sperm is made in the human body at the inner tubule wall of the testis.
sperm is made in the human body at the inner tubule wall of the testis.
where in the testis is sperm made in the human body?
inner tubule wall
under a tough membranous shell, the tunica albuginea, the testis of some teleost fish, contains very fine coiled tubes called seminiferous tubules. the tubules are lined with a layer of cells (germ cells) that from puberty into old age, develop into sperm cells (also known as spermatozoa or male gametes). the developing sperm travel through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly created sperm cells mature (see spermatogenesis). the sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions.
fish reproduction
sperm are immunogenic – that is they will cause an autoimmune reaction if transplanted from the testis into a different part of the body. this has been demonstrated in experiments using rats by lansteiner (1899) and metchinikoff (1900), mice and guinea pigs. the likely reason for their immunogenicity or rather antigenicity is that sperm first mature at puberty, after central tolerance has been established, therefore the body recognizes them as foreign and mounts an immune reaction against them. therefore, mechanisms for their protection must exist in this organ to prevent any autoimmune reaction. the blood–testis barrier is likely to contribute to the survival of sperm. however, it is believed in the field of testicular immunology that the blood–testis barrier cannot account for all immune suppression in the testis, due to (1) its incompleteness at a region called the rete testis and (2) the presence of immunogenic molecules outside the blood–testis barrier, on the surface of spermatogonia. the sertoli cells play a crucial role in the protection of sperm from the immune system. they create the sertoli cell barrier, which complements the blood-testis barrier. the protection is ensured by tight junctions, which appear between two neighboring sertoli cells. another mechanism which is likely to protect sperm is the suppression of immune responses in the testis.
immune privilege