unit 6 with a touch of 7 Flashcards
what reflexes are controlled by the tectum?
visual and auditory
what is on the left of tectum?
auditory
what reflex is on the right side of tectum?
visual
what are the bumps on the medial side of thalamus?
medial geniculate bodies
what are the bumps on the lateral side of the thalamus?
lateral geniculate bodies
what is the bundle of fibers entering into the thalamus?
lateral lemniscus
where do most of the fibers of the lateral lemniscus go?
medial geniculate bodies
after the majority of lateral lemniscus fibers synapse in the lateral lemniscus it goes where?
temporal lobe for interp
some of the lateral lemniscus fibers g where?
tectum to inferior colliculus then to superior colliculus
auditory information from the superior colliculus then goes to where?
descends to SCM then tectospinal tract for reflex and termination
optic tract synapses into lateral geniculutae body and from there get relayed where?
occipital lobe
some of the optic tract fibers bypass the lateral genicularte body and go where?
superior colliculus then same path as auditory information. into SCM and tecto no further down than C4 level
lesions of the tectum do not impair what?
voluntary eye movement they only impair interpretation of motion
cerebral peduncles are located where?
ventral to the cerebral aqueduct
red nucleus, substantia nigra and crus cerebri make up whta?
cerebral peduncles
in gray matter surrounding cerebral aqueduct we find?
origin of CN 3 and 4
the red nucleus is not part of what formation?
reticulatar formation
the superior part of red nucleus extends into?
subthalamic
it is divided into an inferior large cell area called?
magnocellular
and highly vascular superior area called?
parvocelular
most rubrospinal fibers originate in what part of red nucleus?
magnocellular
the magnacellular is smaller in?
humans
wher efo fibers come from that enter red nucleus?
central cerebellar nuclei
cerebral cortex
what is the function of red nucleus?
contralateral motor repsonses for posture control and muscle tone control primarily in flexor musculature
where is substantia nigra located?
between tegmentum and crus
what is the function of substantia nigra?
does shit with dopamine
what is large and extends into the subthalamus of diencephalon?
substantia nigra
the substantia nigra is found only in?
mammals
afferent and efferent exchanged between?
caudate and putamen
2 of basal ganglia
information goes which way in sub nig?
both ways
what gives sub nig its black color?
melanin
melanin is present/neccessary in cells that secrete?
dopamine
functional considerations of parkinson?
lots
what is crus cerebri composed of?
descending pyramidal axons from cerebral cortex
corticospinal- to cord
corticopont- to pons
corticobulb- to M.O
corticomesen- term on nuc. for C.N 3,4 to initiate voluntary eye movement
the tectum is the roof of what structure?
roof of the midbrain
the tectum is posterior to what?
cerebral aqueduct of sylvius
the tectum is composed of a quadrigeminal plate made up of what?
four collicular bodies
inferior and superior
the cerebral aqueduct of sylvius is a channel for CSF exchange between what two structures?
third and fourth ventricles
the cerebral aqueduct is surrounded by what?
periaqueductual gray substance
nuclei for which cranial nerves can be found in or near the periaqueductual gray substance?
cranial nerves 3 and 4
what else can be found in the periaqueductual gray substance?
endorphins and enkephalins
the cerebral peduncles are ________ to the cerebral aqueduct?
ventral
the cerebral peduncles include what three areas?
tegmentum (just ventral to aqueduct) substantia nigra (toward the middle) Crus cerebri (ventral and lateral aspect)
in relation to fibers, which is the smallest cranial nerve?
4 trochlear
2100-2300 fibers
which cranial nerve innervates the superior oblique muscle of the extraocular eye muscle?
CN4 trochlear
which cranial nerve has an apparent origin unquely out of the mid-dorsal aspect just inferior to the inferior colliculus?
cranial nerve 4 trochlear
when do the fibers of the trochlear nucleus cross over?
they cross over as they exit the CNS
which cranial nerve has the apparent origin, ventral from the interpeduncular fossa (into the cistern)?
cranial nerve 3
oculomotor nerve
the six oculomotor nuclei of origin are located where?
periaqueductual gray substance area
what are the four muscles that the oculomotor cranial nerve innervates?
superior rectus
inferior rectus
medial rectus
inferior oblique
what nucleus contributes preganglionic parasympathetic fibers to C.N 3?
Edinger-Westphals (accessory oculomotor) nucleus of the midbrain
the fibers contributed from the accessory oculomotor innervates the smooth musculature of what?
ciliary process allowing for lens accomodation.
they also innervate the iris musculature causing pupil constriction
the levator palpebrae muscle is innervated from which nerve?
cranial nerve 3
oculomotor
how many bumps exist in the mammilian tectum?
four
what are the four bumps on the mammilian tectum called?
superior and inferior colliculus
what do the superior colliculi deal with?
visual reflexes
what does the inferior colliculi deal with?
auditory reflexes
both sets of colliculi utilize which tract for their protective reflexes?
tectospinal
the tectospinal tract influences the neurons in the upper cervical through which cranial nerve?
