Male Reproductive System 1 1. Male reproductive organs 2. Embryonic development 3. The testes and spermatogenesis 4. Intratesticular genital ducts 5. The epididymis SPLANCHNOLOGY Male reproductive system ° Male reproductive system, systema genitalia masculina: V a part of the human reproductive process ° Male reproductive organs, organa genitalia masculina: V internal genital organs: testicle, testis epididymis, epididymis ductus deferens, ductus (vas) deferens seminal vesicle, vesicula seminalis ejaculatory duct, ductus ejaculatorius prostate gland, prostata V external genital organs: penis, penis scrotum, scrotum bulbourethral glands, glandulae bulbourethrales Prof. Dr. Nikolai Lazarov 2 SPLANCHNOLOGY Embryonic development ° Embryonic origin – intermediate mesoderm: V genital (gonadal) ridge – 5th we. ° Embryogenesis of genital organs: V testicle, testis – induced by the SRY gene: the primitive sex cords – Sox-9 transcription factor testis (medullary) cords: o rete testis, tunica albuginea – mesenchyme o Sertoli cells Leydig cells (2 nd mo .) V other genital organs – induction of Hox genes: ductus mesonephricus (Wolffian duct) o ductuli efferentes testis – Wolffian body o ductus epididymidis o dictus deferens o vesicula seminalis ductus paramesonephricus (Mülleri) – 6th we. o regression – antimüllerian hormone o appendix testis, utriculus prostaticus Prof. Dr. Nikolai Lazarov 3 SPLANCHNOLOGY Descensus testis Prof. Dr. Nikolai Lazarov 4 SPLANCHNOLOGY Testicle, testis ° Testicle, testis (Gr. orchis, didymis): V a pair of oval-shaped organs V two basic functions: production of sperm (spermatogenesis) secretion of androgens (male sex hormones) ° Testis in situ: V within an extension of the abdomen, scrotum V size: 40-45 mm in length 25-35 mm in height 20-30 mm in breadth V weigth – 10-14 g V external appearance: extremitas superior et extremitas inferior facies lateralis et facies medialis margo anterior et margo posterior epididymis Prof. Dr. Nikolai Lazarov 5 SPLANCHNOLOGY Macroscopic anatomy ° tunica vaginalis testis: V lamina parietalis V lamina visceralis ° tunica albuginea: V mediastinum testis V septula testis V lobuli testis – 200-300 ° tunica vasculosa Prof. Dr. Nikolai Lazarov 6 SPLANCHNOLOGY Microscopic anatomy ° Testicular lobules, lobuli testis: V tubuli seminiferi contorti – 400-600 V tubuli seminiferi recti rete testis V ductuli efferentes testis – 12-20 V lobuli epididymis (coni vasculosi) V ductus epididymidis head, body and tail of epididymis Prof. Dr. Nikolai Lazarov 7 SPLANCHNOLOGY Microscopic anatomy ° Convoluted seminiferous tubules, tubuli seminiferi contorti: V seminiferous epithelium: cells of spermatogenic lineage supporting (Sertoli) cells – epitheliocyti sustentantes (Sertoli) V stratum myoideum – myoid cells V stratum fibrosum Enrico Sertoli (1842-1910) Prof. Dr. Nikolai Lazarov 8 SPLANCHNOLOGY Microscopic anatomy ° Spermatogenic lineage cells, cellulae spermatogenicae: V spermatogonia V primary spermatocytes V secondary spermatocytes (prespermatids) V spermatids – early and late V spermatozoa Prof. Dr. Nikolai Lazarov 9 SPLANCHNOLOGY Regulation of spermatogenesis ° Central regulation stimulatory influence: V hypothalamus – GRH (hypophysis) V adenohypophysis – FSH (seminiferous tubules ) LH ( Leydig cells) ° Local regulation – stimulatory and inhibitory: V Sertoli cells – ABP and inhibin V Leydig cells – testosterone ° Spermatogenesis regulating factors: V temperature ~35°C (cryptorchidism ) rich venous plexus, pampiniform plexus evaporation of sweat from scrotum contraction of cremaster muscles V malnutrition V alcoholism V action of certain toxic drugs V X-ray irradiation V disturbance in blood supply Prof. Dr. Nikolai Lazarov 10 SPLANCHNOLOGY Interstitial tissue of the testis ° Interstitial (Leydig) cells, endocrinocyti interstitiales (Leydig): V 12 % of the testicular volume V located in the interstitium testis: isolated or in small clusters fenestrated capillaries V crystals of Reinke V steroid-secreting cells – production of androgens (testosterone) V stimulation by the LH (ICSH) from adenohypophysis Franz von Leydig (1821-1908) Prof. Dr. Nikolai Lazarov 11 SPLANCHNOLOGY Intratesticular ducts ° Rete testis: V straight seminiferous tubules, tubuli seminiferi recti: simple cuboidal epithelium transport of sperm V ductuli efferentes testis: pseudostratified columnar epithelium – cell types: o ciliated columnar cells o cuboidal secretory cells stratum fibromusculare Prof. Dr. Nikolai Lazarov 12 SPLANCHNOLOGY Excurrent duct system ° Duct of the epididymis, ductus epididymidis: V ~6 m in length V forms the body and tail of the epididymis V structure of the wall: pseudostratified columnar epithelium: o epitheliocyti microvilosi – stereocilia o epitheliocyti basales o lymphocytes , halo cells tunica fibromuscularia o smooth muscle and elastic fibers tunica adventitia Prof. Dr. Nikolai Lazarov 13 SPLANCHNOLOGY Testicular vessels ° Blood supply : V a. testicularis tunica vascularis V a. ductus deferentis ° Venous drainage: V plexus pampiniformis v. testicularis Prof. Dr. Nikolai Lazarov 14 SPLANCHNOLOGY Lymphatic drainage ° lymph vessels in funiculus spermaticus ° along the testicular vessels ° lumbar lymph nodes, nodi lumbales Prof. Dr. Nikolai Lazarov 15 SPLANCHNOLOGY Innervation of the testis ° Plexus testicularis et plexus deferentialis: V sympathetic nerves V sensory nerves ІХ th -Хth thoracic spinal nerves Prof. Dr. Nikolai Lazarov 16 SPLANCHNOLOGY Thank you .... to be continued ... Prof. Dr. Nikolai Lazarov 17.