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2010-05-24 01:54:17
neuroscience hypothalamus neuroanatomy HUBIO Felicia Lucas project neuro

Hypothalamus (HUBIO 532)
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  1. What is the function of the hypothalamus?
    • Homeostasis via
    • Endocrine regulation (e.g. pituitary)
    • ANS regulation & (e.g. temperature, digestion, CSF condition)
    • Limbic system regulation (e.g. drive-related behavior, sex behavior)

    • Hypothalamus is just a small collection of neurons organized into dozens of nuclei and subnuclei in ventral diencephalon
    • involved in all unconscious and involuntary aspects of everyday survival of the individual
  2. What are the parts of the hypothalamus?
    • mammillary bodies (2) ("dangle" in interpeduncal fossa)
    • infundibulum
    • tuber cinereum (floor) (central part surrounding infundibulum = median eminence)
    • (all of these parts are exposed to CSF within the subarachnoid space of the 3rd ventricle --> sense CSF condition)

    • preoptic region (anterolateral to supraoptic regions)
    • anterior (supraoptic) regions
    • middle (tuberal) regions
    • posterior (mammillary) regions

    lateral region: medial forebrain bundle
  3. What does the hypothalamus look like?
    • ventral diencephalon (i.e. between mesencephalon and telencephalon)
    • inferior to anterior commissure (anterior portion of hypothalamus)
    • surrounds anterior/inferior portion of 3rd ventricle (abuts thalamus, which covers posterior/superior portion of 3rd ventricle)
    • 3 bumps inferior to hypothalamus: 2 posteriorly: mammillary bodies, 1 at midline: infundibulum
    • diamond shaped (ventral view)
  4. Where is the hypothalamus?
    • ventral diencephalon
    • inferior to anterior commissure (anterior portion of hypothalamus)
    • surrounds anterior/inferior portion of 3rd ventricle (abuts thalamus, which covers posterior/superior portion of 3rd ventricle)
    • posterior to optic chiasm and tracts
    • anterior to cerebral peduncles (midbrain)
    • close to middle cerebral artery
    • medial to amygdala
    • basal forebrain is fluid with antero-lateral border of hypothalamus
  5. What is considered "unique" about the hypothalamus as compared to other brain structures?
    • The hypothalamus has inputs and outputs with both neural and non-neural (e.g. humoral; physical stimuli) sources
    • inputs: neural and non-neural (e.g. humoral, physical stimuli)
    • outputs: neural and non-neural (e.g. neuroendocrine outputs)

    Cells of hypothalamus act directly as their own sensory organs for physical stimuli arising from the internal environment (visceral information) such as temp/hormone levels

    part of hypothalamus resides outside of blood brain barrier (i.e. circumventricular organ system)

    some hypothalamus axons synapse directly on blood vessels (i.e. neuroendocrine outputs)
  6. What part of the pituitary gland shares the same developmental origin as the hypothalamus?
    posterior lobe of the pituitary (i.e. the neurohypophysis)
  7. What are the borders of the hypothalamus?
    • -anterior border: plane through the anterior commissure and optic chiasm (approximately the same as the lamina terminalis)
    • -lateral border: anteriorly indistinct, blends with the basal forebrain. posteriorly distinct, the internal capsule (posterior limb)
    • -medial border: 3rd ventricle
    • -posterior border: plane drawn coronally through the posterior end of the mammillary bodies (separates the hypothalamus from the subthalamic nucleus and midbrain)
    • -inferior border:
    • -superior border: anteriorly, the anterior commissure and septal nuclei; posteriorly, the hypothalamic sulcus (which separates the hypothalamus and thalamus)
  8. What 2 structures are located at the posterior border of the hypothalamus?
    • subthalamic nucleus
    • midbrain
  9. What 2 structures does the hypothalamic sulcus separate?
    • hypothalamus
    • thalamus
  10. What anatomical relation does the hypothalamus have with the basal forebrain? What disease is particularly associated with the basal forebrain and why?
    • the hypothalamus' anterior portion of its lateral boundary is indistinct with the basal forebrain
    • the basal forebrain is associated with Alzheimer's disease because it has a nucleus that contains ACH-cells, which are degenerated in Alzheimer's
  11. What are the 7 zones/regions of the hypothalamus?
    • paraventricular zone
    • medial zone
    • lateral zone

    • preoptic
    • anterior/supraoptic zone
    • middle/tuberal zone
    • posterior/mammillary zone
  12. What structure traverses the lateral zones of the hypothalamus?
    medial forebrain bundle
  13. In which zone of the hypothalamus are most of the parvocellular cells located?

