How valves work

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Valves ensure blood flows in the correct direction- opened & closed by pressure change

Atrioventricular valves

  • When ventricular walls relax & recoil after contraction- pressure in ventricles drops below pressure in atria
  • This causes the atroventricular valves to open
  • Blood entering the heart flows straight through atria & into ventricles
  • Pressure in atria slowly rises as they fill with blood
  • Valves remain open while atria contract

Semilunar valves

  • When ventricles start to contract- pressure in major arteries is higher than…


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