Lecture 8 Male Genital System (Testis and Scrotum) PDF

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 Copyright notice Material which is made available by way of an electronic database may be subject to certain licensing conditions. These conditions normally entail that you may only use the material for your own private study and research at the University and not for any other purpose. It is expected of you to adhere to these conditions at all times. Printed material is also only made available for class discussion, private study and research purposes. Further reproduction of such material is prohibited /Materiaal wat by wyse van elektroniese databasis aan u beskikbaar gestel is, mag onderhewig wees aan bepaalde lisensievoorwaardes. Sulke voorwaardes behels normaalweg dat u die materiaal slegs vir u eie private studie en navorsing aan die Universiteit kan gebruik en vir geen ander doeleindes hoegenaamd nie. Daar word van u verwag om te alle tye aan hierdie voorwaardes gehoor te gee. Gedrukte materiaal word eweneens slegs vir klasbespreking, private studie en navorsingsdoeleindes beskikbaar gestel. Die verdere reproduksie daarvan is ontoelaatbaar. 2  Outcomes Describe the structure, composition & location of testis and epididymis. Describe the blood & nerve supply of testis. Describe the structure and course of the vas deferens, seminal vesicles and ejaculatory ducts. Describe the macroscopic structure and position of the scrotum. Name the difference in lymphatic drainage of the testis and scrotum. Name the layers covering the spermatic cord and scrotum, and also name the layers of the anterior abdominal wall from which they developed. Name the contents of the spermatic cord. Name the position of the bulbo-urethral glands. 3 MALE REPRODUCTIVE SYSTEM 1 4 OVERVIEW 5  Male genital system Position & structure Testes Internal Relations genital Epididymis Parts organs Ductus deferens Blood supply Seminal glands Nerve supply Ejaculatory ducts Lymphatic drainage Prostate Bulbourethral glands External Scrotum genital Layers Spermatic Penis organs cord Contents 6  Male genitalia Male external genitalia (located in urogenital triangle): Scrotum Penis Male internal genitalia: Testes* Epididymis* Ductus (vas) deferens Seminal glands (vesicles) Ejaculatory ducts Prostate gland Bulbourethral glands * considered as internal genitalia because of embryology. 7 TESTES 8  Testes: Structure Male gonads. Produce sperm and hormones (testosterone). Located in the scrotum, suspended by the spermatic cords. Surface of testis covered by tunica vaginalis: double layer of peritoneum. Visceral layer closely applied to testis, epididymis, and inferior part of ductus deferens. Parietal layer extends onto distal part of spermatic cord. Cavity with fluid in between – allows movement of testis in scrotum. 9  Testes: Structure Tunica albuginea: Tough fibrous outer layer of testis. Forms mediastinum of testis: thickened ridge on internal, posterior aspect. From mediastinum, fibrous septa extend between seminiferous tubules of testis. Seminiferous tubules: Highly coiled tubes, where sperm are produced. Joined by straight tubules to the rete testis (in mediastinum) Retes testis connected to epididymis by efferent ductules. 10  Testis: Blood supply Testicular artery: Arises from abdominal aorta inferior to renal arteries. Pass retroperitoneal, cross over ureters and inferior parts of the external iliac arteries to reach deep inguinal ring. Enter inguinal canal through deep ring. Exit through superficial ring & enters spermatic cord. Anastomoses with artery of the ductus deferens. 11  Testis: Blood supply Venous drainage: Veins from testis and epididymis form pampiniform plexus in spermatic cord. 8-12 veins lying anterior to ductus deferens & surrounding testicular artery. Thermoregulatory function: keep testis at optimal temperature for spermatogenesis. Pampiniform plexus veins form the testicular veins: right testicular vein drains into inferior vena cava. left testicular vein drains into left renal vein. 12 Innervation of testis Autonomic nerves: Testicular plexus of nerves on the testicular artery. Contains sympathetic and visceral afferent fibers from T10(-T11); parasympathetic from Vagus nerve. Lymphatic drainage Right and left lumbar (caval/aortic) and pre- aortic lymph nodes. 