Presentation on theme: "Antrim PE Revision Course AQA AS PHED 1"— Presentation transcript:
1 Antrim PE Revision Course AQA AS PHED 1 Session 3bApplied Physiology – Respiration & Cardiac Function
2 Respiration – need to know Mechanics of breathingDifferent lung volumes and capacitiesInterpret spirometer graphsOxygen and carbon dioxide exchange in lung alveoli and musclesProcess of diffusionConcept of partial pressure
3 Cardiac function – need to know Circulatory systemRole of haemoglobin, myoglobinVenous returnThe a-vO2 differenceHeart structure – cardiac cycleCardiac output, stroke volume, heart rateControl of heart rateEffects of training
5 Autonomic breathing control Chemo-receptorsCO2Inflation of aleveoliMedulla OblongataRespiratoryAccelerator CentreRespiratory Inhibitory CentreParasympatheticVagus nerveSympathetic(Acc nerve)The role of the brain in breathingNormal relaxed rhythmical breathing is controlled unconsciously by the medulla oblongata of the brain.A rise in blood CO2 stimulates the medulla to fire, sending nerve impulses to the breathing muscles.The diaphragm and intercostal muscles contract and so air is breathed in.Inflation of the alveoli causes nerve feedback to the medulla switching off its stimulation of the breathing muscles.Breathing in stops and the lungs recoil causing expiration.The cerebellum allows us to voluntarily control our breathing if desired, e.g., talking, singing and laughingAutonomic breathing controlLungsIntercostal musclesDiaphragm Contract
11 Exercise and oxygen disassociation Rise in temperatureAcidity rise due to CO2 LA increaseCurve moves to the rightJun02Q5Haemoglobin disassociates oxygen more readilyMore O2 available during exerciseAns
12 Pulmonary and systematic circulation Arteries/arterioles/capillaries/venules and veins)Generation of blood pressures/velocitiesVenous return mechanismRedistribution of blood/vascular shuntingArterio – venous oxygen difference (A-VO2 diff).Cardiac functionCardiac cycleCardiac output, stroke volume and heart rate and the relationship between them.Heart rate range in response to exercise; hormonal and nervous effects on heart rate;Role of blood carbon dioxide in changing heart rateCardiac hypertrophy leading to bradycardia/athlete’s heartStarling’s law of the heartCardio-vascular drift.
13 Invisible on this scale Blood vesselsInvisible on this scaleArteriolesVenulesArteries - thick muscular walls; take blood away from heart - high pressure; elasticCapillaries - tiny, very thin walls - diffusion of substances in and outVeins - thin walled; carry blood back to heart - need help - venous return
14 Venous return One-way valves in veins Contraction of skeletal muscles during movements – skeletal pumpCompression of chest veins during inspiration, and lowering of thoracic pressure – respiratory pump‘Suction pressure’ of heart06-19
15 Dynamics of venous return Muscle pumpRespiratory pump
16 Blood pressure and velocity ArteriesVeinsVenulesCapillariesArteriolesVelocity falls and rises – with increasing & decreasing total cross-sectional areaBlood pressureBlood velocityPressure falls - friction & increasing cross-sectional areaTotal cross-sectional areaJun04Q5Ans
17 Starlings Law Increase in fibre length Increase in contractility Trained heart will contract more powerfullySVTrained HeartNormal contractilityLeft ventricleVenous returnIncreased venous returnIncreased filling of left ventricleIncrease in fibre lengthIncrease in contractilityIncreased stroke volume
18 Blood Flow - Redistribution AnsJan04Q1Blood Flow in cm3 per minuteAreaRestMaxMuscles100026000Heart2501200Skin500750Kidneys300Liver & Gut1250375BrainWhole500030000Liver & GutRestLiver & GutMax Exercise
19 Blood Flow Redistribution - Volume Blood Flow in cm3 per minuteIncrease to skeletal muscles & heartAreaRestMax ExMuscles100026000Heart2501200Skin500750Kidneys300Liver & Gut1250375BrainWhole500030000Decrease to liver, gut, kidneysBrain stays sameIncrease in total blood flow (Cardiac Output)SV+ HR+
20 Cardiac cycle Contraction = systole The order of contraction Diastole Relaxation = diastoleAtrial systoleHigh pressure (systole) in chambers forces valves openVentricular systoleValves close when pressure drops again (diastole)
21 Cardiac Output = Heart Rate x Stroke Volume Q. = HR X SVStroke Volume - Volume of blood ejected each contraction (systole) of the ventricleUnits!Rest60bpm x 83ml = 5000ml-1 (5 litres)Max work (trained)200bpm x 170ml = 34000ml-1(34 litres)With a partner trace the route of the blood flow through the heart and the body.You should include the following terms:left atria, right atria, left ventricle, right ventricle, vena cavae, aorta, pulmonary vein, pulmonary artery, mitral valve, tricuspid valve, semi-lunar valves (aortic and pulmonary), lungs, body.
22 Cardiac Hypertrophy Cardio-Vascular Drift Increase in heart size due to trainingSpecifically left ventricleThickening of heart muscleLeads to bradycardia – resting heart rate <60Cardio-Vascular DriftDecreasing venous returnDecrease in stroke volumeHeart rate increases
23 Heart Rate Control Increase in blood pressure Adrenaline Conduction of nerve impulses gets quickerIncreased levels of carbon dioxide, lactic acid
24 Medulla Oblongata Heart Rate Control Chemo-receptors CO2 H+ Movement Muscle actionBaro-receptorsBlood pressureMedulla OblongataCardiac Accelerator CentreCardiac Inhibitory CentreVaso-motorCentreParasympatheticVagus nerveSympathetic(Acc nerve)Vaso-constriction or dilationHeart Rate ControlJan07Q5Ans
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