PNS

Olfactory Nerve (CN I)

sensory nerve that carries afferent impulses for smell.

Location: superior portion of nasal cavity and terminates in olfactory bulbs

Optic Nerve (CN II)

sensory nerve that carries afferent impulses for vision.

Location: Retina

Oculomotor Nerve (CN III)

motor nerve for eye movement, eyelids, lens, and pupil size.

Location: Pupillary sphincter of iris, Ciliary muscles

Trochlear Nerve (CN IV)

Cranial nerve IV; motor nerve for eyeball movement (medial rotation).

Location: Nucleus near midbrain

Trigeminal Nerve (V)

both sensory and motor, it innervates face and muscles of mastication. 3 branches: Ophthalmic, Maxillary, and Mandibular

Ophthalmic

Sensations from forehead, lacrimal glands, eyelids, ciliary bodies, nose sides​

Maxillary

Sensation from eyes to top teeth

Mandibular

Sensations from cheek, lower teeth, mandible, mouth floor

Sensation on tongue - Touch, temp, pressure

Abducens Nerve (CN VI)

motor nerve that abducts the eyeball.

Location: Pons

Facial Nerve (CN VII)

Both motor and sensory, it innervates facial expression muscles and provides taste sensations from the anterior tongue.

Location - Originates in pons and ends in the pons gustatory cortex

Facial nerve (motor)

5 branches, innervates face, scalp, neck muscles

Facial nerve (sensory)

Taste from the anterior two-thirds of the tongue and proprioceptive signals of face and scalp

Vestibulocochlear Nerve (CN VIII)

sensory nerve for hearing and balance.

Vestibular (CN VIII)

Function: orientation and movement of the head

Location: vestibular ganglion

Cochlear (CN VIII)

Function: sense of hearing

Location: spiral ganglion

Glossopharyngeal Nerve (CN IX)

Both sensory and motor, it innervates the pharynx and provides taste to the posterior tongue.

Location: Pharynx and larynx muscle, stimulate saliva glands

Glossopharyngeal nerve (motor)

only innervates the stylopharyngeus muscle

Glossopharyngeal nerve (sensory)

taste on posterior tongue, BP changes in carotid artery, blood chemistry changes

Vagus Nerve (CN X)

Both sensory and motor, it regulates the heart and digestive tract.

Location: Medulla

Accessory Nerve (CN XI)

Motor nerve that innervates sternocleidomastoid and trapezius muscles.

Location: Cranial: medulla oblongata, Spinal: C1-C6, arise from spinal cord

Hypoglossal Nerve (CN XII)

Motor nerve that controls the muscles of the tongue.

Location: Medulla to tongue

Somatic Functions

Voluntary control of skeletal muscles.

Sensory receptors → spinal nerves → ascending tracts of spinal cord → processed in cerebral cortex

Autonomic Functions

Involuntary control of internal organs like heart rate and respiration.

Meissner Corpuscles

Touch receptors in the skin.

Pacinian Corpuscles

Pressure and vibration receptors in the skin.

Merkel Cells

Receptors that sense light, touch, and vibration.

Free Nerve Endings

Pain, temperature, and itch/tickle receptors.

Cervical Plexus

Network of nerves supplying the neck and diaphragm.

• Transverse cervical

• Great auricula

• Lesser occipital

• Supraclavicular

• Phrenic - supplies diaphragm muscle

Brachial Plexus

Network of nerves supplying the upper limb.

·       Supra/subscapular

·       Thoracodorsal

·       Axillary

·       Medial/Lateral Pectoral

·       Musculocutaneous

·       Median

·       Radial/Ulnar

Lumbosacral Plexus

Network of nerves supplying the lower limb.

·       Femoral

·       Ilioinguinal

·       Sciatic – Biggest nerve of plexus

·       Gluteal