Mgen2724 Session 11 September 2024 PDF

MGEN2724 SESSION 11 The structure of the male genital system N Mhobo  Male genital system:  Testes  Epididymis  Ductus deference  Seminal vesicle  Ejaculatory duct  Urethra  Male external:  Scrotum  Penis  Accessory glands:  Prostate...

MGEN2724 SESSION 11 The structure of the male genital system N Mhobo  Male genital system:  Testes  Epididymis  Ductus deference  Seminal vesicle  Ejaculatory duct  Urethra  Male external:  Scrotum  Penis  Accessory glands:  Prostate  Bulbo-urethral Male external: Scrotum Penis  Out pouching of lower anterior abdominal wall containing testes  Protects testes from external injuries  Maintains temperature lower than that of the body (2-3º lower than body)  Bilateral in development  Left half of scrotum lower than the right?? Layers:  Skin  Superficial fascia Dartos m (replace fatty layer) Colle's fascia (continuation of Scarpa's fascia)  External spermatic fascia (external oblique muscle)  Cremasteric fascia (internal oblique muscle)  Internal spermatic fascia (fascia transversalis)  Tunica vaginalis (peritoneum) ease the movement of testes  Blood supply: Superficial and Deep External pudendal Posterior scrotal Anterior scrotal Venous drainage: External pudendal vein Lymphatic drainage: Into horizontal set of Superficial Inguinal lymph nodes Gray’s page 294 Nerves: Anterior 1/3  Ilio-inguinal.  Genitofemoral nerves conveying Fibers from L1 Posterior 2/3 –  Posterior scrotal branches of Pudendal nerve.  Perineal branch of Posterior Femoral Cutaneous nerve. Fibers from S3 & S4 1. Oedema of scrotum 2. Sebaceous cysts 3. Hydrocele 4. Elephantiasis 5. Bifid scrotum Organ of copulation: 2 parts Root: Situated in superficial perineal pouch 3 masses of erectile tissue (1) Right & (2) Left crus of penis (3) Bulb of Penis Body: has  Pair of Corpora Cavernosum  A Corpus Spongiosum – from bulb, extending in the front as glans of penis Cross section of Penis…. Blood supply: Supplied by 3 paired arteries… 1. Arteries to Bulb – supplying Bulb & proximal half of Corpus Spongiosum 2. Deep artery of penis – supplying Corpus Cavernosum 3. Dorsal artery of penis – supplying Glans penis & distal part of Corpus Spongiosum These are terminal branches of INTERNAL PUDENDAL arteries Venous drainage: Drained by 2 sets of unpaired veins Superficial dorsal vein – receiving blood from prepuce & skin of penis & drains into Great Saphenous vein Deep dorsal vein – drains into Prostatic venous plexus. Nerve supply: Somatic nerves – sensory by Dorsal nerve of penis Parasympathetic nerves – Cavernous nerves from Prostatic nerve plexus (responsible for vascular changes which cause erection) Sympathetic nerves – Dorsal nerve of Penis Lymphatic drainage: Skin of Penis – into Superficial Inguinal lymph Glans of penis – into Deep Inguinal & External Iliac lymph nodes Deep structures – into Internal iliac nodes Glans very sensitive VASCULAR EVENT GENERATED BY PARASYMPATHETIC FIBERS CARRIED IN PELVIC SPLENIC NERVES Cavernosum – filled with blood Surrounded by tunica albuginea.. Spongiosum – no covering No contraction of urethra  Erection:  Sexual stimulation dilates the arteries supplying the penis  Blood enters the penis compressing the veins so that the blood is trapped  Parasympathetic reflex causes erection  Ejaculation:  Muscle contractions close sphincter at base of bladder and move fluids through ductus deferens, seminal vesicles, & ejaculation ducts  Ischiocavernosus & Bulbospongiosus complete the job 1. Phimosis/ Paraphimosis 2. Hypospadias (urethra open below) 3. Epispadias 4. Bifid Penis 5. Circumcision Male genital system: Testes Epididymis Ductus deference Seminal vesicle Ejaculatory duct Urethra Primary organ (ovaries) Pair of male gonads Ellipsoid in form Testes (is) singular Suspended within the scrotum by spermatic cord Each filled with seminiferous tubules where sperm is formed Left testis – lower, obliquely tilted forwards & lateral Parts: 2 ends, 2 borders, 2 surfaces Blood: Testicular artery. (abdominal aorta) Artery to the vas deferens from Superior/Inferior vesicular artery (partly) Cremasteric artery from inferior epigastric (rarely) Lymph: Lateral, Lumbar or Pre aortic lymph nodes  Seminiferous tubules  Straight tubules  Rete testis  Efferent ducts  Epididymis  Ductus (Vas) deferens  Sperm survival requires 3 degrees lower  Mechanisms of regulating temperature  Dartos muscle causes wrinkling of scrotal wall  Cremaster muscle in spermatic cord  Elevates testes on exposure to cold & during arousal  Warmth reverses the process  Countercurrent heat exchange  Pampiniform plexus & the branches of the testicular aa Veins: Pampiniform plexus – 4 veins – (superficial inguinal ring) – 2 veins – (deep ring) – Single