Cardiovascular

• Endocardium tissue


  Inner lining of the heart chambers. Composed of a layer of endothelial cells, which are a type of epithelial cells
• myocardium tissue


  The heart muscle cells, arraigned spirally around the heart
• epicardium tissue


  a protective membrane covering the heart
• pericardium tissue


  a fibrous sac that contains the heart
• Contractile cells


  Generate mechanical force, the vast majority of cells
• autorhythmic cells


  several types, some specialized for initiating action potentials, others for fast conductance of depolarization
• Action potentials in the heart

  very different than those in muscle and nerve cells
• autonomic nervous system


  Regulates heart beat (rate and strength of contraction)
• Steps of cardiac ventricular contractile cell potential

  1. Na+ channels open

  2. Na+ and some K+ channels close

  3. L-type Ca2+ channels open

  4. A second type of K+ channel (delayed rectifier K+ channels) open and L-type Ca2+ channels close
• Why is there a lack of flat resting potential in cardiac nodal cell potential?

  F-type Na+ channels
• Steps of cardiac nodal cell potential

  1. F-type (also known as If) Na+ channels open

  2. T-type Ca2+ channels open

  3. L-type Ca2+ channels open

  4. K+ channels open
• Where does depolarization "wave" in heart start and how does it spread

  starts in the SA node and spreads from cell to cell by gap junctions
• P wave


  atrial action potential
• QRS complex


  ventricular action potential
• T wave


  ventricular repolarization
• What can be learned from an ECG?

  Changes in heart rate (tachycardia and bradycardia)

  Abnormalities in heart rhythm (heart block, fibrillation)

  Possible location of damage within the heart

  Effects of drugs on cardiac function
• Stages of systole


  isovolumetric ventricular contraction

  Ventricular ejection (blood flows out of ventricle)
• stages of diastole


  isovolumetric ventricular relaxation

  Ventricular filling (blood flows into ventricles)
• Stages of cardiac cycle

  1. ventricular filling (diastole)

  2. isovolumetric ventricular contraction (start systolic phase)

  3. ventricular ejection (systole)

  4. isovolumetric relaxation (diastole)
• What is cardiac output determined by?

  stroke volume times heart rate
• Inotropy


  force of heart contraction (affects stroke volume)
• Chronotropy


  heart rate
• Stroke volume


  The volume of blood pumped from the left ventricle during each heart beat
• equation for stroke volume

  SV = end diastolic volume - end systolic volume
• How is stroke volume measured


  echocardiogram
• Factors that increase stroke volume

  1. Increased ventricular end-diastolic volume (preload)

  2. Increased sympathetic NS activity

  3. Decreased arterial pressure (afterload)
• Effects of thyroid hormone on cardiac output

  Increased heart rate and force of heart contraction (increased expression of myosin heavy chain, beta1 receptor, Na+/K+ ATPase, delayed rectifier K+ channel subunits)

  Increased blood volume (increased aldosterone production)

  Decreased vascular resistance (vasodilation)
• What does the frank-starling mechanism show?

  How stroke volume is affected by ventricular end-diastolic volume
• Ejection force equation


  Stroke volume / end diastolic volume
• What does sympathetic stimulation do?

  Increases stroke volume independent of ventricular end-diastolic volume

  Affects both the rate at which force develops and rate of relaxation
• What are beta blockers (beta adrenergic receptor antagonists) under for?

  Used to treat hypertension by reducing cardiac output
• Contractile strength (and velocity)

  High Ca2+ release when excited (more cross bridging)

  Faster Ca2+ reuptake (needed for faster heart rate)

  Troponin is phosphorylated, making it more responsive; this property demonstrates cardiac reserve
• What is coronary artery disease caused by?

  atherosclerosis
• Effects of Coronary Artery Disease

  Thickening of the inner arterial wall causes reduced blood flow and increased blood pressure
• HDL cholesterol


  good cholesterol since excreted from body via bile
• LDL cholesterol


  "bad" cholesterol; carry lipids in bloodstream
• Large artery


  many layers of smooth muscle and connective tissue; several elastic layers
• Large vein


  few layers of smooth muscle and connective tissue; few elastic layers; wide endothelium
• Flow of blood through vascular system

  large artery -> arteriole -> capillary -> venule -> large vein
• compliance equation


  change in volume / change in pressure