Heart

• where is the heart?

  In the mediastinum with the lungs

  level of 2nd rib
• which way does the apex of heart point?

  towards the right
• why is the base at the top and apex at the top?

  As the heart starts as a tube and the apex is where there heart tube folds up and closes up
• how many layers to pericardium?

  3
• what are the layers of pericardium?

  fibrous pericardium

  serous pericardium

  epicardium
• whic layer of pericardium is fluid filled?

  serous
• what is the role of serous pericardium?


  lubrication
• what does pericarditis sound like?


  scratchy
• what are the types of chronic pericarditis?

  fusive

  constrictive
• what is the bag that the heart sits in?

  pericardium
• formation of pericardium?


  serous pericardium is wrapped round heart as heart sinks into the heart
• what are the main layers of the heart?

  epicardium, myocardium, endocardium
• what do the atrioventricular vavles do?


  prevent backflow from atria to ventricles
• what holds the atrioventricular valves in place?

  chordaw tendinae
• which side is the tricuspid valve on?

  right
• what do semilunar valves do?

  prevent back flow from arteries into ventricles
• what is the structure of semilunar valve?


  tricuspid
• what are the two main problems with valves?

  incompetent valves, valvular stenosis
• what is an incompetent valve?

  do not fully close so there is regurgitant flow
• what is valvular stenosis?

  stiffened valves
• what is the cause of valvular stenosis?

  repeated infection, congenital disease or calcium deposits
• what are the 3 layers of blood vessels?


  tunica adventitia/externa, tunica media, tunica intima
• where are nerves found in the blood vessel?

  tunica externa
• which layer effects resistance to blood flow?

  tunica media
• what is the tunica media made up?


  smooth muscle
• how does the tunica media affect blood pressure?

  affects lumen size, smaller increases blood pressure
• what are the layers of arterial system?

  large arteries, small arteries, arterioles, capillaries
• describe a large artery:

  • very muscular
  • do NOT affect blood pressure
  • distribution role
  • renal
  • carotid
  • mesenteric
  • elastic to absorb high volume and pressure from heart
• Describe small arteries:

  • distribution
  • resistance
  • highly innervated - open and close a lot
  • regulate arterial pressure
  • receptor for circulating hormones
  • produces local signals (K+, NO)
• describe arterioles:

  • allow organs to be bypassed
  • resistance vessels
• describe capillaries:

  • small and thin to allow for exchange of material
  • no smooth muscle
  • high exchange
• what are the types of capillaries?


  continuous, fenestrated, sinusoid
• what is the function of fenestrated capillaries?


  Allows signals (hormones) from system to pass into bloodstream
• what are sinusoid capillaries designed for?


  to allow new blood cells to enter blood flow
• what are the roles of valves in the vein?

  to prevent backflow
• features of veins:

  • less smooth muscle
  • stretchy
  • under less pressure than arteries
• Why is the majority in our venous system?

  storage
• why is there a change supine and upright position blood distrubtion?


  gravity, and muscules require blood (when standing up legs require more blood for muscles, when lying down more blood is required in central for heart and stomach process)
• what are the three distrubtion system?

  pulmonary circulation, systemic, coronary circulation
• Pulmonary circulation:

  • positioned towards back of heart
  • crescent shaped
  • RHS
  • blood in through venae cavae
  • back out through pulmonary artery