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brainstem soneira
brainstem packet self-study
Question | Answer |
---|---|
Name the three parts of the brainstem | medulla, pons, midbrain |
What brain structure largely covers the three parts of the brainstem? | cerebellum |
The brainstem is continuous inferiorly with | spinal cord at foramen magnum |
the brainstem is continuous superiorly with | diencephalon |
Where is the anterior median fissure? | anterior (ventral) surface of brainstem on medulla |
Where are the pyramids? | one on each side of anterior median fissure |
what is in the pyramids? | descending fibers of corticospinal tracts |
What happens to fibers of the corticospinal tract in the lower medulla? | 90% decussate, or cross to contralateral side |
When corticospinal tracts decussate, where do they go? | descend in lateral funiculus of spinal cord as lateral corticospinal tract |
What happens to fibers that do not decussate? | descend in anterior funiculus as anterior corticospinal tract |
A lesion on the right pyramid of the medulla above the decussation would cause paralysis or causes paresis on which side of the body? | contralateral side..left side |
A lesion on the right pyramid of the medulla below the decussation would cause paralysis or causes paresis on which side of the body? | ipsilateral side...the right (same) side |
Where is the olive? | oval elevation lateral to upper part of pyramid |
What forms the olive? | inferior olivary nuclear complex |
where does the rootlets of the hypoglossal nerve attach? | between pyramid and olive in preolivary sulcus |
where do the rootlets of the glossopharyngeal and vagus nerves attach? | posterior to the olive at the postolivary (retro-olivary) sulcus |
What are the rootlets of the vagus nerve in line with? | attachment of rootlets of accessory nerve |
What nerves attach along the medullopontine sulcus (medial to lateral) | abducens, CN VI (most medial) facial, CN VII (bib = motor root, small = int.nerve) vestibulocochlear nerve, CN VIII |
What is continuous on each side with a large fiber bundle that terminates in the middle cerebellar peduncle? | Pons |
What marks the anterior surface of the pons | transverse bands that mark fiber bundles that originate at pons and enter cerebellum via pontocerebellar fibers (middle cerebellar peduncle) |
Where does the trigeminal nerve attach? | boundary between pons and middle cerebellar peduncle |
What is the large root of the trigeminal nerve | sensory root |
what is the small root of the trigeminal | motor root |
What is the shallow groove along the anterior midline of the pons? | basilar suclus which is related to basilar artery |
What and where are the cerebral crura? | 2 columns of descending fibers that emerge from the cerebral hemisphere run posteriolaterally then disappear into pons |
What are found in the cerebral crura? What structure do they mark? | fibers that originate in cerebral cortex and go to brainstem or spinal cord Marks midbrain |
What nerve attaches to the medial border of the cerebral crus? | oculomotor nerve, cn III |
What is the name of the space in between the cerebral crura? | interpeduncular fossa |
Since many blood vessels penetrate it, what is the floor of the interpeduncular fossa called? | posterior perforated substance |
The small cavity in the "closed" part of the medulla is a continuation of what? | central canal of the spinal cord |
The upper/open part of the medulla forms the floor of what? | floor of the 4th ventricle |
What has to be removed to view the posterior surface of the brainstem? | cut 3 pairs of cerebellar peduncles to remove cerebellum |
Which cerebellar peduncle is the one that can be seen from the front? | the middle, superior and inferior are only visible from back |
What do the alar plates give rise to? | sensory nuclei of the spinal cord, though actually interneurons, not true sensory neurons |
What do the basal plates give rise to? | motor nuclei of the spinal cord, really interneurons because transmit to muscles |
Which plates, alar or basal, are located in the dorsal horn | alar |
What does the sulcus limitans becomes as you descend from the medulla? | central canal of spinal cord?? |
What is the boundary between sensory nuclei and motor nuclei (alar and basal) | sulcus limitans |
What is the position of the alar plate adn continue into fourth ventricle? | becomes lateral to basal plate |
What is the position of the alar to basal plates in the closed medulla? | posterior |
When the alar plates rejoin at the midline what happens to the cavity of the 4th ventricle | It shrinks to become the small cerebral aqueduct of the midbrain. |
The gracile and cuneate fasciculi terminate where? | Superiorly in the closed medulla at the gracile and cuneate tubercles |
