3.1 Mammalian Gaseous Exchange

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  • Created by: elbungay1
  • Created on: 23-03-19 14:04
Describe the process of inspiration
Diaphragm contracts and flattens, digestive orgasn moved downwards. Intercostal muscles contract to raise ribs. Volume of chest cavity increases and pressure decreases below atmospheric levels, air moves in
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Describe the process of expiration
Diaphragm relaxes and is pushed upwards, external intercostal muscles relax and the ribs fall (can contract to force air out rapidly e.g coughing), volume of chest cavity decreased and pressure raised above surroundings, air moves out
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Describe lung tissue
Consist of air scas called alveoli which are comprised of squamos epithelium. Alveolus walls contain elastic fibres that stretch during inspiration but then recoil to help push air out in expiration
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What tissues comprise the airways
Trachea, bronchi and bronchioles
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What are the roles of ciliated epithelium
they form a layer of cells that have hair like extensions which trap pathogens and redistribute mucus
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What is the role of goblet cells
Found in epithelium and secrete mucus which traps pathogens
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Describe the structure of the trachea and bronchi
Supported by C-shaped rings of cartilage which allows flexibility and space for food to pass down oesophagus. Bronchi are slightly narrower than trachea
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Describe the structure of the bronchioles
Much narrower than bronchi, only some have cartilage. Wall mostly comprised of smooth muscle and elastic fibres. The bronchioles end in alveoli
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What are the roles of smooth muscle and elastic tissue in the airways
Smooth muscle can constrict the airway, narrowing the lumen and can restrict the flow of air into alveoli, useful if harmful substances is in the air. Smooth muscle is elongated by elastic tissue, recoiling them back to original size
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How can lung volumes be measured?
Using a spirometer. Vital capacity is the amximum volume of air taht can be moved by the lungs in one breath. reisdual volume is the volume of air that remains after forced expiration. Tidal volume is the volume of air moved in and out at rest
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How can oxygen uptake be measured by a spirometer trace?
Oxygen absorbed by blood is presumed equal to the amount of CO2 expired. The CO2 is absorbed by the soda lime so the change in volume in the spirometer equals the amount of oxygen absorbed.
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Describe how gills are adapted to their function
Contain gill filaments which are comprised of lamellae which have a large surface area. Blood flows along gill arch in the opposite direction of water flow, maximising oxygen absorption of the water.
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How does ventilation occur in bony fish
Floor of buccal cavity drops, increasing volume and drawing water in. The mouth closes and floor raised pushing water through the gills, as water is pushed from buccal cavitity, the operculum moves outwards, movement decreases pressure pulling water
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Describe gas exchange in insects
Air enters pore called spiracle, passing through tracheae to tracheoles. tracheoles contain tracheal fluid in which gas exchange occurs
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How does ventilation in insects occur?
Contraction of tracheal wall ventilates tracheal system. Wings alter the volume of thorax, pushing air in/out of tracheal system. Opening and closing of valves in spiracles changes volume
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Other cards in this set

Card 2

Front

Describe the process of expiration

Back

Diaphragm relaxes and is pushed upwards, external intercostal muscles relax and the ribs fall (can contract to force air out rapidly e.g coughing), volume of chest cavity decreased and pressure raised above surroundings, air moves out

Card 3

Front

Describe lung tissue

Back

Preview of the front of card 3

Card 4

Front

What tissues comprise the airways

Back

Preview of the front of card 4

Card 5

Front

What are the roles of ciliated epithelium

Back

Preview of the front of card 5
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