Lecture 9 Male Genital System (Prostate and Penis) 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/objectives Describe the location, shape and structure of the prostate. Describe the superior, infero-lateral, anterior and the posterior relationships of the prostate. Describe the structures in the posterior surface of the prostatic urethra. Describe the blood supply, nerve supply and lymphatic drainage of the prostate. Describe the structure of the penis. Describe the blood supply, nerve supply and lymphatic drainage of the penis. Explain the mechanism of erection of the penis. MALE REPRODUCTIVE SYSTEM 2 4 PROSTATE GLAND 5 Prostate Gland: Location & Structure Located inferior to bladder, anterior to rectum. Surrounds prostatic urethra. 6 Prostate Gland: Structure & Relations Base – neck of urinary bladder. Apex – in contact with the superior fascia of urethral sphincter & deep perineal muscles. Muscular anterior surface – separated from pubic symphysis by retroperitoneal fat in retropubic space. Posterior surface – ampulla of rectum. Inferolaterior surfaces – related to levator ani muscles. 7  Prostate Gland: Location & Structure Structure: Fibrous capsule: contains prostatic plexuses of veins and nerves. Lobes (anatomically not clearly distinct ): Isthmus: anterior to urethra (fibromuscular). Right and left (glandular): separated anteriorly by isthmus, posteriorly by longitudinal furrow. Zones: peripheral, central zones, transitional zones: transitional is site of benign prostatic hypertrophy. 8  Prostatic urethra Prostatic ducts open into prostatic sinuses – on either side of seminal colliculus on the posterior wall of the prostatic urethra. Seminal colliculus is an eminence in the middle of the urethral crest. Urethral crest is a median ridge between the bilateral grooves called the prostatic sinuses. prevents backward flow of semen into bladder. Prostatic utricle is a small slit on the seminal colliculus. Embryological remnant of the uterovaginal canal (forms uterus & part of vagina in females). Opening of ejaculatory ducts below utricle. Prostatic fluid: contributes 20% to volume of semen. Reproductive and urinary tracts merge in the prostatic urethra. 9 BLOOD, NERVE & LYMPH OF PROSTATE 10  Prostate Gland: Arterial supply Prostatic arteries arise from branches of internal iliac artery: Inferior vesical arteries, internal pudendal, middle rectal. 11 Prostate Gland: Venous Drainage Veins draining prostate gland form a plexus around the sides and base: Prostatic venous plexus Located between the fibrous capsule of prostate and the prostatic sheath. Continuous superiorly with the vesical plexus. Communicates posteriorly with the internal vertebral venous plexus. Drains into internal iliac veins. 12  Prostate Gland: Innervation Innervation: Sympathetic – T12-L2, lumbar splanchnic nerves, hypogastric and pelvic plexuses. Stimulates secretion from the prostate during ejaculation. Parasympathetic - pelvic splanchnic nerves, inferior hypogastric, pelvic plexuses. Prostatic plexus is connected with pelvic plexus. Gives rise to cavernous nerves: supply erectile tissues of penis (erection) - parasympathetic. 13  Prostate Gland: Lymphatic drainage Lymph draining prostate gland drains to internal iliac nodes. 14 PENIS 15  Penis Located in the urogenital triangle Male copulatory organ. Common outlet for urine and semen. Consists of a root, body, and glans. Anatomical position of penis = erect: Dorsal and ventral surfaces. 16  Penis Three cylindrical bodies of erectile cavernous tissue: Corpora (plural) cavernosa – paired and dorsally: Separated by septum. Corpus (singular) spongiosum – single and ventrally: contains spongy/penile urethra. Each erectile tissue is surrounded by fibrous covering: tunica albuginea Deep fascia of penis binds corpora together: continuation of deep perineal fascia. 17  Penis: root Attached part. Consists of crura (plural), bulb, ischiocavernosus & bulbospongiosus muscles. Located in the superficial perineal pouch, between the perineal membrane (superior) and the deep perineal fascia (inferior). Crura and bulb consists of erectile tissue: corpus cavernosum & corpus spongiosum. Crura attached to ischial ramus. Posterior part of bulb: penetrated by urethra. 18  Penis: Body Suspended from the pubic symphysis. No muscles. Penis consists of thin skin, connective tissue, blood & lymphatics, fascia, corpora, urethra. Skin is connected to tunica albuginea by loose connective tissue. 19  Penis: Glans Distal expansion of corpus spongiosum. Corona: projection of glans beyond ends of corpora cavernosa. Neck separates glans from body. External urethral orifice/meatus: near the tip of the glans. Skin and fascia form a double layer: prepuce (foreskin) Covers the glans penis. Frenulum of prepuce: median fold that attaches deep layer of prepuce to the glans. 20 LIGAMENTS OF PENIS 21  Penis: Ligaments Suspensory: condensation of deep fascia arising from the anterior surface of the pubic symphysis. passes inferiorly and splits to form a sling that attaches to the deep fascia of the penis (at the junction of the body & root). anchors erectile bodies to pubic symphysis. Short and taut. Fundiform: irregular condensation of collagen and elastic fibres of the subcutaneous tissues Descends in midline from linea alba to the pubic symphysis Splits to surround the penis, then reunites and blends inferiorly with dartos fascia forming the scrotal septum. superficial to suspensory ligament, blends with dartos fascia forming scrotal septum. Long and loose. 22 BLOOD, NERVE & LYMPH OF PENIS 23  Penis: Arterial supply Penile skin: Superficial and deep branches of external pudendal artery (from femoral arteries). Branches of internal pudendal artery: ❑Skin & fascia of penis, corpus spongiosum, spongy urethra: dorsal artery of penis. Runs on each side of deep dorsal vein in dorsal groove between corpora cavernosa. ❑Corpora cavernosa: deep artery of penis. Pierces crura & runs through center of corpus. Give off cavernous arteries. Involved in erection. ❑ Bulb of corpus spongiosum and urethra within it & bulbourethral glands: artery of bulb of penis 24  Penis: Venous drainage Deep dorsal vein: drains blood from cavernous spaces via venous plexus that drains into prostatic venous plexus. Passes between the laminae of the suspensory ligament, inferior to the inferior pubic ligament, anterior to the perineal membrane. Superficial dorsal vein: drains blood from skin & subcutaneous tissue. Drains into superficial external pudendal vein. 25  Penis: Innervation Nerves arise from S2, S3, S4, either through pelvic splanchnic and pudendal nerves. Skin and glans penis – dorsal nerve of penis from pudendal nerve (sensory and sympathetic) Passes through pudendal canal & deep perineal pouch Runs lateral to deep dorsal artery on the dorsum of penis. Glans has rich supply of nerve endings. Skin of root – ilioinguinal nerve. Parasympathetic vasodilator nerves from pelvic splanchnic nerves supply erectile tissue via cavernous nerves (through prostatic plexus). 26  Penis: Lymphatic drainage Skin of penis drains into superficial inguinal nodes. Glans and distal spongy urethra drain into deep inguinal nodes. Cavernous bodies and proximal spongy urethra drain into internal iliac nodes. 27 ERECTION 28  Erection Stimulation. Parasympathetic innervation: cavernous nerves relax smooth muscle in cavernous arteries. Arteries straighten, enlarge their lumen. Increases blood flow into the cavernous spaces of the corpora cavernosum. Muscles of perineum (bulbospongiosus & ischiocavernosus) compress veins draining corpora cavernosum, preventing their drainage. Erectile tissues engorged with blood and become rigid. 29 THANK YOU FOR LISTENING!! 30