Unit VI & VII Flashcards
“roof” of the midbrain
tectum
what is the tectum posterior to
cerebral aqueduct
what is the tectum composed of
a quadrigeminal plate;
four collicular bodies
the cerebral aqueduct is a channel for CSF exchange between what 2 structures
third and fourth ventricles
what surrounds the cerebral aqueduct
periaqueductual gray substance
what cranial nerve nuclei are found in or near the periaqueductual gray substance
CN III and IV
what painkillers are present in the periaqueductual gray substance
Endorphins and Enkephalins
what are the 3 parts of the cerebral peduncles
Tegmentum;
substantia nigra;
crus cerebri
what is the smallest cranial nerve
CN IV
what is the name of the CN IV
Trochlear
what does CN IV innervate
superior oblique of the extraocular eye musculature
what innervates the superior oblique of the extraocular eye muscles
CN IV
what CN is the only one w/ an apparent origin on post. brainstem
CN IV
CN IV characteristics
smallest;
only one w/ apparent origin on post. brainstem;
only one that crosses as it exits the CNS;
travels further inside cranial vault;
where is the apparent origin of CN III
ventral from the interpeduncular fossa
what innervates 4 of the 6 extraocular muscles
CN III
what does CN III innervate
4 of the 6 extraocular;
superior rectus, inferior rectus, medial rectus, inferior oblique
what raises the upper eyelids
levator palpebrae superioris
what kind of axons does the oculomotor n carry
preganglionic parasympathetic
the oculomotor nerve carries preganglionic parasympathetic axons from _ to _
accessory oculomotor nucleus;
ciliary and sphincter pupillae muscles of eye
accessory oculomotor nucleus aka
Edinger-Westphal
how many bumps exist in the mammalian tectum
4 (superior and inferior colliculi)
what reflexes does the superior colliculi deal with
visual
what reflexes does the inferior colliculi deal with
auditory
what tracts do the superior and inferior colliculi use
tectospinal
where does the tectospinal tract influence neurons through CN XI
upper cervical
what muscles does CN XI contract
SCM;
trapezius
lesions dont impair _ eye movements, only perceptions of _ of objects in the field of vision.
voluntary;
motion
what is just ventral to the cerebral aqueduct
tegmentum
nuclei of origin for CN III and IV are located where
tegmentum
the reticular formation of the midbrain is located here
tegmentum
the red nucleus is primarily located in what
midbrain
the superior part of the red nucleus extends into the
diencephalon’s subthalamic region
the red nucleus is divided into:
inf. (magnocellular area);
highly vascular sup. area (parvocellular);
where do most rubrospinal tract fibers originate
magnocellular area of the midbrain
what is contained in the cerebral peduncles
tegmentum;
substantia nigra;
crus cerebri
input fibers come to the red nucleus from
central cerebellar nuclei;
cerebral cortex
function of the red nucleus
contralateral motor for postural control and muscle tone control in flexor musculature
this is located in the tegmentum and crus
substantia nigra
where does the substantia nigra extend
subthalamus of the diencephalon
what gives substantia nigra its black appearance
melanin
afferent and efferent fibers of the substantia nigra exchange between
telencephalon’s caudate and putamen nuclei
what disease is associated with the substantia nigra
Parkinson’s
symptoms of Parkinson’s
shaking of the digits, hands, and tongue AT REST
what is located at the ventrolateral aspect of the cerebral peduncle
crus cerebri
crus cerebri is composed of
descending tract fibers from the cerebral cortex
what are the 4 descending tracts in the crus cerebri
corticospinal fibers;
corticopontine fibers;
corticobulbar fibers;
corticomesencephalic fibers
corticospinal fibers travel
to the cord
corticopontine fibers travel
to the pons
corticobulbar fibers travel
to MO
corticomesencephalic fibers travel
terminate on CN nuclei III and IV to initiate voluntary motor movements of the eyes
what does diencephalon mean
“between brain”
what are the major parts of the diencephalon
third ventricle; epithalamus; thalamus (includes metathalamus); hypothalamus; subthalamus
the diencephalon is the most significant relay center for sensory input to where
cerebrum (all sensation except olfaction)
the diencephalon is a significant center for control of
autonomic and endocrine functions
pineal gland aka
epiphysis cerebri
what are numerous in the pineal gland
fenestrated vascular capillary beds;
glial support cells
calcification of the pineal gland
“brain sand” (not a tumor)
what does the pineal gland secrete
melatonin, seratonin, norepinephrine
