. Analysis of development. Embryology; Embryology. Ontogeny of Endocrine Correlation 587 tions in sex development, this has not been substantiated for the mouse (Howard-Miller, '27, '39; Howard, '46). According to Gersh and Grollman ('39a,b), the function of the x-zone and the more peripheral fascicular and glomerular zones is identical; both respond to stimulation but not equally, the x-zone being less responsive. Furthermore, the wide- meshed capillary plexus of the x-zone is altered by excessive activity so as to resemble more closely the capillaries of the fasciculate zone (Gersh and Groll
. Analysis of development. Embryology; Embryology. Ontogeny of Endocrine Correlation 587 tions in sex development, this has not been substantiated for the mouse (Howard-Miller, '27, '39; Howard, '46). According to Gersh and Grollman ('39a,b), the function of the x-zone and the more peripheral fascicular and glomerular zones is identical; both respond to stimulation but not equally, the x-zone being less responsive. Furthermore, the wide- meshed capillary plexus of the x-zone is altered by excessive activity so as to resemble more closely the capillaries of the fasciculate zone (Gersh and Grollman, '41). (For a thor- ough analysis of the relation of the adrenal cortex to the reproductive system in fetal and young postnatal rats, see Moore, '53.) The changes in vascular pattern of the growing cortex offer a possible index of the onset of functional activity (see Figs. 209^, B, and C). During the early stages of adrenal growth in the embryo the arrangement of the cortical cells is haphazard, at which time the capillaries of the cortex are in the form of a loosely woven and irregular plexus. Vt later stages with the growth of the cortex, portion of the cortical cells becomes ar- ranged into parallel cords or columns of the fascicular zone, the commonly supposed secretory zone of the adrenal of juvenile and adidt mammals. With this change in cellular arrangement the earlier unoriented type of capillary circvdation is gradually recon- structed into a more or less longitudinally oriented pattern of vessels, , in rather sim- ple lines the plan of the adult circulation (Flint, '00; Whitehead, '33). The significance of the changes in vascular pattern may be interpreted in terms of function (Gersh and Grollman, '41). The change is from a type which permits a slow rate of blood flow to one which favors a much more efficient flow of blood, thus assuring a richer supply of blood to the cortex. The fact that the more efficient mode of blood transportation arises as the cortica
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Keywords: ., bookcentury1900, bookpublisherphiladelphi, booksubjectembryology
