Nervous System 2

Nervous System 2

1. Synapses

   • Axodendritic
     • Axon--> dendrite
   • Axosomatic
     • Axon --> cell
   • Axoaxonic
     • Axon --> Axon

2. PNS

   • Ganglia - groups of neuron cell bodies
     • A peripheral collection of nerve cell bodies together with afferent and efferent axons
     • Dorsal root ganglia are sensory cells within the spinal nerves
     • Efferent motor ganglia in ANS
     • Cranial nerve ganglia
   • Nerves - bundles of axons
     • Spinal nerves connected to spinal cord and cranial nerves connected to brain
     • Epineurium surrounds entire nerve trunk
       • Perineurium surrounds axons and endoneurium to form fassicles
         • Endoneurium surrounds individual axons
     • Motor - from CNS
     • Sensory - to CNS
     • Mixed- sensory and motor

3. CNS

   • Spinal Cord
     • Begins at base of medulla oblongata + extends as slender cord to level of intervertebral disc between the first and second lumbar vertebrae
     • 31 segements each with a pair of spinal nerves
     • Spinal nerves
       • 8 Cervical
       • 12 Thoratic
       • 5 Lumbar
       • 5 Sacral
       • 1 coccygeal
       • Link information to and from brain
       • Spinal reflexes
     • Sagital section of lower spine
       • Inferior terminal at level of the 2nd lumbar vertabra. Branches from lumbar region pass downward from cone-shaped tip (conus medullaris) of spinal cord forming cauda equina (horse's tail)
     • Grey matter within, white matter outside
     • Ventral root of spinal nerve (motor)
     • Dorsal root of spinal nerve (sensory)
     • Spinal nerve (mixed nerve)