Neuro 2 Flashcards
What makes up the brainstem?
What type of information does the brainstem receive?
mibrain, pons and medulla oblongata (MPM)
connects cerebrum with spinal cord
cardiac and respiratory functions, controls heart rate and breathing
sensory and motor from the trunk and limbs travelling through the ascending and descending nerve tracts
What is another name of midbrain?
What are the important features of the midbrain?
What is the function of the midbrain?
mesencephalon
1.tectum = dorsal to cerebral aqueduct, made of 4 (2 superior and 2 inferior) colliculi: superior = visual
inferior = auditory
2. cerebral aqueduct: to connect 3rd and 4th ventricles of ventricular system
3. reticular formation, forms centre - contains nuclei for alertness, sleep and consciousness
4. tegmentum has red nucleus: motor coordination
5. cerebral peduncles, anterior and laterally: connect brain to brain stem
auditory and visual processing: eye movement motor response
maintaining consciousness
What is the reticular formation?
interconnected pathway of nuclei in the brainstem mediating the overall level of consciousness, sleep, alertness.
What is the tectum?
- roof of the midbrain
- corpora quadrigemina (2 superior and 2 inferior colliuculi)
superior = visual
inferior = auditory
What structure is the midbrain continuous with superiorly?
thalamus through the tentorial notch
What is the tegmentum?
ventral to cerebral aqueduct segmented into 2 regions: red nucleus and periaqueductal grey region - motor coordination
the pedicles are for connection
What is the red nucleus in charge of?
coordination of movement
What are cerebral peduncles?
two lobe (anterior and lateral) on either side of tegmentum separated by interpeduncular fossa
What information do the superior and inferior colliculi process?
superior = visual
inferior = auditory
What is the function of the pons?
What is the structure of the pons?
regulate breathing and sleep cycles
- cerebellar peduncles (superior: pons to cerebrum and middle: pons to cerebellum)
- basilar sulcus running down the middle of 2 halves allowing basilar artery to travel through
has:
- descending corticol spinal tract => motor tract to the contralateral side of body
- ascending spinothalamic tract => pass information about pain and temp
also called metencephalon
What are the cerebellar peduncles?
2 middle => connect pons to cerebrum
2 superior => connect pons to cerebellum
What travel on the middle of the pons?
- descending corticol spinal tract => motor tract to the contralateral side of body
- ascending spinothalamic tract => pass information about pain and temp
What is the structure of the medulla oblongata?
- 2 pyramids either side of anterior fissure (midline)
- 2 olive on either side of ventero-lateral sulcus and postero-lateral sulcus
What does the pyramid contain?
corticospinal tract
What is the path of the corticospinal tract?
upper motor neurones from brain to brainstem => decussate at level of pyramid and spinomedullary junction => travel down other side of spinal cord
What do the olives have and what does it do?
olivaric nucleus which are involved in perception of sound and motor control
What is the blood supply to the brainstem?
vertebrobasilar system
SPA (3 terminal branches of basilar artery) VP (arteries joining to form basilar artery)
What are the 12 cranial nerve pairs? And what type of nerve is it (sensory, motor or both)?
- Olfactory - S
- Optic - S
- Oculomotor - M
- Trochlear - M
- Trigeminal - B
- Abducens - M
- Facial - B
- Vestibulocochlear - S
- Glossopharyngeal - B
- Vagus - B
- Accessory - M
- Hypogloassal - M
Where do the 1st and 2nd cranial nerves come from?
cerebrum
Where do 3 - 12 cranial nerves come from?
brainstem
- midbrain => trochlear(4)
- midbrain-pontine junction =>oculomotor (3)
- pons => trigeminal (5)
- pontine-medulla junction => abducens, facial, vestibulocochlear (6, 7, 8)
- medulla oblongata => glossopharyngeal, vagus and accessory (9, 10, 11 - posterior to olive) and hypoglossal (12 - anterior to olive)
How does the olfactory nerve travel?
olfactory receptor in the upper part of nasal cavity => excited and signal travel to nerve fascicle originating in olfactory mucosa => through olfactory bulb => olfactory tract => cribriform plate with foramina
SMELL
How does the optic nerve travel through?
VISION
light enters eye and hits the retina => contains photoreceptors => carry signal and impulse to optic nerve => optic nerve exit through optic canal => enter cranial cavity => cross at optic chiasm which is level of sella turcica => both tracts project posterior on primary visual cortex
Where does the oculomotor travel through?
function of the oculomotor nerve?
EYE MOVEMENT, PUPIL SIZE and LENS
superior orbital fissure
involuntary movements of eye
- help extraocular muscle except superior oblique and lateral rectus muscle
- involuntary action of pupilae muscle during bright light / dim light
Where does the trochlear nerve travel through?
What is the function of the trochlear nerve?
superior orbital fissure
control superior oblique muscle = move your eyes towards your nose / away
At what level dos the trigeminal nerve branch?
What are the 3 branches of the trigeminal?
control superior oblique muscle = move your eyes towards your nose / away
at the level of the temporal bone, trigeminal nerve forms a ganglion located in the trigeminal cave
What does the opthalmic branch of the trigeminal do?
What is the function of the maxillary branch of the trigeminal?
