CARDIOVASCULAR SYSTEM

VASOMOTOR CONTROL CENTRE Is responsible for regulating blood pressure VASODILATION dilation of arterioles and opening of precapillary sphincters Increases blood flow to active muscle VASOCONSTRICTION constriction of arterioles and closure of precapillary sphincters reduces blood flow to inactive organs

Blood flow changes dramatically once exercise commences. At rest, only 15-20% of cardiac output is directed to skeletal muscle (the majority of it goes to the liver (27%) and the kidneys (22%). Blood is redirected to areas where it is needed most. This is known as the VASCULAR SHUNT MECHANISM or Accommodation Chemoreceptors in muscles inform VCC of increase in Lactic Acid and Carbon dioxide Baroreceptors in aorta and carotid arteries inform VCC systolic pressure has increased/decreased

The redistribution of blood is controlled primarily by the vasoconstriction and vasodilatation of arterioles. It reacts to chemical changes of the local tissues. For example, vasodilatation will occur when arterioles sense a decrease in oxygen concentration or an increase in acidity due to higher CO2 and lactic acid concentrations.

ACTIVITY 1 COMPLETE WORKSHEETS &

THE TRANSPORT OF OXYGEN 97% of Oxygen is carried by red blood cells combined with Haemoglobin in the blood plasma HAEMOGLOBIN + OXYGEN = OXYHAEMOGLOBIN Hb+O 2 = HbO 2

ACTIVITY 2 DRAW THIS GRAPH AND THEN ADD THE FOLLOWING – BLOOD FLOW CHANGES TO SKELETAL MUSCLE AND ALL OTHER ORGANS BLOOD FLOW (% OF CARDIAC OUTPUT) EXERCISE INTENSITY (%)

WHICH LEGAL HABIT IS THE MOST DESTRUCTIVE AND DANGEROUS TO A PERSONS HEALTH ?

SMOKING This simply has a negative effect on aerobic fitness Oxygen wants to attach to the Haemoglobin but the waste product from the smoke (Carbon Monoxide) attaches first therefore the oxygen supply to muscles is greatly reduced

CARBON DIOXIDE Carbon Dioxide produced in the body tissues is transported in blood in different ways 8% is dissolved in blood plasma 20% combines with Haemoglobin to form Carbaminohaemoglobin 70% dissolved in water as Carbonic Acid

ACTIVITY 3 COMPLETE WORKSHEET

WRITE A LIST OF ALL THE REASONS YOU CAN THINK OF AS TO WHY PRIOR TO PARTICAPTION IN AN ACTIVTY YOU PERFROM A WARM UP *REMEMBER WE ARE IN THE CARDIOVASUCLAR SYSTEM THINK ABOUT THE LAST COUPLE OF WEEKS* ACTIVITY 4

Warm Ups Improves oxygen supply to muscles via increase in Heart Rate Increases venous return therefore stroke volume Initiates Vascular Shunt Mechanism which redistributes blood to the working muscles Increase in body temp so reduction in blood viscosity Delays D.O.M.S. – so can work harder for longer

EXERCISE AS PART OF A HEALTHY LIFESTYLE Cardiovascular disease (CVD) is the main cause of death in the industrialised World and is estimated at 40% of all UK deaths Independent risk factors These are so called because either one will greatly increase the chance of developing CVD Following: Smoking and eating a high fat diet

There are several forms of CVD -Atherosclerosis, the deposition of fatty deposits in the arteries -Coronary Artery Disease, the narrowing of coronary arteries which can lead to angina or myocardial infarction (heart attack) -Stroke, a blockage of the arteries supplying the brain -Hypertension, permanently high blood pressure

Dependent risk factors These are so named because they may not necessarily cause CVD but will increase the chances Heredity – Genetics through family history Personality/Stress – How you deal/cope Lack of exercise – Working at 70%MaxHR can reduce risk by 30% Age (older) Gender (men more likely)

ACTIVITY 5 YOU HAVE BEEN ASKED TO DESIGN A TRAINING PROGRAMME FOR MIDDLE AGED MEN WHO HAVE BEEN REALTIVELY INACTIVE FOR YEARS 1.WHAT FACTORS DO YOU NEED TO TAKE INTO CONSIDERATION 2.STATE WHICH TYPE OF EXERCISE YOU WOULD RECOMMEND