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Lesson 7 – Structure and Processes of Respiratory System. 4 Important Structural Features. The human respiratory system has four important structural features that enable it to function properly: A thin permeable respiratory membrane through which diffusion can occur
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4 Important Structural Features The human respiratory system has four important structural features that enable it to function properly: • A thin permeable respiratory membrane through which diffusion can occur • A large surface area for gas exchange • A good supply of blood • A breathing system for bringing oxygen-rich air to the respiratory membrane
How do cells get the oxygen ? Ventilation: the process in more complex organisms that ensures a flow of oxygen-rich air to the lungs. (aka: breathing) Gas Exchange: the processes whereby the body cells obtain oxygen and get rid of carbon dioxide. (aka: diffusion of gases)
CILIA (in pink) MUCUS CELLS (in red)
Mucus • The oil in the machine of our body • We make about 1 – 1.5 litres per day • When sick, consistency changes (or from dehydration) • Allergies (and some infections) cause leakage of mucus producing cells • Green colour can be from neutrophils (most abundant white blood cell in humans)
Pathway of Air: Alveoli (air sacs)
Gas Exchange in the Alveoli • High Surface area • Air is 37oC and moist • Membrane is one cell thick • Passive Transport.
The Mechanism of Ventilation: • Breathing is based on negative pressure
Model of the lung • http://www.youtube.com/watch?v=CBv2BqqAydE
Pleural Membranes • Pleura space (area between visceral and parietal pleura) is filled with fluid to minimize friction
Pneumothorax • If air is introduced into the pleural cavity (ie: through a stabbing or broken rib), the membranes separate. This causes the lung to collapse in a condition called pneumothorax. If pneumothorax occurs, the lung cannot inflate because nothing is pulling on it to increase its volume and reduce its air pressure. This leads to difficulty breathing.
Pneumothorax • http://www.youtube.com/watch?v=i-sZzZ4TMnY
Oxygen Usage: • Physical activity depends on the energy released during aerobic cellular respiration which depends on the rate of oxygen delivery • a high maximum rate of oxygen usage indicates an efficient respiratory system. • The rate of oxygen usage can be calculated using a spirometer. VO2: It is an estimated or measured value representing the rate at which oxygen is used in the body. It is measured in millilitres per kilogram per minute (mL/kg/min) VO2max: The maximum rate at which oxygen can be used in an individual. It is the maximum amount of oxygen that an individual can use during sustained, intense physical activity. It is also measured in mL/kg/min.
Performance Enhancement • EPO -- a hormone naturally produced by human kidneys to stimulate red blood cell production
Lung Transplants: • http://www.youtube.com/watch?v=_3HVzBMFcD8 • http://www.youtube.com/watch?v=7dG4b7Pz-J4