week 3 and 4 control Flashcards
what are the general functions of the brain stem?
conduit –> allows ascending and descending pathways to reach the thalamus and cerebellum from the spinal cord
integrative –> has a lot of functions –> respiratory, cardiovascular, consicousness
cranial nerve –> root
what structure is between the 3rd and 4th ventricle? What is a possible problem that could occur?
it is the cerebral aqueduct. It can become blocked and therefore CSF can build up in this space and can cause swelling of the brain. In kids the skull is flexible and can adapt to the growing brain but in adults the skull is fixed and therefore more of a problem.
what structure is the brain stem continous with caudally?
it is continous with the spinal cord at the level of the formamen magnum
what structure is the brain stem continous with rostrally?
it is continous with the diencephalon that contains the thalamus and hypothalamus
what structures make the brain stem?
pons, midbrain, medulla oblaganta and diencephalon
what structures are ventral and dorsal to the brain stem?
the clivus of the occipital bone is ventral to the brain stem.
Cerebellum is dorsal to the brain stem.
what type of fibres are on the ventral surface of the medulla?
motor fibres
what seperates the medulla from the pons?
pontomedulla junction
what is the structure that seperates the two pyramids
anterior median fissure
what type of fibers are within the pyramids?
motor fibers
what sulcus seperates the pyramid from the olive? what nerve is present here?
anterolateral sulcus seperates the 2. Olive contains nucleus
The hypoglossal nerve –> cranial nerve 12 is present here
at what sulcus does the vagus and glossopharyngeal nerve emerge?
the posterolateral sulcus that is dorsal to the olive
what do you have to do to view the dorsal surface of the brain stem?
have to remove the cerebellum
what structure is formed in the medulla. What does it do and how is it formed?
the central canal open up into the 4th ventricle at the point of the obex where CSF fluid is produced.
what are the two parts of the medulla fromed by the 4th ventricle?
the closed (caudual) --> central canal the open ( rostral) --> 4th ventricle
what is the name of the name of the floor of the 4th ventricle?
Rhomboid fossa –> grooves and elevation shows underlying nuclei
what is the name of the structures either side of the midline of the dorsal surface of the medulla?
gracile fascile which is axon bundles that transfer sensory information from the lower limbs. It moves rostrally to form gracile tubercle which contain cell bodies
what structure is formed laterally to the gracile fascile?
the cuneate which contain axons and transfer sensory information from the upper limbs. It travels rostrally to form the cuneate tubercle –> contains cell bodies
what pathway is the gracile and cuneate fascile part of?
they are part of the dorsal collumn pathway that transfers sensory information from the body to the brain
what structure bridges the two cerebral hemispheres?
the corpus callosum –> contain white matter
what is the junction between pons and midbrain?
the pontomesencephalic junction?
what nerves emerge from Cerebellopontine angle?
facial nerve and vestibucochlear nerve
what nerve emerges from the pontomedullar junction?
the abducens nerve
what pon connects the medulla to the cerebellum?
the inferior cerebellar peduncles
what two structures are connected by the superior cerebellar peduncles
the midbrain and cerebellum
what is the middle cerebellar peduncles
connect pons to cerebellum
what is a peduncle?
is a stalk that connects two structures and bundle of axons –> white matter
what is the roof of the 4th ventricle formed from?
superior cerebellar peduncles
what is the cerebral peduncle?
it connects the midbrain to the cerebellar
what structure is between the cerebral peduncle and what is its importnace?
it is the interpeduncle fossa and contains the occulomotor nerve
what is the superior and inferior colliculi associated with?
superior –> sight pathway
inferior –> auditory pathway
what is the only nerve to emergy from the dorsal aspect of the brain stem?
cranial nerve 4 –> troclear nerve
which two nerves come from the diecaphalon? are a outgrowth?
optic and olfactory nerves
in the mid brain what structure is the tectum?
the superior and inferior colliculi
what does the basal contain?
pons, midbrain and peduncles
what does the tegmentum contan?
