5. blood pressure

• what is elevated blood pressure known as?

  hypertension (units=mmHg)
• what is peripheral resistance?

  contact between the blood and vessel walls causes friction and slows blood flow
• when is blood pressure at its highest/lowest?

  • highest= ventricular systole (systolic pressure).
  • lowest= ventricular diastole (diastolic pressure).~
• explain the changes in the graph shown below


  • mean blood pressure decreases due to peripheral resistance.
  • fluctuations in pressure in arteries is caused by contraction/relaxation of heart. as blood is expelled from heart, systole pressure is higher
  • during diastole, pressure is slightly lower but maintained
  • arteries and capillaries have greater SA, resisting flow more and decreasing blood pressure

  
• is oedema?

  fluid building up in tissues causing swelling (sign of hypertension and high blood pressure)
• explain 1, 2, 3 and 4


  1. tissue fluid formed when plasma is forced out capillaries, carrying nutrients and oxygen with it
  2. cells absorb nutrients and oxygen from tissue fluid, giving out waste
  3. tissue fluid moves back to capillaries via osmosis
  4. 20% fluid drains to blind-ended lymph capillary, flows through lymph vessel and returns lymph fluid to blood via thoracic duct in neck