SISTEMA REPRODUTOR MASCULINO

Veterinary Histology UFF Department of Morphology - Biomedic Institute LaBEc - Laboratory of Cellular and Extracellular Biomorphology Veterinary Histology Atlas Versão em Português Introduction Male Reproductive System Functions • Produce and transport the male gamete • Produce the hormone responsible for the male sexual characteristics – testosterone • Secretion of fluids to compose the sperm (or semen) Testicles • Possess tunica albuginea (or capsule of irregular dense connective tissue) associated with the vascular layer of the testis called tunica vasculosa. • The capsule sends septa into the testicle subdividing it into testicular lobules, that are characterized by the seminiferous tubules. • The seminiferous tubules are lined by seminiferous epithelium where we find two cell lineages (seroli cells and spermatogenic cells). • A stroma of vascular loose connective tissue surrounds seminiferous tubules and presents Leydig cells. Tunica Albuginea • Irregular dense connective tissue • Surrounds the testicle externally • Subdivided into testicular lobules characterized by the seminiferous tubules • We find two cell lineages: Sertoli Cells • Pyramid-shaped with an elongated nucleus • Nourish, support and protect the spermatocytes lSpermatogenic Cells • Are organized in four to eight cell layers: I- Spermatogonia • Enter successive mitosis • Originate the prinary spermatocytes II- Primary Spermatocytes • Enter meiosis • Originate the secondary spermatocytes III- Secondary Spermatocytes • Complete the second meiotic division • Originate the spermatids IV- Spermatids • Originate the spermatozoa Spermatogenesis: Process of the formation of spermatozoa Spermiogenesis: Transformation of spermatids into spermatozoa Genital Ducts Tubuli recti • They are short and straight and lined by simple cuboidal epithelium Rete testis • Spaces in labyrinth lined by simple cuboidal epithelium >> Tubuli recti and Rete testis: Connect the seminiferous tubules to the epididymis Epididymis Efferent ductules • Lined by a ciliated and non-ciliated simple columnar epithelium associated with fibroelastic connective tissue and smooth muscle cells. • Drain the spermatozoa from the rete testis • Conduct them to the epididymis duct Epididymis duct • Lined by a stereociliated pseudostratified cylindrical epithelium associated with connective tissue with smooth muscle cells • Highly contorted • During the path through the epididymis, the maturation of the spermatozoa occurs, with the absorption of cytoplasmic residues from the spermiogenesis process. The spermatozoa are stored in the tail of the epididymis until ejaculation. Ductus Deferens • Highly muscular structure; lining mucosa formed by stereociliated pseudostratified cylindrical epithelium supported on fibroelastic lamina propria • Its thick muscular layer is formed by smooth muscle cells • An adventitia of fibroelastic loose connective tissue surrounds the muscular layer externally • Conducts the tail of the epididymis to the ejaculatory duct Accessory genital glands Seminal vesicles • The mucosa with folds is lined by a pseudostratified columnar epithelium that is supported on a fibroelastic lamina propria. • Present a layer of smooth muscle cells and a fibrous adventitia around • Produce a fluid rich in fructose Prostate • It has a capsule of dense irregular fibroelastic connective tissue with smooth muscle cells • The parenchyma is formed by various individual tubuloalveolar glands • The mucosa with folds of the glands is lined by a variable epithelium. It can be simple cuboidal or simple columnar epithelium. In some regions, it is pseudostratified columnar epithelium. • The mucosa is supoorted on a fibroelastic connective tissue that is highly vascularised and has smooth muscle cells • Produces a white and serous fluid Bulbourethrals • Located at the root of the penis • Possess capsule of dense irregular connective tissue that sends septa and subdivides the gland into lobules • The lumen is lined by a variable epithelium: it can be simple cuboidal or simple columnar • Produce lubricant mucus for the urethra Penis • Copulating and urine excreting organ. In domestic animals, they can be vascular (studs, carnivores) or fibroelastic (swines, bovines) • Surrounded by skin • Possesses a thick layer of irregular dense connective tissue (tunica albuginea) que encerra os três corpos cilíndricos de tecido erétil • Its terminal portion dilates, forming the glans penis • The vascularised spaces of erectile tissue are lined by endothelium and, between these spaces we find fibrous connective tissue and highly vascularised • Two corpora cavernosa are located dorsally • Corpus cavernosum (or spongiosum) of the urethra is located ventrally • Corpus cavernosum (or spongiosum) of the urethra is lined by a variable epithelium. It can be pseudostratified columnar or stratified columnar epithelium, and in some regions stratified squamous epithelium • We find the glands of Littré (mucous secretion) throughout the urethra. • The three corpora cavernosa are surrounded by a tunica albuginea of the penis. 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