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Cards In This Set
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What are the two halves of circulation and what are their main function?
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 Systemic Circulation: (Left ventrical --> Right Atrium) Carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart. Pulmonary Circulation: (Right Ventrical --> Left Atrium). Carriesoxygen-depleted blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart. |
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What part of the circulatory system can create great resistance to flow? When would this action be needed?
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Arterioles: Has great variation in diameter due to their muscular walls, and are the primary site of vascular resistance.
Exercise: To increase bood flow to skeletal muscle via vasodilation (decreasing resistance).
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What facrots regulation resistance?
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Flow = Pressure Gradient + Resistance to flow (Ohms Law)
MAP = Change in pressire
MAP = CO x TPR - Hence if the MAP is maintained failry constant, the blood flow to any muscular bed is deendent only on the vascular resistance (mainly arterial resistance) |
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What is Tidal Volume (VT)?
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The amount of air entering (or leaving) the mouth and nose in one breath. = ~.5L
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What is the VO2?
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The Amount of O2 absorbed into the pulmonary blood/min.
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Why is the partial pressure of O2 in arterial blood closely match the partial pressure of O2 in the Alveoli?
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Because of extremely rapid exchange of O2.
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How does O2 and CO2 move?
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Diffusion down pressure/concentration gradient
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How do the tissues get the right supply of O2?
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Feedback system matches supply to demand bia two mechanisms:
(1) Metabolic regulation of local vascular resistance (2) Maintenance of perfusion pressure (MAP) by feedback control system. |
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How do changes to:
a) Increased metabolic activity b) Decreased atmospheric pressure c) Hyperventilation d) Hypoventilation e) Increased dead space Effect PO2 and PCO2? |
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Draw a flow diagram outlining the main response to increased metabolic activity. (6 steps)
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Describe the Baroreflex Pathway?
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Inputs from receptors which signal changes in blood pressure go to the brain and reflexly influence the activity of sympathetic nerves to the heart and blood vessles.
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Describe the Baroreflex?
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 The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms for maintaining blood pressure (STRETCH SENSITIVE). It provides a negative feedback loop in which an elevated blood pressure reflexively causes heart rate to decrease therefore causing blood pressure to decrease; likewise, decreased blood pressure activates the baroreflex, causing heart rate to increase thus causing an increase in blood pressure. |
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Which fibre type (myelinated or unmyelinated) have a higher threshold and saturation point?
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A. Unmyelinated:
Unmyelinated fbres show little adaption when pressure levels are high, and hence making unmyelinated fibres better able to signal sustained long term changes in arterial presure. |
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What does resetting the baroreflex mean?
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 The baroreflex can be reset during exercise/sleep, to regulate the arterial pressure around whatever the apropriate pressure requires. Eg during exercise, the curves are shifted to a higher operating range, eg your BP is increased but the baroreceptor re-adjusts/reset around a higher MAP. |
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What are the two types of atrial receptors and when do they fire?
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 Type A: Increase their firing rate in response to atrial contraction. Type B: Increase their firing rate in response to atrial filling |
