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24 Cards in this Set
- Front
- Back
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Thalamus |
-major part of the diencephalon -important cell station that receives sensory tracts (except the olfactory pathway) mainly from contralateral side. |
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Lesions of thalamus |
-may result from thrombosis or hemorrhage of one of the arteries that supplies it -lead to contralateral impairment of all sensations such as touch, tactile localization and discrimination, and loss of appreciation of joint movements. |
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Subthalamus |
-has the cranial ends of the red nucleus & the substantia nigra -it is involved in the control of muscle activity through its connection to corpus striatum -important tracts such as parts of medial, spinal and trigeminal lemnisci are also found here |
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Lesions of the subthalamus |
results in sudden, forceful involuntary movements in a contralateral extremity -the movement may be jerky (choreiform) or violent (ballistic) |
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Epithalamus |
consists of habernular nucles and their connections, and the pineal gland |
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Habernular nucleus |
is a center for integration of olfactory, visceral, and somatic afferent pathways |
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Pineal gland (body) |
-two types of cells (pinealocytes & glial cells) -contains no nerve cells, but some sympathetic fibers and blood vessels -calcification within the gland occurs by age, called brain sand. |
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Functions of the Pineal gland |
-it is an endocrine gland that influences the activity of pituitary gland, islets of langherns of the pancreas, the parathyroid, the adrenals and the gonads |
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Pineal secretions are made by |
-pinealocytes and reach their targets via blood or CSF
-they inhibit hormone production directly or by inhibiting the release factors of hypthalamus |
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When is the pineal gland mostly active? |
Most active during darkness and the probable pathway runs from retina to the suprachiasmatic nucleus of the hypothalamus to the pineal gland to stimulate its secretions |
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Tumors of pineal gland |
cause changes in regulation of the reproductive function |
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Hypothalamus functions |
-controls emotional states, and assists in the regulation of fat, carbohydrates and water metabolism. -it influences body temperature, genital functions, sleep and food intake -it also controls pituitary hormone release |
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Syndromes of the hypothalamus |
-tumors such as craniopharyngioma or chromophobe adenoma of the pituitary & pineal tumors interfere with the function of the hypothalamus |
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Common abnormalities of syndromes of the hypothalamus |
genital hypoplasia or atrophy, diabetes insipidus, obesity, disturbances of sleep, irregular pyrexia and emaciation |
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Patients with lesions involving insula have difficulty |
in pronouncing phonemes in their proper order and usually produce sounds that are close to the target word but are not exactly correct. |
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Function of corpus striatum |
is involved in muscular movement, by controlling the cerebral cortex |
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Tumors of the caudate or lentiform nuclei may cause |
severe motor or sensory symptoms on the opposite side of the body, due to involving the internal capsule |
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Nerve fibers from white matter of the cerebral hemispheres are classified into 3 groups: |
1. commissural fibers 2. association fibers 3. projection fibers |
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Commissural fibers |
-these fibers basically connect corresponding regions of the two hemispheres -corpus callosum -the ant. commissure -te post. commissure -the fornix -the habenular commissure |
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Association fibers |
these fibers essentially connect various cortical regions within the same hemispheres and is divided into short and long groups -Uncinate fasciculus -Cingulum |
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Uncinate fasciculus |
connecting the motor speech with the temporal lobe |
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Cingulum |
in the cingulate gyrus, connects the frontal and parietal lobes with parahippocampal gyrus |
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Projection fibers |
afferent and efferent fibers passing to and from the brainstem to the entire cerebral cortex -Internal capsule is an example |
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Alzheimer's disease |
-some forms of familial alzheimer's might be due to mutations in several genes such as APP, Presenilin 1 and Presenilin 2 -degeneration of the cholinergic fibers -loss of ascending projection fibers -senile plaques |
