Nervous System

Nervous System

1. CNS

   • Brain
   • Spinal Cord

2. PNS

   • Somatic
     • Afferent (sensory)
     • Efferent (motor)
       • Single neuron
   • Visceral
     • Afferent (sensory)
     • Efferent (motor) = Autonomic Nervous System
       • Parasympathetic
         • Craniosacral origin
           • Cranial = vagal nerve to abdominal viscera
           • Sacral = pelvic viscera
         • Long pre-ganglionic neurons
         • Ach from pre and post-ganglionic neurons
         • Homeostasis
       • Sympathetic
         • Thoracolumbar origin, run in sympathetic trunk (paravertebral ganglia)
         • Short pre-ganglionic neurons
         • Ach from pre-ganglionic neurons
         • Norepeniphrine from post-ganglionic neurons
           • Alpha = vasoconstriction in muscles (less) and gut
           • Beta2 = vasodilation in muscles and coronary arteries
           • Beta1 = HR + contractility in myocytes
         • 'Fight or flight'
       • Pre- and post- ganglionic neurons