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Microscopy of the hypothalamus, the hypothalamo-hypophyseal system Viktória Vereczki M.D., PhD. Department of Anatomy, Histology and Embryology Semmelweis.

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Presentation on theme: "Microscopy of the hypothalamus, the hypothalamo-hypophyseal system Viktória Vereczki M.D., PhD. Department of Anatomy, Histology and Embryology Semmelweis."— Presentation transcript:

1 Microscopy of the hypothalamus, the hypothalamo-hypophyseal system Viktória Vereczki M.D., PhD. Department of Anatomy, Histology and Embryology Semmelweis University :00 a.m

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6 The structure of hypothalamus

7 Preoptic area lateral preoptic nucleus medial preoptic nucleus: tr. hypothalamo- hypophysealis LHRH Lateral zone: Cardiovascular functions, regulation of food and water intake lateralis hypothalamic nucleus tuberal nuclei medial forebrain bundle

8 Preoptic area

9 Medial zone 1. regio anterior ( supraoptic region) supraoptic n.: supraopticohypophyseal tract (VAS, OXI) paraventricular n.: paraventriculohypophysealis tract (VAS, OXI) anterior n. suprachiasmatic n.: retinohypothalamic tract (VIP) 2. medial region ( tuberal region) ventromedial n. :satiety center dorsomedial n.: behavioral center arcuate n.: tr. hypothalamo-hypophysealis (relasing hormons) 3. posterior region (mamillary region) mamillary bodies dorsal hypothalamic nucleus

10 Medial Zone 1.

11 Medial zone 1. regio anterior ( supraoptic region) supraoptic n.: supraopticohypophyseal tract (VAS, OXI) paraventricular n.:paraventriculohypophysealis tract(VAS, OXI) anterior n. suprachiasmatic n.: retinohypothalamic tract (VIP) 2. medial region ( tuberal region) ventromedial n. :satiety center dorsomedial n.: behavioral center arcuate n.: hypothalamo-hypophyseal tract (releasing hormons) 3. posterior region (mamillary region) mamillary bodies dorsal hypothalamic nucleus

12 Medial Zone 2. regio anterior regio posterior regio medialis

13 Afferent connections: 1. Fornix hippocampus-subicumum mamillary bodies 2. Medial forebrain bundle septum pellucidum zona lateralis hypothalami tegmentum mesencephali 3. Stria terminalis corpus amygdaloideum zona preoptica, medialis hypothalamus 4. Others: reticular formation (Ser, NA) nucleus of solitary tract parabrachial nucleus dorsomedial nucleus of thalamus retina prefrontal cortex

14 Afferent connetions of hypothalamus

15 Efferent connections: A. Reciprocal paths to the limbic system B. Descending polysynaptic paths to lower autonomic and motor center C. Nervous and vascular links with the hypophysis: Hypothalamo- hypophyseal system

16 Efferent connections: 1. Fornix hippocampus-subicumum mamillary bodies 2. Medial forebrain bundle septum pellucidum zona lateralis hypothalami mesencephalic tementum 3. Stria terminalis corpus amygdaloideum zona preoptica, medialis hypothalamus 4. Mamillothalamic (Vicq d’Azyr) tract, part of the PAPEZ –ring mamillary bodies anterior thalamic nucleus 5. Hypothalamospinal tract paraventricular n. n. dorsalis nervi vagi és dorsomedial n. n. tr. solitarius 6. Dorsal longitudinal fascicle (Schütz-bundle) medial zone of hypothalamus substantia grisea centralis of mesencephalon 7. Mamillotegmental tract: mamillary bodies reticular formation of mesencephalic tementum

17 Efferent connetions of hypothalamus

18 Regulation of endocrine organs Közp. idegr. Releasing hormon (pl. CRF) Adenohypophysis sejt (pl. corticotrop) Glandotrop hormon (pl. ACTH) •Neurosecretion: secreration of neruon gets to the bloodstream NEUROENDOCRINOLOGY „The hypothalamus is the „head ganglion” of the autonomic nervous system (Sherrington1947) •Portal circulation of hypophysys: hypothalamic factors reach directly the adenohypophysist •Glandotrop hormons through systematic circulation reach endocrin glands •Negative feedback: hormons of targeted organ inhibit the adenohypophysis

