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40 Cards in this Set
- Front
- Back
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Hypothalamus: functions?
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Maintains heomeostasis via control of the endocrine and ANS
Major component of the limbic system |
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Hypothalamus: location?
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Walls and floor of inferior third vent
Roof of interpeduncular cistern Anterior border = lamina terminalis Most posterior regions blend into the mesencephalon |
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List the 4 rostral to caudal regions of the hypothalamus and their corresponding landmarks.
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Preoptic - anterior to optic chiasm
Supraoptic - level of optic chiasm Tuberal region - level of tuber cinereum Mammillary region - level of mammillary bodies |
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Medial preoptic area: function?
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Release of gonadotropic hormones FSH and LH from the anterior pituitary via GnRH
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Describe the timing of release of gonadotropic hormones in males and females.
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Females - cyclical for menstrual cycle
Males - continual |
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Medial preoptic area: aka? why?
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Sexually dimorphic nucleus
Larger in males |
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Lateral preoptic area: function? MOA?
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Specifically the VLPO = sleep promoting region. Uses GABA to inhibit wake-promoting neurons in the posterior hypothalamus and brainstem.
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Supraoptic region: list the 4 nuclei.
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Supraoptic
Paraventricular Anterior Suprachiasmatic |
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How are the supraoptic region nuclei stained and what does this result in?
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Supraoptic and paraventricular nuclei are the largest cells, and can be identified when stained. Termed magnocellular hypothalamic nuclei.
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Supraoptic nucleus: function?
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Produces ADH
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ADH: pathway?
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Conjugated to neurophysin and transported along the supraoptichypophyseal tract to posterior pituitary where it is stored in Herring bodies. When released into the systemic circulation, ADH binds to receptors in the distal tubules and collecting ducts of the kidneys and promotes the reabsorption of free water into the circulation.
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What regulates production and release of ADH?
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Plasma osmolarity detected by osmoreceptors in the hypothalamus
Blood pressure |
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What diseases result from too much and too little ADH?
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Diabetes insipidus (too little)
SIADH (too much) |
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Paraventricular nucleus: function? general pathways?
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Produces oxytocin, CRH, and TRH
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Oxytocin: pathway and function?
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Transported via the paraventriculohypophyseal tract and released from the posterior pituitary. Enhances uterine smooth muscle contraction and contraction of mammillary myoepithelial cells.
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CRH: pathway and function?
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Released by the paraventricular nucleus into the hypothalamic-hypophyseal portal system and then stimulates the anterior lobe of the pituitary to produce and release ACTH, which subsequently induces steroid biosynthesis in the adrenal glands.
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TRH: pathway and function?
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Released by the paraventricular nucleus into the hypothalamic-hypophyseal portal system and then stimulates the anterior lobe of the pituitary to produce and release TSH, which subsequently induces the thyroid gland to produce and release thyroid hormone.
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Anterior nucleus: function? destruction?
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Controls the parasympathetic nervous system
Heat dissipation Hyperthermia |
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Suprachiasmatic nucleus: function?
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'Biological clock' - receives direct input from retinal ganglion cells and establishes circadian rhythms
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Explain the nuclei in the tuberal region.
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Median zone: ventromedial, dorsomedial, and arcuate nuclei
Lateral zone: lateral hypothalamic area (LHA) and fiber tract pathway called medial forebrain bundle (MFB) |
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Dorsomedial nucleus: function?
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Numerous - autonomic, stress responses, eating behaviors, etc.
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Ventromedial nucleus: function?
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Satiety center - when activated, urge to eat is inhibited
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Arcuate nucleus: function?
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Produces GH releasing hormone
Appetite regulation Releases dopamine to anterior pituitary, which inhibits the synthesis and release of prolactin |
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LHA: function? What do stimulation and lesions result in?
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"feeding center"
Stimulation increases appetite and eating Bilateral lesions result in anorexia |
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Medial forebrain bundle: Contents?
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Includes fibers connecting the VTA to the nucleus accumbens and fibers from the olfactory cortex that are thought to influence appetite
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Nuclei in the mammillary region
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Mammillary nuclei
Posterior hypothalamic nuclei |
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Mammillary nuclei: function? contents?
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memory
Contain histaminergic neurons, involved in arousal |
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Posterior nuclei of mammillary region: function?
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Controls sympathetic nervous system
Heat conservation Maintaining the wake state via hypocretin/orexin neurons |
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Narcolepsy: define. Pathology?
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Chronic neurological disorder caused by disruption of normal sleep/wake cycle
Fewer H/O neurons in posterior hypothalamus and low levels of CSF H/O |
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What are CVOs?
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Specific loci around the margins of the third and fourth ventricles where the BBB is attenuated. Clusters of neurons detect hormones and relay this information to the hypothalamus.
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Name the CVOs.
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Pineal gland
Median eminence Subfornical organ Area postrema Vascular organ of the lamina terminalis |
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What are the feeding centers and satiety centers?
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LHA - feeding center
Ventromedial nucleus - satiety center |
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Define sleep.
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Physiological state of relative unconsciousness and inaction of voluntary muscles.
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What areas of the hypothalamus promote the sleep and wake states, generally?
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Anterior - sleep
Posterior - wake |
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What is the neurotransmitter of sleep promotion?
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GABA
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What are the neurotransmitters of wake promoting nuclei?
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Tuberomammillary nucleus - histamine
H/O neurons of posterior hypothalamus Locus coeruleus - NE Dorsal raphe - 5HT Pontine tegmentum nuclei - acetylcholine |
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What are the nuclei involved in heat dissipation and conservation?
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Anterior region - heat dissipation
Posterior region - heat conservation |
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What results from damage to both temperature regulating centers?
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Poikilothermia, a condition in which body temperature varies with the environment.
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How is fever produced?
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Immunological challenges lead to production of prostaglandins which stimulate the anterior hypothalamus to elevate the temperature set point.
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How does the hypothalamus relate to emotions?
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Every component of the limbic system directly or indirectly projects to and receives projections from the hypothalamus.
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