Posted by Bennie (220.127.116.11) on January 29, 2000 at 10:15:45:
In Reply to: Not a whiz... posted by Paco on January 29, 2000 at 06:47:43:
Thanks for the tip, Paco. As you can see the article appears but not the picture I wanted to put with it.
I just can't quit. I'm too stubborn.
Nobody needs to read the stuff below. It was just posted for practice.
A structure in the brain which has been called the "guardian" of the body and "head ganglion of the autonomic nervous system" is the hypothalamus. As implied in the name, the hypothalamus is a part of the brain, specifically the diencephalon, that lies beneath the thalamus. Studies indicate the hypothalamus has a vast array of multifaceted functions which cover two main areas: the maintenance of homeostasis and the control of behavior patterns. The hypothalamus regulates homeostasis through integration of the functions of the autonomic nervous system. The hypothalamus regulates homeostasis through integration of the functions of the autonomic nervous system. The anterior portion of the hypothalamus activates the parasympathetic system and inhibits the sympathetic system. The posterior portion, on the other hand, activates the sympathetic system. Additionally there is evidence that the control exerted by the hypothalamus is mediated by the endocrine system.
Generally the hypothalamus receives its major input from the non- specific reticular activating system as well as the olfactory system and the hippocampus in the brain. There are also less well defined pathways connecting the hypothalamus with the limbic system, the frontal cortex, the thalamus, and the periaqueductal gray matter. The hypothalamus, in turn, sends projections to most of these areas. Furthermore fiber tracts pass from the hypothalamic nuclei into the posterior lobe of the pituitary gland (hypophysis). There is likewise a direct vascular link, called hypophysial portal vessel system, between the hypothalamus and the anterior pituitary.
The reticular formation consists of interconnected regions in the tegmentum of the brain stem; the lateral hypothalamic area; and the medial, intralaminar, and reticular nuclei of the thalamus. The term is derived from its characteristic appearance of varied sizes and shapes of cells embedded in a dense network of cell processes including dendrites and axons. The reticular formation performs a non-specific, generalized function of regulating arousal and level of consciousness. The neurons of the activating portion of the reticular formation are stimulated by a wide variety of sensory stimuli received from the somatosensory, auditory, visual, and visceral sensory systems.
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