Transcript Nervous system

Peripheral Nervous system
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Nerves and neuronal cell bodies (ganglia)
Structure of nerve
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A bundle of neuron fibers found outside the CNS.
Endoneurium
Perineurirm
Epineurirm
Mixed nerve: all spinal nerves are mixed nerves
Afferent or sensory nerves
Efferent or motor nerves
Cranial nerves
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Olfactory …purely sensory (smell)
Optic…purely sensory (vision)
Oculomotor…motor fibers to four muscles of
the eye.
Trochlear ….motor to superior oblique
Trigeminal… sensory from skin of the face
and mucosa of the nose and mouth &motor to
chewing muscles
Abducens… motor to lateral rectus muscle
Facial …motor for muscles of facial
expression & sensory for anterior part of
tongue.
 Vestibulocohlear…sensory(balance & hearing)
 Glossopharyngeal…motor fibers to pharynx &
sensory for posterior part tongue.
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Vagus…sensory & motor for pharynx, larynx
and abdominal and thoracic viscera
(parasympathetic).
Accessory….motor (sternocleidomastoid &
trapezius).
Hypoglossal… sensory & motor for tongue
Spinal nerves and nerve plexuses
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31pairs of human spinal nerves
Spinal nerves are formed by combination of
Ventral and dorsal roots
it divides into dorsal and ventral rami
Both the spinal nerve and rami contain both
motor and sensory
The smaller dorsal rami ….skin and muscles of
posterior body trunk
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The ventral rami of T1-T12 …intercostal
nerves….supply the muscles of anterior and
lateral trunk
Pleuxes…cervical C1-C5
brachial C5-C8 and T1
lumbar L1-L4
sacral L4-L5 and S1-S4
Autonomic nervous system
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Is the motor subdivision of the PNS that
controls body activities automatically .
Special group of neurons that regulate cardiac,
smooth muscles and glands.
Support body activities.
Involuntary nervous system.
Somatic nervous system
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Somatic (voluntary) and autonomic
(involuntary)
In somatic , the cell bodies of the motor
neurons are inside the CNS, and their axons (in
spinal nerves) extend all the way to the skeletal
muscle.
autonomic nervous system
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Autonomic nervous system, has a chain of two
motor neurons
The first neuron (in brain or spinal cord),it’s
axon (preganglionic axon) leave the CNS to
synapse with the second motor neuron in a
ganglion outside the CNS. The axon of this
neuron, (the postganglionic axon), that extends
to the organ it serves.
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Sympathetic and parasympathetic are two arms
of ANS.
Both of them serve the same organs but cause
the opposite effects.
Sympathetic part ( fear, exercise)
Parasympathetic part ( conserve energy)
Anatomy of parasympathetic
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The first neurons of the parasympathetic
division are located in brain nuclei of several
cranial nerves –3,7,9, and 10.
And in S2 through S4.
The first neurons (cranial) send their axons
(preganglionic), they synapse with second
neuron in terminal ganglion to send
postganglionic axon to organ.
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In sacral region, preganglionic axon ( pelvic
nerves)..also called pelvic splanchnic nerves to
synapse in the terminal ganglia close to the
organ.
Anatomy of sympathetic
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Thoracolumbar division T1-L2
The preganglionic axon leave the cord in the
ventral root to enter the spinal nerve and pass
through ramus communicans to enter
sympathetic chain synapse at the same level
or different level or it didn’t synapse
(splanchnic nerves) to synapse into collateral
ganglion (celiac, superior, inferior)