histology final pt 2

16 Pages
Unlock Document

Western University
Anatomy and Cell Biology
Anatomy and Cell Biology 3309
Martin Sandig

AnatomyCell Biology 33099500 Martin SandigMALEREPRODUCTIVESYSTEM TESTISCapsule layers 1 tunica vaginalismesothelial cells 2 tunica albugineadense ct and smooth musclehelp to move sperm 3 tunica vasculosanetwork of blood vesselstunica albuginea forms mediastinum testis at the posterior poleregion of entrance and exitradial septa from the mediastinum form 250 lobules which contain the seminiferous tubulesSeminiferous tubuleseach testis contains about 800 highly convoluted seminiferous tubules 14 in each lobuleeach tubule is 30 to 100 cm long and about200 m in diameterthey are lined by germinal seminiferous epitheliumthey are surrounded by ct and contractile myoid cells boundary or peritubular tissueSeminiferous epitheliuma modified statified cuboidal epitheliumcells at the periphery of the tubule rest on a basement membrane there are 2 categories of cells Sertoli cellstall cells with irregular indistinct outlinesthey have a central pale nucleus and a prominent nucleolus which aids in identificationthey have abundant smooth ER andlysosomes Functions 1support and nutrition of the germ cells developing sperm 2bloodtestis barrier 3release of spermatozoa 4removal of residual sperm cytoplasm 5produce androgen binding protein ABP which maintains a sufficient concentration oftestosterone in the tubules for spermatogenesis to occur Spermatogenic cellslocated within the seminiferous epithelium amongst sertoli cells48 cells deep Spermatogenesis the entire sequence of events by which spermatogonia are transformed into spermatozoa 1Spermatogonia located adjacent to the basement membrane 2 typesType Afine chromatin 12 nucleoli against envelope division yields an A and a B typeType Bcoarser chromatin 1 central nucleolus successive division yields primary spermatocytes 2Primary Spermatocyteslarge spherical cells with coarse chromatin they are located in the middle zone of the epithelium primary spermatocytes undergo the first meiotic division 3Secondary Spermatocytesthey are smaller cells and are nearer the lumen their lifespan is of short duration so few are seen they undergo the second meiotic division 4Spermatids1AnatomyCell Biology 33099500 Martin Sandigthey are even smaller and are locatednext to the lumen they are spherical cells with round nuclei cell division is incomplete therefore they remain attached by intercellular bridges to form a syncytiumSpermiogenesisthe sequence of events by which spermatids are transformed into spermatozoa 1the nucleus becomes elongated then fusiform 2 an acrosome forms a headcap over the nucleus 3 centrioles pass to opposite poles of the cell and a flagellum forms 4 mitochondria regroup around the base of the flagellum 5 surplus cytoplasm is cast off as a residual bodySpermatozoa 1Head the nucleus is streamlined to enhance motion and condensed to reduce size the acrosome contains hyaluronidase which is released at the ovumit helps the sperm to pass through the corona radiata prior to fertilization 2Neckcontains two centrioles 3MidPiececontains an axoneme consisting of 92 microtubules in the corenine outer dense fibers are present 4Principal Piece mitochondria are absent but the microtubules continueouter dense fibers continue and a fibrous sheath appears 5End Piecethe microtubules continuethe outer dense fibers and the fibrous sheath are absentLeydig Cells interstitial cells they are large acidophilic cells that occur in clusters in spaces between the tubulesextensive smooth ER and a well developed Golgithey produce testosterone DUCT SYSTEMTubuli Recti they are formed by merging of the seminiferous tubulesthey are located at the apex of each lobuleSertoli cells but no spermatogenic cells are present within them Rete Testis it serves to combine the spermatozoa from different tubulesit comprises a network rete of anastomosing channels in the mediastinumit is lined with simple cuboidal or squamous epitheliumfew sperms are seen within it because they traverse the rete quickly Ductuli Efferentes comprise several spiral ducts which emerge on the surface of the testisthey are lined with a simple columnar epithelium with ciliatedsome glandular cells smooth muscle and ct underlies the epithelium Ductus Epididymis 2
More Less

Related notes for Anatomy and Cell Biology 3309

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.