19 Hypothalamo-hypophyseal system

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21 LPV: Long portal vessels Vessels of the hypophysis Arteries (from ICA) SHA: Superior hypophyseal artery IHA: Inferior hypophyseal artery SPV: short portal vessels Portal vessels Carrying hormone releasing factors Lateral hypophyseal vein Drains to cavernous sinus

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23 1.Parvocellular tuberoinfundibular tract Tuberal nuclei: Arcuate nucleus (DA) Periventricular zone Paraventricular nucleus parvocellular part Supraopticus parvocellular part hypothalamic hormone Effect CRH POMC: ACTH+ β-LPH+ TRH TSH+ LHRH (GnRH) FSH+, LH+ GHRH GH+ DA PL- Somatostatin GH-, TH- Paraventricular nucleus Tuberal nuclei

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25 2. Magnocellular hypothalmo- neurohypophyseal system Paraventricular nucleus magnocellular part Supraoptic nucleus magnocellular part hormones effect Antidiuretic or resorption of water vasopressin Oxytocin 1. ejection of milk 2. uterine contraction Herring –bodies store them (neurophysisn 1 and 2) in the neurohypophysis N.paraventricularis N.supraopticus

26 Eminentia mediana EZ TRH IZ EZ AVP AVP= Arginin- Vasopressin TRH= thyreotropin releasing hormon (Dr. Kántor O.)

27 Neurohypophysis: Terminations of Supraotico- paraventriculohypo- physeal tract Herring –bodies store OXI and Vas (neurophysisn 1 and 2) in the neurohypophysis

28 Effects of oxytocin, vasopressin Oxytocin: ♀: uterus: contraction during delivery breast: contraction of myoepithel cells → ejection of milk ♂: role in ejaculation? Vasopressin (antidiuretic hormon, ADH): kidney: distal convoluted tubules and collecting ducts Aquaporin-2 (water channel) → reauptake of water, concentration of urine. Destruction of the magnocellular hypothalamo-hypophysial tract: diabetes insipidus vessels: vasoconstrictor → elevates blood pressure ↑ ♂: role in sexual attachment

29 Functions of hypothalamus 1. thermoregulation 2. food intake 3. water metabolism 4. behavior: emotions, sexual behavior, 5.control of circadian rhytms (SCH, tr retinohypothalamicus

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32 Functions of hypothalamus 1. thermoregulation 2. food intake 3. water metabolism 4. behavior: emotions, sexual behavior, anger reactions 5.control of circadian rhytms (SCH, tr retinohypothalamicus

33 Functions of hypothalamus 1. thermoregulation 2. food intake 3. water metabolism 4. behaviour: emotions, sexual behavior, anger,etc. 5. control of circadian rhytms (SCH, tr retinohypothalamicus ICC of Orexin in narcoleptic patient compared to control

34 Medial zone Suprachiasmaticus nucleus (VIP) : retinohypothalamic tract of rat (Scale: 100 µm. OX= optic chiasm;SCH=suprachiasmatic nucleus) 5. control of circadian rhytms: retinohypothalamic tract

35 Clinical disorders associated with hypothalamic lesions -Obesity and wasting -bulimia or anorexia

36 - Sexual disorders : In childood: pubertas precox, sexual retardation After puberty: impotence or amenoohea 4,5 years old boy suffering in pubertas precox

37 -Hyperthermia and hypothermia -Diabetes insipidus

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39 Literature Williams PL, Marwick R, Dyson M, Bannister LH. Gray’s Anatomy 37th ed. (Churchill Livingstone, 1989) Antony L. Mescher: Junqueira’s Basic Histology 12th ed.( Mc Gaw Hil, 2010) Netter’s concise Neuroanatomy Richard S. Snell: Clinical Neuroanatomy for medical students 3rd ed.(Little, Brown and Co. 1992)


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