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The Respiratory System. Main Functions of the Respiratory System. 3 main functions: 1) Supply oxygen to the blood 2) Remove carbon dioxide from the blood 3) Regulate blood pH. 3 Types of Respiration. 3 Types of Respiration. 1) External respiration :
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Main Functions of the Respiratory System • 3 main functions: • 1) Supply oxygen to the blood • 2) Remove carbon dioxide from the blood • 3) Regulate blood pH
3 Types of Respiration 1) External respiration: • within the lungs, exchange of carbon dioxide and oxygen 2) Internal respiration: • At the tissue level, delivery of oxygen and removal of carbon dioxide 3) Cellular respiration: • At the cellular level, use of oxygen to generate energy
Alveoli • Little sacs that provide a large surface area in the lungs for gas exchange • Average person has 300 million alveoli with enough surface area to cover a tennis court http://www.sk.lung.ca/graphics/anatomy/alveoli.gif
Mechanisms of Breathing • Air moves from regions of higher pressure to regions of lower pressure http://epswww.unm.edu/coursinf/eps462/graphics/diffusion.gif
Inhalation- An active process • Chest and abdominal cavity are separated by the diaphragm • Diaphragm contracts and moves down towards the abdominal cavity causing pressure to increase in the abdominal cavity and decrease in the chest cavity • This causes the pressure in the chest cavity to be lower than the atmospheric pressure forcing the air into the lungs
Inhalation & Exhalation When the diaphragm contracts and moves lower, the chest cavity enlarges, reducing the pressure outside the lungs. To equalize the pressure, air enters the lungs. When the diaphragm relaxes and moves back up, the elasticity of the lungs and chest wall pushes air out of the lungs. http://www.merckmanuals.com/home/lung_and_airway_disorders/biology_of_the_lungs_and_airways/control_of_breathing.html
Exhalation- An active or passive process • Quiet breathing (passive): Alveoli relax to let the air out (like air out of a balloon) http://chickscope.beckman.uiuc.edu/explore/embryology/day15/graphics/exhale.gif
Exhalation- An active or passive process • Forced breathing (active): When passive is not fast enough the abdominal muscles contract to decrease the volume of the lungs http://news.bbc.co.uk/olmedia/1475000/images/_1478287_split300as.jpg
Control of Ventilation • Controlled by the brain • Associated with the overall need for: • Oxygen, • Muscle activity • The production of carbon dioxide
Gas Exchange • Gas exchange occurs between capillaries and lungs and capillaries and tissues • It is a result of diffusion http://www.merck.com/media/mmhe2/figures/fg038_2.gif
Gas Exchange • Diffusion: • The movement of a gas, liquid or solid from a region of high concentration to a region of low concentration http://www.people.vcu.edu/~mikuleck/courses/resp2/img007.gif
Concentration Gradient • For diffusion to place there must be a difference in concentration between two regions • The greater the concentration gradient, the quicker the speed of diffusion
Oxygen Transport • Two was oxygen transport is achieved: • 1) Oxygen is dissolved in the plasma (small amount) • (0.5mL oxygen/ 100 mL blood) • 2) Oxygen is bound to hemoglobin (large amount) • (21.4mL oxygen/ 100 mL blood)
Oxygen Transport http://www.daviddarling.info/images/hemoglobin.jpg
Oxygen Transport • The amount of oxygen that will bind to hemoglobin depends on certain conditions
Oxygen Transport • This relationship ensures that oxygen will be delivered where it is needed http://www.jcu.edu/biology/RESP5.JPG
Carbon Dioxide Transport • Carbon dioxide must be moved from the body back to the lungs so it can be exhaled http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/respiratory%20system/image391.gif
3 Ways to Transport CO2 • Dissolved in plasma 2) Diffused into the RBC • Bound to Hemoglobin forming carbaminohemoglobin (only when oxygen concentration is low) 3) Bicarbonate System