Topic #6 Development of the Peripheral Nervous System Flashcards
derived from neural crest cells. it consists of cranial and spinal nerves and their ganglia.
Peripheral Nervous System
composed of axons (nerve fibers) of neurons whose cell bodies are located within the CNS or in ganglia.
Cranial and Spinal Nerves
connective tissue cells of the PNS.
neurolemmocytes
form satellites cells of the nerve cell bodies within ganglia.
amphicytes
has only one process, the axon.
unipolar neuron
has two processes that arise separately from the cell body, fuse for a while to form 1 process and divide shortly thereafter into axon and dendrite.
pseudounipolar neuron
has 2 processes, 1 axon and 1 dendrite
bipolar neuron
has three or more processes: one axon and 2 or more dendrites.
multipolar neuron
conduct impulses from the receptor organs to the CNS
Sensory or afferent neuron
afferent neurons also originate from?
placodes
conduct impulses from the CNS to target organs
Motor or efferent neurons
transfer sensory impulses from sensory neurons to efferent neurons.
association neurons or interneurons
innervate voluntary muscles and structures w/ epithelia derived from ectoderm like skin.
somatic neurons
innervate involuntary muscles and structures derived from splanchnopleure like blood vessels and visceral organs.
visceral neurons
an axon of neuron and it’s sheath that connects peripheral structures the brain or spinal cord.
nerve fiber
cell bodies of the nerves are either buried in the CNS to form?
nuclei
massed at some point along the nerve to form?
ganglia
several nerves form a?
never bundle or nerve fascicle
are myelinated nerves segmentally arranged along the spinal cord
spinal nerves
majority of the nerves in the PNS ends and begin in the spinal cord
spinal nerves
a few (12) end and begin w/ brain
cranial nerves
the adult spinal nerve connects w/ the spinal cord by two (2) roots. what are these?
dorsal root and ventral root
is the pathway for sensory (afferent) nerve fibers
dorsal root
for motor (efferent) nerve fibers.
ventral root
it unite outside and lateral to the spinal cord to form a spinal nerve.
dorsal and ventral root
which extends ventral to the sympathetic ganglion
ramus communicans
conduct impulses from afferent nerve endings for touch, pain and temperature in the skin to the spinal cord.
exteroceptive GSA spinal nerves
conduct impulses for positional sense from joints, tendons and muscles to the spinal cord
proprioceptive GSA spinal nerves
nonmyelinated; lacks a ganglion. arise from olfactory hair cells and terminate in the rhinencephalon.
olfactory nerve
arise from sensory neurons in retina and terminate in the superior colliculus of corpora quadrigemina in the brainstem.
optic nerve
arise from the basal plate of mesencephalon and terminate in the inferior oblique and the superior, inferior and internal rectus muscles of the eyeball.
oculomotor nerve
arise from the basal plate of mesencephalon and terminate in the superior oblique muscle of the eye.
trochlear nerve
mixed (sensory and motor) three main divisions that arise from the semilunar ganglion: a. opthalmic, b. maxillary, c. mandibular division
trigeminal nerve
arise from the basal plate of myelencephalon and terminate in the external rectus muscle of the eyeball.
abducens nerve
arise from the taste buds and terminate in the brain
sensory fibers
arise from the basal plate of myelencephalon and synapse
1st motor fibers
mixed (motor and sensory)
facial nerve
sensory; presents an acoustic ganglion beneath the auditory vesicle, caudal to the geniculate ganglion of CN VII
Auditory Nerve
later divides into spiral ganglion and vestibular ganglion
acoustic ganglion
gives off short afferent nerve fibers that supply the cochlear duct and receive stimuli for the sense or hearing.
spiral ganglion
gives off short afferent nerve fibers that supply the semicircular canal, utricule and saccule and receive stimuli for the sense of equilibrium.
vestibular ganglion
sensory fibers from the superior ganglion and extend to the skin of external ear.
glossopharyngeal nerve
sensory fibers extend from the skin of external ear via the superior (jugular) ganglion and from the pharynx, larynx, trachea, esophagus and thoracic abdominal viscera via the inferior
vagus nerve
motor nerve. it has a commissural ganglion, which is a continuation of the jugular ganglion.
accessory nerve
predominantly motor nerve fibers that arise separately from the posterior myelencephalon and form a single trunk to supply the skeletal muscles of tongue.
hypoglossal nerve
primitive in cranial nerves and do not unite outside the brain.
ventral and dorsal roots
established contact with the nearest somite, somitomere, placode or pharyngeal arch and innervate derivatives of these embryonic structures.
peripheral nerves
surround the CNS and the roots of spinal and cranial nerves.
meninges
three meningeal layers
dura mater
arachnoid
pia matter
cavity becomes the subarachnoid space w/ which contains??
cerebrospinal fluid (CSF)
