how is the diffusion distance reduced from the alveolus to the capillaries?
1. squamous epithelial cells 2. narrow capillaries so the red blood cells touch the capillary walls, 3. capillary walls are one cell thick.
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what is a squamous epithelial cell?
a flattened cell, with a very thin layer of cytoplasm separating their membrane.
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how is the diffusion distance increased between the alveolus and the capillaries?
oxygen is dissolved in the surface film of the water BUT it is necessary for diffusion (gases dissolve in it in order to diffuse).
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how is rate of diffusion sped up?
1. steep concentration gradient is maintained. 2. thin cell wall of the alveolus and the capillary.
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how is the steep concentration gradient maintained between the alveolus and the capillaries?
the oxygenated blood is constantly flowing away from the lungs and being replaced by deoxygenated blood. also ventalation keeps a high concentration of oxygen in the lungs.
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what is surfactant made up of?
phosphlipids
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why do we need surfactant in our alveolus?
to prevent the alveolar membranes from sticking together which would prevent then expanding to let air in.
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what happened to the volume and pressure in the lungs when you breathe in?
volume increases and pressure decreases.
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how does air get into the lungs?
when the pressure decreases to below atmospheric pressure in the lungs air rushes in to level it out.
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when breathing out do the intercostal muscles contract or relax?
relax
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what's the formula for ventilation rate?
ventilation rate = tidal volume x number of breaths.
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what is the vital capacity?
the amount of air that can be expired forcibly after a maximum intake of air
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what is tidal volume?
the volume of air breathed in and out while resting
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what is residual volume?
the volume of air remaining after a maximal expiration
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how is pulmonary tuberculosis transmitted?
it is an air born droplet bacteria which is transmitted by coughing sneezing speaking etc.
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how does the tuberculosis bacteria affect the lungs?
the bacteria is engulfed by phagocytes, which then form tubercles. when the tubercles are liberated the surrounding alveolus can burst, leaving inelastic scar tissue.
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how does the burst alveoli in tuberculosis affect rate of diffusion?
there is less surface area for diffusion due to the scar tissue. also because of the inelastic scar tissue the lungs can't expand and collapse efficiently meaning less air moves in and out of the lungs.
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how is emphysema caused?
excessive smoking - airways become damaged by the smoke.
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how does cigarette smoke effect the lungs?
the smoke stimulate white blood cells to release digestive enzymes which target the alveoli walls and surrounding elastic tissue.
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Other cards in this set
Card 2
Front
what is a squamous epithelial cell?
Back
a flattened cell, with a very thin layer of cytoplasm separating their membrane.
Card 3
Front
how is the diffusion distance increased between the alveolus and the capillaries?
Back
Card 4
Front
how is rate of diffusion sped up?
Back
Card 5
Front
how is the steep concentration gradient maintained between the alveolus and the capillaries?
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