vein (Testicular vein) Left drains = Left renal vein at 90º → IVC Right drains = IVC (acute 30º) Plexus very NB!! – absorbs back heat, testis temperature lower than body (spermatogenesis) Nerves: Sympathetic nerves- Renal & Aortic plexuses Preganglionic - 10th & 11th thoracic segment Pain referred to Umbilical region – Segmental innervation Testis Coverings……. Tunica Vaginalis (visceral layer) Covers whole testis, except posterior border & epididymis. Tunica albuginea: thick fibrous membrane Posterior border – mediastinum testis Anterior surface – numerous fibrous septa – lobules (cone shaped 200 to 300) Smooth muscle fibers – contraction , excessive secretion of testes. Tunica Vasculosa: areolar & vascular membrane – lines individual lobule. Parts….. 1. Upper end – overlapped by head of epididymis 2. Lower end – Tail of epididymis by areolar tissue & tunica vaginalis 3. Posterior border – Broad, flat, occupied (spermatic cord attached to upper part of posterior border 4. Anterior border – Smooth, convex 5. Medial surface – Smooth, convex 6. Lateral surface – Convex, smooth & overlapped by epididymis  Structure of testis Macroscopic 200 -300 lobules Interstitial cells of Leydig 1 -3 seminiferous tubules in each lobule Seminiferous tubules – 70-80 cm when uncoiled, convoluted & straight part (plexiform network as rete testis) 12-20 efferent ductules from upper end enter head of epididymis Efferent ductules unite – single duct (canal of epididymis) body & tail of epididymis Microscopic 1. Seminiferous tubules 2. Spermatogenesis 3. Sertoli cells 4. Leydig cells 4th month - Iliac fossa 7th month – Deep inguinal ring 8th month – Traverses inguinal canal 9th month – scrotum Factors for descent: Gubernaculum guiding force Intra abdominal pressure & temperature Uncurling of foetal curves Anomalies of descent…. 1. Anorchism (Cryptorchism) – in abdomen- sterile- prone to malignant changes 2. Monorchism – 1 testis abdominal, other normal 3. Partially descended testis – deep ring, inguinal canal, superficial ring (treat by hormones) 4. Ectopic testis- not on path (front of pubic symphysis, perineum, femoral) 5. Patent process vaginalis – (causes of congenital inguinal hernia) 6. Inversion of testis – process vaginalis behind testis  Along the lateral part of posterior border of testis Head (receive multiple efferent ducts), body and tail Epididymis (continues as ductus deferens on the medial side of epididymis) Formed by coiling of a single duct the canal of epididymis Spermiogenesis –final maturation of sperms takes place here Stores spermatozoa until ejaculation Transports sperms from testis to ductus deferens (propels sperm forward) Ends is continuous with ductus deferens Blood- branch of inferior vesical a.(supplying ductus deference) Lymph – external & internal iliac (hypogastric) nodes Nerves – hypogastric plexus Male genital organs: Contributors to semen: Images LWW Ltd. Moore et al: Clinically Oriented Anatomy 6th edition Ductus deferens Crosses over ext. testes iliac vessels  seminal glands enters pelvis prostate bulbo-urethral glands Passes along lateral Penetrates wall (external to abdominal parietal peritoneum) wall Joins duct of (inguinal seminal gland  canal) ejaculatory duct Begins at tail of epididymis  Composed of ductus deference, testicular artery (aorta), testicular vein (pampiniform plexus) – to IVC & left renal v., testicular lymph vessels (follow the artery), autonomic nerves (sympathetic – follow the artery), remnants of processus vaginalis- peritoneum, genital branch of genitofemoral nerve (cremaster muscle)  Location: extends from tail of epididymis to abdominal inguinal ring  Blood: internal & external spermatic a. & artery to ductus deference  Lymph: external iliac nodes  Nerves: sympathetic fibers from spermatic & pelvic plexuses Seminal vesicle Position: above base of prostate gland, between posterior surface of bladder & anterior of rectum Function: secret alkaline secretion, portion of semen (nutrient) Blood: branches of middle & inferior vesical a. & middle rectal branch Venous: seminal venous plexuses Lymph: Internal iliac (hypogastric) nodes Nerve: Hypogastric plexus Ejaculatory ducts Union of ductus deference & ductus of seminal vesicles From base of prostate, through substance of prostate, opens into prostatic urethra Function: passageway for semen Prostate gland Position: below bladder, rests against superior fascia of urogenital diaphragm Has a base, apex, & 4 surfaces Function: secretes slightly alkaline, milky fluid with characteristic odor Ligaments: connected to fascial sheath Anteriorly – puboprostatic ligament Posteriorly – rectovesical septum Blood: Internal pudendal, inferior vesical & middle rectal branches