Bhattacharya 2 Flashcards
- Part of the peripheral nervous system (along with spinal nerves)
- 12 named pairs of nerves indicated by Roman numerals I- XII (unlike spinal nerves)
- Primarily arise from the brain stem…..but there are some exceptions
Cranial nerves
Exceptions: Cranial nerves that do NOT arise from brain stem
- Olfactory (I) - Telencephalon
- Optic (II) - Diencephalon
- Spinal Accessory (XI) - Spinal Cord
Cranial nerves that arise from the Midbrain of the Brainstem
III Oculomotor
IV Trochlear
Cranial nerves that arise from the Pons of the Brainstem
V Trigeminal
VI Abducens
VII Facial
Cranial nerves that arise from the Medulla of the Brainstem
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XII Hypoglossal
Cranial nerves grouped by nerve fiber composition
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M: motor
S: sensory
B: both
Parasympathetic: III, VII, IX, X
Cranial nerves are NOT formed by the union of ventral (anterior) and dorsal (posterior) roots. This means that NOT all cranial nerves are _____ nerves, i.e. not all cranial nerves carry both motor (efferent) and sensory (afferent) nerve fibers.
mixed
Some cranial nerves have _______ associated with them (similar to dorsal root ganglia for spinal nerves).
sensory ganglia
Spinal nerves have connections (rami communicans) to the sympathetic trunk. Cranial nerves _____ have similar connections to the sympathetic trunk
and _____ contain sympathetic fibers at their origin from the brainstem.
- DO NOT
- NEVER
Some fibers NOT found in spinal nerves
• Afferent fibers of “special” sensation with receptors aggregated in “special” sense organs
(1) Olfaction – CN I
(2) Vision – CN II
(3) Hearing and Equilibrium - CN VIII (4) Taste – VII, IX and X
• Efferent fibers to skeletal muscles that arise from the mesoderm of pharyngeal arches.
Cranial nerve supplying the musculature of pharyngeal arch 1
Mandibular division of trigeminal (V3)
Muscles of mastication, mylohyoid, ant. digastric, tensor tympani, tensor veli palatini
Cranial nerve supplying the musculature of pharyngeal arch 2
Facial (VII)
Muscles of facial expression, post. digastric, stapedius, stylohyoid
Cranial nerve supplying the musculature of pharyngeal arch 3
Glossopharyngeal (IX)
Stylopharyngeus
Cranial nerve supplying the musculature of pharyngeal arch 4 & 6
- Branches of vagus (X) including superior laryngeal n.
(Muscles of soft palate EXCEPT tensor veli patatini &
Cricothyroid and muscles of the pharynx EXCEPT stylopharyngeus) - Recurrent laryngeal branch of vagus (X)
(Intrinsic muscles of the larynx EXCEPT cricothyroid)
_____ is a collection of nerve cell bodies within the CNS.
_____ is a collection of nerve cell bodies outside the CNS
- Nucleus
- Ganglion
Cranial nerves containing afferent fibers
Trigeminal (V) Facial (VII) Vestibulocochlear (VIII) Glossopharyngeal (IX) Vagus (X)
Location of Trigeminal (V) cell bodies containing afferent fibers
Trigeminal ganglion
Location of Facial (VII) cell bodies containing afferent fibers
Geniculate ganglion
Location of Vestibulocochlear (VIII) cell bodies containing afferent fibers
Vestibular ganglion
Spiral ganglion
Location of Glossopharyngeal (IX) cell bodies containing afferent fibers
Superior ganglion
Inferior ganglion
Location of Vagus (X) cell bodies containing afferent fibers
Superior (jugular) ganglion
Inferior (nodose) ganglion
Cranial Nerves Containing Efferent Fibers to Skeletal Muscle
Oculomotor III Trochlear IV Trigeminal V Abducens VI Facial VII Glossopharyngeal IX Vagus X Spinal Accessory XI Hypoglossal XII
The locations of the cell bodies for Cranial Nerves Containing Efferent Fibers to Skeletal Muscle are named after their corresponding cranial nerve except Glossopharyngeal IX and Vagus X which are in ________.
