VPB 121: Veterinary Physiology - II (2+1)

FUNCTIONS OF ANS

• Preserves cellular environment of animal to maintain homeostasis
• Sympathetic and para sympathetic system makes fine adjustments to rectify the effect of minor internal and external stress in a resting
• It involves specific reflex activities of an organ or a part of the organ.
• In stress, sympathetic systemic activity is modified. They involve accelerated response in whole of the visceral motor system
• Referred by Cannon as FIGHT OR FLIGHT RESPONSE
• This ends up in the immobilization of energy and reroute the circulation to vital organs for nutrients.
• Psychological modification evident in fight/flight response are due to sympathetic activity are
  • Increased Heart rate
  • Increased B.P
  • Vasocostrictor of blood vessels of skin and viscera
  • Vasodilatation and increase in blood supply to skeletal muscles
  • Spleenic contraction to increased oxygen carrying capacity of blood
  • Increased bronchodilation and vasodilatation of lung facilitate increased oxygen uptake and used up Carbondioxide release
  • Pupillary dilation to widen the visual receptivity
  • Piloerection to conserve body heat (calorigenic and glycogenic effect)
  • Muscle glycogenolysis and hepatic glycogenolysis (to some extent) to mobilze glucose to skeletal muscle for energy need.
  • Increased activity of many receptor organs to sense changes in homeostasis like mechanoceptors of skin and mesentery, muscle spindle response, gustatory and olfactory activity are evident.
  • Potentiated by adrenal medullary involvement as an autonomical counterpart - sympathetic adrenal system
• Parasympathetic system plays an important role in co-coordinating specific functions of digestive tract.