744892
Description
Flashcards by Stephen Cole, updated more than 1 year ago
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Created by Stephen Cole
over 10 years ago
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| Question | Answer |
| Complete the equation: Pulmonary ventilation= | Tidal volume x breathing rate |
| Give four risk factors, other than smoking, which are associated with emphysema. | Air pollution, chemicals, poisonous gases, asthma |
| Give four steps to show what happens when we exhale. | 1. Diaphragm muscles relax and diaphragm pulls back up 2. External intercostal muscles relax and ribs move back down due to gravity 3. Volume inside thorax decreases, so pressure increases 4. Air moves down a concentration gradient out of the lungs until equilibrium. |
| Give four steps to show what happens when we inhale. | 1. Diaphragm muscles contract and diaphragm flattens 2. External intercostal muscles contract, pulling ribcage up and out 3. Volume inside chest cavity (thorax) increases, so pressure decreases 4. Air moves down a pressure gradient into the lungs |
| How does emphysema reduce the efficiency of gas exchange? | Destroys alveolar walls, so lower surface area => lower rate of diffusion of oxygen and carbon dioxide |
| How does fibrosis result in scar tissue? | Macrophages may accumulate in connective tissue between alveoli - eventually forming hard lumps |
| How do emphysema and fibrosis affect ventilation? | Elasticity of lung tissue reduced, so cannot expire as effectively/can't get all air out of lungs |
| Name three things that happen during an asthma attack. | Muscle around bronchi contracts; Mast cells release histamine, causing inflammation of the airways; Extra mucus is produced. |
| What four properties of exchange surfaces make them easily colonised by pathogens? | Thin; moist and sticky; good blood supply; large surface area |
| What is the principal risk factor associated with emphysema? | Smoking (90% of cases) |
| What is the purpose of ventilation? | To maintain a concentration gradient of oxygen and carbon dioxide between the alveoli and capillaries. |
| When a person starts to breathe out, the percentage of oxygen in the air first exhaled is the same as the percentage of oxygen in the atmospheric air. Explain why. | This air is from the nose/trachea/bronchi; gas exchange occurs only in the alveoli. |
| Why do people suffering from TB cough up blood and mucus? | TB pathogen multiplies, creating cavities in the lung tissue - parts of lung collapse, allowing fluids to enter the lungs. |
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