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PNS

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ilm1993's version from 2017-07-20 12:56

PNS

Question Answer
Cervical and lumbar enlargementssites where nerves serving the upper and lower limbs emerge
Cauda equinacollection of nerve roots at the inferior end of the vertebral canal
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Grey Matter and Spinal Roots

Question Answer
Gray matter consistsof soma, unmyelinated processes, and neuroglia
Gray commissureconnects masses of gray matter; encloses central canal
Posterior (dorsal) hornsinterneurons; sensory and ganglia
Anterior (ventral) hornsinterneurons and somatic motor neurons
Lateral hornscontain sympathetic nerve fibers
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Pathways

Question Answer
Descending tractsMotor
Ascending pathwaysSensory
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Diseases

Question Answer
PolioDestruction of the anterior horn motor neurons by the poliovirus
ALSneuromuscular condition involving destruction of anterior horn motor neurons and fibers of the pyramidal tract
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Sensory Receptor

Question Answer
Structures specialized torespond to stimuli
Activation of sensory receptors results indepolarizations that trigger impulses to the CNS
The realization of these stimuli, sensation and perceptionoccur in the brain
Receptor levelthe sensor receptors
Circuit levelascending pathways
Perceptual levelneuronal circuits in the cerebral cortex
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Nerves

Question Answer
Nervecordlike organ of the PNS consisting of peripheral axons enclosed by connective tissue
Endoneuriumloose connective tissue that surrounds axons
Perineuriumcoarse connective tissue that bundles fibers into fascicles
Epineuriumtough fibrous sheath around a nerve
Sensory (afferent)carry impulse to the CNS
Motor (efferent)carry impulses from CNS
Mixedsensory and motor fibers carry impulses to and from CNS; most common type of nerve
Mixed nervescarry somatic (sensory) and autonomic (visceral) impulses
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Regeneration in nerves

Question Answer
Regeneration involves coordinated activity amongMacrophages, Schwann cells, Axons
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Cranial Nerves

Question Answer
Olfactory(sensory) smell
Optic(sensory) afferent impulses for vision
Oculomotor(motor) move eyeball
Trochlear(motor) directs eyeball
Trigeminal(both) innervates jaw
Abducens (motor)
Facial(both) movement of face
Vestibulocular(sensory) hearing and equilibrium
Glossopharyngeal(both) tongue and throat
Vagus(both) only nerve you can touch
Accessory(motor) part of brainstem/ neck. Involves neck
Hypoglossal(motor) below tongue
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Spinal Nerves

Question Answer
Spinal nerves31 pairs attach to the cord by paired roots
8cervical (C1-C8)
12thoracic (T1-T12)
5Lumbar (L1-L5)
5Sacral (S1-S5)
1Coccygeal (C0)
Ventral roots arise fromthe anterior horn and contain motor (efferent) fibers
Dorsal roots arise fromsensory neurons in the dorsal root ganglion and contain sensory (afferent) fibers
RamiBranches/ divisions of the horns
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Plexus

Question Answer
interlacing nerve networks calledplexuses
Intercostal nerves supplymuscles of the ribs, anterolateral thorax, and abdominal wall
The phrenic nerve isthe major motor and sensory nerve of the diaphragm (cervical)
Brachial plexusparalyzation in this creates paralyzation in arm (c5-t1)
Sacral Plexussciatic nerve
Cervical Plexusc1-c4
Lumbar PlexusL1-L4. The major nerves are the femoral and the obturator
Sacral PlexusL4-S4 and serves the buttock, lower limb, pelvic structures, and the perineum
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Sciatic: the longest and thickest nerve of the body

Dermatome

Question Answer
A dermatome isthe area of skin innervated by the cutaneous branches of a single spinal nerve
Hilton’s lawany nerve serving a muscle that produces movement at a joint also innervates the joint itself and the skin over the joint
A reflex isa rapid, predictable motor response to a stimulus
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