    A. paraventricular zone
    B. lateral zone
    C. medial zone
    A. paraventricular zone
    (this multiple choice question has been scrambled)
  14. In which hypothalamic zone(s) do most of the well-defined hypothalamic nuclei reside?

    A. lateral and posterior zones
    B. anterior/supraoptic zone
    C. middle/tuberal and preoptic zones
    D. medial and paraventricular zones
    D. medial and paraventricular zones
    (this multiple choice question has been scrambled)
  15. Which of the following hypothalamic regions functions as though it is hypothalamic but does not share the same origin as the rest?

    A. posterior/mammillary region
    B. middle/tuberal region
    C. anterior/supraoptic region
    D. preoptic region
    D. preoptic region
    (this multiple choice question has been scrambled)
  16. What contributes to the lateral region of the hypothalamus?
    medial forebrain bundle
  17. What contributes to the anterior/supraoptic region of the hypothalamus?
    • anterior hypothalamic nucleus
    • supraoptic nucleus
    • suprachiasmatic nucleus
    • paraventricular nucleus
  18. What contributes to the middle/tuberal region of the hypothalamus?
    • dorsomedial hypothalamic nucleus (DMH)
    • ventromedial hypothalamic nucleus (VMH)
    • infundibular nucleus (INF) (aka arcuate nucleus, ARC)
  19. What contributes to the posterior/mammillary region of the hypothalamus?
    • posterior hypothalamic nucleus (PMH)
    • mammillary bodies/nuclei (MAM)
  20. Which statement is false?

    a. to generate clinical concern generally there must be bilateral damage to hypothalamic nuclei, unilateral damage is not usually enough to cause symptoms
    b. because of the hypothalamus' small size, hypothalamic lesions usually damage many nuclei at once
    c. the suprachiasmatic nuclei (hypothalamus) rests on the optic chiasm and has retinal input
    d. the anterior hypothalamus senses heat loss and initiates heat conservation while the posterior hypothalamus senses heat increase and starts heat loss behavior
    • d. the anterior hypothalamus senses heat loss and initiates heat conservation while the posterior hypothalamus senses heat increase and
    • starts heat loss behavior

    • (the anterior hypothalamus senses heat increase and initiates heat loss behavior while the posterior hypothalamus senses heat loss and
    • starts heat conservation)
  21. True or false: the infundibular nuclei of the hypothalamus is the same as the arcuate nucleus
  22. What are the functions of the anterior/supraoptic hypothalamic nuclei?
    • preoptic nucleus: water intake, sleep, have parvocellular cells
    • suprachiasmatic: circadian rhythms, retina input (b/c on top of optic chiasm), sexual behavior (?)
    • supraoptic: oxytocin, ADH production
    • anterior hypothalamic: temperature (heat loss), sleep-waking, have parvocellular cells
    • paraventricular: oxytocin, ADH production, have parvocellular cells
  23. Which hypothalamic nuclei has connections to both the anterior and posterior pituitary thus regulating endocrine functions and also controls the ANS via "regular" neurons that send axons down to brainstem and spinal cord neuron targets?
    paraventricular nucleus (in anterior/supraoptic region of hypothalamus)
  24. What are parvocellular cells?
    • they are small cells within (hypothalamic) nuclei that control endocrine secretion of anterior pituitary cells by secreting releasing or inhibitory factors
    • e.g. growth hormone, LH, FSH, ACTH, TSH
  25. What are magnocellular cells?
    • magnocellular cells are large cells in (hypothalamic) nuclei that secrete ADH and oxytocin from posterior pituitary gland
    • found in supraoptic and paraventricular hypothalamic nuclei
  26. Which hypothalamic nuclei have magnocellular cells?
    • Supraoptic
    • Paraventricular
  27. What are the functions of the middle/tuberal hypothalamic nuclei?
    • dorsomedial hypothalamus: feeding, rage
    • ventromedial hypothalamus: feeding (satiety center), rage, has parvocellular cells
    • infundibular/arcuate: endocrine control (e.g. senses decreased sex hormones), has parvocellular cells
    • (tuberomammillary nucleus: sleep/waking)
  28. What would happen to a mouse's appetite if it had a bilateral lesion through its ventromedial hypothalamic nuclei?
    the mouse would never feel satiated; it would continually eat
  29. Where are the brain "centers" that contribute to the sensation of satiety and decrease appetite?
    • ventromedial hypothalamic nucleus (middle/tuberal region)
    • lateral hypothalamus
  30. What are the functions of the posterior/mammillary hypothalamic nuclei?
    • mammillary bodies/nuclei: memory
    • posterior hypothalamus: temperature (heat conservation), sleep-waking, have parvocellular cells
  31. What clinical presentation is associated with degenerated mammillary bodies?
    • Wernicke-Korsakoff syndrome (thiamine-deficiency-related)
    • memory loss
  32. Which hypothalamic nuclei have cells whose axons go down through the infundibular stalk and release neurohormones into bloodstream for circulation to distant targets (e.g. smooth muscle of uterus)?
    • paraventricular nuclei
    • supraoptic nuclei

