Exam 1: Unit 1- CNS Review Flashcards
What are the structrual subdivisions of the NS?
- CNS
2. PNS
What does the CNS include?
brain and spinal cord
What does the PNS include?
- Cranial Nerves (12 pairs)
- Spinal Nerves (31 pairs–mixed)
What type of openings do cranial nerves exit the skull?
via patent openings
patent = “open”; cannot change shape so nerve not compressed
Cranial nerves have nucleus of origin and nuclei of termination, what function do they ass. with?
nucleus of origin – ass. with motor fxn
nucleus of termination – ass. with sensory fxn
What is the apparent origin of a CN?
place on CNS where CN attaches
How are spinal nerves attached to the spinal cord?
by ventral (anterior) rootlets and dorsal (posterior) rootlets
What does the dorsal root contain and what info does it carry?
contains a dorsal root (spinal) ganglion and carries sensory info going to the cord
What does each spinal nerve split into and what information do they carry?
a ventral (anterior) primary ramus and a dorsal (posterior) primary ramus; BOTH carry motor and sensory info
What are the functional subdivisions of the NS?
- Somatic
2. Visceral
What type of tissue does the somatic subdivision of NS affect and how many neurons are needed and what are the pathways?
skeletal muscle; one neuron needed; sensory (afferent) and motor (efferent) pathways
What does the somatic motor (efferent) neuron release at the target tissue?
ACh = excitatory; technically is a LMN influenced by an UMN
What does the Visceral (autonomic) subdivision of the NS affect?
- controls vital body fxns
- smooth muscle, cardiac muscle, and glandular tissue
What are the divisions of the Visceral NS and what nerve or cord levels are ass. with each?
- Sympathetic Division (T1-L2/L3)
2. Parasympathetic Division (S2,3,4 and CN III, VII, IX, X)
What tissues does the sympathetic NS innervate?
heart, lungs, abdominopelvic organs, blood vessels, arrector pili (essentially same as Parasympathetic too)
- fight or flight
How many efferent neurons are needed for a sympathetic pathway and what are the “lengths” and what NT do they release? Ratio?
2 neurons needed:
- preganglionic neurons = short and releases ACh
- postganglionic neuron = longer and releases NE
1: 17 - -Adrenergic –> NE
T/F. The splanchnic nerves are part of the sympathetic NS.
true, but more specific–> there is Greater, Lesser, and Least–> all carry preganglionic axons (exception to the short pre and long post rule)
How many efferent neurons are needed to reach the target tissue for the parasympathetic NS? How “long” are they and what do they release? Ratio?
2 neurons needed
- preganglionic neuron = longer; releases ACh
- postganglionic neuron = shorter; releases ACh
1: 2 - -cholinergic –> ACh
What splanchnic nerves are ass. with the parasympathetic NS?
pelvic
For visceral afferents, where are the cell body locations? (for spinal nerves and CNs)
spinal nerves cell body = DRG
CN cell body = cranial nerve ganglion
List the CN in order and if they are sensory, motor, or mixed.
I. Olfactory (S) II. Optic (S) III. Oculomotor (M) IV. Trochlear (M) V. Trigeminal (B) VI. Abducens (M) VII. Facial (B) VIII. Vestibulocochlear (S) IX. Glossopharyngeal (B) X. Vagus (B) XI. Accessory (M) XII. Hypoglossal (M)
What type of information does the CN I carry?
Olfactory N.
- carries special sensory (smell)
Where to fibers in olfactory travel across and then synapse?
traverse the cribiform plate and synapse on olfactory bulb
What type of information does CN II carry?
Optic N.
- carries special sensory (vision)
Where are fibers from the retina that converge on the optic disc carried next?
carried in the optic nerve, chiasma, and tract to the lateral geniculate bodies
What type of information does Oculomotor nerve carry?
CN III
- carries motor; and somatic and parasympathetic fibers
What muscles does CN III supply?
Oculomotor N.
- supplies 5 somatic muscles and 2 visceral (smooth) muscles
- (LR6 SO4 / 3)
What type of fibers does CN IV carry? What does it supply?
Trochlear N.
- carries somatic motor
- supplies superior oblique muscle
What are three unique things about Trochlear N.?
- smallest of CNs, fewest fibers
- crosses
- apparent origin on dorsal surface of brain
What type of fibers does Trigeminal N carry?
CN V
- carries mixed; somatic motor and sensory
What nerve is known as “The Great Sensory Nerve of the Face”?
Trigeminal N (CN V)--(unique b/c also is motor) - including orbit, nasal cavity and paranasal sinuses, oral cavity, ear, and internal skull
T/F. Facial N. is known as the largest CN.
False, Trigeminal N is the largest CN
What CN has motor supply to muscle of mastication?
