The Heart

• Tissue - Group of cells working together to perform a function.
• Organ - Group of tissues working together to perform a specific function.
• The development of Coronary heart disease:

  Fatty deposits narrow the coronary arteries. Fatty deposits (called plaques) can build up inside the coronary arteries that supply the heart. This narrows the blood vessels, and therefore occludes the blood supply to the heart, and therefore reduces the oxygen supply to the heart.
• How is Coronary heart disease treated?

  Stents --> balloon placed into artery --> widens artery --> metal coil frame holds artery open

  Statins

  • Break down chelestorol
  • Long term
  • Has side effects

  Exercise and Diet
• How may it be possible to live without a heart?

  The use of an artificial heart as it carries out the same function.
• The heart is a pumping organ that keeps blood flowing.
• Valves:

  • Undirectional flow
  • Prevents back flow and clotting
• The cardiac cycle:

  • Atria contract creating pressure in the chambers which forces blood through tricuspid valves into relaxed ventricles.
  • Ventricles contract and atria relax, Ventricles now filled with blood contract increasing the pressure in the chambers tricuspid valves are forced shut meaning blood must flow out via the pulmonary artery and this flow forced open the bicuspid valves.
  • Ventricles relax and atria relaxes, both ventricles are now relaxed and pressure in the blood vessels force Bicuspid valves to shut. High blood pressure in the Vena Cava causes blood to fill again.
• Cardiac Contraction --> Systole

  Cardiac Relaxation --> Diastole
• Adaptations of the heart:

  • Valves - Prevent backflow which can lead to clotting
  • Cardiac walls - The wall of the left ventricle is thicker to pump blood further
  • Blood vessels - Vessels attached to each chamber
• The heart is adapted for its function because it has valves, that open one way meaning blood flow always travels in the same direction. This prevents back flow of blood which can lead to clotting, if this happens it would create a blockage making the heart unable to carry out its function. Another adaptation of the heart is the cardiac walls, the wall of the left ventricle is thicker and this increases pump action.
• The heart is a double circulatory system.
• What happens on the the right side?

  Deoxygenated blood from the body is returned to the heart to be pumped into the lungs.
• What happens in the left side of the heart?

  Oxygenated blood from the lungs enter the heart and is pumped to the body organs and tissues.
• The two atria have thin walls and receive blood from the veins.
• The two ventricles have thick muscular walls and they pump blood through the arteries.
• Each atrium is connected to its own ventricle and the opening has a valve.
• Multi-cellular organisms like mammals have a low SA:V ratio so they need a transport system to carry raw materials from exchange organs to body cells.
• The circulatory system is made up of the heart and blood vessels. The heart pumps blood through the blood vessels to reach different parts of the body.
• The blood transports respiratory gases, products of digestion, metabolic wastes and hormones around the body.
• There are two circuits: one takes blood from the heart to the lungs and back to the heart, the other takes blood around the rest of the body.
• The heart has its own blood supply, the coronary artery.
• The vena cava carries deoxygenated blood to the heart.
• The aorta carries oxygenated blood to the body.
• The pulmonary artery carries deoxygenated blood to the lungs.
• Arteries carry blood from the heart tot he rest of the body. Their walls are thick, muscular and have elastic tissue to stretch and recoil as the heart beats and this helps to maintain high blood pressure. The endothelium (inner lining) is folded and this allows the artery to stretch and maintain a high blood pressure.
• All arteries carry oxygenated blood except for pulmonary arteries which take deoxygenated blood to the lungs.
• Arteries divide into arterioles which form a network around the body.
• Blood is directed to different areas of demand in the body by muscles inside the arterioles, which contract and restrict blood flow or relax to allow full blood flow.
• What vessel brings blood from the heart to the kidney?

  Renal artery
• What vessel brings blood from the kidney to the heart?

  Renal vein
• Which vessel brings blood from the heart to the liver?

  Hepatic artery
• Which vessel takes blood from the liver to the heart?

  Hepatic vein
• Coronary heart disease (CHD) occurs when the blood vessels coronary arteries get blocked.
• CHD

  • Damage to the endothelium layer
  • White blood cells and lipids clump together under the lining forming fatty streaks
  • Cells, connective tissues and lipids build up to form fibrous plaque called atheroma
• Risk factors of CHD:

  • Poor diet - increase in cholesterol levels
  • Lack of excersise
  • Stress - increase blood pressure
  • Smoking - Increases blood pressure and carbon monoxide reduces function of haemoglobin
  • Salt - High Blood Pressure
  • Generic
• Aneurysm - A balloon like swelling of the artery. Blood at a high pressure travelling down a weakened vessel pushes inner layers through the elastic layer.
• Thrombosis - formation of a blood clot. Atheroma plaque rupture and damages the artery walls, causing platelets and fibrin to build up.
• What causes Myocardial Infarction (MI)?

  Thrombosis stopping the blood flow
• What is Myocardial Infarction (MI)?

  A sudden blockage of the blood flow into the heart.