L7-9 cardiovascular system

• where is the heart?

  in the mediastinum with the heart, central with base pointing towards the right (apex towards the left)
• apex is at the bottom of the heart because of development of the heart, the base folds up to form the apex
• how many layers of the pericardium are there?

  3
• the 3 layers of the pericardium are:

  • fibrous pericardium
  • serous pericardium
  • epicardium
• what does pericarditis sound like?

  rubber sound
• pericarditis causes:


  impact to movement and function of the heart
• how many layers does the heart wall have?

  3
• what are the 3 main layers of the heart wall?

  epicardium, myocardium and the endocardium
• the heart wall function:

  provide contractile properties of the heart as they are muscular layers
• the heart has 4 chambers and 4 valves
• atrioventricular valves prevent::


  backflow from the atria to the ventricles
• semilunar valves prevent:


  backflow from aorta/pulmonary artery into the ventricles
• chordae tendinae stop valves:

  swinging open in both directions
• semilunar valves are tricuspid
• main problems with heart valves:

  incompetent valves (leaky)

  valvular stenosis (stiffened valves, narrow opening so insufficient blood flow)
• what are the 3 layers of arteries and veins?


  tunica externa, tunica media, tunica intima
• tunica externa contains:


  nerves and blood vessels
• tunica externa function:


  supportive outer layer
• tunica media is composed of smooth muscle
• tunica media function:


  affects resistance to blood flow (controls blood pressure)
• tunica intima function:


  smooth surface and involved in communication
• large arteries function:


  distribution role becuase doesn't affect blood pressure, absorb high volume and pressure from the heart
• the large arteries are elastic and have very muscular walls to push blood along to organs
• small arteries function:


  distribution and resistance
• describe small arteries:


  regulate arterial pressures, receptors for circulating hormones
• arterioles function:


  resistance, constriction/dilation, bypass blood flow to organs
• capillaries function:


  exchange of materials
• name the 3 types of capillaries:


  continuous, fenestrated, sinusoid
• continuous capillaries are the most common, only have _ junctions

  tight
• continuous capillaries are found in the:


  CNS, lungs, muscle tissue, skin
• fenestrated capillaries are found in:


  choroid plexus, kidneys, endocrine glands
• sinusoid capillaries function:


  allow blood cells through
• sinusoid capillaries found in:

  bone marrow, endocrine glands, placenta
• supine= lying down
• why is there a difference in where blood is upright versus supine?

  gravity, muscles demand for blood
• what are the 3 distribution systems?

  pulmonary circulation (RHS), systemic circulation (LHS), coronary circulation (from aorta)
• left hand side is thicker than right hand side as:

  blood needs to be pushed all the way around the body, requires higher pressure
• coronary circulation is important:

  blood supply to the heart, can cause a heart attack if blocked
• veins structure:

  • less smooth muscle
  • stretchy
  • larger veins have valves to prevent backflow
• how many blood groups?

  43