Neuroscience Lab 2 midbrain
Terms
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copy deck
- (see under pyramids)
- anterior (ventral) median fissure
- lies just lateral to the optic chiasm; pierced by the central branches of the anterior and middle cerebral arteries
- anterior perforated substance
- primary visual cortex or area 17; cortex represented in the cuneus (dorsally) and lingual (ventrally) gyri surrounding (and in the banks of) the calcarine fissure
- calcarine cortex
- a narrow channel running through the midbrain that connects the third and fourth ventricles
- cerebral aqueduct (of sylvius)
- (see under fourth ventricle)
- central canal
- while not entirely accurate, for purposes of this class, the ____ and the crus cerebri are approximately the same structure; the term _____ actually encompasses some other areas as well
- cerebral peduncles
- a cortical area which begins beneath the corpus callosum (the “subcallosal†area) and continues over the top of the corpus callosum; associated with the limbic system; involved in emotional behavior; cell bodies of origin of the cingulum
- cingulate gyrus
- arterial circle which lies in the subarachnoid space in the interpeduncular cistern; provides a route (theoretically) through which blood entering by either internal carotid artery or the basilar artery may be distributed to any part of the cerebral hemi
- circle of willis
- "little hills" in the roof (tectum) of the midbrain; superior (anterior) and inferior (posterior) ____ are involved with visual and auditory reflexes, respectively; the superior colliculus has important connections to cervical regions of the sp
- colliculi
- bundle of nerve fibers passing from one hemisphere of the brain (or spinal cord) to the other; important ____s in the brain include the:
- commissure
- a massive fiber bundle connecting the two cerebral hemispheres; the "rostrum" or "beak" is the part of the ____ from the genu to the lamina terminalis; the "genu" is the bend of the anterior portion of the ____; the main par
- corpus callosum
- fiber bundle crossing in the lamina terminalis; fibers arise mainly in the temporal lobe
- anterior commissure
- fiber bundle crossing in the median plane just inferior to the root of the pineal body (a glandular structure which lies between the superior colliculi); composed mainly of fibers arising in the midbrain
- posterior commissure
- ("structure(s) resembling a leg or pair of legs"): two large bundles of nerve fibers, each originating from the ipsilateral cerebral hemisphere; contains major descending nerve fiber tracts (e.g., corticospinal, corticopontine, corticobulbar tr
- crus (plural crura) cerebri:
- "c"-shaped paired structure, one in each hemisphere (so closely fused they often appear as one structure); cell bodies of origin primarily in the hippocampus; fibers end in the mammillary bodies of the hypothalamus
- fornix
- ventricle beneath the cerebellum; joins the ventricular system to the subarachnoid space through apertures in its roof; ____ continues downward in the spinal cord as the central canal
- fourth ventricle
- separates the thalamus above from the hypothalamus below
- hypothalamic sulcus
- part of the diencephalon; made up of many small nuclei which have important autonomic and endocrine functions
- hypothalamus
- cortex of the temporal lobe which is buried in the sylvian (lateral) fissure
- insula
- deep median hollow on the inferior surface of the brain which lies between the cerebral peduncles (crura cerebri) of the midbrain; other surrounding structures include the optic chiasm anteriorly, and the pons posteriorly; the hypothalamus forms the roof
- interpeduncular fossa
- point of attachment of the thalamus on both sides of the brain (the thalamus is a paired structure); not a commissure; no known functional significance
- interthalamic adhesion
- two openings in the septum pellucidum which are the only route of communication between the lateral and third ventricles
- interventricular foramina of monro
- a thin membrane which forms the anterior wall of the third ventricle; the anterior commissure runs in the ____; during development, the corpus callosum develops from fibers running between the developing hemispheres through the ____
- lamina terminalis
- c-shaped cavity in each hemisphere; each ____ consists of an anterior horn (frontal lobe), a body (parietal lobe), a posterior or occipital horn (occipital lobe), and an inferior or temporal horn (temporal lobe); csf is made by the choroid plexus primari