contains cranial nerve nuclie and tracts –> some ascending and descending pathways. A lot of nucleis in which the cranial nerves synpase from come from the tegmentum. –> reticular formation
Damage to which part of the brain stem causes lock in syndrome?
the basal as it is most anterior and contains ascending and descending fibers from the cerebral cortex
what functions is the reticular formation involved in?
arousal, sleep wake cycle and modulate pain
what does the reticular formation contain?
a reticular nuclei that gives rise to descending motor pathways
vital autonomic centres such as cardiovascular and respiratory
Cells giving rise to Ascending Reticular Activating System – pass to the cortex and involved in consciousness (damage = coma
what seperates the middle cranial fossae from the posterior cranial fossae?
the middle ridge of the petrous part of the temporal bone
which sinus drains into the jugular foramen?
sigmoid sinus
what route does the olfactory nerves take to enter the nasal cavity?
it passes through a series of small holes in the cribiform plate
what two structures run along the optic canal to supply the eye?
the optic nerve and opthalmic artery
what nerves pass through the superior orbital fissure?
opthalmic division (V1) of trigeminal nerve occolumotor nerve --3 trochlear neve --4 abducens nerve --6 all there supply the extraocular muscles
what formane is posterior to the superior orbital fissurea and what structure passess through here?
the foramen rotundum and allows the maxillary divison of the trigeminal to pass through here
which foramen does the mandibular divison of the trigeminal to pass through?
the foramen ovale
what is the importane of foramen lacerum?
dry skull –> contains cartiladge not a lot goes through there however it is posterior to the carotid canal. The itnernal carotid artery passes superiorly over the foramen lacerum to form the circulis of willis
which formane allows the middle meningeal artery and vein to pass through?
the foramen spinous
what two structures run through the internal acoustic meatus?
the facial nerve –7
the vestibulocochlear nerve –> 8th
what foramen does cranial nerve 11 ,9 and 10 pass through?
the jugular foramen?
what sinus is the internal jugular vein continous with?
sigmoid sinus
what nerve runs through the hypoglossal canal?
hypoglossal nerve –> 12
what foramen allows the facial nerve to leave the skull?
stylomastoid foramen
what is the importance of the formane magnum
allows the continuation of the spinal cord as the brain stem to the cerebellar
which 4 cranial nerves contain autonomic fibers?
occulomotor nerve –> 3
facial nerve –> 7
glossopharyngeal nerve –> 9
vagus –> 10
explain the route of the autonimic fibers of the vagus nerve?
it is affected structures of the thoracic and abdominal viscera
what is the route of the autonomic fibers of the occular motor nerve?
presynaptic fibres to the ciliary ganglion then postsynaptic fibers to the sphincter pupillae. The postsynaptic fiber travels via the V1 division of the trigeminal nerve. The sphincter of pupilae causes the constriction of the pupil
how is the lacrimal gland innervated, palatine gland and mucosa of the nasal cavity
it is innervated by the facial nerve –> presynaptic fiber to the Pterygopalatine ganglion then post synaptic fibre via the second divison of the trigeminal
how is submandibular and sublingual glands innervated?
Both are salivary glands and innervated by the facial nerve. Pre synaptic fibers to the submandibular ganglion then post synaptic fibers via the V3 divison of the trigeminal nerve to the glands. THe submandibular gland is positioned underneath your mandible
the sublingual gland is positioned underneath your tongue
what is the route of the autonomic fiber of the glossopharyngeal nerve?
pre synaptic to the optic ganglion then via V3 trigeminal divison post synaptic to the parotid gland
what is the sympathetic input of the autonomic fibers?
from the superior cervial ganglion the upper limits of the sympathetic chain –> branches will follow the birifucation of the common carotid artery –> internal and external to the specific organs
what does the ascending reticular activate system contain?
ascending pathways that communicate with the cerebral cortex
descending pathways that controls bodily posture and reflex mechanism
what are the two types of cranial nerve nucleus?
sensory and motor
what are the positioning of the sensory and motor cranial nerve nucleus ?
