Term
| What are the functions of the hypothalamus? |
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Definition
Anterior hypothalamus:
Thermoregulation
Water balance
Circadian rhythms
Maternal behavior
Autonomic
Tuberal hypothalamus:
Sexual behavior
Feeding behavior
Aggressive behavior |
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Term
| What are the boundaries of the hypothalamus? |
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Definition
Superiorly: hypothalamic sulcus
Rostrally: lamina terminalis
Inferiorly: optic chiasm and pituitary stalk
Caudally: mamillary bodies
Laterally: internal capsule |
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Term
| What are the three divisions of the hypothalamus? |
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Definition
Anterior: supraoptic
Middle: tuberal
Posterior: mammillary |
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Term
| From where does the hypothalamus receive inputs? What part of the hypothalamus do these inputs reach? |
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Definition
Reticular formation
- via Medial Forebrain Bundle (MFB)
- inputs to lateral hypothalamus
Hippocampal formation
- via fornix directly or indirectly by anterior commissure
- inputs to medial hypothalamus
Amygdala
- via stria terminalis (centromedian nucleus of amygdala) and ventral amydalofugal pathway (central and basolateral nuclei)
Prefrontal cortex and Anterior cingulate gyrus
via centromedian amygdala nucleus
Septal area
projects to medial hypothalamus
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Term
| What is the function of the ascending and descending parts of the dorsal longitudinal fasciculus (DLF)? Where does it travel? |
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Definition
DLF travels in periaqueductal gray
Ascending:
- conveys taste from nucleus solitarius to paraventricular and posterior nuclei of hypothalamus
Descending:
- conveys information from paraventricular and supraoptic nucleus to areas for pain and autonomic functions |
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Term
| What regions of the hypothalamus have autonomic function? |
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Definition
Ventral medial - sympathetic
Anterior - parasympathetic |
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Term
| What are the two tracts that come from the mamillary fasciulus? what do they do? |
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Definition
Mamillo-tegmental and mamillo-thalamic
Function: nobody knows for sure. |
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Term
| What are the classes of hypothalamic peptides? |
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Definition
1) Neurohypophyseal peptides - oxytocin (paraventricular nucleus) and ADH (supraoptic)
2) Hypophysiotropic peptides - TRH, LRH, CRH, CHRH, somatostatin
3) Gut peptides - CCK, Substance P
4) Endorphins
5) Enkephalins
6) Other: angiotensin II, neuropeptide Y |
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Term
| What areas of the hypothalamus are involved in thermoregulation? What are their functions? |
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Definition
Preoptic area - has thermoreceptor
Anterior hypothalamus - heat loss (i.e. sweating)
Posterior hypothalamus - heat retention (i.e. vasoconstriction) |
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Term
| What are the circumventricular organs of the hypothalamus and what do they do? |
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Definition
Pineal gland - secretes melatonin
Median eminence - regulates anterior pituitary w/ neurohormones
Organum vasculosum of lamina terminalis (OVLT) - detects peptides, has osmoreceptors
Subfornical organ (SFO) - activated by angiotensin; regulates body fluids
Subcommisural organ - secretes somatostatin
Area postrema - vomiting center of the brain |
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Term
| Which nucleus is involved in sexual behaviors? |
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Definition
Ventromedian nucleus
- responsive to estradiol in females
- causes lordosis reflex (think "doggy style") |
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Term
| How is the hypothalamus involved in circadian rhythm? |
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Definition
Suprachiasmatic nucleus receives input from optic tract (retinohypothalamic fibers) and carry CLOCK PROTEINS. |
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Term
| What nuclei in the hypothalamus are involved in feeding behaviors? What hormones? |
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Definition
Arcuate and paraventricular nuclei
Hormones:
Neuropeptide Y (from arcuate nucleus) - Eat
CCK, Insulin (short-term) & Leptin (long-term) - Stop eating
Also, alpha melanocyte feeding hormone |
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Term
| What are some dysfunctions of the hypothalamus? |
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Definition
- Cystic lesions - Craniopharyngioma
- Tumors at base of brain
- Hyperthermia
- Hypothermia
- Genital dystrophy and abnormalities of development
- Obesity/emaciation
- Diabetes insipidus
- Hypertension
- Sleep disorders
- Aggression and rage
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Term
| Where does craniopharyngioma occur? |
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Definition
- Cystic lesions - Craniopharyngioma at Rathke's pouch
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Term
| Lesions to what region would cause hyperthemia? hypothermia |
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Definition
- Hyperthermia - anterior hypothalamus
- Hypothermia - posterior hypothalamus
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Term
| Lesions to what region of the hypothalamus would cause genital dystrophy and abnormalities of development? |
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Definition
- Genital dystrophy and abnormalities of development - tuberal region
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Term
| Lesions of what nucleus of the hypothalamus will cause obesity? emaciation? |
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Definition
- Obesity - ventromedial
- Emaciation - lateral respectively
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Term
| What lesions of the hypothalamus will cause diabetes insipidus? |
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Definition
- Diabetes insipidus - paraventricular and supraoptic nucleus (ADH production lost)
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Term
| What lesions of the hypothalamus will cause hypertension? |
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Definition
- Lesion to medial hypothalamus --> excess corticotrophic releasing factor and induce horner's syndrome
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Term
| What lesions of the hypothalamus will cause sleep disorder? |
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Definition
| Lesion to the posterior hypothalamus-midbrain border |
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Term
| A lesion to what part of the hypothalamus can induce rage and aggression behavior? |
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Definition
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Term
| The components of the limbic system must communicated with what? |
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Definition
| The hypothalamus or midbrain periaqueductal gray (PAG) |
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Term
| What structures are associated with the limbic system? |
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Definition
- Hippocampal formation
- Septal nuclei
- Amygdala
- Prefrontal cortex
- Anterior cingulate gyrus
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Term
| Between what does the fornix communicate? |
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Definition
| Fornix: from hippocampal formation --> mamillary body |
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Term
| Between what does the mamillothalamic tract communicate? |
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Definition
| From mamillary bodies and fornix to dorsal and ventral tegmental nuclei and anterior thalamic nucleus |
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Term
| Between what does the stria terminalis communicate? What processes is it involved in? |
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Definition
From amygdala to medial hypothalamus and autonomic parts of brainstem
Processes: endocrine, autonomic and affective |
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Term
| Between what does the ventral amygdalofugal pathway communicate? |
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Definition
| From basolateral amydala to lateral hypothalamus and PAG |
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Term
| Between what does the medial forebrain bundle (MFB) communicate? What processes is it involved in? |
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Definition
From basal olfactory region, periamygdaloid regon, and septal area
To lateral hypothalamus and tegmentum
Processes: mesolimbic system - relay information between ventral tegmentum and nucleus accubens (reward center) |
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Term
| What kind of sensory inputs go to the limbic system? |
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Definition
1) Objective
2) Emotional/affective |
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