transport in animals

• what is an open circulatory system

  blood is not contained in vessels and pumped directly to muscles and back
• what is a closed circulatory system

  blood is in closed vessels transporting to tissues, experiences single and double circulation
• single circulation

  blood passes through the heart once per circuit eg. heart -> gills -> tissues
• double circulation

  blood passes through the heart twice per circuit eg heart -> lungs -> heart -> body
• what are the sequence of events in cardiac cycle

  • atrial systole
  • ventricular systole
  • diastole
• what does myogenic mean

  contractions are initiated from within the heart not from hormones or nervous system
• describe sequence of how cardiac cycle is controlled

  1. s-a node sends signal through atria
  2. atrial systole
  3. a-v node holds signal then it goes down the septum through the bundle of his
  4. signal spreads through purkinji fibres in ventricle walls
  5. ventricular systole
  6. diastole
• what blood vessels have valves

  veins
• what is a ecg

  an electrocardiogram traces the voltage changes produced by the heart detected by electrodes in the skin
• how is tissue fluid formed

  plasma is forced through the cappilary walls as there is high hydrostatic pressure, and bathes tissue cells in fluid
• what is action potential

  movement of an electrical impulse that causes the heart to contract
• what is the Bohr effect

  the higher partial pressure of CO2 the more the oxygen dissociation curve will move to the right
• how is carbon dioxide transported

  • dissolved in the plasma (5%)
  • associated with haemoglobin (10%)
  • hydrogen carbonate ions (85%)
• explain the association of CO2 with haemoglobin

  • co2 dissolves in the cell
  • dissolves in water + forms carbonic acid
  • dissociates to form H+ and hydrogen carbonate ions
  • H+ binds with oxyhaemoglobin to make oxygen and hb acid
  • chlorine ions diffuse in the cell to maintain electrochemical neutrality
• why is the human 02 dissociation curve sigmoidal

  first oxygen hard to add the next two are easy to associate then confirmational change in structure is made so fourth oxygen is harder to add.