sensory is lateral and motor is medial
what occurs at the sensory cranial nerve nucleus
fibers enter the brain stem within the cranial nerve . Synapse at the nucleus and then send fibres at appropiate high centre
what occurs at the motor cranial nerve nucleus?
recieve motor information from the higher centre to the nucleus –> synapse and then send motor fibers within the cranial nerve where it leaves
what are the two fibers within the occulomotor?
somatic motor fiber –> control extraoccular muscles
visceral motor fiber –> sphincter pupillae and ciliary muscles
what are the two nucleus that occulomotor nerve synapse at
somatic motor fiber –> occulomotor nucleus
visceral motor fiber –> edinger westphal nucleus
how does the falx cerebri attach anteriorly to the skull?
via the cristae galli
what is the cristae galli?
it is ridge of bone that projects from the cribiform plate of the ethmodial bone
where does the olfactor bulb lie?
either side of the cristae galli
how does the falx cerebri attach posteriorly to the skull?
the internal occipital protuberance
what muscle does the glossopharyngeal nerve supply?
the stylopharyngeus muscle
how can taste sensation of the facial nerve be damaged?
if there is a lesion at the petrous temporal bone where the geniculate ganglion of the sensory part of the temporal bone –> cause damage
what structure on the skull does the trapezius attach to?
the external occipital protuberance
what does the 4th ventricle drain into?
the cerebral aqueduct into the midbrain –> the 4th ventricle tapers off
what are the cuneate and gracile tubercle part of?
dorsal column pathway
what is the role of the dorsal column pathway?
precise sensory information from your body through the spinal cord
how does motor fibers run down from the cerebral cortex to the spinal cord?
descending motor fibers come from the cerebral cortex –> to the cerebral peduncles and then down the medulla via the pyramids. As they go down they decussation ( cross over) at the midline
what does the substantia nigra contain and what does it do?
contains dopamingeric fibers that are important in movement
what happens when damaging substantia nigra?
Leads to Parkinson’s disease
what is the anterior and posterior limits of the dopaminergic fibers?
posterior limit –> mammillary bodies
anterior limit –> optic chiasma
what is acoustic neuroma, what nerves are affected?
it is a benign tumor that compressed the vestibulocochlear nerve 8 and compress of nerves and adjacent structures to the cerebellopontine angle.
what inherited disease causes acoustic neurome?
neurofibromatosis causes unilateral or bilateral acoustic neuroma
what are the signs and symptoms of acoustic neurome?
Attacks of dizziness accompanied by profound deafness occur; with expansion of the tumour and paralysis of the cranial nerves (especially V–VII) and the limbs follow
what is parasomia and hypsomia ? What is the cause
parosmia –> is altered sense of smell
hypsomia –> is reduction in sense of smell and detecting odors
caused by damage to the olfactory nerve
what does the sensory component of the trigeminal nerve supply?
skin, teeth, muscous membrane of the face, anterior scalp and the dura
what does the motor component of the trigeminal nerve supply?
supplies the 4 muscles of mastication
muscles involved in swallowing
tensor tympani which dampens the amplitude of vibration of the tympanic mebrane
what is tensor tympani muscle –>
muscle within the ear
name the branches of the V1 opthalmic nerve and the ganglion that synapse there
lacrimal nerve and ciliary ganglion
name the branches of the V2 maxillary nerve and the ganglion that synapse there
infraorbital nerve, temporal nerve, superior alveolar nerve
pterygopalantine ganglion
name the branches of the V3 mandibular nerve and the ganglion that synapse there
buccal nerve, inferior alveolar nerve, lingual nerve and auriculotemporal nerve
what are the 4 muscle of mastication?
masseter
medial pterygoid muscle
lateral pterygoid muscle
temporalis
which of the muscles of masstication is involved in elevation (closing of the mouth)
masseter, medial pterygoid and temporalis
which muscles of masstication are involved in depressin ( opening of the mouth)
lateral pterygoid and hyoid muscle
which muscles are involved in protrusion of the mouth?
lateral pterygoid
which muscles are invovled in side to side movement of the jaw?
lateral and medial pterygoid
which muscles are involved in retrusion of the jaw?
