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13 Cards in this Set
- Front
- Back
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Gas Exchange Surfaces
- Characteristics |
- Thin giving a short diffusion pathway
- Large surface area - Can maintain a steep concentration gradient - Moist - Gasses can dissolve into a film before they diffuse across the membrane - Permeable |
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Adaptations for gas exchange
- Annelids |
USE THEUR BODY SURFACE FOR GAS EXCHANGE
- Secrete mucus - Moist - Elongated - large SA to VR - Good capillary network, with blood containing haemoglobin close to the skin - short diffusion pathway. |
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Adaptations for gas exchange
- Insects |
- Spiracles in the exoskeleton lead to a system of trachea.
- Tracheole tube endings come into contact with every tissue, making them the gas exchange surface. - No circulation or heamaglobin |
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Adaptations for gas exchange
- Amphibians |
Tadpole - Gills
Active Frog - Lungs Inactive Frog - Moist Skin |
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Adaptations for gas exchange
- Reptiles |
- Lungs - Highly folded - Large SA
- Rib cage, can ventilate their lungs |
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Adaptations for gas exchange
- Birds |
Lungs
Air sacs |
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Adaptations for gas exchange
- Mammals |
Diaphragm, intercostal muscles and rib cage
Ribs go up and out, volume of the thoracic cavity increases and the pressure decreases, air rushes into the lungs and they then inflate. Lots of Alveoli - Large SA, one cell thick - Short diffusion pathway. |
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Ventilation
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movement of the respiratory system over the gas exchange surface
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Inspiration
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Inhaling
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Expiration
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Expiration
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Adaptations for gas exchange
- FISH |
Gills - extract O2 from water
Gill filaments and gill lamelle - large SA Blood capillaries close to the surface - short diffusion pathway Counter-current flow |
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Adaptations for gas exchange
- Plants - LEAVES |
Thin - Short diffusion pathway - light can pass through
Large SA - for light harvesting Spongy mesophyll layer Waxy cuticle - reduce water loss |
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Opening and closing of the stomata
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- Chloroplasts produce ATP
- This is used to pump POTASSIUM IONS into the guard cells, which break down STARCH into MALATE. - WATER POTENTIAL in guard cells LOWERS so water enters by OSMOSIS - Cell becomes TURGID - Bend outward - Opening the stomata. Closed at night - No photosynthesis - No ATP Bright day - wider pores. Plant dehydrated - cells loose water - become flacid - close - preventing water loss. |
