HEPC01HEPC01Sport & Exercise Sport & Exercise Physiology & Physiology & AnatomyAnatomyThe Cardiovascular SystemThe Cardiovascular System

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Respiratory recapRespiratory recap

Describe the passage of air through the respiratory system

How is gas breathed in and out mechanically?

What factors affect the rate that we breath at?

What is FVC?

What happens if you hold your breath whilst exercising?

Aims/ObjectivesAims/Objectives

The components of CV system

Factors that affect the Heart’s output

How blood is transported around the body

Blood pressure and response

Electrical activity of the heart

Regulation of the heart’s activity

Some responses to activity

OxygenatedBlood

DeoxygenatedBlood

Major Cardiovascular Functions

Delivery (O2 and nutrients)

Removal (CO2 waste products)

Transportation (Hormones)

Maintenance (Body temperature, pH)

Prevention (Infection—immune function)

What are the functions?

The HeartThe Heart

The HeartThe Heart Wall comprised of 3 layersWall comprised of 3 layers Outer layer: Outer layer: pericardiumpericardium Middle layer: Middle layer: myocardiummyocardium Inner layer: Inner layer: endocardiumendocardium

Valve FunctionValve Function

Atrioventricular (AV) Atrioventricular (AV) valvesvalves

Separate the Separate the atria from the atria from the ventriclesventricles– bicuspid (mitral) bicuspid (mitral)

valve – left sidevalve – left side– tricuspid valve – tricuspid valve –

right sideright side

anterior

Semilunar valvesSemilunar valves

Pulmonary semilunar valves

Aortic semilunar valves

Things that can go wrong– Incompetent – does’nt

close correctly– Stenosis – hardened,

even calcified, and does not close correctly

Contraction - SystoleRelaxation - Diastole

The Cardiac The Cardiac cyclecycle

Cardiac Output (Q)Cardiac Output (Q)

SV = Stroke Volume SV = Stroke Volume (ml/beat)(ml/beat)

HR = Heart Rate (beats/min)HR = Heart Rate (beats/min)

Q = Cardiac Output (ml/min)Q = Cardiac Output (ml/min)

Factors Affecting SVFactors Affecting SV

3 most important factors:3 most important factors:

– Preload

– ContractilityContractility

– AfterloadAfterload

amount ventricles are amount ventricles are stretched stretched by contained blood by contained blood

cardiac cell contractile force cardiac cell contractile force

due to factors other than EDV due to factors other than EDV

back pressure exerted by back pressure exerted by blood in the large arteries leaving the heart blood in the large arteries leaving the heart

The Blood VesselsThe Blood Vessels

ARTERY

VEIN

CAPILLARY

Aorta Arteries Arterioles Capillaries

Capillaries Venules Veins Vena Cava (S or

I)

Arterial systemArterial system

High pressure High pressure tubes, conduct Otubes, conduct O22 rich bloodrich blood

Composed of layers Composed of layers of connective of connective tissue and smooth tissue and smooth musclemuscle

Thick walls so no Thick walls so no gas exchange gas exchange occursoccurs

AortaAorta ArteriolesArterioles CapillariesCapillaries

ARTERY

blood to the heart

backflow prevented vein valve

openvein valve

closed

The veinsThe veins

Capacitance Capacitance vesselsvessels

Venous PoolingVenous Pooling Varicose veinsVaricose veins

Blood pressureBlood pressure Surge of blood enters aorta with each Surge of blood enters aorta with each

contractioncontraction

Peripheral vessels do not allow run off as Peripheral vessels do not allow run off as rapidly as it is ejected from heartrapidly as it is ejected from heart

Therefore a portion is stored in aortaTherefore a portion is stored in aorta

This creates pressure down arterial system This creates pressure down arterial system to remote branches (pulse)to remote branches (pulse)

Arterial blood pressureArterial blood pressure BP = force exerted by blood against BP = force exerted by blood against

arterial walls arterial walls – How much blood is pumpedHow much blood is pumped– Resistance to blood flowResistance to blood flow

SphygmomanometerSphygmomanometer Normal - 120 mmHg Normal - 120 mmHg

8080 Systolic / diastolicSystolic / diastolic

Blood Pressure

Blood pressureBlood pressure

SystolicSystolic blood ejected during blood ejected during ventricular ventricular

systolesystole

DiastolicDiastolic ventricular relaxationventricular relaxation

Factors increasing BPFactors increasing BP

HypertensionHypertension

<120/<80 – normal<120/<80 – normal 140-159 / 90-99 – Stage 1 140-159 / 90-99 – Stage 1

hypertensionhypertension 160 or higher / 100 or higher – Stage 160 or higher / 100 or higher – Stage

