Deep Pain and Visceral Pain Quiz

Medical CNS Lecture Notes

• Lecture Schedule:
  • Lec 11: 1
  • Lec 12: 10
  • Lec 13: 19
  • Lec 14: 26
  • Lec 15: 39
  • Lec 16: 50
  • Lec 17: 60
  • Lec 18: 69
  • Lec 19: 78
  • Lec 20: 88

Nerves of Head and Neck (I)

• Cranial nerves are part of the peripheral nervous system (PNS).
• 12 pairs of cranial nerves.
• All nerves except the spinal accessory nerve (XI) originate from the brain.
• Cranial nerves have both somatic and visceral components.
• Some cranial nerves have special sensory and motor components.
• Special sensory components are associated with hearing, vision, smell, balance, and taste
• Special motor components innervate muscles derived from pharyngeal arches.

Cranial Nerve Functional Components

• General Somatic Afferent (GSA): Touch, pain, and temperature perception.
• General Visceral Afferent (GVA): Sensory input from viscera
• Special Somatic Afferent (SSA): Vision, hearing, balance, and equilibrium.
• Special Visceral Afferent (SVA): Smell and taste.
• General Somatic Efferent (GSE): Voluntary innervation to skeletal muscles.
• General Visceral Efferent (GVE): Parasympathetic innervation to smooth muscle, glands, and heart.
• Special Visceral Efferent (SVE): Voluntary innervation to skeletal muscles derived from pharyngeal arches.

Olfactory Nerve (SVA)

• First cranial nerve and nerve of smell.
• Originates from the olfactory epithelium in the nasal cavity.
• Passes through the cribriform plate of the ethmoid bone.
• Lesion results in loss of smell (anosmia).

Optic Nerve (SSA)

• Carries sensory fibers for vision.
• Fibers originate in photoreceptors in the retina.
• Enters the cranial cavity through the optic canal.

Oculomotor Nerve (GSE-GVE)

• Third cranial nerve that controls most eye movements and eyelid elevation.
• GSE fibers innervate extraocular muscles (levator palpebrae superioris, superior, inferior rectus, medial rectus, and inferior oblique).
• GVE fibers innervate the sphincter pupillae (pupil constriction) and ciliary muscle (accommodation).
• Lesion results in ptosis, deviation, fixed and dilated pupil and loss of accommodation.

Trochlear Nerve (GSE)

• Fourth cranial nerve that controls superior oblique muscle.
• Motor fibers innervate the superior oblique muscle of the eye.
• It exits the brainstem posteriorly.

Trigeminal Nerve (GSA, SVE)

• Largest cranial nerve.
• Contains sensory (GSA) and motor (SVE) fibers.
• Sensory fibers transmit sensations from the face, scalp, oral and nasal cavities.
• Motor fibers control mastication muscles.
• Three main branches: ophthalmic, maxillary, and mandibular nerves.

Abducens Nerve (GSE)

• Sixth cranial nerve.
• Innervates the lateral rectus muscle, responsible for abduction of the eye.
• Carries motor impulses to the outer rectus muscle.

Facial Nerve (GVA, GSA, SVE)

• Seventh cranial nerve.
• Contains sensory fibers for taste and sensory information from part of the external ear canal and parts of the nasal and oral cavities.
• Contains motor fibers that control muscles for facial expression, and also taste.

Vestibulocochlear Nerve (SSA)

• Eighth cranial nerve.
• Contains two parts: vestibular and cochlear.
• The vestibular part provides balance sensations.
• The cochlear part provides hearing sensations.

Glossopharyngeal Nerve (GVA, GSA, SVA, GVE, & SVE)

• Ninth cranial nerve,
• Includes general and special visceral sensory fibers, and general and special visceral motor fibers.
• GSA carries general sensory information from parts of the tongue, soft palate, tympanic membrane, and external ear.
• SVA carries taste sensation from posterior one-third of tongue.
• GVE parasympathetic innervation to parotid gland.
• SVE motor to stylopharyngeus muscles .

Vagus Nerve (GSA, GVA, SVA, GVE, & SVE)

• Tenth cranial nerve.
• Sensory fibers provide general sensations from the pharynx, larynx, trachea, bronchi, lungs, heart, and abdominal viscera.
• Special sensory (SVA) fibers transmit taste information from the epiglottis.
• Efferent (GVE) fibers regulate activity of many visceral organs.
• Efferent (SVE) fibers innervate muscles of the pharynx, larynx, and soft palate.

Accessory Nerve (SVE)

• Eleventh cranial nerve.
• Two roots (spinal and cranial). Innervates sternocleidomastoid and trapezius muscles.

Hypoglossal Nerve (GSE)

• Twelfth cranial nerve.
• Contains motor fibers that control tongue movements

Cervical Plexus

• Network of nerves formed from the first four cervical nerves (C1-C4).
• Cervical plexus is located deep to the sternocleidomastoid muscle.
• Supplies motor innervation to neck muscles.
• Sensory innervation to parts of the head and neck.
• The phrenic nerve, from the cervical plexus, innervates the diaphragm.

Infections of CNS (meningitis & encephalitis)

• Define meningitis and encephalitis.
• Discuss routes, types, morphology, and complications.

Basic Pathology of CNS

• Describe neuronal reaction to injury.
• Describe glial reaction to injury.
• Discuss various types of CNS tissue lesions.
• Discuss hydrocephalus.