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| Question | Answer |
| Why do organisms need special exchange surfaces? | -oxygen for aerobic respiration -glucose as a source of energy -proteins for growth and repair -minerals to maintain their w.p. |
| Name the features of a good exchange surface. | -Large SA - provides space for molecules to pass through -thin barrier to reduce diffusion path -fresh supply of molecules on once side (high conc.) -removal of required molecules on either side (low conc.) |
| Name some examples of exchange surfaces | -small intestine - nutrients are absorbed -liver - levels of sugars in the blood are adjusted -root hairs of plants - waters and minerals are absorbed |
| How are lungs adapted for exchange? | -Large SA - provides more space for molecules to pass through -barrier permeable to O2 and CO2 - allows diffusion |
| How do lungs make a thin barrier to reduce diffusion distance? | -alveolus and capillary walls are one cell thick -walls consist of squamous cells -capillaries are in close contact with alveolus walls -total barrier to diffusion is only two flattened cells thick |
| Process of inhaling | -diaphragm contracts to become flatter - pushes digestive organs down -external intercostal muscles contract to raise ribs -vol. of chest cavity increases -pressure in chest cavity drops atmospheric pressure -air moves into lungs |
| Process of exhaling | -diaphragm relaxes - pushed up by displaces organs underneath -external intercostal muscles relax - ribs fall -vol. of chest cavity decreases -pressure in lungs increase + rises above atmospheric pressure -air moves out of lungs |
| What is the structure/function of trachea? | -wide flexible tube kept open by 20 c-shaped cartilage -acts as a pathway for gases to and from the lungs -keeps lungs free from particles and bacteria (mucosa/submucosa) |
| What is mucosa? | made up of epithelial cells w/ cilia and goblet cells -elastin is present - plays a role in warming air |
| What is submucosa? | -humidifies inspired air -together with mucus from goblet cells - trap particles from air |
| What is the structure/function of bronchi? | -trachea branches into primary, secondary and tertiary bronchi -contains smooth muscles - controls diameter and length of bronchi -contains mucosa and submucosa |
| What is the structure/function of bronchioles? | -no cartilage and no glands -diameter of 1mm or less and wall structure |
| What is smooth muscles? | -involuntary muscles found in internal organs -contract/relax to allow airways to be controlled -during exercise muscles relaxes - widens airways aiding ventilation |
| What are elastic fibers? | -long fibers of the protein elastic - can stretch and recoil -stretched to allow expansion during inhalation and recoil during exhalation |
| What are C-shaped rings of caritalge? | -prevents collapse of airways during inhalation -allows flexibility during movement w/o narrowing airways -structural support -allows esophagus to expand during swallowing |
| What are goblet cells? | -secrete mucus to trap particles -reduces risk of infection or inflammation |
| What are ciliated epithelium? | -waft mucus containing bacteria towards the throat to be swallowed -inside the stomach acid kills the bacteria preventing infection -cells containing numerous mitochondria |
| What is a spirometer? | -consists of a chamber filled with oxygen that floats on a tank of -subject breathes from a disposable mouthpiece attached to a tube connected to a chamber of oxygen |
| Why is soda lime used? | -level of CO2 will increase -used to absorb the CO2 exhaled -total vol. of gas will go down carbon is removed. -reduction is equal to the vol. of O2 used by the person breathing in/out |
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