The heart and cardiovascular system

• Anatomy


  Internal and external structures of the body
• Physiology


  The function of these structures
• Cardiovascular system components


  • The Heart
  • Arteries and veins
  • Blood and blood cells
• Cardiovascular system


  • The main transport system of the body, carrying oxygen, carbon dioxide, amino acids, glucose and digested fats, hormones, antibodies and urea
• Heart


  A muscular pump which forces blood around the body through a system of blood vessels, arteries, veins and capillaries
• Blood


  • Carries dissolved oxygen around the body cells and at the same time removes the waste products of respiration (breathing): carbon dioxide and water
  • Distributes heat around the body and hormones, nutrients, salts enzymes and urea
• Circulation types


  • Pulmonary circulation (to and from the lungs)
  • Systemic circulation (around the body)
• Blood vessel types


  • Arteries (carry blood away from the heart)
  • Veins (carry blood towards the heart)
  • Capillaries (connect arteries and veins)
• Blood components


  • Platelets
  • White blood cells
  • Red blood cells
  • Plasma
• Plasma components


  • Water (90%)
  • Glucose
  • Amino acids
  • Vitamins
  • Minerals
  • Albumin
  • Fibrinogen
  • Antibodies
  • Lipoproteins
  • Carbon dioxide
  • Urea
  • Electrolytes
• Red blood cells (Erythrocytes)

  Carry oxygen and some carbon dioxide
• White blood cells (Leucocytes)

  • Neutrophils (B-type cells produce antibodies)
  • Lymphocytes (T-type cells destroy viruses and cancer cells)
  • Monocyte (Removes dead cells and bacteria)
• Platelets


  Triggers blood clotting
• Heart chambers


  • Right atrium
  • Right ventricle
  • Left atrium
  • Left ventricle
• Heart valves


  • Tricuspid valve (between right atrium and right ventricle)
  • Mitral valve (between left atrium and left ventricle)
  • Aortic valve (between left ventricle and aorta)
  • Pulmonary valve (between right ventricle and pulmonary arteries)
• Blood vessel types


  • Arteries (carry oxygen-rich blood from heart to body)
  • Veins (carry oxygen-poor blood back to heart)
  • Capillaries (small blood vessels where gas/nutrient exchange occurs)
• Coronary arteries


  Arteries that serve the heart itself
• Cardiac cycle


  1. Atrial and Ventricular diastole (chambers are relaxed and filling with blood)

  2. Atrial systole (atria contract and remaining blood is pushed into ventricles)

  3. Ventricular systole (ventricles contract and push blood out through aorta and pulmonary artery)
• Purkinje fibres


  Very fine specialised cardiac muscles fibres that rapidly transmit impulses from atrioventricular node to the ventricles
• Sinoatrial (SA) node


  The key structure responsible for the generation of a regular heartbeat, situated in the upper wall of the right atrium
• Atrioventricular (AV) node


  Responsible for delaying the electrical impulses it receives from the SA node, allowing time for the blood to empty out of the atria into the ventricles
• ECG trace waves


  • P wave (atrial contraction/systole)
  • QRS waves (ventricular contraction)
  • T wave (ventricular relaxation)
• Blood flow through the heart

  1. Blood from lungs enters left atrium

  2. Passes through mitral valve into left ventricle

  3. Forced out to aorta and body

  4. Deoxygenated blood returns to right atrium

  5. Passes through tricuspid valve into right ventricle

  6. Forced through pulmonary artery to lungs
• Blood vessel types


  • Veins (carry blood towards heart, thin walls, large lumen, contain valves)
  • Capillaries (smallest blood vessels, connect arteries and veins, allow gas/nutrient diffusion)
  • Arteries (carry blood away from heart, thick muscular walls, small lumen)
• Hydrostatic pressure


  Pressure caused by heart contractions that forces water in plasma out of cells
• Blood proteins


  Found in the plasma
• Lymphatic system


  • Lymph vessels branch through body like blood vessels
  • Lymph contains lymphocytes that fight infection and destroy damaged/abnormal cells
  • Lymph fluid collects waste, bacteria, damaged cells and cancer cells
  • Lymph flows through lymph glands which filter out bacteria and damaged cells
  • Lymph eventually returns to blood circulation
• Around 26,000 people under 75 in UK die from CHD each year
• CHD death rates are highest in Scotland and north of England
• Since BHF was established, annual CHD deaths in UK have fallen by more than half
• There are 2.3 million people in UK living with CHD - 1.5 million men, 830,000 women
• Stroke


  Where blood supply to part of brain is cut off
• TIA (Transient Ischemic Attack)


  A mini-stroke where blood supply to part of brain is temporarily cut off
• Treatments for heart disease

  • Ping smoking
  • Medicines
  • Angioplasty - balloons and stents used to treat narrow heart arteries
  • Surgery
• Peripheral arterial disease


  The narrowing or blockage of the vessels that carry blood from the heart to the legs, primarily caused by the buildup of fatty plaque in the arteries (atherosclerosis)
• Medicines for peripheral arterial disease

  Aspirin and clopidogrel
• Around 26,000 people under the age of 75 in the UK die from CHD each year
• CHD death rates are highest in Scotland and the north of England
• Since the BHF was established the annual number of CHD deaths in the UK has fallen by more than half
• There are 2.3 million people in the UK living with CHD - around 1.5 million men and 830,000 women