Transport in Animals

• Transport in Animals

  • Transport system is means which materials are moved from exchange surface to cells located in organism
  • E.g. O_2, CO_2, glucose, amino acids, vitamins, minerals, heat, hormones, plasma proteins, leukocytes and platelets
  • Good transport system:
  • Medium to carry nutrients
  • Pump to push
  • Exchange surface for O_2
  • Vessels to carry it by mass flow
  • Two circuits, one to pick up O_2 and other to deliver it
  • Three factors affect need for transport system:
  • SA:V
  • Size
  • Activity
• Key Words:

  • Closed Circulatory System: Fluid contained in vessels
  • Double Circulatory System: Separate systemic and pulmonary circulation; blood passes through heart twice
  • Haemolymph: Fluid circulating in invertebrate body, remain in direct contact with animal tissues
  • Open Circulatory System: Fluid flows through body cavity
  • Pulmonary Circulation: Blood circuit from heart to lungs to heart
  • Single Circulatory system: Combined systematic and exchange surface circulation blood flows once through heart
  • Systemic Circulation: Blood circuit from heart to rest of body to heart
• Open vs Closed Circulatory System

  • Open Circulatory System:
  • Blood pumped from heart to body cavities (haemocoel)
  • Low pressure
  • Direct contact with tissue (forms haemolymph)
  • Transports dissolved nutrients, not gas, when heart relaxes it returns and re-pumped
  • Advantages:
  • Needs less energy
  • Less complexities of pressure changes
  • Easy to lose heat
  • No directional control
  • Closed Circulatory Systems:
  • Blood pumped by muscular heart
  • High pressure
  • In continuous vessel system
  • Can be a single or double
  • Advantages:
  • Faster
  • Flow diverted to elsewhere (vasoconstriction and vasodilation)
• Single Vs Double Ciruclatory System

  • Single Closed:
  • Blood once through heart per circuit
  • Heart to respiratory organ and body
  • No separate pulmonary and systemic
  • Disadvantages:
  • Blood loses pressure
  • Slower
  • Double Closed:
  • Blood twice through heart per circuit
  • Right pumps to lungs (pulmonary)
  • Left pumps at higher pressure to body (systemic)
  • Blood pressure different levels
  • Pulmonary low; lung’s capillaries undamaged
  • Systemic high; quicker flow
  • Advantages:
  • Oxygenated and deoxygenated blood separate
  • Better O_2 and glucose supply
  • Maintain constant temperature (endothermic)