I. INTRODUCTION
A. Overall function
1. Sensory {senses changes}
2. Integrates {interprets info.}
3. Motor {responds to info.}
B. Organization
1. Central Nervous System
a. Brain
b. Spinal cord
2. Peripheral Nervous System
a. Definition
b. Afferent System (sensory)
1. Somatic
Surface of body
2. Visceral
Internal
c. Efferent System (motor)
1. Somatic
To skeletal muscles
2. Visceral =Autonomic Nervous System
To smooth muscle, cardiac muscle, glands
a. Parasympathetic
Rest & digest
b. Sympathetic
Fight or flight
II. NERVOUS TISSUE
A. Neuron
= Nerve cell
1. Cell body
a. Nuclei
Groups of cell bodies in CNS
b. Ganglia
Groups of cell bodies in PNS
2. Cytoplasmic Processes
a. Dendrite
Receptive end
b. Axon(nerve fibers)
Conducting end
B. Nerve Bundle of axons in PNS
C. Structural Classification
1. Bipolar
Two cytoplasmic extensions, one dendrite and one axon. e.g. nervous layer of retina
2. Multipolar
Many extensions, one axon and numerous dendrites. e.g. motor neurons
3. Unipolar
“T” shaped extensions that branch into dendrite and axon. e.g. sensory neurons
D. Neuroglia
“Nerve glue”, supporting and protecting tissue
1. Schwann Cells
PNS
a. Myelin
1. White matter
2. Function
Insulate and greatly speed up rate of nerve impulse transmission
b. Nodes of Ranvier
Gaps in myelin sheath
2. Regeneration of axons [1-5 mm/day]
Possible due to Schwann cells providing structural scaffold. Slow process.
3. Oligodendrocytes
Myelin production in CNS
4. Astrocytes
Maintenance of blood brain barrier