1. Chapter 6 Nervous System
CNS = brain & spinal cord
PNS = peripheral nerves
ANS = autonomic nervous system
- sympathetic = stress & stimulation
- parasympathetic = energy conservation

2. Nervous Tissue (Neurons)
Cell body
Dendrites
Axons
Gray matter
White matter
Nerve fiber
Synapse
Tract
Motor (efferent) neuron
Sensory (afferent) neuron
Interneuron
Dendrites – receive
Axons = transmit
Gray matter = unmyelinated; central cortex & central spinal cord
White matter = myelinated; spinal cord tracts & fiber systems
Nerve fiber – conductor of impulses from neuron
Synapse – transmission from one neuron to another
Tracts = group of myelinated nerve fibers within CNS that carry specific information; aka fascciculus; penduncle; brachium; column leminiscus
Motor – anterior horn
Sensory – posterior horn

3. Central Nervous System (CNS)
Brain
Cerebrum
Brainstem
Cerebellum
Brain protection
Spinal cord
Posterior horn
Anterior horn
Upper and lower motor neurons
Posterior columns
Cerebrum – Right & Left hemispheres; joined in center by corpus callosum; 4 lobes per hemisphere;
1. Frontal – anterior; personality; motor movement; expressive speech
2. Occipital – posterior; vision; recognition of size, shape & color
3. Parietal – between frontal and occipital; reading; gross sensation – touch, pressure; fine sensation – texture, weight, size, shape
4. Temporal – just above ear; behavior, hearing, language reception & understanding
Thalamus – deep to cerebrum; relay station for body sensations; where pain is perceived;
Hypothalamus – under thalamus – hormone function & behavior
Basal Ganglia – coordination of motor movement
Brainstem – 3 parts
1. Midbrain – visual reflexes;
2. Pons – bridge b/t midbrain & medulla
3. Medulla Oblongata – continuous with spinal cord; automatic control of respiration & HR
Brain Protection – bony, membranous, fluid; Skull; 3 meningeal layers
1. Dura mater – thickest, most fibrous, tough outer layer
2. Arachnoid – middle thinner layer
a. subarachnoid space; CSF
3. Pia mater – blood vessels to the brain;
Spinal Cord – conus medullaris; L2; cauda equina L2-S5 nerve roots
- gray matter – central butterfly shaped H; neuronal bodies and synapses;
posterior horn – sensory
anterior horn – motor; Upper & lower motor neurons – see Table 6.1 page 61
Posterior Columns – proprioception, pressure, vibration
White matter – ascending (sensory) & descending (motor)

4. Peripheral Nervous System
Cranial nerves
Spinal nerves
Posterior and anterior rami
Dermatomes
Thoracic nerves
Cranial nerves; 12 pairs; Table 6-2; page 62
Spinal nerves – 31 pairs;
posterior – (dorsal) – smaller; innervates skin & muscles of posterior trunk
anterior – continuation of spinal nerve

5. Peripheral Nervous System
Functional significance of spinal cord level
Plexus formation
Cervical plexus
Brachial plexus
Lumbosacral plexus
C3 & above – unable to breathe without assistance
C5 – shoulder abduction & elbow flexion present
Cervical Plexus – C1-C4; some muscles; phrenic nerve C3-C5 diaphragm
Brachial Plexus – C5-T1
1. Roots – C5-T1
2. Trunks – superior (C5,C6), middle (C7), inferior (C8,T1)
3. Division – anterior & posterior
4. Cords – lateral, posterior, medial
5. Branches – peripheral nerves; axillary, musculocutaneous, radial, median, ulnar
See PP to learn UE peripheral nerves
Lumbosacral Plexus – L1-S3
Lumbar section – thigh; L1-L4
Sacral Section – leg & foot; L5-S3
3 sensory nerves – iliohypogastric, ilioinguinal, genitofemoral (L1, L2)
Terminal Nerves of lumboscaral plexus (see pp )
1. Obturator nerve
2. Femoral Nerve
3. Superior Gluteal nerve
4. Inferior Gluteal Nerve
5. Sciatic Nerve (tibial & common peroneal)

6. Common Pathologies of the CNS
Congenital
Spinal cord trauma
Disorders of muscle and neuromuscular junction
Degenerative diseases
Demyelinating diseases
Congenital
- spina bifida – occulta, meningocele, myelomeningocele
- hydrocephalus
- cerebral palsy
Spinal Cord Trauma
- depends on spinal level and area of damage
- quadriplegia vs. paraplegia (T2)
- Central Cord Syndrome (UE >LE)
- Brown Sequard’s syndrome (one side injury; weakness & proprioceptive loss on side of injury; pain & temp loss opposite side)
- Anterior cord syndrome – muscle function, pain & thermal sensation loss
- Autonomic dysreflexia – hyperreflexia; at or above T10; noxious stimuli below injury level; spike in BP
Disorders of muscle & neuromuscular junction
- Myasthenia gravis – neuromuscular junction
- muscular dystrophy – hereditary & progressive; proximal > distal
Degenerative Diseases
- ALS – upper & lower motor neurons
- Alzheimer’s disease – dementia; loss of cognitive functioning
Demyelinating Diseases
- Multiple Sclerosis

7. Common Peripheral Nerve Pathologies
Thoracic outlet syndrome
Carpal tunnel syndrome
Sciatica
Foot drop
Neuropathy – classified according to cause or anatomical location
Bell’s palsy – facial nerve
Scapular winging – long thoracic nerve
Thoracic Outlet Syndrome – brachial plexus
Burner/Stinger Syndrome – stretch or compression injury
Erb’s palsy – traction injury of brachial plexus at birth
Saturday night palsy – radial nerve
Wrist Drop – radial nerve
Carpal Tunnel Syndrome – median nerve
Cubital Tunnel Syndrome – ulnar nerve
Sciatica – irritation of sciatic nerve root
Drop foot – peroneal nerve
Morton’s neuroma – 3rd & 4th toes