Apedia

A-Level Biology OCR A

Blood Pressure Ventricles Contract Rises Volume Fill Atria

Ventricular pressure starts low, rises sharply during contraction to push blood into the aorta, then falls during relaxation. Atrial pressure is generally low but peaks during contraction. Aortic pressure rises with ventricular contraction and falls gradually due to elastic recoil. Ventricular volume increases as blood fills the ventricles and decreases sharply when blood is ejected.

Ventricular pressure starts low, rises sharply during contraction to push blood into the aorta, then falls during relaxation. Atrial pressure is generally low but peaks during contraction. Aortic pressure rises with ventricular contraction and falls gradually due to elastic recoil. Ventricular volume increases as blood fills the ventricles and decreases sharply when blood is ejected.

Front Interpret a graph of pressure change and volume change in diff chambers of the heart.
Back
Pressure & volume graph

Ventricular pressure:
  • Low at first, increases gradually as ventricles fill as atria contract
  • AV valves close, pressure rises drastically as ventricles contract
  • Since higher pressure than aorta, blood is forced into the aorta 

Atrial pressure:
  • Relatively low always bc thin walls cant create much force
  • Highest when contracting, drops when AV valve closes and walls relax
  • Atria then build up with blood - gradual increase in pressure until AV valve opens & blood moves into ventricle

Aortic pressure:
  • Rises when ventricles contract - blood is forced into aorta and then gradually falls
  • Bc elastic recoil produces temporary rise in pressure at start of diastole

Ventricular volume:
  • Rises as atria contract & ventricles fill with blood
  • Drops suddenly as blood is forced out the aorta when semilunar valve opens
  • Volume rises again as ventricles fill with blood

Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.

Next card: Ventricular p(v pressure valve opens systole aorta/pulm artery

Previous card: Ventricles pressure atria valve aorta atrioventricular open semilunar

Up to card list: A-Level Biology OCR A