cavity; increase in volume When volume increases, pressure inside chest cavity and lungs decreases Air moves down through trachea into lungs, to fill extra space During breathing out, Intercostal muscles between ribs relax dropping down to their normal position Muscles in diaphragm relax allowing the diaphragm to become its normal, domed shape These movements make less space inside chest cavity; decrease in volume When volume decreases, pressure inside chest cavity and lungs increases So air is squeezed out of the lungs