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21 Cards in this Set
- Front
- Back
Functions of Respiratory System:
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provide oxygen
expel CO2, water vapour and volatile gases balance pH filter invading microorganisms produce sound assist in olfaction (smell) |
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Passageways in resp. system:
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nasal passages
sinuses nasopharynx trachea bronchi bronchioles alveoli |
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Functions of nasal passageway:
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warms and moisturises air passing through
olfaction |
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What places does resp. filtration occur?
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large: nose
middle: bronchi & bronchioles small: macrophages |
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What occurs at inspiration?
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diaphragm descends: rib cage rises
thoracic cavity volume increases lungs stretch air flows into lungs until pressure inside=pressure in atmosphere |
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What occurs at external respiration?
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exchange O2 and CO2 with the environment
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What occurs at internal respiration?
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"cellular respiration"
uptake of O2 and production and expulsion of CO2 by cells |
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What processes are involved in external respiration?
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1. ventilation
2. gas diffusion across membranes and capillaries 3. transport of CO2 and O2 |
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What are the two circulations to the lungs?
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pulmonary: carry oxygenated blood from resp. zones to heart
bronchial: provide systemic blood to lung tissue |
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Approx. what is the composition of air?
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Nitrogen: 78.6 %
Oxygen: 20.9 % H2O: 0.5% CO2: 0.04% |
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What is the atmospheric pressure?
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760mmHg
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What occurs at alveolar capillaries and why?
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O2 enters the blood, CO2 leaves the blood.
Due to the partial pressures of the blood arriving: low O2, high CO2. Molecules diffuse in order to reach an equilibrium |
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Environmental factors that affect haemoglobin:
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O2 partial pressure in blood
blood pH temperature metabolic activity in RBC's |
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What does O2 bind with to be transported?
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haemoglobin: called oxyhaemoglobin once binded
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What molecule affects the pH in body fluids?
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CO2
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More oxygen is released by haemoglobin when:
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pH drops
or temperature rises |
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Less oxygen is released by haemoglobin when:
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pH rises
or temperature drops |
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Why is CO2 produced?
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by-product of cellular respiration (aerobic metabolism)
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3 ways CO2 can be carried in the bloodstream?
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1. converted to carbonic acid (carbonic anhydrase catalyses H2O and CO2)
2. bound to haemoglobin 3. dissolved in plasma |
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How is most of CO2 carried?
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70% as carbonic acid
23% binds to haemoglobin 7% in plasma |
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Which centres in the brain are responsible for the control of respiration?
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Pons and medulla oblongata
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