  33. Label each circled hypothalamic nucleus. What region of the hypothalamus is this?
    • A = paraventricular nucleus
    • B = suprachiasmatic nucleus
    • C = supraoptic nucleus

    this is the anterior/supraoptic region of the hypothalamus

  34. Which area has magnocellular cells? Which area has retinal input and sets the Circcadian rhythms of the body?
    • A and C (i.e. paraventricular nucleus and supraoptic nucleus) have magnocellular cells
    • B (i.e. suprachiasmatic nucleus) has retinal iput and sets the Circcadian rhthms of the body
  35. Which hypothalamic nuclei have parvocellular cells (i.e. cells that control endocrine secretion of anterior pituitary hormones by secreting releasing or inhibiting factors)?
    • preoptic nucleus
    • paraventricular nucleus
    • anterior hypothalamic nucleus
    • venteromedial hypothalamic nucleus
    • infundibular/arcuate nucleus
    • posterior hypothalamic nucleus
  36. What happens if a person suffers a bilateral lesion through their suprachiasmatic nuclei?
    • sleep-waking cycles disrupted
    • Circadian rhythms disrupted
    • temperature regulation disrupted
  37. Which factor could possibly be dysfunctional in an obese person?

    A. ghrelin
    B. neuropeptide Y
    C. leptin
    D. orexin (hypocretin) A, B
    C. leptin
    (this multiple choice question has been scrambled)
  38. What are some orexigenic factors of the body and what do they do? What are some anorexigenic factors of the body and what do they do?
    • orexigenic factors: stimulate eating/appetite (e.g. ghrelin, orexin (hypocretin) A & B, neuropeptide Y (NPY))
    • anorexigenic factors: stimulate satiety/inhibit appetite (e.g. leptin, melanocortins, insulin, PYY)
  39. Which hypothalamic nuclei are thought to play a role in sexual behavior because of comparative size differences between homosexual and heterosexual men?
    • interstitial nuclei of anterior hypothalamic nuclei (INAH)
    • suprachiasmatic nucleus
  40. Which structures give input to the hypothalamus?

    a. retina
    b. rostral limbic stuctures
    c. brainstem
    d. non-neuronal inputs
    e. cerebral cortex
    f. all of the above
    f. all of the above
  41. Through which structures does the hypothalamus receive signals from the rostral limbic system?
    • fornix (hippocampus)
    • stria terminalis (amygdala)
    • medial forebrain bundle (MFB) (olfactory areas and limbic structures)
    • ventral amygdalofugal tract (VAF)
  42. Through which structures does the hypothalamus receive signals from the cerebral cortex?
    medial forebrain bundle (MFB)
  43. Through which structures does the hypothalamus receive signals from the retina?
    optic tract to suprachiasmatic nucleus
  44. What are the target areas of the descending tracts of the DLF from the hypothalamus?
    • midbrain central grey (pain modulation)
    • medullary autonomic centers (heart rate, blood pressure, respiration)
    • ventral tegmental area
    • brainstem parasympathetic nuclei (e.g. DMNX, salivatory nucleus --> eyes)
    • thoraco-lumber preganglionic sympathetic neurons
    • lumbo-sacral preganglionic parasympathetic neurons
  45. What are the outputs generated by the hypothalamus and where are they directed?
    • reciprocal to same places that send input (e.g. optic tract, DLF, etc.)
    • neurohormones: to pituitary
    • mammillothalamic tract: anterior nucleus of thalamus
    • connections to other thalamic nuclei
    • descending projections to brainstem and spinal cord: DLF (parasympathetic nuclei), IML (sympathetic nuclei)
  46. What are the inputs received by the hypothalamus and where do they originate?
    • MFB: olfactory areas and limbic structures
    • fornix: hippocampus
    • stria terminalis: amygdala
    • DLF: brainstem (e.g. solitary nucleus)
    • suprachiasmatic nucleus (hypothalamus): optic tract
    • non-neural inputs: blood osmolarity, temperature, hormone levels
  47. How does the hypothalamus receive signals from non-neural inputs?
    • temperature
    • osmolarity
    • hormones
  48. Through which structures does the hypothalamus receive signals from the brainstem?
    dorsal longitudinal fasciculus
  49. What input from the body does the brain need to maintain homeostasis? How does this information reach the hypothalamus?
    • visceral afferents
    • somatic afferents
    • gustatory afferents

