Foundations in Biology

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Why are gas exchange surfaces often moist?
Oxygen and CO2 can only cross cell membranes when they are dissolved in water or an aqueous solution
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What are the three main factors that affect the need for an exchange system?
Size, level of activity, SA:V ratio
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Why do multicellular organisms require gas exchange systems?
1) Low SA:V,
2) Some cells are deep within the body - so there is a large distance between them and the outside environment,
3) High metabolic rate means oxygen and glucose are used up faster
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Why is a good bloody supply and ventilation important for efficient exchange?
Good, constant blood supply maintains a large diffusion gradient and ensures that the exchanged substances are constantly moving to the area needed.
Ventilation maintains the diffusion gradient, thus making the process more efficient
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What are the 4 things needed for an effective exchange system?
1) Large surface area
2) Thin layers so short diffusion distance
3) Blood supply/Ventilation
4) Moist surface
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How are alveoli adapted for their function?
Large capillary network and breathing mechanism to maintain concentration gradient,
One cell thick - so there is a short diffusion gradient,
Millions of alveoli - meaning that there is a large surface area provided
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How are fish gills adapted to their function?
Large network of capillaries and freshwater supply means that a steep concentration gradient is maintained,
One cell thick - so there is a short diffusion gradient,
Lamellae and filaments provide a massive surface area
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How is cartilage adapted to its function?
Cartilage is a flexible connective tissue that provides strength and support to joint and bones.
Cartilage is composed of cells surrounded by mucopolysaccharides
Cartilage is resistant to compression and tension, but is still flexible
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What are the hair like structures on the surface of epithelial cells called?
Cilia
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What do ciliated epithelial cells do?
They have tiny hairs (cilia) on the ends of them that beat and push mucus up the passages towards the nose and throat where it can be removed
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How do goblet cells and ciliated epithelial cells stop pathogens from entering the body through the lungs?
Goblet cells produce mucus which traps bacteria, dust and particles.
Cilia beat and push the mucus away from the lungs towards the throat
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What are the two types of epithelial tissue found in the lungs and airways?
Ciliated epithelium
Squamous epithelium
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Other cards in this set

Card 2

Front

What are the three main factors that affect the need for an exchange system?

Back

Size, level of activity, SA:V ratio

Card 3

Front

Why do multicellular organisms require gas exchange systems?

Back

Preview of the front of card 3

Card 4

Front

Why is a good bloody supply and ventilation important for efficient exchange?

Back

Preview of the front of card 4

Card 5

Front

What are the 4 things needed for an effective exchange system?

Back

Preview of the front of card 5
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