What does the mandibular branch of the trigeminal do?>
give sensation to part of the eye like the cornea, mucosa and skin of the top of the nose
sensation to middle third of face, side of nose, upper teeth
sensation to lower third of face, tongue and lower teeth
What muscle does the abducens nerve innervate?
What is the function of the abducens nerve?
How does the abducens muscle travel to the lateral rectus muscle?
carry efferent nerve axons to innervate the lateral rectus muscle
abducts the eye on the ipsilateral side
start in the pons => through cavernous sinus => via orbital fissure => end at lateral rectus muscle
What does the facial nerve start from?
What are the functions of facial nerve?
What are the 3 main branches of the facial nerve?
severe nuclei in the brainstem
- muscle of fascial expression (frontalis, zygomaticus)
- muscles of external ear and stapedius (middle ear) => important in dampening of loud noise
- sensory info from anterior 2/3 of tongue and taste and outer ear
- lacrimal gland and mucous gland of paranasal sinuses
- submandibular and sublingual glands
- facial nerve proper
- chorda tympani
- greater petrosal nerve
What is the function of the vestibulocochlear nerve?
How does the vestibulocochlear nerve enter the cranial cavity?
vestibular potion => maintain balance
cochlear portion => respond to vibration in middle ear and send info to brain
exit to inner ear => internal acoustic meatus
What type of nerve is the glossopharyngeal nerve?
How does the glossopharyngeal nerve exit the brainstem?
How does the glossopharyngeal nerve leave the skull?
What are the functions of the glossopharyngeal nerve?
mixed nerve with afferent sensory and efferent motor
out the sides of the upper medualla, anterior to the vagus nerve
via the jugular foramen
- general somatic sensory fibre from the tonsil, pharynx and middle and posterior 1/3 of tongue
- visceral sensory fibres from carotid body and sinus
- parasymp. fibre to parotid gland via otic ganglion
- motor fibre to stylopharyngeus muscle
What is the function of the vagus nerve?
- innervates skin of external acoustic meatus and internal surface of laryngopharynx and larynx
- visceral sensation to heart and abdominal viscera
- taste sensation to epiglottis ad root of tongue
- motor innervation to muscle of pharynx, soft palate and larynx
- parasymp. innervation to smooth muscle of trachea, bronchi and GI
Which muscles does the accessory nerve supply?
What are the 2 parts of the accessory nerve?
How does the accessory nerve exit the skull?
sternocleidomasotid m. and trapezius
spinal (come from neurones of upper spinal cord [C1 - 5/6] where these coalesce to travel superiorly and enter the cranial cavity through the foramen magnum) and cranial (fuses with the vagus nerve)
tranverse the posterior cranial fossa to reach the jugular foramen => spinal part descend with the internal carotid artery to reach the sternocleidomastoid muscle
What does the hypoglossal nerve innervate?
all intrinsic and extrinsic muscle of tongue except from palatoglossus - vagus nerve
What nerve innervates the palatoglossus muscle?
vagus nerve
How many cranial nerves are strictly motor nerves?
4
Which of the following nerves is involved in affecting the heart rate?
vagus
abducens
trigeminal
facial
accessory
vagus
Bell’s Palsy is an affliction of one of the cranial nerves. Typically, a person with Bell’s Palsy has a difficult time tasting food. Based on that bit of information, which cranial nerve is affected?
facial
Which of the following cranial nerves is involved in tear production (to keep the eyes lubricated)?
facial
Which of the cranial nerves is involved in the blinking reflex?
occulomotor
How many cranial nerves are involved with the extrinsic muscles of the eye to cause eye movement (either up or down or side to side, etc.)?
3
What is the function of cerebellum?
Where is the cerebellum?
What are the 2 layers of cerebellum?
What are the lobes of the cerebellum?
balance, muscular co-ordination and dexterity
hindbrain with the pons and medulla
Outer layer of grey matter => cerebllar cortex (arbor vine)
Inner layer of white matter => 4 nuclei
- highly convoluted
L and R hemisphere which are divided into anterior and posterior lobe
- flocconodular lobe too
part of hindbrain
What are the fissures in the cerebellum?
- primary fissure => divides anterior and posterior lobes
- posterolateral fissure => divided posterior lobe from flocconudular lobe
- horizontal fissure => along the posterior lobe
What are the zones of the cerebellum?
- central vermis
- either side of central vermis = intermediate zone
- either side of intermediate zone = lateral zone
=> no difference in gross anatomy between intermediate and lateral zones
What are the 3 paired cerebellar peduncles?
- superior cerebellar peduncle (mainly efferent fibres)
- middle cerebellar peduncle (largest carrying motor info)
- inferior cerebellar peduncle (many types of input and output integrating proprioceptive sensory)
What are the 3 functional divisions of the cerebellum?
- cerebrocerebellum - lateral zones
- spinocerebellum - vermis and intermediate
- vestibulocerebellum - floccomodular
What is the arterial blood supply to the cerebellum?
- superior cerebellar artery
- anterior inferior cerebellar artery
- posterior inferior cerebellar artery
What is the superior cerebellar artery and anterior inferior cerebellar artery branches of?
basilar artery which wrap around the anterior aspect of the pons before reaching the cerebellum
What is the posterior inferior cerebellar artery a branch of?
vertebral artery
what does cerebral aqueduct do?
connect 3rd and 4th CSF ventricles
