Neural endocrine glands Hypothalamus and Pituitary Hypothalamus • Present in all vertebrates • Integrative site • Controls pituitary • Regulates behavior, sex drive, temperature, feed intake, release of other hormones Functions and Components • Anterior • Middle • Posterior – Bordered anteriorly by the optic chiasma, Bordered posteriorly by the mammary nuclei • Compartmentalized and sends axons to the pituitary gland • SCN • VMN Functions and Components • Uses individual pockets of nuclei to regulate the pituitary • Hypophysiotropic area • 1:1 relationship between hypothalamic and pituitary hormones • Cyclic and tonic releases Functions and Components • Direct regulation of pituitary– Axonoplasmic flow of oxytocin and vasopressin through axons • Indirect regulation of pituitary – Median Eminence to anterior pituitary through the circulatory system Functions and Components • Hypothalmal Hypophysial portal system – The vessels that connect the hypothalamic circulation with the pituitary circulation • All hypothalamic hormones are peptides • Best known are TRF, LH,GHIF, GHSF Releasing factors • Hypothalamic hormones are called releasing factors – Regulated by both internal and external stimuli as well as chronotropic effects – Examples Pituitary • Sits in the sella turcica • Must be directly connected to the hypothalamus to function correctly • Not really a master gland • Dual organ – Anterior/posterior • Essential to life?Pituitary • Adenohypophysis (anterior, glandular) – Pars Distalis • Largest, 80% – Pars intermedia • Small in adults, large in infants – Pars tuberalis • Wraps around P.I., contains portal system – produces 8 hormones Pituitary • Neurohypophysis (posterior, neural) – Pars Nervosa – Pars infidibulum • Stalk attaching the PP to thehypothalamus • Turns into the Median eminence -releases 2 hormones Pituitary • Nerve supply • Blood supply • Zonation • Start here Pituitary• Microanatomy – Pars distalis – 75% chromophils • Acidophils GH PRL • Basophils FSH,LH,TSH – 25% chromophobes – Cells change morphology – Not clear where ACTH,LPH, and MSH are formed Pituitary • Microanatomy – Pars Intermedia – Not present in all mammals – Contains – Type I - MSH – Type II cells-MSH, LPH, ACTH Pituitary • Microanatomy – Neurohypophysis • Modified neural tissue • Neurophysin • Pituicytes Quiz 2 • Compare the Anterior and posterior