2/25/2013

2 Divisions of this:
        a. Somatic - "Voluntary". Control of Skeletal Muscle
        b. Antonomic - "involuntary".      "    Cardiac & Smooth Muscle
2 Divisions:
           i. Sympathetic - "waking" - involves neurons that increase activity & involve excitatory neurotransmitters.
           ii. Perasympathetic - "Sleeping" - involves neurons that decrease activity & involve inhibitory  neurotransmitters.
II. Cells
  A. Supporting Cells
      1. In the CNS. 2 types"
           a. Astrocytes - fat cells that invade arteries leading into the CNS. Sets up the Blood-Brain Barrier. Only fat-soluable substances should be able to pass through. protects us from viruses & other toxins that are water soluable. Reason why the CNS has its own immune system.
           b. Oligodendrocytes - fat cells that form the myelin sheeth of CNS neurons. Wrap around the axon of a neuron insulating it & making the impulse more efficient & faster. MS - these cells are being destroyed.
      2. In th PNS: Schwann Cells - form the myelin sheeth of PNS Neurons.
  B. Neurons - Cells that conduct electricity.

Nerve - Bundle of neurons. Are either motor or sensory. Ex. Funny Bone.
Ganglion - Cluster of neurons. are both motor and sensory.

Neuron:

1.  Cell Body - contains nucleus & other organelles. Performs all of the normal cell tasks
2. Axon - longest part. Where the initial electricity is generated.