- lateral ventricle
- two rounded nuclei in the floor of the hypothalamus; they are part of the hypothalamus which can be seen in the interpeduncular fossa; receive input from the hippocampus via the fornix
- mamillary bodies
- ____ oblongata; the "bulb"; part of the brainstem; important clinically because it contains nuclei of many of the cranial nerves and the ____ry reticular formation; continuous with the spinal cord at the foramen magnum
- medulla
- also called the brachium pontis; axons of neurons deep within the pons (pontine nuclei) cross the median plane and form the ____ on their way to the cerebellar cortex
- middle cerebellar peduncle
- the olfactory bulbs lie on the dura immediately above the cribriform plate of the ethmoid, and these structures alone separate it from the nasal mucous membrane; fractures of the anterior cranial fossa may damage the olfactory bulb and to lead to blood a
- olfactory tracts/bulbs
- a medullary structure lateral to the pyramid and separated from it by fibers of the xii cranial nerve (hypoglossal); this elevation is produced by the underlying inferior ___ nucleus which projects to the cerebellum
- olive
- the optic nerve consists of axons of retinal ganglion cells leaving one eye; at the chiasm or crossing, fibers from the nasal half of each retina cross to the opposite side of the brain; temporal fibers from each retina do not cross but continue ipsilate
- optic nerve/chiasm/tract
- primarily an "old" cortical area; located medial and ventral in the temporal lobe; the uncus is part of the ____; just slightly posterior to the uncus is the pyriform ("pear") cortex, a part of the ____ which represents primary olfact
- parahippocampal gyrus
- sulcus which runs primarily on the medial aspect of the hemisphere; a line from the sulcus to the pre-occipital notch is used as a landmark to delineate the occipital, parietal and temporal lobes
- parieto-occipital sulcus
- (usually torn off when the brain is removed from the skull post-mortem); hypophysis; part of the hypothalamus attached to the brain by the tuber cinereum and infundibulum
- pituitary
- on a gross level (seen superficially on the exterior surface of the brain), the ____ can be divided into the ____ proper anteriorly (rostrally) and the middle cerebellar peduncle posteriorly (caudally); the dividing mark between the ____ proper and the p
- pons
- a single layer of gray matter in the angle between the crura cerebri in the interpeduncular fossa; pierced by the central branches of the posterior cerebral arteries
- posterior perforated substance
- two large elevations visible on the ventral aspect of the brain and separated by the anterior (ventral) median fissure in the medulla; bundles of nerve fibers originate from cells in the cerebral cortex, principally in the precentral gyrus (area 4), and
- pyramids
- (see olfactory tracts/bulbs and parahippocampal gyrus)
- pyriform cortex
- a thin vertical partition consisting of two parallel laminae; lies primarily between the anterior horns of the two lateral ventricles
- septum pellucidum
- a small area lying ventral to the thalamus, medial to the internal capsule, and caudal to the hypothalamus
- subthalamic region
- "roof" of the midbrain; inferior and superior colliculi are major structures of the midbrain ____
- tectum
- (“covering structureâ€): the "floor" or ventral portion of the midbrain lying beneath the aqueduct of sylvius; contains major ascending and descending tracts; an important nucleus in this area would include the substantia nigra (involved in
- tegmentum
- ("anteroom"): structure made up of a large number of individual nuclei; some of the nuclei of the ____ are relay nuclei, or nuclei which relay information to the cortex (for example, the lateral geniculate nucleus receives input from the eyes a
- thalamus
- a single, midline ventricle; borders formed anteriorly by the lamina terminalis, laterally by the thalamus, and posteriorly by the superior end of the aqueduct and root of the pineal
- third ventricle
- a structure lying medially in the cerebellum; downward pressure on the brain produced by space occupying lesions can cause the ____ to herniate into the foramen magnum
- tonsil
- (parahippocampal gyrus)
- uncus
- medial part of the cerebellum; the tonsil lies nearest the midline and is continuous with the ____
- vermis