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The Respiratory System. Supplies oxygen to cells and removes carbon dioxide Defending body against micro-organism invasion Producing sounds for speaking Assists in control of body fluid pH. Components of Respiration. Breathing is process by which oxygen is taken in from external environment
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The Respiratory System • Supplies oxygen to cells and removes carbon dioxide • Defending body against micro-organism invasion • Producing sounds for speaking • Assists in control of body fluid pH
Components of Respiration • Breathing is process by which oxygen is taken in from external environment • Involves inhalation and exhalation • Three types of respiration: • External respiration • Internal respiration • Cellular respiration
External Respiration • Lungs are site of external respiration involving exchange of gases across respiratory surface between alveoli and blood • Respiratory surface must be moist so that diffusion can occur • Circulatory system functions as a link between different components of respiration
Internal Respiration • Is the exchange of gases between the blood in capillaries and individual cells of tissue • O2 diffuses out of the blood and CO2 diffuses in • This exchange allows cellular respiration to occur
Cellular Respiration • Process occurs on the cellular level in mitochondria • Uses oxygen to aid in harvesting of energy from food molecules • Product is ATP and waste is CO2
Regulation of Breathing • Breathing is an involuntary activity controlled through a negative feedback loop between chemoreceptors that detect changes in the pH of the blood in the medulla oblongata in the brain and the lungs • When CO2 mixes with water it forms carbonic acid which breaks down into HCO3- and H+ causing blood pH to drop
Drop in pH causes the medulla oblongata to relay messages to the muscles of the diaphragm and rib cage to stimulate breathing • Breathing expels excess carbon dioxide and restores blood pH to normal inactivating the chemoreceptors