KN 152

• Cardiovascular System


  "Cardio" = Heart, "Vascular" = Vessels (arteries & veins)

  
• 3 main categories of the CV System

  • The Heart
  • The Vascular System
  • The Blood

  
• Jobs of the CV System

  • Deliver O2 and energy substances
  • Remove CO2 and other waste products
  • Transport hormones and other molecules
  • Thermoregulation
  • Acid-base balance
  • Regulation of immune system
• CV Anatomy Overview


  • Includes three major circulatory elements: Pump (heart), Channels or tubes (blood vessels), Fluid medium (blood)
  • Heart generates pressure to drive blood through vessels
  • Blood flow must meet metabolic demands

  
• The Heart


  • The heart's anatomy allows it to create PRESSURE
  • That's how it pumps blood
• Inside the Pump (Heart)

  • Four chambers: Right and left atria (RA, LA), Right and left ventricles (RV, LV)
  • Right heart: pulmonary circulation, Pumps deoxygenated blood from body to lungs
  • Left heart: systemic circulation, Pumps oxygenated blood from lungs to body

  
• Right coronary artery


  Supplies right side of heart

  
• Left (main) coronary artery


  Supplies left side of heart

  
• Atherosclerosis → coronary artery disease
• Cardiac Cycle


  One cycle = 1 contraction + 1 Relaxation, This is one full beat of the heart
• Two Control Centers


  • Intrinsic (inside the heart)
  • Extrinsic (outside the heart)
• Intrinsic Rhythm Control


  • Spontaneous rhythmicity: Special heart cells generate and spread electrical signal
  • Intrinsic heart rate (HR) would be 100 beats/min
  • Observed in heart transplant patients (no neural innervation)
• Extrinsic Regulation of HR

  • Autonomic control
  • Hormones/Chemicals (ie, epinepherine, beta-blockers)
  • Temperature
  • Emotions
  • Gender
  • Age
• Autonomic Control of HR


  • Parasympathetic: Via Vagus Nerve, SLOWS HR
  • Sympathetic: Via Cardiac Accelerator Nerves, INCREASES HR
• Electrocardiogram (ECG)


  Recording of heart's electrical activity, Diagnostic tool for coronary artery disease

  
• Cardiac Arrythmias


  • Bradycardia (pathological vs. exercise induced)
  • Tachycardia (pathological vs. exercise induced)
  • Premature ventricular contraction
  • Atrial flutter, fibrillation
  • Ventricular tachycardia
  • Ventricular fibrillation
• Arteries vs Veins


  • Similarities: O2 and CO2
  • Differences: Vessel thickness. Arteries are thicker, Valves (only veins have them) Direction of Blood Flow Arteries->AWAY from the heart to body/ Blood pressure-> Lower in veins
• Vascular System Definitions


  • Arteries: Carry blood away from heart
  • Arterioles: Control blood flow, feed capillaries
  • Capillaries: Provide site for nutrient and waste exchange
  • Venules: Collect blood from capillaries
  • Veins: Carry blood from venules back to heart

  
• Systemic circuit – left side

  • Pumps oxygenated blood from LV to the whole body via aorta, Returns deoxygenated blood to the RA via vena cavae

  
• Pulmonary circuit – right side


  • Pumps deoxygenated blood from RV to the lungs via pulmonary arteries, Returns oxygenated blood to the LA via pulmonary veins

  
• A common problem with veins
• The Cardiac Cycle


  All mechanical and electrical events occurring during one heartbeat

  Diastole: relaxation phase/ chambers fill with blood

  Systole: contraction phase/ blood expelled into aorta and pulmonary arteries
• Ventricular Systole


  Contraction begins, Ventricular pressure rises, Atrioventricular valves close, Semilunar valves open, Blood is ejected, At end, blood in ventricle = end-systolic volume (ESV)
• Ventricular Diastole


  Relaxation begins, Ventricular pressure drops, Semilunar valves close, Atrioventricular valves open, Fill 70% passively, 30% by atrial contraction, At end, blood in ventricle = end-diastolic volume (EDV)
• Stroke Volume (SV)


  The amount of blood pumped out of the left ventricle per beat
• Cardiac Output (Q)


  The total amount of blood pumped by the heart in one minute

  
• Ejection Fraction (EF)


  Percentage of the EDV that was pumped out, Clinical index of heart contractile function
• Constant or Intermittent Flow?
• Blood Pressure


  Systolic pressure (SBP), Diastolic pressure (DBP), Mean arterial pressure (MAP)

  
• Hemodynamics: The Pressure Gradient

  Blood flow from region of high pressure (LV, arteries) to region of low pressure (veins, RA), Resistance: force that opposes flow
• Cardiac Output

  the total amount of blood pumped by the heart in one minute

  
• The amount of bllod pumped in one heartbeat

  EDV- heart rest (most full)

  ESV- heart contracts (most empty)

  SV- amount the heart ejected out

  ESV= EDV- SV
• Ejection Fraction

  • Percentage of the EDV that was pumped out
  • EF=SV/EDV
  • Normal= 50-60% rest