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Questions and Answers
What is the main purpose of the gill filaments and lamellae in fish?
What is the main purpose of the gill filaments and lamellae in fish?
In the fish gill system, why is it important that blood and water flow in a counter current direction?
In the fish gill system, why is it important that blood and water flow in a counter current direction?
What is the role of spiracles in terrestrial insects?
What is the role of spiracles in terrestrial insects?
How do plants facilitate efficient gas exchange in their leaves?
How do plants facilitate efficient gas exchange in their leaves?
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What is the function of the rib cage in the mammalian gaseous exchange system?
What is the function of the rib cage in the mammalian gaseous exchange system?
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How does the diaphragm help in mammalian breathing?
How does the diaphragm help in mammalian breathing?
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What factor influences the need for specialised exchange surfaces in organisms?
What factor influences the need for specialised exchange surfaces in organisms?
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Which type of organisms require specialised exchange surfaces due to a larger distance for substances to cross over?
Which type of organisms require specialised exchange surfaces due to a larger distance for substances to cross over?
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What is a feature of an efficient exchange surface as mentioned in the text?
What is a feature of an efficient exchange surface as mentioned in the text?
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Why do fish require a specialised gas exchange surface according to the text?
Why do fish require a specialised gas exchange surface according to the text?
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Which organism mentioned in the text has an impermeable skin for gas exchange?
Which organism mentioned in the text has an impermeable skin for gas exchange?
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How does the requirement of a good blood supply/ventilation affect an efficient exchange surface?
How does the requirement of a good blood supply/ventilation affect an efficient exchange surface?
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Study Notes
Exchange Surfaces
- Specialised exchange surfaces are necessary for efficient gas exchange in multicellular organisms due to their larger surface area to volume ratio.
- Features of an efficient exchange surface include:
- Large surface area (e.g., root hair cells, folded membranes like mitochondria)
- Thinness to reduce diffusion distance
- Good blood supply/ventilation to maintain a steep gradient
Gas Exchange in Fish
- Fish have a small surface area to volume ratio for gas exchange and an impermeable membrane, requiring a specialised gas exchange surface.
- Bony fish have four pairs of gills, each with:
- Gill filaments with lamellae for gas exchange
- Counter-current flow of blood and water to maintain a steep diffusion gradient
- Water flow holds gill filaments apart, ensuring efficient gas exchange
- Ventilation is required to maintain a continuous unidirectional flow, involving:
- Mouth opening and closing
- Buccal cavity floor raising and lowering
- Operculum acting as a valve and pump
Gas Exchange in Insects
- Insects lack a transport system, so oxygen is transported directly to tissues undergoing respiration through:
- Spiracles (small openings) leading to trachea or tracheoles
- Gases move in and out through diffusion, muscle contraction, and volume changes in tracheoles
Gas Exchange in Plants
- Plants have adaptations for efficient gas exchange in their leaves, including:
- Many small holes called stomata for gas entry and exit
- Large number of stomata reducing diffusion distance
- Air spaces allowing gases to move around the leaf and come into contact with photosynthesising mesophyll cells
Mammalian Gaseous Exchange System
- The lungs are a pair of lobed structures with a large surface area, located in the chest cavity, able to inflate.
- The lungs are surrounded by the rib cage, which:
- Protects the lungs
- Contracts and relaxes with the help of external and internal intercostal muscles
- The diaphragm separates the lungs from the abdomen area.
- Air enters through the nose, along the trachea, and into the lungs.
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Description
Learn about the need for specialised exchange surfaces in organisms, focusing on single-celled and multicellular organisms. Understand the impact of size and surface area to volume ratio on substance exchange.
