Week 27 Case Study

• What happens if an artery is partially blocked

  1. Radius for blood flow decreases

  2. Resistance increases

  3. Velocity increases
• Gap junctions


  Electrically link the cells of the heart
• A wave of depolarisation through the heart bypasses a myocardial cell


  The myocardial cell will not contract
• Failure to contract creates a non-functioning region of heart muscle and impairs the pumping function of the heart
• 1. T depression on ECG

  2. T segment drawn below the baseline
• Troponin


  Part of the contractile apparatus of the striated muscle cell
• Elevated troponin blood levels


  Indicate heart damage
• Nitroglycerin


  Metabolised into nitric oxide, which dilates blood vessels and improves blood flow
• Infusion of isotonic solution

  Extracellular fluid volume increases, intracellular fluid volume and total body osmolarity don't change
• Beta blocker


  Decreases heart rate and lowers oxygen demand
• Beta blocker decreases heart rate


  Helpful response following a heart attack
• Heart attack damages left ventricle muscle


  Stroke volume may decrease
• Decreased stroke volume


  Decreases cardiac output