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10 Cards in this Set
- Front
- Back
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What is the gaseous exchange surface in humans?
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The alveoli in the lungs. |
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Describe the structure of the lungs.
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The trachea branches out into bronchi, which in turn branches out into the bronchioles. Along the bronchioles are large numbers of alveoli. Surrounding the lungs is the ribcage. Between each rib are the external intercostal muscles, which contract to during inspiration. At the bottom of the lungs is the diaphragm, which contracts during expiration.
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How does oxygen/carbon dioxide diffuse easily from the alveoli to the capillaries?
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1.) The squamous epithelial tissue is just one cell thick, creating a very short diffusion pathway. 2.) The oxygen concentration is always very low in the capillaries and very high in the alveoli, creating a high concentration gradient which allows for easy diffusion. The opposite is true for carbon dioxide. 3.) The capillaries are very thin so the erythrocytes have to squeeze through, meaning they are always very close to the edge. |
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Describe how the ciliated epithelium keeps the airways clean.
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The goblet cells produce mucus that traps dust, dirt and microorganisms that enter the lungs. The cilia on the ciliated tissue then waft the mucus back to the throat and then swallowed. |
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Why does the alveoli produce a surfactant? |
To reduce surface tension and stop the alveoli sticking together. |
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Why is soda lime used in a spirometer?
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To absorb any carbon dioxide from the air and prevent you breathing it in when you inhale. |
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Define the following terms: tidal volume, breathing rate, vital capacity.
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Breathing rate: Mean no. of breaths per minute. Vital capacity: The max volume of air that can be breathed out after breathing in as deeply as possible. |
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Define the following terms: ventilation rate, inspiratory reserve volume, expiratory reserve volume.
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Ventilation rate: The mean breathing rate multiplied by the mean tidal volume. Inspiratory reserve volume: The maximum volume of air, above and over the tidal volume, that can be breathed in with one breath. Expiratory reserve volume: The maximum volume of air, above and over the tidal volume, that can be breathed out with one breath. |
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What are the three main factors that affect the need for a transport system?
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Size, surface area to volume ratio, level of activity. |
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Summarise the circulatory system in insects.
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Single system (heart to tissues), open system, |