how is the pineal gland sensitive to light indirectly
pathway in retina and synapsing in the hypothalamus (suprachiasmatic nucleus)
melatonin levels appear to be a function of what cycle
circadial cycle
what small structure is just superior to the midbrain tectum
posterior commissure
where are the pupillary light reflex fibers and nuclei are located here
posterior commissure
just anterior and inferior to the posterior commissure is a small structure called
subcommissural organ
what may the subcommissural organ produce
aldosterone
what is the subcommissural organ is primary composed of
specialized ependymal cells
what composes the metathalamus
lateral and medial geniculate bodies
what is the bridge of gray substance that joins the 2 equal left and ride sides of the thalamus
massa intermedia or interthalamic adhesion
the thalamus forms the bulk of the lateral walls of what
third ventricle
what is lateral to each thalamic mass
posterior limb of the internal capsule
what is the only sensory input to NOT be relayed and integrated in the thalamus
olfaction
what runs through the substance of each thalamic mass and helps divide them into subdivisions
internal medullary lamina
what is the largest part of the thalamus
pulvinar
what is only found among the highest of primates
pulvinar
where is the hypothalamus located
below thalamus
what forms the floor and portions of the lateral walls of the third ventricle
hypothalamus
what 2 structures are included in the hypothalamus
infundibular stalk;
optic chiasma;
(NOT the pituitary gland)
the medial zone of the hypothalamus is subdivided into
ant., intermediate, and post. areas
what basic drives does the hypothalamus control
hunger, thirst, and sex
what part of emotional expression does the hypothalamus control
physical aspects (crying)
what has central control over visceral functions
hypothalamus
examples of hypothalamus parasympathetic control
anterior and intermediate areas;
increase digestive motility;
decrease heart rate;
constrict pupil
examples of hypothalamus sympathetic control
posterior area;
increase heart rate and vasoconstriction;
decrease digestive motility;
pupil dilation, piloerection, and sweat gland secretions
direct endocrine control from the hypothalamus
via neuron axon extensions into the posterior pituitary
indirect endocrine control from the hypothalamus
via neurohormones to control the release of anterior pituitary hormones
what nuclei are located in the anterior area of the hypothalamus
supraoptic and paraventricular nuclei;
suprachiasmatic nuclei
what tract sends axons down through the infundibular stalk from the supraoptic and paraventricular nuclei
hypothalamohypophyseal OR
supra-opticohypophyseal
where do axons from the supraoptic and paraventricular nuclei terminate
posterior pituitary
what hormones are released from the posterior pituitary
oxytocin;
antidiuretic hormone
what is oxytocin for
breast milk let down;
uterine contraction
what nuclei is responsible for much of our circadial rhythms such as temp, sleep, light, and feeding
suprachiasmatic nuclei
which nuclei is associated w the pineal gland and its secretions into the blood stream
suprachiasmatic nuclei
what is the anterior nucleus known for
parasympathetic function
what is the preoptic area function
“preworkout” a thermo-regulator as body heats up
this nuclei has a significant GI tract parasympathetic influence
dorsomedial nuclei
nuclei for eating and thirst gratification
ventromedial nuclei
what is the function of the ventromedial nuclei
satiety center (fullness)
what tract do arcuate nuclei contribute axons to
tuberoinfundibular tract
tuberoinfundibular tract is associated w that nuclei
arcuate
where do axons from the tuberoinfundibular tract terminate and release neurohormones
perivascular space of the infundibular stalk
neurohormones from the tuberoinfundiblar tract pass into the _ by way of the _ where they influence the release of _
anterior pituitary;
bloodstream;
pituitary hormones (Releasing Factors)
a term used to describe the uldulating bulge between the infundibular stalk and the large mammillary bodies
tuber cinereum
a nucleus important for short-term memory
mammillary bodies
what is the posterior nuclei responsible for
“postworkout” a thermoregulator, as body cools down; stimulates shivering
what is the posterior area known for
diverse sympathetic actions
what would fibers from the hypothalamic nuclei be doing if they descend to specific nuclei for CN III, VII, IX, X
parasympathetic function
what about those that directly or indirectly reach the intermediolateral cells of rexed lamina seven at cord levels T1-L2? or cord level S2,3,4?
