Heart

Folie 1

• Blood is pumped away from the heart into arteries and returns to the heart in veins.
• The septum is a thick wall of tissue that prevents deoxygenated blood on the right side mixing with oxygenated blood on the left side.
• The left ventricle has a more muscular wall than the right ventricle because it has to pump blood around the body and overcome more resistance to flow.
• The atria have less muscular walls because blood is returning to the heart there and they don't have to pump it around the body/ to the lungs.
• 

Systole and diastole

• SYSTOLE
• This is when the heart muscles contract.
• The atria contract and force blood into the ventricles. The valves between the atria and ventricles open due to the pressure of blood against them.
• Then the ventricles contract to force blood out into the arteries. The valves close to prevent blood flowing back into the atria.
• DIASTOLE
• This is when the heart muscles relax.
• Blood flows into the atria from the veins.

The heart and exercise (1)

• The activity of the heart can be monitored by ECG, pulse rate, and listening to sounds of valves closing.
• During exercise:
• Muscles need more energy from respiration in order to contract.
• Heart beats faster and arteries supplying muscles dilate.
• Increase in supply of oxygen and glucose (needed).
• Increase in removal of carbon dioxide.
• Pulse rate increases as left ventricles beats faster to increase blood supply.
• Pulse rate = heart rate

The heart and exercise (2)

• After exercise:
• Heart rate remains high.
• Takes time for oxygen debt to be repaid.
• More oxygen is needed.
• Lactic acid builds up in muscles and needs to be cleared away - broken down and respired.

Coronary heart disease (CHD)

• CHD is caused by the blockage of the coronary arteries (thrombosis) that supply the heart with glucose and oxygen.
• If they are continually starved of oxygen it could lead to a heart attack. If the heart stops beating altogether, it is called cardiac arrest.
• The coronary arteries may be blocked by cholesterol that sticks to the lining of the arteries, narrowing it. This is atherosclerosis.
• If the coronary artery is partially blocked it can cause chest pains. This is called angina - lack of oxygen in the heart muscle.
• Possible risk factors:
• Diet
• Stress
• Smoking
• Genetic predisposition
• Age
• Gender
• 

Prevention and treatment of CHD

• PREVENTION
• Taking care of your diet, e.g. eating less fatty foods and red meat, and eating more fresh fruit and vegetables.
• Regular exercise
• Not smoking
• TREATMENT
• Drug treatment with aspirin: decreases inflammation, inhibits blood clots, and reduces the risk of death.
• Surgery:
• Bypass - An artery or vein is taken from another part of your body and used to divert blood around the narrowing or blockage.
• Angioplasty - A thin, flexible tube with a balloon on the end is threaded to the blocked coronary artery. Then, the balloon is inflated to compress the plaque against the wall of the artery, restoring blood flow.
• Stents - small mesh tube that helps prevent blockages in the artery after angioplasty.