Trigeminal N (CN V)
- masseter
- temporalis
- medial pterygoid
- lateral pterygoid
What type of fibers does CN VI carry and what does it supply?
Abducens N.
- carries motor fibers and supplies lateral rectus muscle
What type of fibers does CN VII carry?
Facial N.
- mixed; motor; somatic and parasympathetic–
- sensory for somatic (general) and special
What CN is known was “Nerve of Facial Expression”?
CN VII, Facial N
What does CN VII (Facial N) supply or carry info back from?
- muscles of facial expression; including stylohyoid and stapedius
- lacrimal and salivary glands
- taste info from anterior 2/3 of tongue
What type of fibers does Vestibulocochlear N carry?
CN VIII
- special sensory–> 2 separate nerves for sensory info from cochlea and vestibule
What type of fibers does CN IX carry? (5)
Glossopharyngeal N.
- Mixed; motor;
- branchiomotor and parasympathetic:
- sensory; somatic, special and visceral
What is the info CN IX carry in, and waht motor supply does it have?
- carries taste info from posterior 1/3 of tongue
- motor supply to stylopharyngeus
- parasympathetic supply to parotid gland
What CN is known as “the wonderer”?
Vagus N.
What type of fibers does CN X carry? (5)
Vagus N.
- mixed;
- motor; bronchiomotor and parasympathetic
- sensory; somatic, special and visceral
Which CN is the longest of all CNs?
Vagus N (CN X)
What does the Vagus N have motor supply to? parasympathetic supply?
Motor– to pharyngeal constrictors
Parasympathetic – to bronchi, heart, and GI tract from esophagus to distal 1/3 of transverse colon
What type of fibers does the Accessory N carry?
CN XI
- motor
~does contain Cranial and Spinal parts
What muscles does the Accessory N supply?
Cranial Part–>
muscles of pharynx, larynx, and palate
Spinal Part–> trapezius and SCM
What type of fibers does the Hypoglossal N. carry and what does it supply?
CN XII
- motor
- supplies intrinsic and extrinsic muscles of the tongue
NO TASTE
What CN goes through the Optic Canal?
CN II, Optic N
What opening in the skull does the Oculomotor N go through?
(CN III), the Superior Orbital Fissure
Where does the Olfactory N (CN I) pass through the skull?
cribiform plate of ethmoid bone
T/F. The Trochlear N leaves the skull via the superior orbital fissure.
True
Where do the 3 divisions of the Trigeminal N pass through the skull?
V1 – Superior orbital fissure
V2 – foramen rotundum
V3 – foramen ovale
Where does the Abducens N (CN VI) pass through the skull?
superior orbital fissure
What two CNs pass through the skull via the internal acoustic meatus?
CN VII, Facial N.
CN VIII, Vestibulocochlear N,
What CNs pass through the skull via the Jugular foramen?
CN IX, Glossopharyngeal N.
CN X, Vagus N.
CN XI, Accessory N.
Where does the Hypoglossal N. pass through the skull?
via the hypoglossal canal
What neurons are involved in the Somatic Motor Pathway?
2 neurons:
- UMN
- LMN
What are the two types of UMNs?
- Pyramidal
2. Extrapyramidal
Where are the cell bodies of Pyramidal neurons located?
in cerebral cortex (esp. BMA 4,6,8, even 1,2,3)
Where are the cell bodies of extrapyramidal neurons located?
in the brain stem
What is the pathway the UMNs take when going from the cerebral cortex to the grey matter of cord?
descend through corona radiata, internal capsule, crus cerebri–> most cross in pyramids–> and descend in lateral corticospinal tract–> then synapse in anterior horn (primarily Rexed lamina VII) of gray matter
Where is the cell body located of a LMN?
in anterior horn OR for a CN, in nucleus of origin (both in CNS)
What do LMN exit the cord through? and what kind of nerves are they carried in?
exit cord via anterior (ventral) rootlets
carried in named nerves to supply somatic (skeletal) muscle
How many neurons are used from the trunk and extremities to get from receptor to cerebral cortex in Somatic Sensory input?
3 neurons
- Primary (first order) sensory neuron
- Secondary (second order) sensory neuron
- Tertiary (third order) sensory neuron
Where are the cell bodies of Primary (first order) sensory neurons located? What info do they carry? Where do they synapse?
- cell bodies are in dorsal root (spinal) ganglion
- convey info form receptor to CNS
- synapse in spinal cord (fibers carried in post. columns synapse in M.O.)
What does secondary (second order) neurons path look like?
decussate (cross) and convey info to thalamus
Where do tertiary (third order) neurons relay info to?
cerebral cortex (primarily the post central gyrus) where sensory info is integrated
Somatic neurons in the PNS will carry either ________ or ____________ .
axons of LMN’s or primary (first order) sensory neurons
T/F. In the PNS we will see synapses of only autonomic neurons.
true