Peripheral Nervous systemPeripheral Nervous system

Nerves and neuronal cell bodies (ganglia)Nerves and neuronal cell bodies (ganglia)

Structure of nerveStructure of nerve

A bundle of neuron fibers found outside the CNS.A bundle of neuron fibers found outside the CNS. Endoneurium Endoneurium PerineurirmPerineurirm EpineurirmEpineurirm

Mixed nerve: all spinal nerves are mixed nervesMixed nerve: all spinal nerves are mixed nerves

Afferent or sensory nervesAfferent or sensory nerves

Efferent or motor nervesEfferent or motor nerves

Cranial nervesCranial nerves

Olfactory Olfactory ……purely sensory (smell)purely sensory (smell) Optic…purely sensoryOptic…purely sensory ( (vision)vision) OculomotorOculomotor……motor fibers to four muscles of motor fibers to four muscles of

the eye.the eye. Trochlear Trochlear …….motor to superior oblique.motor to superior oblique TrigeminalTrigeminal…… sensory from skin of the face sensory from skin of the face

and mucosa of the nose and mouth &motor to and mucosa of the nose and mouth &motor to chewing muscleschewing muscles

AbducensAbducens…… motor to lateral rectus muscle motor to lateral rectus muscle

Facial Facial …m…motor for muscles of facial otor for muscles of facial expression & sensory for anterior part of expression & sensory for anterior part of tongue.tongue.

Vestibulocohlear…sensory(balance & hearing)Vestibulocohlear…sensory(balance & hearing) GlossopharyngealGlossopharyngeal……motor fibers to pharynx & motor fibers to pharynx &

sensory for posterior part tongue.sensory for posterior part tongue.

VagusVagus……sensory & motor for pharynx, larynx sensory & motor for pharynx, larynx and abdominal and thoracic viscera and abdominal and thoracic viscera (parasympathetic).(parasympathetic).

AccessoryAccessory…….motor (sternocleidomastoid & .motor (sternocleidomastoid & trapezius).trapezius).

HypoglossalHypoglossal…… sensory & motor for tongue sensory & motor for tongue

Spinal nerves and nerve plexusesSpinal nerves and nerve plexuses

31pairs of human spinal nerves31pairs of human spinal nerves Spinal nerves are formed by combination of Spinal nerves are formed by combination of

Ventral and dorsal rootsVentral and dorsal roots it divides into dorsal and ventral ramiit divides into dorsal and ventral rami Both the spinal nerve and rami contain both Both the spinal nerve and rami contain both

motor and sensorymotor and sensory The smaller dorsal rami The smaller dorsal rami …….skin and muscles .skin and muscles

of posterior body trunkof posterior body trunk

The ventral rami of T1-T12 The ventral rami of T1-T12 ……intercostal intercostal nervesnerves…….supply the muscles of anterior and .supply the muscles of anterior and lateral trunklateral trunk

PleuxesPleuxes……cervical C1-C5 cervical C1-C5

brachial C5-C8 and T1brachial C5-C8 and T1

lumbar L1-L4lumbar L1-L4

sacral L4-L5 and S1-S4sacral L4-L5 and S1-S4

Autonomic nervous systemAutonomic nervous system

Is the motor subdivision of the PNS that Is the motor subdivision of the PNS that controls body activities automatically .controls body activities automatically .

Special group of neurons that regulate cardiac, Special group of neurons that regulate cardiac, smooth muscles and glands.smooth muscles and glands.

Support body activities.Support body activities. Involuntary nervous system. Involuntary nervous system.

Somatic nervous systemSomatic nervous system

Somatic (voluntary) and autonomic Somatic (voluntary) and autonomic (involuntary)(involuntary)

In somatic , the cell bodies of the motor In somatic , the cell bodies of the motor neurons are inside the CNS, and their axons neurons are inside the CNS, and their axons (in spinal nerves) extend all the way to the (in spinal nerves) extend all the way to the skeletal muscle.skeletal muscle.

autonomic nervous systemautonomic nervous system

Autonomic nervous system, has a chain of two Autonomic nervous system, has a chain of two motor neurons motor neurons

The first neuron (in brain or spinal cord),itThe first neuron (in brain or spinal cord),it ’’s s axon (preganglionic axon) leave the CNS to axon (preganglionic axon) leave the CNS to synapse with the second motor neuron in a synapse with the second motor neuron in a ganglion outside the CNS. The axon of this ganglion outside the CNS. The axon of this neuron, (the postganglionic axon), that extends neuron, (the postganglionic axon), that extends to the organ it serves.to the organ it serves.

Sympathetic and parasympathetic are two Sympathetic and parasympathetic are two arms of ANS.arms of ANS.

Both of them serve the same organs but cause Both of them serve the same organs but cause the opposite effects.the opposite effects.

Sympathetic part ( fear, exercise)Sympathetic part ( fear, exercise) Parasympathetic part ( conserve energy)Parasympathetic part ( conserve energy)

Anatomy of parasympatheticAnatomy of parasympathetic

The first neurons of the parasympathetic The first neurons of the parasympathetic division are located in brain nuclei of several division are located in brain nuclei of several cranial nerves cranial nerves ––3,7,9, and 10.3,7,9, and 10.

And in S2 through S4.And in S2 through S4. The first neurons (cranial)The first neurons (cranial) send their axons send their axons

(preganglionic), they synapse with second (preganglionic), they synapse with second neuron in terminal ganglion to send neuron in terminal ganglion to send postganglionic axon to organ. postganglionic axon to organ.

In sacral region, preganglionic axon ( pelvic In sacral region, preganglionic axon ( pelvic nerves)..also called pelvic splanchnic nerves to nerves)..also called pelvic splanchnic nerves to synapse in the terminal ganglia close to the synapse in the terminal ganglia close to the organ.organ.

Anatomy of sympatheticAnatomy of sympathetic

Thoracolumbar division T1-L2Thoracolumbar division T1-L2 The preganglionic axon leave the cord in the The preganglionic axon leave the cord in the

ventral root to enter the spinal nerve and pass ventral root to enter the spinal nerve and pass through ramus communicans to enter through ramus communicans to enter sympathetic chain synapse at the same level sympathetic chain synapse at the same level or different level or it didnor different level or it didn ’’t synapse t synapse (splanchnic nerves) to synapse into collateral (splanchnic nerves) to synapse into collateral ganglion (celiac, superior, inferior)ganglion (celiac, superior, inferior)