sympathetic;
parsympathetic
which area gives rise to the anterior pituitary and intermediate pituitary
rathke’s pouch
what is a mere extension of the brain and neurons run directly into its substance
posterior pituitary
what must receive its hypothalamic influence via the bloodstream
anterior pituitary
the subthalamus includes the following nuclei
parvocellular region of the red nucleus;
superior portion of the substantia nigra;
subthalamic nuclei (corpus Luysi)
the subthalamic nuclei sends and receives fibers to and from what
globus pallidus of the telencephalon
the subthalamic nuclei is part of what system
extrapyramidal
lesions in the subthalamic nuclei lead to what movement
ballism or hemiballism
what is the outer convoluted gray cerebral cortex of the telencephalon called
pallium
in the telencephalon, there is an underlying mass of white fibers are collectively known as
centrum semiovale
deep within the white matter of the telencephalon are collections of neuron cell bodies called the
basal ganglia
what are the lobes of the brain
frontal lobe - largest;
temporal lobe;
parietal lobe;
occipital lobe - smallest
general functions of the telencephalon
final integration; memory and associative memory; abstract thinking (emotional response)
total surface area of the pallium
2.5 square feet
2/3 of the surface area of the pallium is down in the
sulci
thickness of the pallium is how many mm
1.5-4.5
in the pallium which cortex is thicker
gyrus cortex is thicker than the sulcus cortex
how many neurons in the cerebral cortex
100 billion
each neuron in the cerebral cortex will synapse with an average of how many others
600-4000
what are the subdivisions of the cerebral cortex
neocortex;
allocortex
which subdivision of the cortex occupies 90% and and is homogenous
neocortex
which subdivision of the cortex occupies 10% and includes 2 ancient parts (olfactory and hippocampal). heterogenous
allocortex
which subdivision of the cortex is associated with lamina
neocortex
name of lamina I
molecular (plexiform)
name of lamina II
external granular
name of lamina III
external pyramidal
name of lamina IV
internal granular
name of lamina Vl
internal pyramidal (ganglionic)
name of lamina VI
multiform (fusiform)
the outermost lamina and nearest to the pia mater;
filled with synaptic activity
lamina I
lamina with granular neurons;
axons extend into deeper lamina of this same cortex area
lamina II
lamina pyramidal-shaped neurons;
axons extend to white matter then return to gray (projection, association, commissural fibers)
lamina III
what lamina is called the “Intercortical Association” layer
lamina III
what lamina is called the “Intracortical Association” layer
lamina II
what lamina are called the “associative lamina”
lamina II & III
what lamina receives Thalamic Inputs, some of which will reach the molecular layer
lamina IV
what is well developed in lamina IV
sensory areas (touch, pain, sight, hearing)
what is located in lamina V
giant pyramidal (Betz) cells
where do axons project to in lamina V
corticospinal;
corticobulbar
what lamina is a mix of incoming and outgoing fibers: “projection”
lamina VI
what is lamina V and VI known as
“projection laminae”