    • taste and visceral info routed through solitary nucleus, rostral and caudal, and various brainstem nuclei on way to hypothalamus
    • dorsal longitudinal fasciculus
    • medial forebrain bundle
    • non-neural inputs
  50. Which brain structures does the hypothalamus have a give-and-receive relationship with?
    • brainstem
    • rostral limbic structures
    • (cerebral cortex via thalamus and limbic system)
  51. What structures receive outputs from the hypothalamus?
    • thalamus (--> cerebral cortex)
    • rostral limbic structures
    • brainstem
    • pituitary
  52. Through which pathways (e.g. parasympathetic) and structures does the hypothalamus affect homeostasis via ANS control
    • ANS=autonomic nervous system
    • parasympathetic fibers: preganglionic cells in brainstem and sacral cord; signals sent though brainstem (dorsal longitudinal fasciculus)
    • sympathetic fibers: preganglionic cells in thoracolumbar cord; signals sent through brainstem (hypothalamo-spinal tract)
  53. What is an example of a tract that connects the hypothalamus with the thalamus?
    mammillothalamic tract
  54. What is an example of a tract that connects the hypothalamus with the brainstem?
    • dorsal longitudinal fasciculus (DLF)
    • hypothalamo-spinal tract
  55. What is an example of a tract that connects the hypothalamus with the rostral limbic structures?
    • ventral amygdalofugal (VAF)
    • medial forebrain bundle (MFB)
    • fornix (hippocampus)
    • stria terminalis (amydgala)
  56. What are the parts of the pituitary gland and what is their dominant cell type?
    • pituitary gland = hypophysis = adenohypophysis + neurohypophysis = anterior lobe + posterior lobe
    • anterior lobe/adenohypophysis = endocrine cells
    • posterior lobe/neurohypophysis = (magnocellular cell) axon terminals of supraoptic and paraventricular nuclei
  57. Where is the pituitary gland located?
    sella turcica
  58. What is the embryologic origin of each of pituitary lobes?
    • anterior lobe/adenohypophysis origin: Rathke's pouch (ectoderm)
    • posterior lobe/neurohypophysis origin: dragged down hypothalamus
  59. What hormones does the anterior pituitary secrete? What structure controls their secretion?
    • GH
    • Prolactin

    • FSH
    • LH
    • ACTH
    • TSH

    the hypothalamus controls their secretion
  60. In what two ways does the hypothalamus control the pituitary gland?
    • hypothalamo-hypophyseal TRACT: axons of cells in the SO and PV nuclei transmit signals to blood vessels in the neurohypophysis
    • hypothalamo-hypophyseal PORTAL SYTEM: hypothalamic controlling factors are released onto a private venous portal system (at level of median eminance) that transmits signals to the adenohypophysis, where receptor cells are located
  61. What factors does the posterior pituitary release into the bloodstream? What are their target organs?
    • vasopressin (ADH): kidney tubules (conserve water)
    • oxytocin: smooth muscle of uterus (parturition), breast (lactation)
  62. What affect does alcohol have on ADH levels and what are the consequences of this change, if any?
    • alcohol inhibits release of ADH (antidiuretic hormone)
    • the change in blood osmolarity is sensed by the hypothalamus, which triggers the kidney tubules to increase urination
    • a person becomes flooded with uninhibited diurectic signals --> uninhibited increased urination
  63. What is the effects of diabetes insipidus on ADH levels and what are its associated symptoms?
    • diabets insipidus reflects a marked decrease in ADH levels
    • symptoms: increased thirst and drinking, increased urination of vast quantities of dilute urine
  64. Describe the hypothalamus-pituitary-axis pathway that controls ACTH release.
    • note negative feedback on two levels
    • (side note: adrenal cortex is backup to ANS activated in prolonged stress response)
  65. What are some parasympathetic innervated structures in the brainstem?
    • DMNX (dorsal motor nucleus of Vagus)
    • Edinger-Westphal nucleus
    • salivary nucleus
  66. Where are some sympathetic innervated structures of the ANS in the spinal cord?
    lateral horn in T1-L2
  67. Through which two tracts does the hypothalamus regulate the autonomic nervous system?
    • dorsal longitudinal fasciculus: (through brainstem) parasympathetic preganglionic cells in brainstem
    • hypothalamo-spinal tract: (through brainstem) sympathetic preganglionic cells in lateral horn of spinal cord (T1-L2)

