Gas Exchange Biology

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What are the adaptations of lungs which give a large surface area to volume ratio and a short diffusion distance for efficient gas exchange?
Large surface area to volume ratio-300 million alveoli/ huge number of capillaries surround alveoli. short diffusion distance-walls of alveoli only 1 cell thick/ epithelial cells in alveoli wall are flat/walls of capillaries 1 cell thick
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What are the adaptations of lungs which give a steep diffusion gradient for efficient gas exchange?
Steep diffusion gradient-blood moving through capillary keeps low O2 in the blood and keeps high CO2 in the blood. Ventilation of lungs keeps high O2 in alveolus and keeps low CO2 in alveolus
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Why is it more difficult to obtain oxygen from air than water?
Water has lower concentration of oxygen/water is much denser than air/water is more viscous than air
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Why do fish use a one way flow of water across the gill?
It would be much harder to move water back in the opposite direction so a two way flow would waste lots of energy and be very inefficient
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How do the gills fulfil the features of a good exchange system?
Large surface area- 4 pairs of gills each with lots of lamellae/ each lamellae has lots of gill plates(secondary lamellae). Short diffusion distance- surface of gill plates are 1 cell thick/capillary wall cells are flattened
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What are the adaptations of insects which give efficient gas exchange?
large surface area-Lots of tracheae. small diffusion distance- gases diffuse straight to respiring tissues/moist surface- hairs trap a layer of moisture around the spiracles. steep diffusion gradient-gases move in both directions by diffusion
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What methods do insects use to reduce water loss?
waterproof exoskeleton/valves over spiracles so they can be shut/hairs around/ hairs around spiracles- trap a moist layer of air
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What are xerophytes?
Plants adapted to a dry habitat
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How does a leaf fulfil the 4 features of an efficient gas exchange surface?
large surface area- large palisade cells with lots of chloroplasts/leaves have a large SA. small diffusion distance-thin leaves. partially permeable- gases can diffuse into and out of cells. steep concentration gradient- no ventilation
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What controls the opening and closing of the stomata?
guard cells
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What are the ways plants reduce water loss?
waxy cuticle on top of leaf/close stomata when short of water/hairs around stomata/stomata in pits/leaves which can roll up to protect stomata
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What features do xerophytes posess to reduces water loss?
thick cuticle to stop uncontrolled evaporation through leaf cells/small surface area less surface area for evaporation/sunken stomata maintains humid air around stomata
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What is pulmonary ventilation?
it is the total volume of air that is moved into the lungs during one minute
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What is tidal volume?
This is the volume of air normally taken at each breath when the body is at rest. This is normally arund 0.5dm
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How do you work out pulmonary ventilation?
tidal volume x ventilation rate
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Why is the layer of water in alveoli so important despite its disadvantages?
To prevent the moist walls of the alveolus from sticking together
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In the lungs oxygen passes from the alveoli to the blood. Describe and explain the features that make this process rapid and efficient?
Large surface area/thin alveolar wall/ventilation of alveoli keeps oxygen concentration high/ circulation of blood keeps oxygen concentration low.
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As the water temperature rises, the rate of ventilation in a fish also rises. Explain the advantage of this?
Metabolic rate/respiration increases so more more oxygen is required.
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Other cards in this set

Card 2

Front

What are the adaptations of lungs which give a steep diffusion gradient for efficient gas exchange?

Back

Steep diffusion gradient-blood moving through capillary keeps low O2 in the blood and keeps high CO2 in the blood. Ventilation of lungs keeps high O2 in alveolus and keeps low CO2 in alveolus

Card 3

Front

Why is it more difficult to obtain oxygen from air than water?

Back

Preview of the front of card 3

Card 4

Front

Why do fish use a one way flow of water across the gill?

Back

Preview of the front of card 4

Card 5

Front

How do the gills fulfil the features of a good exchange system?

Back

Preview of the front of card 5
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