APK2100C Chapter 14 (PNS)

What are the two main divisions of the PNS?

Afferent (Sensory)

Efferent (Motor)

True or False: Cranial Nerves are part of the CNS

False, they are part of the PNS because they extend beyond the brain and spinal cord

For the following Cranial Nerves, Identify the nerve name, the kind of nerve, the function, and the cranial foramen it exits from.

I

Olfactory

Sensory Nerve (Special Visceral)

Sense of Smell

Cribriform Plate (Ethmoid Bone)

II

Optic

Sensory Nerve (Special Somatic)

Vision

Optic Canal

III

Oculomotor

Motor Nerve (Somatic and Visceral)

Controls Superior Rectus, Medial R, Inferior R, and Inferior Oblique eye muscles. Also controls pupil dilation

Superior Orbital Fissure

IV

Trochlear

Motor Nerve (Somatic)

Innervates superior oblique eye muscle

Superior orbital fissure

V

Trigeminal (Ophthalmic, Maxillary, and Mandibular)

Mixed (Somatic Motor and Somatic Sensory)

Motor: Mastication

Sensory: Touch, temperature, and pain in face

Opthalmic: Superior Orbital Fissure

Maxillary: Foramen Rotundum

Mandibular: Foramen Ovale

VI

Abducens

Motor (Somatic)

Innervates the lateral rectus muscle of eye, abducts the eye

Superior Orbital Fissure

VII

Facial

Mixed (Somatic Motor, Visceral Sensory)

Motor: Innervating most facial muscles (facial expressions)

Sensory: Taste from 2/3 of tongue (special sense)

Internal Auditory Meatus

VIII

Vestibulocochlear

Sensory Nerve (Special Somatic)

Vestibular Branch: Equilibrium

Cochlear Branch: Hearing

Internal Auditory Meatus

IX

Glossopharyngeal

Mixed Nerve (Somatic Motor, Somatic and Visceral Sensory)

Motor: Swallowing, muscles in pharynx region

Sensory: taste in posterior 1/3 of tongue, middle ear cavity

Jugular Foramen

X

Vagus

Mixed Nerve

Swallowing and vocalization. General innervation of the thoracic and abdominal viscera

Jugular Foramen

XI

Accessory

Motor Nerve (Somatic)

Innervation of trapezius and sternocleido mastoid muscle

Jugular canal and foramen magnum

XII

Hypoglossal

Motor Nerve (Somatic)

Innervates muscles of the tongue

Hypoglossal Canal

Number of nerves in each section of the spinal region corresponds to the number of vertebrae in the region, except for the ________ region, which has ______

Cervical, 8 nerves (one more)

Below the cervical region, all spinal nerves exit _________ their corresponding vertebrae

Below

The dorsal/ventral roots have __________ motor/sensory neurons, while the dorsal rami and spinal nerves have __________ motor/sensory neurons

Only/ either

Both

What is a network of nerves called?

A plexus

The _______ rami make up the plexus

Ventral

Why is it best for nerves to form a plexus?

It means that if a single nerve is damaged it won't paralyze an entire limb muscle

Name the important named nerves and the vertebrae involved in the following plexi

Cervical Plexus

C1-5

Phrenic Nerve (Innervates Diaphragm)

Brachial Plexus

C4-T1

Axillary Nerve (Armpit)

Radial Nerve (Posterior brachial and antebrachial)

Musculocutaneus Nerve (Anterior brachial)

Ulnar Nerve (Anterior Antebrachial)

Medial Nerve (Anterior Antebrachial)

Lumbar Plexus

L1-5

Femoral nerve (Anterior Thigh)

Obturator Nerve (Medial Thigh)

Sacral Plexus

L4-S4

Sciatic Nerve

The ventral rami of the thorax innervate the thorax via ________

Intercostal nerves

The ________ innervate the back of the trunk

Dorsal rami

What is a dematome?

An area of skin that provides sensory input to the CNS via one pair of spinal nerves