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Antrim PE Revision Course AQA AS PHED 1

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Presentation on theme: "Antrim PE Revision Course AQA AS PHED 1"— Presentation transcript:

1 Antrim PE Revision Course AQA AS PHED 1
Session 3b Applied Physiology – Respiration & Cardiac Function

2 Respiration – need to know
Mechanics of breathing Different lung volumes and capacities Interpret spirometer graphs Oxygen and carbon dioxide exchange in lung alveoli and muscles Process of diffusion Concept of partial pressure

3 Cardiac function – need to know
Circulatory system Role of haemoglobin, myoglobin Venous return The a-vO2 difference Heart structure – cardiac cycle Cardiac output, stroke volume, heart rate Control of heart rate Effects of training

4 Breathing Quiet breathing – diaphragm+ intercostals
Deep breathing – sternocleidomastoid + pectorals

5 Autonomic breathing control
Chemo-receptors CO2 Inflation of aleveoli Medulla Oblongata Respiratory Accelerator Centre Respiratory Inhibitory Centre Parasympathetic Vagus nerve Sympathetic (Acc nerve) The role of the brain in breathing Normal 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 laughing Autonomic breathing control Lungs Intercostal muscles Diaphragm Contract

6 Respiration – Lung Volumes
June02Q3 Ans

7 Respiration - Ventilation
Ventilation = Tidal Volume x Frequency (breathing rate) Frequency/Breathing rate: Resting min-1 Peak: min-1 Tidal volume: Resting 0.5L Peak: 2.25 L Minute Ventilation Resting: 6 lt/min Peak:175 lt/min-1

8 Respiration - O2 Transport
Red Blood Cells Haemoglobin > Oxyhaemoglobin From alveoli – to muscle cell boundary Myoglobin > Oxymyoglobin From muscle cell boundary > mitochondria Carbon dioxide 70-80% Bicarbonate carbonic acid HCO3 5-10% Dissolved in plasma 5-10% Carbaminohaemoglobin A-V difference

9 Arterial – Venous Oxygen Difference (a-VO2 diff)
Arterial Blood O2% Venous Blood a-VO2 Diff More oxygen is extracted by working muscles Rest 20 15 5 Intense Exercise 20 5 15 Jun02Q5 Ans

10 Blood Flow in Capillary
CO2 Gas Exchange Alveolus PCO2 40mm Hg PO2 104mm Hg Capillary PCO2 45mm Hg PCO2 40mm Hg PO2 40mm Hg PO2 104mm Hg Blood Flow in Capillary

11 Exercise and oxygen disassociation
Rise in temperature Acidity rise due to CO2 LA increase Curve moves to the right Jun02Q5 Haemoglobin disassociates oxygen more readily More O2 available during exercise Ans

12 Pulmonary and systematic circulation
Arteries/arterioles/capillaries/venules and veins) Generation of blood pressures/velocities Venous return mechanism Redistribution of blood/vascular shunting Arterio – venous oxygen difference (A-VO2 diff). Cardiac function Cardiac cycle Cardiac 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 rate Cardiac hypertrophy leading to bradycardia/athlete’s heart Starling’s law of the heart Cardio-vascular drift.

13 Invisible on this scale
Blood vessels Invisible on this scale Arterioles Venules Arteries - thick muscular walls; take blood away from heart - high pressure; elastic Capillaries - tiny, very thin walls - diffusion of substances in and out Veins - 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 pump Compression of chest veins during inspiration, and lowering of thoracic pressure – respiratory pump ‘Suction pressure’ of heart 06-19

15 Dynamics of venous return
Muscle pump Respiratory pump

16 Blood pressure and velocity
Arteries Veins Venules Capillaries Arterioles Velocity falls and rises – with increasing & decreasing total cross-sectional area Blood pressure Blood velocity Pressure falls - friction & increasing cross-sectional area Total cross-sectional area Jun04Q5 Ans

17 Starlings Law Increase in fibre length Increase in contractility
Trained heart will contract more powerfully SV Trained Heart Normal contractility Left ventricle Venous return Increased venous return Increased filling of left ventricle Increase in fibre length Increase in contractility Increased stroke volume

18 Blood Flow - Redistribution
Ans Jan04Q1 Blood Flow in cm3 per minute Area Rest Max Muscles 1000 26000 Heart 250 1200 Skin 500 750 Kidneys 300 Liver & Gut 1250 375 Brain Whole 5000 30000 Liver & Gut Rest Liver & Gut Max Exercise

19 Blood Flow Redistribution - Volume
Blood Flow in cm3 per minute Increase to skeletal muscles & heart Area Rest Max Ex Muscles 1000 26000 Heart 250 1200 Skin 500 750 Kidneys 300 Liver & Gut 1250 375 Brain Whole 5000 30000 Decrease to liver, gut, kidneys Brain stays same Increase in total blood flow (Cardiac Output) SV+ HR+

20 Cardiac cycle Contraction = systole The order of contraction Diastole
Relaxation = diastole Atrial systole High pressure (systole) in chambers forces valves open Ventricular systole Valves close when pressure drops again (diastole)

21 Cardiac Output = Heart Rate x Stroke Volume
Q. = HR X SV Stroke Volume - Volume of blood ejected each contraction (systole) of the ventricle Units! Rest 60bpm 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 training Specifically left ventricle Thickening of heart muscle Leads to bradycardia – resting heart rate <60 Cardio-Vascular Drift Decreasing venous return Decrease in stroke volume Heart rate increases

23 Heart Rate Control Increase in blood pressure Adrenaline
Conduction of nerve impulses gets quicker Increased levels of carbon dioxide, lactic acid

24 Medulla Oblongata Heart Rate Control Chemo-receptors CO2 H+ Movement
Muscle action Baro-receptors Blood pressure Medulla Oblongata Cardiac Accelerator Centre Cardiac Inhibitory Centre Vaso-motor Centre Parasympathetic Vagus nerve Sympathetic (Acc nerve) Vaso-constriction or dilation Heart Rate Control Jan07Q5 Ans

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