Neural Control of the Pituitary Gland.—I

Abstract

Most endocrine glands either lack a-nerve supply or receive only a scanty innervation.The adrenal cortex is believed to be devoid of any nerve supply (Teitelbaum, 1942), whilst the nerve fibres described in the ovary, testis, thyroid, and adenohypophysis (anterior pituitary gland) are probably vasomotor in function.There is no sound evidence that these glands are dependent for their functional activity on a direct secretomotor nerve supply: such dependency seems to be true for only two endocrine glands-the adrenal medulla and neuro- hypophysis (posterior pituitary gland).P V.N. 5.0N.o. T. m ,,.P/ .T.Diagram of a sagittal section through the hypothalamus and pituitary gland.The three parts of the neurohypophysis include the median eminence (M.E.), the constricted infundibular stem (I.S.), and the infundibular process (I.P.).The adenohypophysis also consists of three divisions-the pars distalis (P.D.), the pars intermedia (P.I.), and the pars tuberalis (P.T.).It is established that the neurohypophysis is innervated by the supraoptic nucleus (S.O.N.), situated above the beginning of the optic tract (O.T.).and the paraventricular nucleus (P.V.N.), which is in intimate relationship with the third ventricle (III.V.).Other fibres con- stituting the tubero-hypophysial tract (T.H.) also run to the hypo- physis, but their origin is unknown.