temporalis
what is the movement invovled with the temporalis muscle?
elevation and retraction of the mandible at the temperomandibular joint.
which two nerves hang of the pterygopalantine ganglion?
greater and less palantine nerve
what does the greater palantine nerve innervate?
the mucosa, the glands of the hard palate and adjacent gingiven
what does the lesser palantine nerve innervate?
the soft palate
what does the temporalis branch of the facial nerve supply?
the frontalis, orbicularis oculi and corrugator supercilli
what does the buccal branch of the facial nerve supply?
the orbicularis oris, buccinator and zygomaticus
what does the zygomatic branch of the facial nerve supply?
orbicularis oculi
what does the mandible branch of the facial nerve supply?
the mentalis
what does the cevical branch of the facial nerve supply?
platysma
what does the chordna tympani do?
it transfers the taste sensation from the anterior 2/3rd of the tongue and also joins with the lingual nerve of V3 and forms the submandibular ganglion
what does the greater petrosal nerve innervate?
it is mainly preganglionic parasympathetic fiber that innervates the lacrimal gland and mucosal glands of the nasal cavity, maxillary sinus and palate
what does dysphagia mean?
unable to or difficulty in swallowing
what does dysphonia mean?
difficulty in speaking
what does dysarthria mean?
difficulty or unclear articulation of speach
what muscles does the vagus nerve supply and with what other nerve?
with the cranial roots of the accessory nerve it carriers motor fibers to the straite muscles of the palate, larynx and pharynx
what are the two parts to the accessory nerve?
cranial roots and spinal roots
where does the spinal root of the accessory nerve originate and what is course and innervation?
it is rootles from the upper segment of the cervical cords –> runs through the foramen magnum to briefly join the cranial nerves to travel heading to the jugular foramen and seperates and supply the SCM and trapezius
what fibers does the hypoglossal nerve contain and what does it innervate?
contains only motor fibers –> extrinsic and intrinsic muscles of the tongue
what muscles does the facial nerve supply?
muscles of facial expression and stapedius
how is the submadnibular ganglion formed?
lingual gland of V3 and chroda tympani nerve
what causes hyperacusis and what happenes?
damage to the facial nerve –> bells palsy
no innervation to the stapedius muscle –> so no control of the stapedius bone and therefore over sensitivity from sound from the external enviroment.
what is the symptoms of bell’s palsy?
pain around ear, inability to close eyes, no corneal reflex, hypercausis on the affected side, weaken facial expression muscles, loss of sensation to the anterior 2/3rd of the tongue
what is bell’s palsy?
lesion of the motor neurone of the lower facial nerve –> vitral eotiology –> swelling and then compression of the facial nerve as it passess through the petrosal bone of the temporal bone
what nerves supply the pharynx, larynx and palate?
the glossopharyngeal, vagus and assecory nerve give motor and sensory innervation
what is the name of the nerves that leave the facial nerve that are not motor?
nervus intermedius
what is nervus intermedius?
they are sensroy, somatic sensory fibres of the facial neve –> alot smaller
what supplies the oropharynx?
the glossopharyngeal nerve
what two nerves supply the striate muscles of the larynx, pharynx and the palate?
branches of the vagus and cranial roots of accessory nerve at the level of jugular foramen
what nerve type does the vagus nerve carry towards the throax and abdominal viscera?
parasympathetic to and sensory fibres back to the brain
damage to the vagus nerve and cranial roots of accessory nerve will cause what?
deviation of the uvula away from the lesion side because of the palate elevating on the side that is stronger
where does the spinal part of the acessory nerve emerge from?
the upper cervical branches, enter the skull through the foramen magnum and then briefly join the cranial root to go out through the jugular foramen to supply th SCM and trapezius
where is the spinal acessory roots most prone to damage?
the posterior cervical neck
what is normal tongue movement important for?
articulation, initating swallowing and chewing
what sort of fibres does hypoglossal nerves contain?
purely motor to the intrnisic and extrinsic muscles
what does the pterygopalantine ganglion supply?
lacrimal glands, palantine glands and mucosa of the nasal cavity