What forms the gracile and cuneate tubercles? Which direction are the fibers running? | the corresponding nuclei are relay stations for the ascending fibers of each that terminate there |
What do the ascending fibers of the gracile and cuneate fasciculi carry? | sensory information: discriminative touch, proprioception, vibration |
On which side of the brain stem are the gracile tubercle and cuneate tubercle? | posterior (dorsal) |
What forms a prominent elevation in the posterolateral medulla, superior to gracile and cuneate tubercles | Restiform body (rope-like) |
What part of the medulla carries impules from medulla and spinal cord to cerebellum (cerebellar afferent fibers)? | restiform body |
what creates two structures join to create the inferior cerebellar peduncle? | juxtarestiform body & restiform body which ascend then turn backward to enter cerebellum |
What is another name for the 4th ventricle? | Rhombiod Fossa |
What divides the 4th ventricle into right and left halves? | median sulcus of the rhombiod fossa |
What longitudinal sulcus is found in each half of the rhomboid fossa | sulcus limitans |
What is the area between the median sulcus and the sulcus limitans? | medial eminence of 4th ventricle |
What nuclei are located between median sulcus and sulcus limitans in the 4th ventricle? | cranial nerve motor nuclei |
Where are cranial nerve sensory nuclei located in relation to the sulcus limitans in the 4th ventricle? | lateral to the suclus limitans |
the two small triangular areas found int he lower part of the medial eminence are called? Which is medial? | The hypoglossal trigone is medial to the vagal trigone in the closed medulla |
What lies deep to the hypoglossal trigone and vagal trigone? | hypoglossal nucleus and dorsal motor nucleus of vagus, respectively |
What does the dorsal motor nucleus of the vagus do? | visceral, parasympathetic? |
Name the rounded elevation of the medial eminence located in the lower pons that marks the location of the abducens nucleus? | Facial colliculus |
What else does the facial colliculus mark along with abducens nucleus? | Internal genu of facial nerve |
What is the internal genu of facial nerve? | fibers that originate from the facial nucleus and loop around the abducens nucleus to form the facial collicus. |
lateral to the sulcus limitans in the upper medulla and lower pons is an "area" that marks what? | the vestibular area marks the location of the vestibular nuclei |
What does the vestibular nuclei gather? | It is a sensory nuclei that receives information from the inner ear to help maintain balance. |
What is the boundary between the pons and medulla? | the straie medullares of 4th ventricle: white strands that cross on dorsal surface of brainstem at the widest part of rhomboid fossa. |
Where do striae medullares of 4th ventricle cross the medulla? | At the widest part of the rhomboid fossa on the dorsal surface of the brainstem |
What does the Obex delineate? Where is it located? | below is the closed medulla at the tip of the 4th ventrical |
What are the four elevations that mark the posterior surface of the brain stem? Role? | 2 inferior colliculi - part of auditory 2 superior colliculi - part of visual |
How are the inferior colliculus connected to the thalamus? | connected to medial geniculate body (part of thalmus) by brachium of inferior colliculus |
The brachium of the superior colliculus connects it where? | brachium connects superior colliculus to lateral geniculate body, also part of thalmus |
which part of the epithalmus is a component of the diencephalon? Where is it located? | the pineal body/gland is located between superior colliculi |
What lies between the superior colliculi, though it is not a part of the brainstem? | pineal body/gland |
What nerve attaches to brainstem? It is the only one on posterior surface of brainstem. | Trochlear (IV) attaches below inferior colliculus |
What are the two groups of Efferent fibers? | Visceral and Somatic |
Where do efferent fibers run? | motor fibers from brainstem to effector |
What are the two classifications of Visceral efferent fibers? Somatic? | General (General Visceral Efferent)=GVE Special (Special Visceral Efferent)=SVE Somatic only has General = GSE |
What do the fibers innervate and which nerves contain the General Visceral Efferent Fibers? | preganglionic parasympathetic fibers, CN's III, VII, IX, X |
What do the fibers innervate and which nerves the Special Visceral Efferent Fibers? | innervate skeletal muscle from pharyngeal (brachial) arches not somites of mesoderm CN V, VII, IX, X |
What do the fibers innervate and which nerves are the General Somatic Efferent fibers | innervate skeletal muscle derived from somites and somitomeres Cn III, IV, VI, XII |
What do the fibers innervate and which nerves are the General Visceral Afferent fibers? | carry sensory info from internal organs CN IX |
