animal transport

• Describe diastole


  Muscle is relaxed

  Pressure increases in atria

  Atria-ventricular valves open slightly

  Blood starts to enter the atria
• What is the acronym for diastole and systole ?

  Muscle

  Pressure

  Volume

  Direction
• Describe atrial systole

  Muscle in atria wall contracts

  Pressure in atria increases

  A-V valves are open when pressure in atria is higher than in ventricles

  Blood flows in the ventricles
• Describe ventricular systole

  Muscle in ventricular wall contracts

  Pressure in the ventricles increases

  A-V valves are forced shut when pressure in the ventricles is higher than in the atria

  Pressure in ventricles is higher than in arteries so semi-lunar valves open

  Blood flows out of the arteries
• Define:

  Heart rate

  Stroke volume

  Cardiac output

  HR: number of heart beats per min

  SV: Volume of blood pumped in one heartbeat

  CO:Volume of blood pumped by heart in one heartbeat
• Why does training lower the resting heart rate of an athlete ?

  size of heart increases

  muscle wall size increases

  strengh of contraction increases

  stroke volume increases

  cardiac output increases
• Describe how tissue fluid is created and returns to the lymphatic system

  There is a high HP in the capillaries due to strong ventricular contraction

  This is greater than the HP outside the capillary

  Water moves out of the capillary by osmosis along with small molecules

  forming tissue fluid

  Larger cells remain inside the capillary

  Loss of water reduces HP in the capillary

  HP is lower inside the capillary than outside

  Water potential is lower inside the capillary than outside due to the large proteins in the capillary

  Water moves in by osmosis down a water potential gradient
• What causes the Bohr shift ?

  In the tissues CO2 is released by respiring cells

  Forms carbonic acid which dissociates into H+ ions lowering the pH

  Acidity changes the shape of Hb so now it has a lower affinity for oxygen

  O2 is more readily released to respiring cells
• What happens to pO2 in low oxygen environment ?

  pO2 is lower

  Hb has a higher affinity for O2 so it can load more of the available oxygen

  Be saturated at a lower pO2

  Dissociation curve shifts to the left
• Why does the Hb of a smaller animal have a lower affinity for oxygen ?

  Sa:Vol ratio is bigger

  Heat loss is increased

  Rate of respiration increases

  Requirement for O2 increases for respiration

  Hb has a lower affinity for oxygen so it releases oxygen more readily