Cardiovascular System

• What is vasodilation?


  Blood vessels become wider, increasing the amount of blood delivered to active areas
• What is vasoconstriction? 


  Blood vessels become narrower restricting the amount of blood that is delivered to inactive areas
• What do veins do and what are their adaptations?

  Carry deoxygenated blood towards the heart from the working muscles and tissues - thin walls, valves, smaller then arteries, large lumen
• What do the arteries do and what are their adaptations? 


  carry oxygenated blood away from the heart and towards the working muscles and tissues - elastic layer (vasodilation and vasoconstriction), large in size, one cell thick
• What do the capillaries do and what are their adaptations? 


  Located at the alveoli - site of gaseous exchange, smallest in size, thinnest walls, one cell thick
• What are the steps of the cardiac cycle?

  1. Deoxygenated blood enters the right atrium via the vena cave
  2. Deoxygenated blood is forced into the right ventricle
  3. Deoxygenated blood is ejected into the lungs..
  4. ...Via the pulmonary artery
  5. Oxygenation of blood occurs at the lungs
  6. Oxygenated blood enters the left atrium via the pulmonary vein
  7. Oxygenated blood is forced into the left ventricle
  8. Oxygenated blood is ejected to the rest of the body..
  9. ...Via the aorta
• What is heart rate?


  (bpm) the number of times the heat beats per minute
• What is stroke volume?


  (mL) the amount of blood that leaves the left ventricle per minute
• What is the cardiac output?


  (L/min) the amount of blood that leaves the left ventricle per minute
• How do you work out cardiac output? 


  Heart rate x Stroke volume = cardiac output