Cranial nerves Flashcards
Trigeminal Nerve Sensory Nuclei
- Spinal trigeminal
- Principal sensory
- Mesencephalic
Located in the medulla
Spinal Trigeminal Nucleus
Receives information about deep/crude touch, pain and temperature from the ipsilateral face
Spinal Trigeminal Nucleus
CNs VII, IX and X also convey pain information from their areas to the ____
Spinal Trigeminal Nucleus
A group of second order neurons which have cell bodies in the caudal pons
Principal Sensory Nucleus
Receives information about discriminative sensation and light touch of the face as well as conscious propioception of the jaw via first order neurons
Principal Sensory Nucleus
Most of the sensory information crosses the midline and travels to the contralateral ventral posteriomedial (VPM) nucleus of the thalamus via the ventral trigeminothalamic tract
Principal Sensory Nucleus
Information from the oral cavity travels to the ipsilateral ventral posteriomedial (VPM) nucleus of the thalamus via the dorsalal trigeminothalamic tract
Principal Sensory Nucleus
Involved with propioception of the face, that is, the feeling of position of the muscles
Mesencephalic Nucleus
Unlike many nuclei within the CNS, this nucleus contains no chemical synapses but are electrically coupled
Mesencephalic Nucleus
Neurons of this nucleus are pseudounipolar cells receiving propioceptive information from the mandible, and sending projections to the motor trigeminal nucleus to mediate monosynaptic jaw jerk reflexes
Mesencephalic Nucleus
The only structure in the CNS to contain the cell bodies of a primary afferent, which are usually contained within ganglia
Mesencephalic Nucleus
Located in the mid-pons
Trigeminal Motor Nucleus
Contains motor neurons that innervate muscles of the first branchial arch, namely the muscles of mastication, the tensor tympani, tensor veli palatini, mylohyoid, and anterior belly of the digastric
Trigeminal Motor Nucleus
Muscles of mastication
- masseter
- temporalis
- medial pterygoid
- lateral pterygoid
Other muscles of mastication
- Tensor veli palatini
- mylohyoid
- anterior belly of digastric
- tensor tympani
Controls the muscles of facial expression
Facial Nerve
Conveys taste sensations from the anterior two-thirds of the tongue and oral cavity
Facial Nerve
Supplies preganglionic parasympathetic fibers to several head and neck ganglia
Facial Nerve
arises from the facial nerve nucleus in the pons
motor part of the facial nerve
the sensory and parasympathetic parts of the facial nerve arise from the ___
nervus intermedius
Forms the geniculate ganglion prior to entering the facial canal
Facial Nerve
Facial Nerve Intracranial Branches
- Greater petrosal nerve
- Nerve to stapedius
- Chorda tympani
- Intrapetrous facial
provides parasympathetic innervation to several glands, including the nasal, palatine, lacrimal and pharyngeal glands
Greater petrosal nerve
also provides parasympathetic innervation to the sphenoid, frontal, maxillary and ethmoid sinuses as well as the nasal cavity
Greater petrosal nerve
Innervates:
Submandibular gland
Sublingual gland
Special sensory taste fibers for the anterior 2/3 of the tongue.
