Lung Structure 0.0 / 5 ? BiologyExchange SurfacesA2/A-levelAQA Created by: me543Created on: 22-02-18 16:56 What are the four main components of the lungs? Trachea, bronchi, bronchioles, alveoli 1 of 12 What are the trachea and bronchi covered in/composed of? Covered in ciliated epithelium and goblet cells, composed of cartilage 2 of 12 What does ciliated epithelium do? wavelike movement moves mucus to the top of the trachea 3 of 12 What do goblet cells do? Secrete mucus, protect from dehydration, traps dust 4 of 12 What does the cartilage do? Strong and flexible - holds airways open, 'c' shaped rings - allow food to pass down 5 of 12 What is loose tissue made up of? Smooth muscle- contracts/relaxes to alter diameter, Elastic fibres - recoil, Glandular tissue - makes mucus, Blood vessels 6 of 12 What is the gas exchange surface for humans? Alveoli 7 of 12 What do alveoli provide? large SA 8 of 12 What are the alveolar walls composed of? Single layer of squamous epithelium - short diffusion distance 9 of 12 What do the elastic fibres in the alveoli do? stretch during inhalation, recoil during exhalation 10 of 12 What do the white blood cells in alveoli do? Provide a moist film where gases can dissolve before diffusion 11 of 12 What does surfactant in the alveoli do? reduces cohesion of water molecules, preventing the alveoli from collapsing 12 of 12
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