Cardiovascular system

• Blood moves from the vena cave, through the right atrium down by the tricuspid value to the right ventricle. Blood then moves out by the pulmary vein and through the pulamnary artery to the lungs. Blood then comes from the lungs into the left atrium through the pulmanary vein. The blood then travels through the left atrium down to the left ventricle by the mitral valve. Blood then moves out to the body by the aorta which the aortic valve opens
• The heart is made up of four chambers; two atria (right and left) and two ventricles (left and right)
• Erythrocytes are red blood cells which are specialised by having a concave shape to increase surface area to maximise oxygen
• Thrombocytes are platelets which are blood clotting proteins, they go to the damaged area and clot.
• Haemoglobin is what carries oxygen around the body
• Some examples of white blood cells include: lymphocytes, Eosinophil, basophil, and neutrophils.
• Atherosclerosis is when fatty deposits build up on the walls of your arteries causing them to narrow or become blocked
• Hypertension is high blood pressure
• Coronary thrombosis is where there's a blockage in one of the coronary arteries that supply blood to the heart muscle
• Myocardial infarction is when part of the heart muscle dies due to lack of oxygen
• Coronary heart disease is where plaque builds up inside the coronary artery that supplies blood to the heart muscle
• Heart attack happens when one of the main coronary arteries becomes completely blocked with a blood clot
• Myocardial infarction is when part of the heart muscle dies because it doesn't get enough blood
• Cardiac arrest is when the heart stops beating
• Plasma is a liquid part of blood. Antibodies are secreted into plasma cells which then are released into plasma
• Arteries carry blood away from the heart at high pressure
• Arteries work best at high pressure
• Arteries are very thick
• Arteries have a very thick muscle layer
• Arteries elastic layer is very thick
• Arteries dont have valves
• Arterioles carry blood, but under lower pressure then arteries
• Arterioles are relatively thick but not as thick as arteries
• Artieroles have a relatively thick muscle and elastic layer
• Capillaries exchange metabolic materials for example, carbon dioxide and oxygen and are 1 cell thick
• Veins carry blood slowly under low pressure from tissue to the heart. Veins have low: pressure, thickness, muscle layer and elastic layer. Veins have valves
• Coronary arteries provide tissues of heart with oxygen and nutrients and pump blood, arteries contract which provided ATP
• There are 2 circuits in the cardiovascular system: The systemic circuit(Body), and the pulmonary circuit(lungs)
• The cardiac cycle involves the 3 repetitive stages: diastole, ventricular systole, atrial systole.
• Diastole is the heart relaxing and filling up with blood, pressure increases in the atria and is higher than the ventricle. The articular valves then open and small amounts of blood trickle into the ventricles
• Atrial systole is when the valves(tricuspid and mitral) are forced open and atria contract, and pressure increases in the atria.
• Ventricular systole is when blood is in the ventricles meaning they contract. They have the highest amount of pressure as they are thicker, so they can pump blood out of the heart. The aortic and pulmonary valves are forced open and blood is pumped out by the aorta and PA
• When the atria pressure is higher than the ventricular prssure, tricupsid and mitral valves are forced open, when the ventricular pressure is higher than the atria pressure, the valves are shut.
• When the ventricular pressure is higher than the arteries pressure, pulmonary and aortic valves are open, but when the arteries have a higher pressure than the ventricles, the valves are closed.
• The heart is myogenic which means it can produce its own electrical impulses
• An initial electrical impulse is sent from the SAN (Sino artial node) and then the impulse is sent across the atria causing contractions
• The signal then reaches the AVN( Atrioventricular node) which causes a slight delay in order for the atria to be fully empty
• The AVN then sends the signal down the Bundle of HIS until it reaches the Purkyne fibres. This is important because the contraction can happen from bottom to top, which means blood can now squeeze up and into the arteries.
• Coordination of heart beats flow chart:

  1. San- Electrical activity, atria contract
  2. AVN- Delays impulse so atria is fully empty
  3. Bundle of HIS- pass impulse to bottom of heart
  4. Purkyne Fibres- Ventricles contract 'bottoms up'
• PQRST- ECG's:

  P- atrial systole

  QRS- Ventricular systole

  T- Diastole