Heart Disease • To get the energy to keep pumping your heart needs food and oxygen (for respiration) • It gets the food & oxygen from its own blood supply carried by the coronary arteries • If these arteries get blocked it leads to heart disease
Cholesterol • Fatty substance that sticks to the inside walls of an artery making them narrower • This slows the blood down • If blood vessels get blocked completely it is called thrombosis and blood flow is stopped
Hypertension • High Blood Pressure • This happens when blood vessels are partly blocked by cholesterol • The heart has to pump much harder to push the blood through = higher pressure on the blood vessels
STROKE • A thrombosis in a blood vessel in the brain is called a stroke • Brain cells die because they have no oxygen • A person who has a stroke may become paralysed or even die
Angina • If a coronary artery gets partially blocked, the heart muscle gets too little food and oxygen • This results in severe chest pains called angina
HEART ATTACK • A thrombosis in the coronary artery can cause a heart attack • This is when the heart stops beating • “CLEAR” – but with the right treatment the heart can be forced to start beating again
Causes of Heart Disease • Smoking • Being overweight • Eating too much cream, butter, eggs, fat or fried foods = high cholesterol in the blood • Not exercising enough • Being stressed (worry, angry, fear)
Avoiding Heart Disease • Cut down on fried food • Boil, steam or grill food instead • Eat less red meat • Eat more poultry (chicken) and fish • Eat less dairy • Eat more vegies and fruit and nuts • Do NOT smoke • Exercise regularly (20 min a day minimum!) • Relax! Don’t get too stressed out – chill out!
Blood Vessels • The blood circulates around the body more than a thousand times a day • Arteries • Arterioles • Capillaries • Venules • Veins
Blood Vessels: Arteries • Carry blood Away from the heart • Carry oxygenated blood – except for the pulmonary artery which is going to the lungs to be re-oxygenated • Have thick, elastic walls to withstand high blood pressure • The blood moves in pulses due to the pumping action of the heart
Arterioles • Smallest arteries • Made mostly of smooth muscle • This means the diameter can vary, so blood can be diverted to where it is most needed.
Blood Vessels: Veins • Carry blood back to the heart – gravity means this is not an easy job! • Carry deoxygenated blood • Have thin walls because the blood travels at low pressure • Muscles around the veins contract to help move the blood back towards the heart • Veins have one-way valves to stop blood flowing backwards
Artery vs. Vein Structure Larger Lumen (space in middle) – less resistance to blood flow Thick muscular & elastic wall – gradually reduces the harsh surge of blood to a steadier flow
Blood Vessels: Capillaries • Join arteries to veins • Very tiny blood vessels that reach all the cells of the body – thin permeable walls • Capillaries provide cells with “food”, oxygen & water and remove wastes like carbon dioxide