Nucleus ambiguus
Cranial Nerves Containing Preganglionic Efferent Fibers
Note:
• At the brainstem only four CN’s exit carrying these fibers
• CN’s can only contain pre- and NOT post-ganglionic parasympathetic fibers
Oculomotor III
Facial VII
Glossopharyngeal IX
Vagus X
Location of cell body for Oculomotor III containing Preganglionic Efferent Fibers
Nucleus of Edinger-Westphal
Location of cell body for Facial VII containing Preganglionic Efferent Fibers
Superior salivatory nucleus
Location of cell body for Glossopharyngeal IX containing Preganglionic Efferent Fibers
Inferior salivatory nucleus
Location of cell body for Vagus X containing Preganglionic Efferent Fibers
Dorsal motor nucleus of vagus
Cranial nerves (in which preganglionic fiber leaves brainstem) associated with Parasympathetic Ganglia
Oculomotor III
Facial VII
Glossopharyngeal IX
Vagus X
Ganglion and Destination of Oculomotor III associated with Parasympathetic Ganglia
- Ciliary: Sphincter pupillae, ciliary muscle
Ganglion and Destination of Facial VII associated with Parasympathetic Ganglia
- Submandibular: Submandibular and sublingual
- Pterygopalatine: Lacrimal gland, glands of palate, nasal cavity, etc.
Ganglion and Destination of Glossopharyngeal IX associated with Parasympathetic Ganglia
- Otic: Parotid gland
Ganglion and Destination of Vagus X associated with Parasympathetic Ganglia
- Terminal: Heart, bronchi, alimentary canal proximal to splenic flexure
But what about sympathetic (thoracolumbar) innervation to the head?
- Preganglionic sympathetic fibers - __________
- Postganglionic sympathetic fibers - ________ - these fibers travel with blood vessels to reach their targets in the head.
- intermediolateral cell column (T1-L2)
2. superior cervical ganglion
Responsible for vision
CN II
Responsible for motor innervation to extraocular muscles (1 for raising eyelid, 6 for eye movement)
CN III, IV, VI
Responsible for sphincter pupillae (constriction of pupil) and ciliary muscle (to change curvature of lens)
CN III (preganglionic parasympathetic innervation to ciliary ganglion)
Responsible for general sensation (such as pain, touch, temperature) in orbit and out on the face
CN V (ophthalmic division)
- major sensory nerve of the face
- general sensation to mouth, teeth and anterior 2/3rd of tongue
- motor innervation for muscles of mastication (and others)
TRIGEMINAL NERVE (CN V) – S and M
Muscles of Mastication
- Temporalis
- Masseter
- Lateral pterygoid (superior and inferior)
- Medial pterygoid (superficial and deep)
- innervates muscles of facial expression (and others)
- taste fibers to anterior 2/3rd of the tongue
- preganglionic parasympathetic innervation to:
- submandibular ganglion (sublingual and submandibular glands)
- pterygopalatine ganglion (mucous glands of nose and palate,
lacrimal gland)
FACIAL NERVE (CN VII) – S, M, PA
- innervates one muscle (stylopharyngeus)
- parasympathetic innervation to otic ganglion (parotid gland)
- general sensation and taste fibers to posterior 1/3rd of the tongue
- general sensation to oropharynx, carotid body and sinus
GLOSSOPHARYNGEAL NERVE (CN IX) – S, M, PA
- motor innervation to muscles of larynx, pharynx and soft palate
- preganglionic parasympathetic innervation to terminal ganglia (of cardiac, smooth muscles and glands in thorax and abdomen)
- sensory to mucosae in larynx and laryngopharynx; visceral sensation (heart, abdominal viscera, etc.)
- taste to epiglottis and root of the tongue
VAGUS (CN X) the “wandering” nerve – S, M, PA
- motor innervation to muscles of the tongue (with one exception)
HYPOGLOSSAL NERVE (CN XII)
