HYPOTHALAMUS AND ITS HORMONES HORMONES OF THE PITUITARY Jana Jurcovicova
HYPOTHALAMUS Part of the limbic system where neural and humoral regulations integrate It extends between: - mammilary bodies (caudally) - optic chiasm (frontally) - optic tract (laterally) - thalamus (dorsally) In its medial part there are clusters of cell bodies of nerve cells producing peptidergic hormones regulating adenopituitary secretion
BASAL VIEW OF THE HYPOTHALAMUS
SCHEMATIC DRAWING OF HYPOTHALAMIC NUCLEI AC: anterior commissure PO: preoptic nucleus SC: suprachiasmatic nucleus OC: optic chiasma TC: tuber cinereum AP: anterior pituitary IN: infundibulum: posterior pituitary ME: median eminence AH: anterior hypothalamic nucleus SO: supraoptic nucleus TH: thalamus PV: paraventricular nucleus (not to be confused with periventricular nucleus, which is not shown) DM: dorsomedial nucleus VM: ventromedial nucleus AR: arcuate nucleus (associated with periventricular nucleus, which is not shown) LT: lateral nucleus PN: posterior nucleus MB: mamillary body
SCHEMATIC CROSS SECTION OF HYPOTHALAMUS suprachiasmatic Guyton and Hall, 2006 Ganong and Hall, 2006
CROSS-SECTION OF THE ROSTRO - MEDIAL PART OF THE BRAIN
CROSS- SECTION OF THE MIDDLE PART OF THE BRAIN
HISTOCHEMICAL STAINING OF HYPOTHALAMIC NUCLEI
HYPOTHALAMO-PITUITARY REGULATION
DEVELOPMENT AND STRUCTURE OF PITUITARY diencephalon Rathke s pouch of pharynx ectoderm neural tissue anterior posterior pars tuberalis pars intermedia pars distalis pars nervosa
HYPOTHALAMO PITUITARY CONNECTION PRL - ; + GH +; - ACTH + FSH + LH + TSH +
INNERVATION OF ANTERIOR AND POSTERIOR PITUITARY BY NEURONES OF PARAVENTRICULAR AND SUPRAOPTIC NUCLEI
HYPOTHALAMIC CONTROL OF POSTERIOR PITUITARY SECRETION Guyton and Hall, 2006
STRUCTURES OF ARGININE VASOPRESSIN AND OXYTOCIN
HYPOTHALAMO - PITUITARY SYSTEM Nc. paraventricularis ** Hypothalamic neurons secreting releasing, inhibiting hormones (nuclei:narc, mpoa NPE) Nc. supraopticus parvocellular magnocellular Primary capilary plexus Portal vein Secretory cells Chiasma opticum ACTH, GH, TSH, LH, FSH, Prolactin Neural lobe Adenopituitary Anterior lobe Oxytocin Vasopresin
HYPOTHALAMIC HORMONES SECRETED HORMONE abbr PRODUCED BY EFFECT Thyrotrophic-releasing hormone (Prolactin-releasing hormone) TRH, PRH Parvocellular neurosecretory neurons Stimulate thyroid-stimulating hormone (TSH) release from anterior pituitary (primarily) Stimulate prolactin release from anterior pituitary Dopamine (Prolactin-inhibiting hormone) DA or PIH Dopamine neurons of the arcuate nucleus Inhibit prolactin release from anterior pituitary Growth hormone-releasing hormone GHR H Neuroendocrine neurons of the Arcuate nucleus Stimulate Growth hormone (GH) release from anterior pituitary Somatostatin (growth hormone-inhibiting hormone) SS, GHI H, or SRIF Neuroendocrine cells of the Periventricular nucleus Inhibit Growth hormone (GH) release from anterior pituitary Inhibit thyroid-stimulating hormone (TSH) release from anterior pituitary Gonadotropin-releasing hormone GnR H or LHR H Neuroendocrine cells of the Preoptic area Stimulate follicle-stimulating hormone (FSH) release from anterior pituitary Stimulate luteinizing hormone (LH) release from anterior pituitary Corticotropin-releasing hormone CRH Parvocellular neurosecretory neurons Stimulate adrenocorticotropic hormone (ACTH) release from anterior pituitary Oxytocin Magnocellular neurosecretory cells Uterine contraction Lactation (letdown reflex) Vasopressin (antidiuretic hormone) ADH or AVP Magnocellular neurosecretory neurons Increase in the permeability to water of the cells of distal tubule and collecting duct in the kidney and thus allows water reabsorption and excretion of concentrated urine
LIST OF PITUITARY HORMONES
STRUCTURE OF PROOPIOMELANOCORTIN PC1 PROHORMONE CONVERTASE1 PC2 PROHORMONE CONVERTASE2
REGULATION OF HYPOTHALAMIC HORMONES BY SHORT LOOP AND ULTRASHORT LOOP FEEDBACK
FEEDBACK REGULATION OF ADENOPITUITARY HORMONES
THE ENDOCRINE HYPOTHALAMUS IS RESPONSIVE TO: Neural inputs transmitted information - arising in particular from higher CNS centers Blood-borne stimuli - including leptin, ghrelin, insulin, pituitary hormones, cytokines, plasma concentrations of glucose, osmolarity, steroids (gonadal steroids and corticosteroids) Light - daylength and photoperiod for synchronizing of circadian rhythms Stress - Invading microorganisms by increasing body temperature, resetting the body's thermostat upward.
NEURAL STIMULI OF THE HYPOTHALAMUS
NEURON synaptic buttons dendrites myelin oligodendroglia Ranvier cleft axon nucleus mitochondrion vesicles with mediator exocytosis synapse postsynaptci receptots
NEUROTRANSMITER SYSTEMS REGULATING HYPOTHALAMIC SECRETION v
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