11
spinal accessory
lesions of the oculomotor nerve doesnt impair voluntary eye movements but does?
impair our perception of motion of objects in the field of view
the tegmentum of the cerebral peduncles is located where?
just ventral cerebral aqueduct
the reticular formation of the midbrain is located where?
tegmentun of cerebral peduncles
the tegmentum of the cerebral peduncles is where the periaqueductual gray substance is located. what cranial nerve have an apparent origin located here?
Cn 3 an 4
the red nucleus is located where?
red nucleus
the red nucleus is primarily n the midbrain but the superior part extends into what?
diencephalon’s subthalamic region
the red nucleus is divided into what two areas?
inferior large cell area called (magnocellular area)
superior- highly vascular area (Parvorcellular area)
most rubrospinal tract fibers originate in what part of the red nucleus?
originate in the magnocellular are of midbrain
input fibers come to the red nucleus from what two places?
- the central cerebellar nuclei (except fastigial)
- cerebral cortex
contralateral motor responses necessary for postural control and muscle tone control primarily in flexor musculature is the function of what nucleus and tract?
red nucleus
rubrospinal tract
where is the substanitia nigra located?
between the tegmentum and crus
the substantia nigra is also very large and extends into what?
subthalamus of the diencephalon
what is the black substance only found in mammals and has greatest development in man?
substantia nigra
what gives the substantia nigra its black appearance?
melanin
afferent and efferent fibers of the substantia nigra are exchanged between the telencephalon’s __________ and _________ nuclei.
caudate and putamen
what two nuclei make up most of the corpus striatum or basal ganglia of the cerebrum?
caudate and putamen nuclei of the telencephalon
parkinson’s disease was first called what, by john hunter?
paralysis agitans in 1768
what are the parkinson’s symptoms that occurs in 95% of victims?
shaking of the digits, hands, and tongue, at REST
what are some “other” symptoms of parkinson’s disease?
odd postures (flexing forward)
pain
shuffling gait
loss of speech
parkinson’s disease is blamed on environmental factors and is associated with a drop in what chemical made in the substantia nigra?
dopamine
what aspect of the cerebral peduncle is the crus cerebri located?
ventrolateral aspect
the crus cerebri is composed of what 4 main descending tracts?
corticospinal (to the cord)
corticopontine (to the pons)
corticobulbar (to M.O)
corticomesencephalic
the axons of the corticomesencephalic tract terminate on C.N nuclei 3 and 4 to intiate what?
voluntary movements of the eyes
what are the major subdivisions of the diencephalon?
third ventricle epithalamus thalamus hypothalamus subthalamus
prosencephalon is the most significant sensory relay center, dealing with every sense except?
olfaction
the prosencephalon is a significant center for control of __________ and __________ functions.
autonomic and endocrine
the epithalamus is located where in relation to the midbrain tectum?
superior to the tectum
the epithalamus includes what structures worth noting?
pineal gland and posterior commissure
the pineal gland is also known as the?
epiphysis cerebri
the pineal gland is filled with highly modified neurons called?
pineal or epiphyseal cells
the pineal gland has numerous fenestrated vascular capillary beds as well as?
glial support cells
what is brain sand inside the pineal gland?
calcifications that have accumulated with age
do pineal gland tumors occur?
yes
hard to remove (only 1% of brain tumors)
the pineal gland is built like an endocrine gland with fenestrated capillaries (no BBB) and secretes what?
melatonin
seratonin
norepinephrine
(active late night 2-4 am)
the pineal gland is not sensitive to light directly, but through a pathway originating in the retina and synapses where? allows for light based regulation.
hypothalamus
specifically the suprachiasmatic nucleus
melatonin levels appear to be a function of the _____________ cycle, not a controller of it.
circadial cycle
what is SAD
seasonal affective disorder
about 1 in 20 affected in US and canada
what is the small but identifiable commisure just superior to the midbrain tectum?
posterior commissure
pupillary light reflex fibers and nuclei are located where?
posterior commissure
just anterior and inferior to the posterior commissure is a small structure called what?
subcommissural organ
what “organ” might produce aldosterone and is primarily composed of specialized ependymal cells?
subcommissural organ
what is the largest of all nuclei in the CNS?
thalamus
though the medial and lateral geniculate bodies are included in the thalamus they are often classified separately as the?
metathalamus
what exists in a position upon which the cerebral hemispheres seem to be sitting? synonymous with couch
thalamus
the thalamus is a single structure composed of two large ovoid masses of?
gray matter
each about 4 cm long
the two large ovoid masses of the thalamus are joined together by?
Massa intermedia
OR
interthalamic adhesion
this bridge is composed of gray matter but is occasionally missing
what forms the bulk of the side (lateral) walls of the third ventricle?
thalamus
what is lateral to each thalamic mass?
posterior limb of the internal capsule
i just realized i have been writing unit 7 notes into unit 6 topic…
to be continued in the proper unit 7 subject!
fuck you
get back on task
