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What does the rhombencephalon become?
hindbrain
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What is the rhombencephalon a part of?
brainstem
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What are the two vesicles of the rhomencephalon?
- metencephalon
- mylencephalon
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What does the metencephalon become?
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Where is the pons in relation to the hindbrain?
most rostral part of hindbrain
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What does the ventral surface of the pons have?
horizontal striations
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The pons is attached indirectly to what structure?
cerebellum
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What indirectly attaches the pons to the cerebellum?
middle cerebellar peduncles
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The pons is separated from the medulla by what?
inferior pontine sulcus
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The pons is separated from the midbrain by what?
superior pontine sulcus
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What is on the midline of the ventral surface of the pons?
basilar sulcus
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What is the basilar sulcus?
depressed area on pons
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What does the basilar sulcus contain?
- basilar artery of the circle of Wilis
- product of 2 vertebral aa fusing
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What does the basilar artery bifurcate into?
2 posterior cerebral aa
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What is b/w the dorsal surfaces of the pons and cerebellum?
4th ventricle
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What are the two parts of the pons?
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What is the dorsal pons referred to as?
tegmentum
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What is the ventral pons referred to as?
pons proper
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Which part of the pons is smaller?
dorsal pons (tegmentum)
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Which part of the pons has transverse fibers?
ventral pons (pons proper)
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What is the tegmentum continuous with?
midbrain and medulla
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What 4 types of things are found in the tegmentum?
- ascending sensory pathways
- pontine reticular nuclei
- cranial nerve nuclei
- physiological functional areas
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Name the ascending sensory pathways of the tegmentum:
- medial lemniscus
- lateral lemniscus
- trigeminal lemniscus
- spinal lemniscus
- medial longitudinal fasciculus
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What does the pontine reticular nuclei deal with?
arousal and sleep
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What does the pontine reticular nuclei contain?
diffuse small, nuclear structures
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Which cranial nerve nuclei are involved with the tegmentum?
V, VI, VII, VIII
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Facial motor nucleus (VII)
- mm of facial expression
- facial N has both motor and sensory function
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Which CNs are involved with the salivatory nuclei?
VII and IX
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Where is the salivatory nuclei?
superior in pons and inferior in superior portion of medulla
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What type of NS funciton is the salivatory nuclei?
parasympathetic function of NS in context to CN VII
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What does the salivatory nuclei innervate?
smooth muscle cells or glands (sublingual, mucus, lacrimal, and submandibular glands)
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What type of function is the salivatory nuclei?
motor nucleu--efferent response
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What does the salivatory nuclei contain?
cell bodies of preganglionic parasympathetic nn
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Which CNs are involved with the solitary nucleus?
VII, IX, and X
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Where is the solitary nucleus located?
tegmentum of medulla (here b/c facial N likes to use it)
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What is the solitary nucleus involved with?
sensory function: taste innervation for anterior 2/3 of tongue, CN VII
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Which CNs are involved with the spinal nucleus of V?
V, VII, IX, X
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Where is the spinal nucleus of V located?
both pons and mostly medulla (at transition)
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What type of function does the spinal nucleus of V have?
- sensory: involved w/ pain temperature, pressure, and crude touch (CN V)
- sensory: pain, temeprature, pressure and crude touch in small area behind external ear (CN VII)
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What is the motor nucleus of the trigeminal nerve involved with?
perceiving general sensations from head and neck
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What does the motor nucleus of the trigeminal nerve innervate?
mm of mastication
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What 3 nerves does the motor nucleus of the trigeminal nerve use?
- opthalmic (V-1)
- maxillary (V-2)
- mandibular (V-3)
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Where is the motor nucleus of the trigeminal nerve found?
pons
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What is the function of the mesencephalic nucleus of V?
sensory nucleus which receives proprioceptive info of head and neck
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What does the mesencephalic nucleus of V contain?
1st order sensory neurons from skeletal mm (cell bodies in nuclei, unlike most which are in ganglia)
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Where is the mesencephalic nucleus of V?
midbrain
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Which CNs are involved with chief sensory nucleus of V?
V, VII, IX, X
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What is the chief sensory nucleus of V involved with?
discrimination of fine touch (2-point discrimination)
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What does the abducent motor nucleus innervate?
lateral rectus extrinsic eye muscles
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What is the cochlear portion of the vesticulocochlear nerve involved with?
perception of hearing
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Where does the cochlear portion of the vestibulocochlear nerve originate?
cochlea of inner ear --where we find dorsal and ventral cochlear nucleus
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What is the vestibulocochlear nerve involved with?
equilibrium
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What is the vestibular nuclei involved with?
equilibrium
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Where does the vestibular nuclei come from?
semicircular canals of inner ear
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What does the vestibular nuclei communicate with?
vestibular nerve
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Where is the vestibular nuclei located?
tegmentum of pons
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What part of the pons is the pons proper?
ventral pons
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What are the parts of the pons proper?
- pontine nuclei
- transverse fibers
- longitudinal fibers
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Are the pontine nuclei large or small?
small
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Are the pontine nuclei few or numerous?
numerous
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What are the pontine nuclei involved with?
giving pons striated appearance
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Where do the transverse fibers of the pons proper originate?
with pontine nuclei
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What do the transverse fibers of the pons proper do?
take info into cerebellum from the pons
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In the transverse fibers, when an UMN goes through the pons on their way to SC, the UMN send off what?
collateral neurons
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The collateral processess synapse w/:
transverse fibers, and the signal travels into cerebellum
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What do the transverse fibers of the pons proper communicate with?
pontine nuclei
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The transverse fibers give rise to what?
middle cerebellar peduncles
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What are the two parts of the middle cerebellar peduncles?
- superficial transverse fibers
- deep transverse fibers
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What separate the superficial and deep transverse fibers?
longitudinal bundles
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Where are the longitudinal fibers?
in b/w superficial and deep transverse fibers
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What are the 2 major groups of longitudinal fibers?
- corticospinal tract
- corticobulbar tract
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Corticospinal tract:
made up of UMN, they are on their way to ventral horns of SC on contralateral side
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Corticobulbar tract:
follows same pathway as corticospinal tract, synapse w/ LMN cell bodies in the brain stem w/ motor nuclei --on its way to motor nuclei of CNs
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What do the UMN of the longitudinal fibers synapse with?
LMN in motor nuclei of CNs
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What are the General functions of the pons?
- relay station b/w midbrain and medula
- allows cerebellum to communicate w/ brainstem
- very important w/ functions of reticular formation (sleep, arousal, alertness, circadian rhythms, consciousness, etc)
- involved w/ CN activity
- secondary respiratory system
- primary sleep center
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