Exchange surfaces and breathing

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What features should an exchange surface have?
short diffusion pathway i.e. one cell thick, large SA:V
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Respiration v Breathing
Respiration is the release of energy for food but breathing is simply the movement of air into and out of the lungs
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Breathing in
nose through pharynx then trachea, bronchi, bronchioles, alveola duct, alveloi. Each lung is surrounded by a plural cavity, which is bound by 2 membranes which secrete plural fluid which cushions the lungs and acts as a lubricant to prevent friction.
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What happens during inspiration?
Diaphragm contracts, moves down and flattens. rib cage moves up and out. intercostal muscles contract, thorax volume increases, lung pressure decreases
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What happens during expiration?
Diaphragm relaxes, moves up and curves, rib cage moves down and in. Intercostal muscles relax, thorax volume decreases and pressure in lungs increases
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What effect would a punctured lung have?
Air will enter the previously airtight thorax preventing a pressure difference between the thorax and air. Breathing relies of this pressure difference so will be adversely affected.
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What does the trachea and bronchus contain?
cartilage, goblet cells, cilia, smooth muscle and elastic fibres. NO SQUAMOUS
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Bronchiole?
a little cartilage in bigger ones, a few goblet cells in bigger ones. a few cilia in bigger ones. elastic fibre. NO SQUAMOUS
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Alveolus?
squamous epithelium and elastic fibres
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What is the function of cartilage?
strength to trachea and bronchus, holds airways open so there's little resistance to flow. this prevents collapse when low pressure inside airways.
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What is the function of goblet cells?
secrete sticky mucus (solution of mucin, which is composed of glycoproteins with carbohydrate chains.
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What is the function of ciliated cells?
moves mucus and trapped particles up airways towards throat
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What is the function of smooth muscle?
Contract to narrow airways, relax to widen. control flow of air.
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What is the function of squamous epithelium?
short diffusion distance between alveoli and blood
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elastic fibres?
stretch during inspiration to increase SA of alveoli. recoil during expiration-helps to force air out of lungs
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How fast is mucus moved?
2cm min-1
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Why are surfactants produced?
To reduce cohesion tension between water molecules, otherwise the alveoli would collapse under the pressure.
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What safety precautions should be taken?
soda lime to absorb CO2, medical grade oxygen and sterile disposable mouthpiece
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What is the tidal volume?
The volume of air exchanged in a normal single breath
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What is vital capacity?
The maximum volume of air that can be breathed in and our
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Inspiratory reserve volume?
volume of extra air that can be inhaled above tidal volume
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Expiratory reserve volume?
volume of extra air that can be exhaled (forced out) after a normal expiration
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Residual volume?
Volume of air that remains in the alveoli after forced expiration
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Dead space?
volume of air that remains in the airways
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How do you calculate breathing rate?
count number of peaks per minute
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How do you calculate the mean tidal volume?
mean of several volumes from the trace
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How do you calculate the ventilation rate?
breathing rate x mean tidal volume
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How do you calculate oxygen consumption?
decrease in peaks over 1 minute
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Other cards in this set

Card 2

Front

Respiration v Breathing

Back

Respiration is the release of energy for food but breathing is simply the movement of air into and out of the lungs

Card 3

Front

Breathing in

Back

Preview of the front of card 3

Card 4

Front

What happens during inspiration?

Back

Preview of the front of card 4

Card 5

Front

What happens during expiration?

Back

Preview of the front of card 5
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