13 Epididymis & vas (ductus) deferens 14  Epididymis Elongated structure on the posterior surface of testis. Efferent ductules transport sperm from rete testis to epidiymis. Composed of a tightly packed convoluted duct. Consists of: Head: superior expanded part. Composed of lobules from the coiled ends of 12-14 efferent ductules. Body: major part, convoluted duct. Tail: continues as the ductus deferens (duct that transports sperm to the ejaculatory duct). 15  Vas (ductus) deferens Structure: Thick-walled muscular tube, thin lumen. Course: originates from tail of epididymis at inferior pole of testis. Ascends posterior to testis, medial to epididymis. Travels through spermatic cord. Passes through anterior abdominal wall in the inguinal canal. Courses over external iliac vessels & enters pelvis. Passes on lateral wall pelvis, underneath parietal peritoneum. Crosses superior to ureter near posterolateral angle of bladder → joins duct of seminal vesicle to form ejaculatory duct. Ampulla: enlarged part before its termination. 16 SEMINAL VESICLES & EJACULATORY DUCTS 17  Seminal vesicles/glands Elongated structure, located between fundus of bladder and rectum. Orientated obliquely superior to the prostate gland Superior ends are posterior to ureters & covered by peritoneum. Superior ends are separated from rectum by rectovesical pouch. Inferior ends are closely related to rectum, separated by rectovesical septum. Produces alkaline fluid with fructose (nutrition) and coagulating substance. Duct of seminal vesicle joins ductus deferens Forms ejaculatory duct. 18  19 Posterior View  Ejaculatory ducts Arise from the union of ducts of seminal vesicle & ductus deferens: Near neck of bladder, pass through posterior part of prostate gland. Open into urethra on seminal colliculus, lateral to prostatic utricle (refer to prostate lecture). Ejaculatory duct 20 SCROTUM & SPERMATIC CORD 21 Scrotum Cutaneous fibromuscular sac containing testes and epididymi. 2 layers: skin & dartos fascia (continuous Scarpa’s fascia of anterior abdominal wall) which contains dartos muscle: Contracts to wrinkle skin (thermoregulation). Posteroinferior to penis and inferior to pubic symphysis. Divided into two compartments by the septum (derived from dartos fascia). Midline scrotal raphe is external marking of septum– continuous with penile raphe and perineal raphe. Line of fusion of labioscrotal swellings (see embryology lecture). Lymphatic drainage to superficial inguinal nodes. 22  Spermatic cord Begins at deep inguinal ring, passes through inguinal canal, exits via superficial inguinal ring ends scrotum at posterior border of testis. Contains structures running to or coming from testes, suspends testes in scrotum. 23 Spermatic cord Contents: Ductus deferens. Arteries (testicular, ductus deferens, cremasteric). Veins (pampiniform plexus, testicular, cremasteric). Nerves (sympathetic & parasympathetic, genital branch of genitofemoral, ilioinguinal). Lymphatic vessels. 24 LAYERS 25  Layers of the spermatic cord & scrotum 1 2 3 3 http://www.med.umich.edu/lrc/coursepages/m1/anat 1. omy2010/html/images/begin_testes_descent.gif https://encrypted- tbn2.gstatic.com/images?q=tbn:ANd9GcTQitbZWuixqV 2. hObhU2QutDQpBhzwMYunf1ztSFKAWXQa9Qz7Z https://media.springernature.com/original/springer 3. -static/image/art%3A10.1007%2Fs00247-016- 3706- 8/MediaObjects/247_2016_3706_Fig4_HTML.gif 26  Layers of the spermatic cord & scrotum 27 28 29 LYMPHATIC DRAINAGE 30 Lymphatic drainage of testis and scrotum Testis: lymphatic drainage into right & left lumbar and pre-aortic nodes (travel with testicular artery and vein). Scrotum: drain into superficial inguinal nodes. 31 BULBOURETHRAL GLANDS 32  Bulbourethral glands Posterolateral to urethra, embedded in the external urethral sphincter. Ducts pass through perineal membrane and open into spongy urethra at the bulb of the penis. Mucous secretion into urethra during sexual arousal. 33 THANK YOU FOR LISTENING 34