Nervous system

Nervous system

1. Branches

   • Central
   • Peripheral
     • Somatic (voulentary)
     • Autonomic (involentary)
       • Sympathetic
       • Parasympathetic

2. Anatomy

   • Sympathetic
     • Thorasic
     • Connects to sympathetic chain
   • Parasympathetic
     • Cranial and Sacral
   • Often converge
   • Spinal cord
     • Pre-ganglionic
       • Post ganglionic

3. Function

   • Sympathtic
     • HR Up
       • Increased peripheral flow
       • Decrease skin + viceral
     • GI down
     • Catabolism of energy
     • Pupils dilate
   • Parasympahteic
     • Decreased HR
     • GI activity
       • Glandular secretion
     • Pupils contract

4. Synapse

   • Producton
     • Transport into cell
       • Transporter / slow block
     • Conversion into neurotransmitter
       • Enzyme / slow block
     • Movement into vesicle
       • Transporter / slow block
   • Release
     • AP activation
       • Ion channel / quick / inhibit
     • Vesicular fusion
       • Complex, block possible
   • Breakdown
     • Degredation / precursor
       • Enzyme block / increases transmission
       • Wider range
     • Re-uptake
       • Increase over large area
   • Regulation
     • Next cell
       • Block / increase fast
     • Releasing cell
   • Easier to turn receptors on / enzymes off

5. Chemistry

   • Parasympathetic
     • Acetylcholine
     • Nicotinic receptors
     • Muscarinic
   • Sympathetic
     • ACh pre-ganglionic + sweat
     • Noradrenaline post-ganglionic
     • A1/2, B1,2 receptors
     • Medulla is ganglion

6. Neuromodulators

   • Effect of mediators on transmission
   • Increase or decrease transmission
   • No direct interaction
   • Slower
   • Pre-Synaptic
     • Homotropic
       • Blocks itself
       • Autoregulatory
         • A2 adrenerugic
         • 10 fold increase
     • Heteroptrophic
       • Blocks other nerve
       • ANS and PNS interaction
   • Other modulators
     • Histamine inhibits NA
     • Adrenaline stimulates NA
   • Post-Synaptic
     • Alter response of firing
     • NPY enhances

7. NANC

   • Non adreneurgic - non colonerurgic
   • NPY and vasoactive peptides are involved
   • Co- transmission
     • Modulate responses
     • In same neuron
     • Long time courses