Nervous System functions
Central Nervous System
brain and spinal cord
Peripheral nervous system
all nervous tissue external to CNS
- everything else (neurons in fingers and arms)
PNS - Sensory receptors
PNS- Nerves
bundles of axons
PNS- Cranial nerves
12 total and originate form the brain
PNS- Spinal nerves
31 pairs; originate form the spinal cord (branch on to both sides)
PNS- Ganglion
collection of cell bodies outside the CNS
PNS- Plexus
Extensive network of axons outside the CNS
PNS- Sensory Division (afferent)
- cell bodies located in the dorsal root ganglion.
PNS- Motor Division (efferent)
- divided into somatic (voluntary) and automatic nervous system
Division of PNS
Sensory(afferent : transmits action potential from receptors to CNS.
Motor(efferent): transmits action potential from the CNS to effectors (muscles, gland).
Neuron cell body
Dendrites (receive)
Axon(send)
Sensory neurons
conduct action potential to CNS
Motor Neurons
conduct action potential away from CNS to muscles or glands (brain -> effector)
Interneuron
conduct action potential from neuron to neuron within the CNS
multipolar neurons
many dendrites and a single axon (brain)
bipolar neurons
one dendrite and one axon (down the arm)
Pseudo-unipolar neurons
single process extending from cell body (fingers)
Neuroglia of the CNS (supporting)
Astrocytes
ependymal cells