    most of both tracts originate in the PV nucleus
  68. In the context of acting as the "head ganglion" of the ANS, what are the inputs and outputs of the hypothalamus?
    • inputs:
    • -viscera (afferents via CN X, IX to caudal solitary nucleus)
    • -somatic afferents
    • -limbic system

    • outputs:
    • -autonomic centers in brainstem
    • -parasympathetic cranial nerve motor nuclei
    • -sympathetic spinal cord motor nuclei

    Hypo controls ans for homeostasis and for emotional expression, therefore needs visceral inputs and external world inputs—and then sends outputs to ans—to parasympathetic neurons, to sympathetic neurons and to brainstem ANS coordinating centers
  69. What are the (preganglionic) parasympathetic nuclei in the brainstem and the (preganglionic) sympathetic nuclei in the spinal cord?
    • Edinger-Westphal nucleus
    • dorsal motor nerve of vagus (DMNX)
    • salivary nucleus

    • interomedial lateral (IML) column in lateral horn in thoracic cord (T1-L2)
    • lateral horn in sacral cord (giving rise to pelvic splanchnic nerves)
  70. Choose correct word: (Descending/Ascending) fibers drive autonomic reticular formation centers and brainstem autonomic nuclei.
    Descending fibers drive autonomic reticular formation centers and brainstem autonomic nuclei.
  71. What will damage to one side of the hypothalamus cause if the lesion is at the level where the ANS and PNS are lateralized?

    a. there will be no clinical presentation, must have bilateral damage to hypothalamus to cause noticeable effects
    b. unilateral, contralateral loss of ANS function
    c. bilateral loss of ANS function
    d. unilateral, ipsilateral loss of ANS function
  72. True or False: On their way to the spianl cord from the hypothalamus, only branches from the dorsal longitudinal fasciculus terminate on nuclei in the brainstem (e.g. DMNX).
    • False
    • Some branches of the descending hypothalamo-spinal tract terminate on nuclei in the brainstem as well as branches from the DLF.
  73. Choose correct word: (Descending/Ascending) fibers drive sympathetic motor nuclei in interomedial lateral (IML) horn/column.
    Descending fibers drive sympathetic motor nuclei in interomedial lateral (IML) horn/column.
  74. What are the symptoms of Horner's Syndrome? Why would a hemisection of the spinal cord at the thoracic level be a possible cause of Horner's Syndrome?
    • Horner's Syndrome: ("Horny PAMELa"): Ptosis, Anhydrosis, Miosis (pupil constriction), Excess mucous, Loss of ciliospinal reflex (also vasodilation)
    • A hemisection of the spinal cord at the thoracic level would be a possible cause of Horner's syndrome because the sympathetic fibers from the hypothalamus (hypothalamo-spinal tract) travel through the lateral funiculus of the spinal cord and synapse on the interomedial lateral horn (IML) and a hemisection through the cord would cause signal blockage to sympathetic system targets

    Trick with horner’s is to remember that the block can be along the length of the pathway: centrally from hypothalamus through brainstem to cord, or peripherally from cord to chain, to superior cervical ganglion to carotid plexus to target in head.
  75. Which of the following is regulated in some way by the hypothalamus?

    a. temperature and metabolism
    b. temperature and blood osmolarity
    c. pituitary gland and ANS
    d. emotional and drive-related behavior
    e. all of the above
    e. all of the above´╗┐
  76. What 2 major cerebral arteries are in close proximity to the hypothalamus?
    • anterior cerebral artery
    • middle cerebral artery