Final Exam Flashcards
Roof of the midbrain ; It is found posterior to the cerebral aqueduct
Tectum
Composed basically of a Quadrigeminal plate made up of four collicular bodies
Tectum
Channel for CSF exchange between the third and fourth ventricles
Cerebral Aqueduct
The cerebral aqueduct is surrounded by this substance that contains nucleus of CN 3 -4 and also contains Endorphins and Enkephalins
Periaqueductal Gray
This portion of the Mesencephalon contains the Tegmentum, Substantia nigra, and the crus cerebri. Found ventral to the cerebral aqueduct
Cerebral Peduncles
These nerves have apparent origins in the Midbrain
3rd and 4th cranial nerves
These nerves are usually paired.
It is also the smallest of the cranial nerves
Known as the Trochlear Nerve
4th Cranial nerve
Innervates the superior oblique muscle of the extra ocular eye musculature
4th Cranial nerve
Apparent origin is uniquely out of the mid dorsal aspect just inferior to the inferior colliculus.
4th Cranial nerve
The fibers of what cranial nerve decussate over from the opposite trochlear nucleus as they exit?
4th cranial nerve
Also known as oculomotor nerves, the apparent origin is ventral from the interpeduncular fossa. The six nuclei of origin are located in the periaqueductal gray substance area
3rd cranial nerve
Large cranial nerve which innervates four of the six extraocular eye muscles (superior, inferior, and medial rectus as well as the inferior oblique)
3rd cranial nerve
Fibers from the Edinger Westphal nucleus contribute preganglionic parasympathetic fibers to this cranial nerve
3rd cranial nerve
Fibers coming from the Edinger Westphal nucleus are autonomic and innervate the smooth musculature of the ciliary process allowing for _____ ____
lens accomodation
Fibers from the nucleus of CN III also innervate this musculature of the eye, causing pupil constriction
Iris
This muscle lifts the upper eyelids and is innervated by the CN III
Levator Palpebrae
How many bumps exist in the mammalian tectum?
four
What reflexes do the superior and inferior colliculi deal with respectively?
Visual (superior)// Auditory (inferior)
Both sets of colliculi utilize THIS tract for protective reflexes which allows us to move our head away from loud sounds and also objects moving rapidly in our field of vision
(IE Football to the face video)
Tectospinal tract
This tract influences the neurons in the upper cervical through cervical nerve XI. It, in turn, contracts the SCM and trapezius muscles to preven head injury
Tectospinal tract
Lesions in this area impair perception of motion of objects in the field of vision
Tectum
This area is just ventral to the cerebral aqueduct .
The nucleus of origin for CN 3-4 and the reticular formation are located here
Tegmentum
The superior part of this nucleus extends into the diencephalon’s subthalamic region.
It is divided into an inferior large cell area (magnocelullar area) and a higly vascular superior area (parvocelullar). Most of the tracts that are part of this nucleus originate in the magnocelullar area.
Red Nucleus
Input fibers come to the red nucleus from these 2 areas
Central cerebellar nuclei and cerebral cortex
This nucleus deals with contralateral motor responses neccessary for postural control and muscle tone control primarily in flexor musculature
Red nucleus
This is located between the tegmentum and the crus. It extends into the subthalamus of the diencephalon.
Its particular appearance and coloration is due to melanin
Substantia nigra
Afferent and efferent fibers of the substantia nigra are exchanged between these nuclei in the telencephalon which make up the corpus striatum or basal ganglia of the cerebrum
caudate and putamen nuclei
The symptoms of this disease include shaking of the digits, hand and tongue at rest. Also included are odd postures, pain, shuffling gaits and loss of speech in the later stages.
It is associated with a drop in dopamine in the substantia nigra of the midbrain
Parkinsons disease
This part of the mesencephalon is found in the ventrolateral aspect of the cerebral peduncle and it is composed of descending tracts of fibers from the cerebral cortex
Crus Cerebri
Axons that terminate on CN nuclei 3-4 to initiate voluntary muscle movements of the eyes are called the :
Corticomesencephalic fibers
Secondary embryonic vesicle from the prosencephalon which is found between the great cerebral hemispheres
Diencephalon
The major parts of the Diencephalon include
Third ventricle, epithalamus, thalamus, hypothalamus, and subthalamus
This secondary embryonic vesicle is the most significant relay center for sensory input to the cerebrum (except olfaction). It integrates and relays information and is a siginifcant control center for autonomic and endocrine functions
Diencephalon
Found just superior to the midbrains tectum, it includes structures such as the pineal gland, and the posterior commissure.
