Respiration & Homeostasis

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RESPIRATION
* The release of energy from food
* All living cells need energy to carry out M R S G R E N, contraction of muscles, build up of larger molecules (e.g. proteins), maintains steady body temperature (homeostasis) * Aerobic:
* needs oxygen
* only occurs when a certain amount of oxygen is available * C6H12O6 + 6O2 6CO2 + 6H2O + Energy
* releases large amount of energy (2900 KJ)
* Anaerobic:
* without oxygen
* [glucose lactic acid] C6H12O6 2C3H6O3
* releases small amount of energy (120 KJ)
* poisonous waste (lactic acid) removed to produce joined with O2, H2O + CO2

BREATHING
* Inhalation: taking air in lungs
* muscles contract – diaphragm, intercostal muscles
* volume increases
* outside of lungs: high atmospheric pressure; inside lungs: low pressure * air flows into the lungs because of the difference in pressure * Inhalation: taking air out of lungs
* muscles relax – diaphragm, intercostal muscles
contract – internal intercostal muscles
* volume decreases
* outside of lungs: low pressure; inside lungs: high pressure * air flows out of the lungs because of the difference in pressure * GASES EXCHANGED INHALED EXHALED * Carbon Dioxide: 0.04% 4% * Nitrogen: 79% 79% * Oxygen: 21% 16% * Water: Variable High * Temperature: Variable High * Alveoli are the site of gas exchange. Adaptations:

* large surface area
* good supply of oxygen and blood (surrounded by capillaries) for rapid diffusion of gas * thin walls
* moist lining for dissolving gases

HOMEOSTASIS

* the maintenance of a constant internal environment in the...
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