Ch. 14 The Peripheral Nervous System

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Ch. 14The Peripheral Nervous System
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Objectives

• Know the divisions of the PNS
• Know the various types of general sense receptors
• Be able to describe the cranial nerves
• Be able to define a nerve plexus
• Be able to describe the nerve plexus

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Divisions of Nervous System
legacy.owensboro.kctcs.edu
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Structures of PNS

• Sensory receptors
• Detect sensor information from the environment
• Nerves and ganglia
• Bundles of axons
• Mixed nerves
• Motor endings
• Innervate the effector

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Sensory Receptors

• Modality (stimulus detected)
• Thermoreceptors, photoreceptors, nociceptors
• Origin (location)
• Exteroceptors
• Interoceptors
• Proprioceptors
• Structure
• General
• Free nerve endings
• Encapsulated nerve endings
• Special

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General Sense Receptors

• Unencapsulated Receptors

• Encapsulated Receptors

• Free nerve endings
• Pain, warmth, cold
• Tactile discs
• Tonic, light touch, texture
• Merkel cells
• Hair receptors
• Monitor movement

• Tactile (Meissners) corpuscles
• Phasic, light touch, texture
• Krause end bulbs
• tactile, mucus membranes
• Lamellated (Pacinian) corpuscles
• Phasic, deep pressure, stretch, tickle, vibration
• Bulbous (Ruffini) corpuscles
• Tonic, heavy touch, pressure, joint movment, skin
  stretching

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General Sense Receptors
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Cranial Nerves
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Cranial Nerves

• Olfactory, Optic, Oculomotor, Trochlear,
  Trigeminal, Abducens, Facial, Vestibulocochlear,
  Glossopharyngeal, Vagus, Accessory, Hypoglossal
• On Occasion Our Trusty Truck Acts Funny --- Very
  Good Vehicle AnyHow
• Functions (sensory, motor, both)
• Some Say Marry Money, But My Brother Says Bad
  Business Marry Money

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Cranial Nerves

• Olfactory nerve
• Sensory (smell)
• Passes through cribriform plate
• Optic nerve
• Sensory (vision)
• Passes through optic canal
• Oculomotor nerve
• Motor (extrinsic eye muscles, iris and ciliary
  bodies)
• Passes through superior orbital fissure
• Trochlear nerve
• Motor (extrinsic eye muscle)
• Passes through superior orbital fissure

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Cranial Nerves

• Trigeminal nerve
• Sensory/motor
• Three divisions
• Ophthalmic (general senses)
• Superior orbital fissure
• Maxillary (general senses)
• Foramen rotundum
• Mandibular (S/M)
• Foramen ovale

medical-dictionary.thefreedictionary.com
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Cranial Nerves

• Abducens nerve
• Motor (extrinsic eye muscle)
• Passes through superior orbital fissure
• Facial nerve
• Sensory/Motor
• Five branches on face (facial muscles)
• Temporal
• Zygomatic
• Buccal
• Mandibular
• Cervical
• Various glands (motor)
• Taste sensation
• Internal acoustic meatus and stylomastoid foramen

daviddarling.info
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Cranial Nerves

• Vestibulocochlear nerve
• Sensory (hearing and equilibrium)
• Passes through internal acoustic meatus
• Glossopharyngeal nerve
• Sensory/Motor
• Passes through jugular foramen
• Innervates pharyngeal muscles and parotid gland
• Taste
• Vagus
• Sensory/Motor
• Passes through jugular foramen
• Autonomic motor control of viscera
• Voluntary control of pharynx and larynx
• General sensory info from viscera

medical-dictionary.thefreedictionary.com
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Cranial Nerves

• Accessory nerve
• Motor (sternocleidomastoid and trapezius)
• Rootlets enter via foramen magnum, exits through
  jugular foramen
• Hypoglossal nerve
• Motor (tongue)
• Passes though the hypoglossal canal

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Spinal Nerves

• Root
• Sensory
• motor
• Spinal Nerve
• mixed
• Ramus
• mixed

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Nerve Plexus

• Network of spinal nerves (ventral rami) that join
  and branch off (exception T2-T12)
• Four plexuses
• Cervical, brachial, lumbar, sacral
• Primarily serve to innervate limbs

medicalook.com
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Cervical Plexus

• Innervation of the neck (C1-C4)
• Cutaneous innervation, some motor
• Phrenic nerves
• Somatic motor and sensory innervation of
  diaphragm
• Necessary for respiration

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Brachial Plexus

• Innervation of upper limb
• Rami from C5-T1
• Converge to form 3 trunks
• Upper, middle, lower
• Trunks split into divisions
• Anterior and posterior
• Divisions converge to form 3 cords
• Lateral, posterior, medial
• Cords split into 5 nerves
• Musculocutaneous, Median, Ulnar, Radial, Axillary

pitt.edu
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Lumbar Plexus

• Rami of L1-L4
• Innervation of lower limb
• Anterior and medial thigh
• Femoral nerve

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Sacral Plexus

• Rami from L4-S4
• Innervation of lower limb, buttocks, pelvis, and
  perineum
• Sciatic nerve
• Tibial and common fibular nerves

doyoutri.net