Epithalamus
Also known as epiphysis cerebri, filled with very highly modified neurons called pineal or epiphyseal cells. The capillary beds in its body are fenestrated and it possesses a large amount of glial cells
It does calcify and is built like an endocrine gland with fenestrated capillaries and secretes melatonin, seratonin and norepinephrine.
It is not sensitive to light directly but through a pathway that originates in the retina synapsing in the hypothalamus
Pineal gland
This neurotransmitter appears to be a function of the circadial cycle although it does not control it
Melatonin
A small but identifiable commissure just superior to the midbrains tectum.
Pupillary light reflex fibers and nuclei are located here as well as the subcommissural organ which produces aldosterone and is primarily composed of ependymal cells
Posterior commissure
A single structure composed of two large ovoid masses of gray matter joined together by a bridge of gray substance called the massa intermedia of the interthalamic adhesion
This structure forms the bulk of the side walls of the third ventricle
Included within structure are the lateral and medial geniculate bodies
Thalamus
Lateral to each thalamic mass is the posterior limb of which capsule?
Internal capsule
This is the “bridge” that is composed of gray matter and is occasionally missing
Massa intermedia
All sensory input to the cerebral hemispheres, except olfaction, is relayed and to some extent integrated in this area.
Thalamus
This, along with the reticular formation input, helps focus the attention of the cerebral cortex; temporarily making certain cortical sensory areas specially receptive and others less so.
It also interprets thermal and pain sensations
Thalamus
This lamina of myelinated fibers runs through the substance of each thalamic mass and helps divide them into subdivisions
Internal medullary
This area is the largest part of the thalamus and is found only among the highest of primates. Functions are varied and complex.
Pulvinar
This structure forms the floor for the third ventricle and portions of the third ventricles lateral walls.
Its structure includes the infundibular stalk and the optic chiasma.
Subdivided into anterior, intermediate and posterior areas
Hypothalamus
While it does not work without help, this structure has vague control over the basic drives of hunger thirst and sex
IT controls the physical aspects of emotional expression
Also controls visceral functions
Hypothalamus
Parasympathetic control of the hypothalamus includes
Anterior and intermediate areas Tuber cinereum included
Increase digestive motility, dec. heart rate, and constriction of the pupil
Sympathetic control of the hypothalamus includes
includes the posterior nuclei and the mammillary bodies
increases heart rate and vasoconstriction, decreases digestive motility, and responsible for pupil dilation, piloerection, and sweat gland secretions
Endocrine control from the hypothalamus happens directly via the _____ and goes into the ______
neuron axon extensions; posterior pituitary
Endocrine control from the hypothalamus happens indirectly via the _____ and goes into the _____
neurohormones; anterior pituitary hormones
Area just above the optic chiasma, important nuclei include the following supraoptic and paraventricular nuclei, supra chiasmatic nuclei, the anterior nucleus and the preoptic area
Anterior area // hypothalamus
These nuclei send axons down the infundibular stalk via the supruaopticohyophyseal tract and they terminate in the posterior pituitary where they are both capable of releasing oxytocin and ADH
Supraoptic and paraventricular nuclei
This hormone stimulates labor and regulates breastmilk
oxytocin
This hormone helps retain water
ADH
This nucleus is responsible for much of our circadial rythms such as temperature, sleep, light, feeding, etc. Complexly connected to the pineal gland and its secretions into the bloodstream
Suprachiasmatic nucleus
This nucleus of the hypothalamus is known for its parasympathetic functions
Anterior nucleus
A thermo regulating nucleus; Specially as the body heats up
Preoptic area
This nucleus found in the intermediate area of the hypothalamus has siginificant GI tract parasympathetic influence and is fairly diffuse.
Dorsomedial nuclei