Bạch huyết chảy từ các xoang tủy vào các mạch bạch huyết ly tâm đó xuất cảnh tại hilum của nút. Máu cung cấp. Động mạch nhỏ vào hilum để cung cấp một đám rối mao mạch trong vỏ bên ngoài. Anastomose mao mạch để tạo thành HEVs trong paracortex và tĩnh mạch nhỏ xuất cảnh tại hilum. | 18. Male Reproductive System 185 Numerous lateral processes surround and invest the maturing germ cells. The most basal of these processes forms a series of tight junctions with similar processes of adjacent Sertoli cells. Blood-testis barrier is formed by occluding junctions that unite the basal processes of adjacent Sertoli cells forming a Basal compartment with access to blood-borne materials and which contains spermatogonia and earliest primary spermatocytes Adluminal compartment - Provides a unique microenvironment for developing germ cells that protects these cells from immunologic attack and concentrates hormones needed for sperm production - Contains later primary spermatocytes secondary spermatocytes and spermatids Functions Mediate exchange of nutrients to germ cells Form blood-testis barrier to protect developing germ cells from immunologic attack Break down excess spermatid cytoplasm Produce testicular fluid Secrete androgen-binding protein that binds to and concentrates testosterone in the seminiferous epithelium Produce inhibin which inhibits the secretion of follicle stimulating hormone FSH from the adenohypophysis Orchestrate movement of germ cells through germinal epithelium and facilitate cytodifferentiation and subsequent release of spermatozoa into the lumen of the seminiferous tubule Germ cells spermatogenic cells Form a stratified germinal seminiferous epithelium Cell types Spermatogonia - Are diploid cells resting on the basement membrane - Are of two varieties. Type A spermatogonia divide mitoti-cally to perpetuate self and to form type B cells. Type B spermatogonia divide mitotically to form primary spermatocytes. 186 Digital Histology - Undergo incomplete cytokinesis so resulting cells remain attached to each other during spermatogenesis - Divide mitotically to produce primary spermatocytes Primary spermatocytes - Are the largest germ cells each nucleus is times larger than that of a spermatogonium. - Form in the basal compartment then
