Gas exchange in Animals Internal (2.3)

Gas exchange in animals  All animals respire aerobically to release energy needed for cellular processes.

Gas exchange in animals  All animals respire aerobically to release energy needed for cellular processes.  Aerobic respiration needs oxygen and it releases carbon dioxide.

Gas exchange in animals  All animals respire aerobically to release energy needed for cellular processes.  Aerobic respiration needs oxygen and it releases carbon dioxide.  These two gases need to be exchanged across membranes: - Skin cells (in earthworms, some amphibians)

Gas exchange in animals  All animals respire aerobically to release energy needed for cellular processes.  Aerobic respiration needs oxygen and it releases carbon dioxide.  These two gases need to be exchanged across membranes: - Skin cells (in earthworms, some amphibians) - Through specialised organs – eg. Gills (fish) and lungs (reptiles, mammals, birds)

All gas exchange surfaces must be:  Moist – O 2 must dissolve before it can diffuse

All gas exchange surfaces must be:  Moist – O 2 must dissolve before it can diffuse  Thin – reduces the diffusion distance, making diffusion quicker

All gas exchange surfaces must be:  Moist – O 2 must dissolve before it can diffuse  Thin – reduces the diffusion distance, making diffusion quicker  Large in surface area – increases quantity of gases diffused per unit time.

Breathing  Animals need to breathe to facilitate gas exchange.

Breathing  Animals need to breathe to facilitate gas exchange.  Breathing is a physical process, involving muscular contractions to move air or water over the gas exchange surfaces (eg. Alveoli in the lungs)

Breathing  Animals need to breathe to facilitate gas exchange.  Breathing is a physical process, involving muscular contractions to move air or water over the gas exchange surfaces (eg. Alveoli in the lungs)  More rapid gas exchange allows for higher rate of respiration.

Breathing  Animals need to breathe to facilitate gas exchange.  Breathing is a physical process, involving muscular contractions to move air or water over the gas exchange surfaces (eg. Alveoli in the lungs)  More rapid gas exchange allows for higher rate of respiration.  This allows for increased metabolism and increased activity for the animal.

Transport of gases  This takes place through the circulatory system in most animals.

Transport of gases  This takes place through the circulatory system in most animals.  Therefore, gas exchange and transport systems are in close contact.