What do the fibers innervate and which nerves are the Special Visceral Afferent fibers? | carry olfactory and gustatory info CN's I, VII, IX, X |
What do the fibers innervate and which nerves are the General Somatic Afferent fibers? | carry sensory info from skin, musc. tendons, ligaments CN's V, VII, IX, X |
What do the fibers innervate and which nerves are the Special Somatic Afferent fibers? | carry visual, auditory, balance info Cn's II and VIII |
What fibers would carry messages that your stomach or bladder were full? | GVA |
What fibers would carry message that your were having a heart attack: Pain? | GVA |
What fibers carry baroreceptor readings such as carotid sinus? | GVA |
What fibers carry stimulation from chemical sources,where a molecule actually binds a receptor? | SVA |
What fibers carry information to the brain about touch, temp, vibration | GSA |
What is the most important GSA nerve? How can we tell? | Trigeminal, it has the most fibers |
What fibers would carry physical sensations such as vision, hearing or balance to the brain? | SSA |
What GSE nucleus is located in the midbrain at the level of the superior colliculus? | oculomotor nucleus |
What GSE nucleus is located in the midbrain at the level of the inferior colliculus? | trochlear nucleus |
What GSE nucleus is located in the lower pons deep to the facial colliculus of the rhomboid fossa? | abducens |
What GSE nucleus is located in the medulla medial to the dorsal motor vagal nerve? | hypoglossal nucleus |
Which motor nuclei give rise to preganglionic parasympathetic fibers? | general visceral efferent (GVE)motor nuclei |
Which motor nuclei are located close to the midline and adjacent to the ventricular system? | general somatic efferent (GSE)motor nuclei |
What GVE nuclei is located in the midbrain at the level of the superior colliculus, immeadiately posterior to oculomotor nucleus? | Edinger-Westphal, cn III nucleus |
The GVE nucleus or what CN is located in the lower pons? | supeior salivatory nucleus of CN VII |
The GVE nucleus of what CN is located in the upper medulla? | inferior salivatory nucleus of CN IX |
The GVE nucleus of what CN is located in the lower medulla lateral to the hypoglossal n. | dorsal motor nucleus of vagus, CN X |
What special visceral efferent motor nuclei innervates mm. derived from 1st pharyngeal arch? | trigeminal motor nucleus |
What are the muscles derived from 1st pharyngeal arch? | muscles of mastication: masseter, termporalis, medial and lateral pterygoids |
Where, Which, what type is the motor nuclei that innervates muscles derived from the 2nd pharyngeal arch? | lower pons, SVE, facial nucleus |
Where, which, what type is the motor nuclei that innervates muscles derived from the 3rd, 4th, 6th pharyngeal arches? | medulla, nucleus ambiguus, SVE fibers to CN IX and X |
What are the muscles of the 3rd, 4th, 6th pharyngeal arches? | muscles of pharynx, larynx and soft palate |
What is the most important general somatic afferent sensory nuclei? Location? | trigeminal sensory nucleus, has three parts and extends the entire length of brainstem |
What part of the trigeminal GSA nucleus extends from lower pons to medulla-spinal cord junction? What does it recieve? | spinal nucleus of trigeminal nerve, receives mostly pain and temperature information |
What part of the trigeminal GSA nucleus is in midpons? What does it receive? | principal sensory (pontine) nucleus of trigeminal nerve. receives touch information |
What part of the trigeminal GSA nucleus extends from midpons to upper mid-brain junction? What does it recieve? | mesencephalic nucleus of trigeminal nerve, receives proprioceptive information |
Which and what type sensory nuclei receive auditory information from the organ of Corti (inner ear)? By what nerve? | cochlear part of VIII travels to ventral and dorsal cochlear nuclei which are SSA, special somatic afferent |
Where are the ventral and dorsal cochlear nuclei located? | posterolaterally at pontomedullary junction on surface of restiform body - this is the widest part of the rhomboid surface |
How many vestibular nuclei exist? Where are they? | 4, superior, inferior, medial and lateral posterolateral part of upper medulla, lower pons underneath vestibular area of rhomboid fossa |
What is the purpose of the vestibular nuclei? | recieve information from teh maculae and ampullary crest (inner ear) via the vestibular part of CN VIII |
Where are the two parts of the solitary nucleus located? | medulla |
Which part of solitary nucleus receives SVA fibers for taste? From what nerves? What is another name for it | Gustatory nucleus of upper part of solitary nucleus receives from CN VII, IX, X |
Which part solitary nucleus receives GVA fibers? Another name? | Cardiorespiratory nucleus is the lower nucleus, receives fibers from cn IX, X |