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Description
Flashcards by Melissa O'Mahony, updated more than 1 year ago
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Created by Melissa O'Mahony
about 7 years ago
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| Question | Answer |
| What are the steps in the mechanism of gas exchange in mammalian lungs? [6] | Nostril ¦ Nasal Cavity ¦ Trachea ¦ Bronchi ¦ Bronchioles ¦ Alveoli |
| Why must gases be exchanged in such high volumes in humans? [2] | 1~ Humans have a small surface area:volume ratio. 2~ Humans are warm blooded and require high metabolic and respiratory rates. |
| How is diffusion made efficient across the alveoli? [4] | [] Red blood cells are flattened against the wall of the capillaries [] Breathing/blood flow maintains concentration gradient [] Alveoli/capillaries have large SA:V ratio [] Alveoli/capillaries have thin walls |
| Explain, step-by-step, the mechanism of inhalation. [7] | ~ Internal intercostal muscles relax ~ External intercostal muscles contract ~ Ribs are pulled upwards and outwards ~ The diaphragm flattens ~ The volume of the thorax increases ~Pressure in lungs < Atmospheric pressure ~ Air is forced into the lungs |
| Explain, step-by-step, the mechanism of exhalation. [7] | ~ Internal intercostal muscles contract ~ External intercostal muscles relax ~ Ribs move downwards and inwards ~ The diaphragm domes ~ The volume of the thorax decreases ~Pressure in lungs > Atmospheric pressure ~ Air is forced out of the lungs |
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