mass transport in animals

• describe the roll of RBc and haemogobin in oxygen transport

  red blood cells contain a lot of haemoglobin-no nucleus biconcave high sa:v ratio short diffusion pathway

  hb associates with o2 at gas exchange surfaces where partial pressures of o2 is high

  this forms oxyhaemoglobin which transports o2

  hb dissociates o2 near cells where po2 is lower
• describe the structure of haemoglobin

  -protein with quarternary structure

  -made of 4 polypeptide chains

  -each chain contains a haem group containing an iron ion
• describe the loading transport... to the dissociation curve

  areas with low po2-hb has a low affinity of o2 so o2 unloads with hb so % saturation is low

  areas with high po2- hb has a high affinity for 02 so readilt associates with hb so % saturation is high
• explain how the s shape occurs

  binding of first oxygen changes tertiary structure of haemoglobin this uncovers haem group binding sites making further binding of oxygens easier
• describe evidence for co operative binding

  a low po2 as oxygen increases there is little increase in % saturation of hb with oxygen when first oxygen is binding

  at higher po2 as oxygen increases there is a big increase in % saturation of hb with oxygen showing it has gotten easier to bind
• what is the bohr effect

  effecof co2 concentration on disassosiation of oxyhaemoglobin-curve shifts to the right
• explain effect of co2 conc of disassociation of oxyhaemoglobin


  increasing blood co2 increased rate of respiration

  lowers blood ph

  reducing hb affinity for oxygen as tertiary structure has changed slightly

  so more faster unloading of oxygen to respiring cells at a given po2
• explain the advantage of the bohr effect

  more disassociation of oxygen = faster aerobic respiration =more atp produced
• explain why different types of haemoglobin have different oxygen transport properties

  different types of hb are made with polypeptide chains with different amino acid sequences

  this results in different tertiary structures which means they have different affinities of oxygen
• explain how organisms can be adapted to their environment by having different types of haemoglobin with different oxygen transport properties

  curve shifts left-hb has higher affinity for oxygen

  which means more o2 associates with hb more readily at GES where po2 is lower eg organisms in low o2 backgrounds

  curve shifts right-hb has lower affinity for oxygen

  more o2 disassociates with hb more readily at respiring tissures where oxygen is more needed
• what is the general pattern of blood circulation in a mammal

  1. deoxygenated blood in RHS is pumped to lungs: oxygenated returns to left side
  2. Oxygenated blood in LHS is pumped to rest of the body: deoxygenated blood returns back to the right side
• Suggest the importance of a double circulatory system

  • prevents mixing of the oxygenated and deoxygenated blood-so blood pumped to body can be fully saturated with oxygen for aerobic respiration
  • blood can be pumped to body at higher pressure so substances can be taken to and removed from cells more efficiently
• name the blood vessels entering and leaving the heart

  • vena cava-transports deoxy blood from respiring blood tissues to the heart
  • pulmonary artery-transports deoxy blood from heart to lungs
  • pulmonary vein- transports oxygenated blood from lungs to heart
  • Aorta-transprts oxygenated blood form heart to respiring body tissues
• name the blood vessels leaving and entering the kidney

  • renal arteries- oxygenated blood to kidneys
  • renal veins- dexoygenated blood to vena cave from kidneys
• name the blood vessels that carry oxygenated blood to the heart muscle

  coronary arteries-located on the surface of the heart branching from aorta
• why is the left ventricle thicker than the right

  • thicker muscles to contract with greater force
  • to generate a higher pressure to pump blood around the body
• sl valves closed 


  pressure in artery is higher than in ventricle to prevent backflow of blood from artery to ventricle
• sl valves open


  when pressure in ventricle is higher than in named artery thanblood flows from ventricle to artery
• av valves closed 


  pressure in ventricle higher than atrium to prevent backflow from ventricles to atrium
• av valves open 


  when pressure in atrium is higher than in ventricle so blood flows from atrium to ventricle
• equation for cardiac output

  =stroke volume(volume of blood pumped in each heartbeat) x heart rate(number of beats per min)
• explain how the structure of heart rate can be calculated from cardiac cycle data

  heart rate (beats per min)=60 seconds /length of one cardiac cycle