topic 1 flascards

• Scientific theory


  Can be tested and has been peer reviewed by other scientists before being published in a scientific journal
• Factors affecting application of science

  • Social
  • Environmental
  • Economic
• Water molecule


  Partly delta positive (hydrogen) and delta negative (oxygen)
• Water as a solvent

  Because of its dipoles which allows bonds to be broken
• Water dipoles


  Give water a cohesive quality
• Specific heat capacity


  Energy needed to break bonds within the molecule and change the state (e.g. liquid to gas)
• Circulatory system


  Transports raw materials in multicellular organisms
• Heart structure


  • Left and right ventricles
  • Atriums above ventricles, separated by septum
  • Atrioventricular valves between atria and ventricles
  • Semilunar valves separate ventricles from vessels
  • Thicker muscular wall around left ventricle
  • Left side contains oxygenated blood, right side contains deoxygenated blood
• Blood journey around body to heart

  1. Deoxygenated blood enters right atrium through superior vena cava, travels to right ventricle, into pulmonary arteries to lungs

  2. Oxygenated blood travels from lungs to left atrium through pulmonary veins, into left ventricle, out through aorta to body
• Vein structure


  • Thin muscle layer, elastic layer, large lumen, valves to prevent backflow
• Capillary structure


  • 1 cell thick endothelium walls to minimise diffusion distance
• Artery structure


  • Thick muscle layer, elastic tissue, folded endothelium to allow expansion and contraction
• Cardiac cycle


  1. Atrial systole - atria contract, blood flows into ventricles

  2. Ventricular systole - ventricles contract, blood pushed out through semilunar valves

  3. Cardiac diastole - ventricles and atria relax, semilunar valves close
• Atheroma formation


  1. Damage to endothelium causes inflammatory response

  2. White blood cells and lipids accumulate, forming fatty streaks

  3. Fatty streaks build up into fibrous plaque, narrowing artery lumen, decreasing elasticity
• Clotting cascade


  1. Damaged blood vessel produces thromboplastin

  2. Thromboplastin catalyses formation of thrombin from prothrombin with Ca2+

  3. Thrombin catalyses conversion of fibrinogen to insoluble fibrin, trapping platelets and red blood cells
• Thrombosis blocking blood flow to heart


  May lead to heart attack (myocardial infarction) due to lack of oxygen
• Thrombosis in blood vessel connected to heart

  Can reduce oxygen reaching that section of heart, causing heart failure
• Thrombosis in artery leading to brain


  Can cause stroke
• Vein damage (e.g. inflammation)

  Can prevent proper blood flow or clot formation, causing deep vein thrombosis
• Symptoms of thrombosis


  • Difficulty breathing
  • Angina
  • Sweating
• Risk factors for CVD

  • Genetic vulnerability
  • Age
  • Sex
  • Stress
  • Alcohol intake
  • Lack of exercise
  • Diet
  • Smoking
• Genetic vulnerability


  Some alleles cause higher blood cholesterol and blood pressure levels
• Age


  Fatty streaks build up over time
• Sex


  Men more likely to develop CVD due to lack of oestrogen causing higher cholesterol
• Stress


  High levels increase blood pressure
• Alcohol intake


  Too much increases blood pressure
• Lack of exercise


  Increases blood pressure
• Diet


  Too much salt increases blood pressure, too much saturated fat increases cholesterol
• Smoking


  Carbon monoxide binds to haemoglobin reducing oxygen transport, nicotine increases platelet stickiness, decreases antioxidants increasing cell wall damage
• Antihypertensives


  Reduce blood pressure
• Types of antihypertensives


  • Beta blockers - stop messages telling heart to beat harder and faster
  • Diuretics - lower sodium absorption in kidneys, decreasing blood volume
  • Vasodilators - widen blood vessel lumen to lower pressure
• Pros and cons of antihypertensives

  • Pros: blood pressure easily monitored, work well with other medication
  • Cons: headaches, fainting, allergic reactions, depression, palpitations
• Stent


  Mesh tube that widens and smooths artery lumen to decrease blood pressure
• Statins


  Taken to lower blood cholesterol by limiting LDL
• Pros and cons of statins

  • Pros: lower risk of developing CVD
  • Cons: nausea, digestive problems, increased diabetes risk, nose bleeds, muscle/joint pain, headaches
• Anticoagulants and platelet inhibitors

  Prevent growth/formation of blood clots
• Anticoagulants


  • Warfarin, heparin
• Side effects of anticoagulants


  • Digestive problems, excessive bleeding, osteoporosis, allergic reaction, tissue swelling, foetal damage
• Side effects of platelet inhibitors

  • Diarrhoea, excessive bleeding, allergic reaction, nausea, liver function problems
• Aspirin


  Example platelet inhibitor drug that works by inhibiting platelet aggregation