PowerPoint Presentation

James BarracloughBlood Pressure

Lesson 21AS PE Anatomy & Physiology Starter From last weeks lesson: In same pairs write 5 quiz questions to ask classmates on YOUR topicsKhalifa & Aidan: functions of blood; blood viscosity & double circulatory system -Transportation, protection, homeostasis; Resistance, training; Pulmonary & systemic circulation Joe & Lamiko: blood vessels - Arteries/arterioles, veins/venules, capillaries, vasoconstriction/dilation, pre-capillary sphinctersRobin & Ali: venous return mechanism - Muscle pump, pocket valves, respiratory pump, smooth muscle, gravity

Homework Answers

Aims: Blood PressureObjectives:ALL learners will be able to understand:Blood pressureDistribution of Cardiac Output at rest & during exerciseBlood PressureBlood pressure = force exerted by blood against walls of blood vesselsNecessary to maintain blood flow though circulatory systemDetermined by 2 main factors Cardiac Output volume of blood flowing into system from LVResistance to flow impedance offered by blood vessels to blood flowBP increases when either cardiac output or resistance increasesBP in arteries also increases & decreases in pattern corresponding to cardiac cycle during ventricular systoleCOMPLETE QUIZ PART 1: 15 MINUTES

Quiz AnswersBP = cardiac output x resistanceUsually measured at brachial arterySphygnamometerRecorded as mmHg (millimetres of Mercury) of systolic pressure over diastolic pressureSYSTOLE pressure is experienced when the heart pumps blood into the systemDIASTOLIC pressure is recorded when the heart is relaxing and filling with blood.Highest when blood pumped into aorta Lowest during ventricular diastoleTypical Reading = 120mmHg 80mmHg

USING BP MONITOR TAKE & RECORD YOUR OWN BPBlood Vessels & Pressure

BP & Exercise Quiz Part 2Aerobic exercise - systolic pressure increases as result of increased cardiac output & diastolic pressure remains constant (in well trained athletes may even drop as blood feeds into working muscles) adequate blood supplied to working muscles (graph next slide)Isometric/anaerobic exercise both systolic & diastolic pressure rise significantly due to increased resistance of blood vessels (graph next slide)High BP can lead to serious problems with heart, brain & kidneysConstant high BP = HYPERTENSION Low BP can mean insufficient O & nutrients reaching muscle cellshttp://www.youtube.com/watch?v=qWti317qb_w

Distribution of Cardiac Output Part 315 20%Liver (27%) & kidneys (22%)During exercise blood redirected to areas most in need Up to 80%VASCULAR SHUNT MECHANISMRedistribution of blood determined by vasoconstriction & vasodilation of arteriolesLactic acid, carbon dioxide; chemoreceptorsBlood & Oxygen, wastehttp://www.youtube.com/watch?v=cR2N59zegSE

Blood Flow at Rest & During Exercise

Blood Distribution at Rest

Vasomotor ControlSympathetic nerves (SN) also important in redistributing blood from 1 area of body to anotherTunica Media (smooth muscle layer of blood vessels) controlled by SNSRemains in state of slight contraction = vasomotor toneIncrease in sympathetic stimulation vasoconstriction of blood flow to lesser needed areas & redistributed to areas in more needAs SN control decreases vasodilation occurs & blood flow allowed back to that partVasomotor ControlPre-capillary sphincters are structures that also aid blood redistribution:Ring-shaped muscles at openings of capillariesControl blood flow into capillary bedWhen sphincter contracts restricts blood flow through capillary & deprives tissue of OWhen it relaxes increases blood flow to capillary bed

Recap Activity Mind Map

Homework

191919Next LessonTransport of O2 & CO2Effects of warm-up & cool-downHealth-related considerations