22 Absolute contraindicaction - Absolute contraindicaction -

Mean Arterial PressureMean Arterial Pressure

DBP +PP (pulse pressure)DBP +PP (pulse pressure) The pressure the arteries would The pressure the arteries would

sustain if blood flow was constantsustain if blood flow was constant

See also See also Rate-Pressure ProductRate-Pressure Product The workload of the myocardiumThe workload of the myocardium SBPxHR/100SBPxHR/100 Angina…Angina…

INTRINSIC CONDUCTION SYSTEM

Electrical ActivityElectrical Activity

SA node generates impulse; atrial excitation beginsImpulse delayed at AV node, then passed to ventriclesEnters AV bundle branches, excitation begins at apexPurkinje Fibres spread throughout vent. (speed x6)

PHASES OF A RESTING ECG

TAKING AN EXERCISE ECG

Extrinsic Regulation of Extrinsic Regulation of HRHR

Parasympathetic Parasympathetic (( HR) HR)– Acetylcholine– Acts through vagus nerve, affects atria– Reduced stimuli increases HR to 100

Sympathetic Sympathetic (( HR & force of contraction) HR & force of contraction)– Adrenaline / noradrenaline– Accelerates SA depolarization (chronotropic) (atria &

vent)– Myocardial contractility x2 (inotropic)– Vasoconstriction around body

Central RegulationCentral Regulation– Greatest control of Greatest control of

HR in Ex.HR in Ex.– Anticipatory HRAnticipatory HR

Peripheral InputPeripheral Input– ChemoreceptorsChemoreceptors– MechanoreceptorsMechanoreceptors– BaroreceptorBaroreceptor

What

What influences your heart rate?

Cardiac ArrythmiasCardiac Arrythmias 1) Irregular heart rhythm1) Irregular heart rhythm

– Bradycardia (“slow heart”)Bradycardia (“slow heart”)– Tachycardia (“fast heart”)Tachycardia (“fast heart”)

2) Premature Ventricular Contraction 2) Premature Ventricular Contraction PVC PVC (skipped/extra beats)(skipped/extra beats)

– Pulses outside SA nodePulses outside SA node

3) Atrial flutter + atrial fibrillation 3) Atrial flutter + atrial fibrillation (200-400 beats/min)(200-400 beats/min)

– Little blood pumpedLittle blood pumped

Cardiac Arrhythmia Cardiac Arrhythmia

4) Ventricular tachycardia4) Ventricular tachycardia– 3 or more premature contractions 3 or more premature contractions

can lead to ventricular fibrillationcan lead to ventricular fibrillation– Heart cannot pump bloodHeart cannot pump blood– Cause of most cardiac deathsCause of most cardiac deaths– CPR CPR

Cardiovascular response Cardiovascular response to exerciseto exercise

Anticipatory Heart Rate

The brain releases chemicals when you think you are about to exercise. This increases HR before any physical activity is performed.

Redirection of blood flow

Vasodilation

Vasoconstriction

Increase in heart rate in line with intensity

What would the maximum HR be?

Short Term changes are seen when exercise is being performed.

Blood Flow Changes During Exercise in Blood Flow Changes During Exercise in cmcm33/min/min

Short term response to Short term response to exercise – exercise – Blood PressureBlood Pressure

250mmHg!!

115mmHg!!

+20mmHg!!

HR response– Incremental, proportional– Cardiovascular drift

SV response– Increases then plateaus

Q response Plasma volume VO2

Cardiovascular response Cardiovascular response to exerciseto exercise

(McArdle, 2010)

Cardiac DimensionsCardiac Output

VO2max

Blood Pressure Blood Volume Blood Lipids & lipoproteins

Review of the Aims/ObjectivesReview of the Aims/Objectives

The components of CV systemThe components of CV system

Factors that affect the Heart’s outputFactors that affect the Heart’s output

How blood is transported around the bodyHow blood is transported around the body

Blood pressure and responseBlood pressure and response

Electrical activity of the heartElectrical activity of the heart

Regulation of the heart’s activityRegulation of the heart’s activity

Some responses to activitySome responses to activity

Further readingFurther reading

LearningSpace for notes & review LearningSpace for notes & review questionsquestions