Lecture 45 Cranial Nerves 1 Flashcards
Which region of the skull is most intimately tied to the cranial nerves?
the foramina of the chondrocranial base
What are our “two skulls” in humans?
chondrocranial base and the desmocranium
Which of our two skulls is under tighter evolutionary control?
chondrocranial base
Name the twelve cranial nerves.
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulo-Cochlear, Glossopharyngeal, Vagus, Spinal Accessory, Hypoglossal
Cranial Nerve I
Olfactory
Cranial Nerve II
Optic
Cranial Nerve III
Oculomotor
Cranial Nerve IV
Trochlear
Cranial Nerve V
Trigeminal
Cranial Nerve VI
Abducens
Cranial Nerve VII
Facial
Cranial Nerve VIII
Vestibulo-Cochlear
Cranial Nerve IX
Glossopharyngeal
Cranial Nerve X
Vagus
Cranial Nerve XI
Spinal Accessory
Cranial Nerve XII
Hypoglossal
The _____ is defined as the brain and the spinal cord. The _____ includes all nerves and neural structures which lie outside that.
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
The PNS consists of _____ pairs of spinal nerves which exit the cord segmentally, the ____ pairs of cranial nerves originating from the brain and the ______.
31
12
Autonomic Nervous System (ANS)
What system is used to classify the 12 cranial nerves along functional and evolutionary lines into a more understandable grouping?
3-4-5 System of Subdividing Cranial Nerves; Special Sensory, Myotomal, Branchiomeric
Cranial nerves may have as many as _____ types of fibers, but the max number found is _____.
7; 5
What is the general function of special visceral afferent (SVA) fibers?
convey taste and smell from the nasal, buccal, and pharyngeal areas to the appropriate areas of the cortex
What type of fibers found in the head and neck carry sensory information from ectodermal placodal (cranial placodes that have neurogenic potential ie. those that give rise to neurons associated with the special senses and cranial ganglia) structures such as the eye and ear?
special somatic afferent (SSA) fibers
Why is smell classified as visceral when discussing fibers?
It is considered visceral on the basis of gustatory function (relating to the gut)
What type of special fiber is NOT found in the head and neck?
Special Somatic Efferents (SSE)
What three nerves are part of the special sensory nerves grouping?
Olfactory (CN I), Optic (CN II), and Vestibulo-Cochlear (CN VIII)
Why are cranial nerves I, III, and VIII called the special sensory nerves?
They are classified as only containing afferent fibers, CN I contains SVA and CN II and VIII contain SSA
The nasal palcode and its derivative the olfactory epithelium are classified as what?
special visceral afferent (SVA)
Groups of SVA filaments originate high on the nasal septum, in the supreme or superior conchae, pass in ____ to ___ small nerve bundles, or the olfactory “nerves”, through the _____ of the _____ bone to enter and synapse with cells in the olfactory bulb.
12 to 20
Cribriform plate
Ethmoid
The bulb and tract of CN I are conventionally referred to as what?
Olfactory nerve
Vision is carried by what type of fibers?
Special somatic afferent (SSA)
Fibers from both nasal retinal areas cross at the ______ so that information from the R visual field ends up at the L occipital (visual) cortex, and from the L visual field in the R occipital pole.
optic chaisma
Since vision brings information from afar, what is this sense sometimes classified as?
Telereceptive
What foramen does the Olfactory nerve (CN I) pass through?
Cribriform plate of ethmoid bone