applied anatomy and physiology

• the heart

  A) pulmonary artery

  B) pulmonary vein

  C) aorta

  D) superior vena cava

  E) right atrium

  F) right ventricle

  G) left ventricle

  H) left atrium

  
• vena cava- brings deoxygenated blood back to the right atrium
• pulmonary vein- delivers oxygenated blood back to left atrium
• pulmonary artery- leaves the right ventricle with deoxygenated blood to go to the lungs
• aorta- leaves the left ventricle with oxygenated blood to go to the body
• valves

  • regulate blood flow
  • prevent backflow
• pulmonary circulation

  1. heart
  2. lungs
  3. heart
• systematic

  1. heart
  2. body
  3. heart
• blood pressure- blood flow x resistance
• vascular shunt mechanism- the redirecting of blood flow to the areas of the body that need it most
• vasodilation- widening of the blood vessels to increase the flow of blood into the capillaries
• vasoconstriction- narrowing of the blood vessels to reduce blood flow into the capillaries
• pre capillary sphincters- tiny rings of muscle located at the opening of capillaries
• importance of redistribution of blood

  • oxygen delivered to working muscles
  • blood gets rid of heat at skin through sweating
  • remove waste products from muscles
  • more blood directed to the heart
• diastol- relaxation
• systol- contraction
• cardiac conduction system

  1. SAN generates a pulse that spreads across the atria- atrial systol
  2. impulse delayed at the AVN for 0.1sec to allow ventricles to fill
  3. impulse travels through bundle of His
  4. purkinje fibres causes ventricles to contract- ventricular systol
• chemoreceptors- detect increase in carbon dioxide, increase heart rate
• baroreceptors- detect increase in blood pressure, decrease heart rate
• proprioceptors- increase in muscle movement, increase in heart rate
• sympathetic nervous system- stimulates the heart to beat faster
• parasympathetic nervous system- returns the heart to resting level
• central nervous system

  • brain
  • spinal cord
• peripheral nervous system

  • nerve cells
• hormonal control mechanism

  1. adrenaline stimulates SAN
  2. increase in speed and force of contraction
  3. increase in cardiac out put
  4. increase in blood flow to working muscles
• stroke volume- amount of blood ejected from the heart per beat (ml)
• venous return- volume of blood that returns to the right atrium via the vena cava
• starlings law of the heart

  1. increased venous return as more carbon dioxide is present in blood and needs to be removed
  2. greater diastolic filling of the heart and cardiac muscle stretches
  3. ventricles hold more blood so there is a greater force of contraction
  4. increased ejection fraction
• elasticity of cardiac fibers- the more the fibers can stretch, the greater the force of contraction
• ejection fraction- an increase in contraction force of the heart during exercise increases ejection fraction
• ejection fraction (%)= volume of blood ejected from the left ventricle/ total volume of blood in the left ventricle
• heart rate- number of times the heart beats per minute
• cardiac hypertrophy- the thickening of the muscular wall of the heart so it becomes bigger and stronger
• bradycardia- a decrease in resting heart rate below 60 bpm
• cardiac output- amount of blood ejected from the heart per minute
• cardiac output (Q)= heart rate (HR) x stroke volume (SV)
• heart disease risk factors

  • high fat/ salt diet
  • lack of exercise
  • smoking
  • high blood pressure
• atheroscherosis- fatty deposits (atheroma) in the coronary blood vessels which narrow the lumen- increased risk of blockage
• angina- pain in the heart due to a lack of oxygen to the cardiac muscle
• heart disease

  1. atheroma/blood clots
  2. cause a blockage in the coronary vessel
  3. no oxygen supplied to the heart
  4. cardiac arrest