Chorda tympani
provides motor innervation for stapedius muscle in middle ear
Nerve to stapedius
Distal to stylomastoid foramen, the following nerves branch off the facial nerve:
- Posterior auricular nerve
- Branch to posterior belly of digastric as well as the stylohyoid muscles
- Five major facial branches (in parotid gland)
controls movements of some of the scalp muscles around the ear
Posterior auricular nerve
Five major facial branches
- temporal
- zygomatic
- buccal
- marginal mandibular
- cervical
Mixed motor and sensory but mostly sensory
Glossopharyngeal Nerve
Aids in tasting, swallowing and salivary secretions. Its superior and inferior (petrous) ganglia contain the cell bodies of pain fibers
Glossopharyngeal Nerve
Projects into many different structures in the brainstem
Glossopharyngeal Nerve
Glossopharyngeal Nerve Brainstem Connections
- Solitary nucleus
- Spinal nucleus of trigeminal nerve
- Lateral nucleus of ala cinerea
- Nucleus ambiguus
- Inferior salivatory nucleus
taste from the posterior one-third of the tongue and information from carotid baroreceptors and carotid body chemoreceptors
Solitary nucleus
somatic sensory fibers from the middle ear
Spinal nucleus of trigeminal nerve
visceral pain
Lateral nucleus of ala cinerea
the lower motor neurons for the stylopharyngeus muscle
Nucleus ambiguus
parasympathetic input to the parotid and mucus glands
Inferior salivatory nucleus
Glossopharyngeal Nerve Branches
- Tympanic
- Stylopharyngeal
- Tonsillar
- Nerve to carotid sinus
- Branches to the posterior third of the tongue
- Lingual branches
- A communicating branch to the Vagus Nerve
runs posterior to the common carotid artery and internal jugular vein inside the carotid sheath
Vagus Nerve
Vagus Nerve includes axons which emerge from or converge onto four nuclei of the medulla:
- Dorsal nucleus of vagus
- Nucleus ambiguus
- Solitary nucleus
- Spinal trigeminal nucleus
sends parasympathetic output to the viscera, especially the intestines
Dorsal nucleus of vagus
gives rise to the branchial efferent motor fibers of the vagus nerve and preganglionic parasympathetic neurons that innervate the heart
Nucleus ambiguus
receives afferent taste information and primary afferents from visceral organs
Solitary nucleus
receives information about deep/crude touch, pain, and temperature of the outer ear, the dura of the posterior cranial fossa and the mucosa of the larynx
Spinal trigeminal nucleus
Contributes to visceral innervation
Vagus Nerve
Also conveys sensory information about the state of the body’s organs to the CNS
Vagus Nerve
% of the nerve fibers in the vagus nerve are afferent nerves communicating the state of the viscera to the brain
80-90
Vagus Nerve Innervations part 1
- Auricular nerve
- Pharyngeal nerve
- Superior laryngeal nerve
- Superior cervical cardiac branches of vagus nerve
- Inferior cervical cardiac branch
- Recurrent laryngeal nerve
Vagus Nerve Innervations part 2
- Thoracic cardiac branches
- Branches to the pulmonary plexus
- Branches to the esophageal plexus
- Anterior vagal trunk
- Posterior vagal trunk
- Hering-Breuer reflex in alveoli
Provides motor innervation from the CNS to two muscles of the neck: the sternocleidomastoid and the trapezius muscles
Accessory Nerve
tilts and rotates the head
Sternocleidomastoid muscle
elevates shoulder and adducts the scapula
Trapezius
Supplies motor fibres to all of the muscles of the tongue, except the palatoglossus muscle
Hypoglossal Nerve
If afferent
somatic (touch/pain/temperature/propioception) or special (special senses)
If efferent
visceral (internal organs) or somatic (skeletal muscles)
Smell
I Olfactory
Vision
II Optic
Eye movements other than those mediated by IV & VI. Elevation of upper eyelid
III Oculomotor
Constriction of pupil (ciliary ganglion)
III Oculomotor
Certain downward eye movements
IV Trochlear
Muscles that open and close the mouth; tensor tympani muscle of middle ear
V Trigeminal
Skin of face; mouth, teeth, nose, sinuses, dura mater of anterior and middle fossa
V Trigeminal
Abduction of eye
VI Abducens
Muscles of face; stapedius muscle of middle ear
VII Facial
Lacrimal and nasal glands (pterygopalatine ganglion); sublingual & submandibular salivary glands (submandibular ganglion)
VII Facial
Part of external ear and tympanic membrane
VII Facial
Taste: palate & anterior two thirds of tongue
VII Facial
Equilibration
Hearing
VIII Vestibulocochlear:
Vestibular
Cochlear
Stylopharyngeus muscle
IX Glossopharyngeal
Parotid gland (otic ganglion)
IX Glossopharyngeal
Pharynx, middle ear, posterior third of tongue
IX Glossopharyngeal
Taste: posterior third of tongue
IX Glossopharyngeal
Muscles of larynx & pharynx
X Vagus
Slows heart (cardiac ganglia); increases gastric acid secretion and empties stomach (enteric nervous system)
X Vagus
Larynx, trachea, oesophagus, dura of posterior fossa; part of external ear and tympanic membrane
X Vagus
Taste: epiglottis
X Vagus
Trapezius and sternocleidomastoid muscles
XI Accessory³ (Spinal component)
Muscles that move the tongue
XII Hypoglossal