Venous: Prostatic plexus draining into internal iliac veins (hypogastric) Lymph: Internal iliac (hypogastric) nodes Nerve: Inferior Hypogastric plexus  Cowper's gland  2 small glands urethra  Urogenital diaphragm (on either sides of membranous urethra)  Secret clear alkaline (added to seminal fluid) neutralizes acidity of vaginal secretion of female  Male urethra…. Urethra: Intramural urethra – Bladder neck Prostatic urethra – Through prostate Membranous urethra – Through deep perineal perineal pouch Spongy urethra – In corpus spongiosum -ends with navicular fossa and external urethral orifice  Ductus Deferens: Superior vesical a., Inferior vesical Arteries -Artery to ductus deferens from superior vesical a. -Anastomosis – Testicular a. from abdominal aorta a., Middle rectal a. & Internal Veins -Testicular v. pudendal a. all from internal iliac Internal male genital organs: Neuro -Also drains to vesicular/ prostatic venous plexus a. Lymph n. -External iliac nodes Images LWW Ltd. Moore et al: Clinically Oriented Anatomy 6th edition Ejaculatory Ducts: Arteries -Artery to ductus deferens Veins -Veins join prostatic/ vesical venous plexuses Lymph n. -Iliac nodes vasculature Seminal Glands: Arteries -Inferior vesical & middle rectal aa. Veins = Arteries Lymph n. -Internal & external iliac nodes Prostate: Arteries -Prostatic a. branch of inferior vesical a. -Also internal pudendal a. & middle rectal a. Veins -Prostatic venous plexus (between capsule & sheath) -Drains to internal iliac v. -Communicates with vesical & internal vertebral plexuses (cancer spreads to vertebrae and brain) Lymph n. -Internal iliac & sacral nodes Innervation: Sympathetic fibres -Contraction & secretion  ejaculation Parasympathetic fibres -Some traverse prostatic n. plexus to form cavernous n.  erection  Distal Male Urethra: Images LWW Ltd. Moore et al: Clinically Oriented Anatomy 6th edition Arteries -Branches from dorsal a. of penis External male genital organs: Neuro Elsevier Ltd. Drake et al: Gray’s Anatomy for Students Veins = Arteries www.studentconsult.com Lymph n. -Intermediate  internal iliac nodes -Spongy  deep inguinal & external iliac nodes Scrotum: vasculature Arteries: Anterior scrotum: Anterior scrotal a. Terminal branches of external pudendal a. from femoral a. Posterior scrotum: Posterior scrotal aa. A terminal branch of internal pudendal a. from internal iliac a. Veins = Arteries Lymph n. Superficial inguinal nodes Nerves: Anterior: Anterior scrotal nn. From lumbar plexus Posterior: Posterior scrotal nn. Branches of superficial perineal n. from pudendal n. from sacral plexus External male genital organs: Penis - Neuro Penis: Arteries: Mainly branches from Internal pudendal a.: −Dorsal a. of penis −Deep a. of penis Elsevier Ltd. Drake et al: Gray’s Anatomy for Students www.studentconsult.com Images LWW Ltd. Moore et al: Clinically Oriented Anatomy 6th edition  helicine arteries (coiled) Responsible for erection −Artery of bulb of the penis External pudendal a.: −Penile skin (anastomose with internal pudendal a.) vasculature Veins: Blood from Cavernous spaces −Deep dorsal v.  prostatic plexus Blood from skin & subcutaneous tissue −Superficial dorsal v. −Drains mainly superficial external pudendal v. Nerves: Sensory - & sympathetic innervation −Dorsal n. of penis from pudendal n. Parasympathetic −Cavernous n. from prostatic plexus  helicline arteries of erectile tissue Lymph n.: Skin & prepuce  Superficial inguinal nodes Glans & deep tissue  deep inguinal nodes  external iliac nodes Produced by fluid in the sac normally surrounding the testicle. Presents as painless swelling in the scrotum Comon in babies In adults caused by injury, inflammation caused by infection Goes away on its own (otherwise urologist) Diagnosis: shine a light through scrotum (transillumination), the light will outline the clear fluid Urethral stricture: Involves scarring that narrows the urethra. Restricts the flow of urine from the bladder , can cause urinary tract problems including inflammation or infection Circumcision: Surgical removal of the skin covering the tip of the penis (foreskin) Several Health benefits Phimosis can also occur if the foreskin is forced back before it's ready. This can cause a fibrous scar to form, which may prevent future retraction of the foreskin. Paraphimosis occurs when the foreskin is retracted behind the corona (or crown) of the penis and cannot be returned to the unretracted position. Surgical procedure to prevent sperm from getting to the semen when ejaculation takes place Birth control (male sterilization).  Gonorrhea: sexually transmitted infection (STI) Transmitted by having oral, anal, vaginal sex Burning or pain during urination , discharge or drip from penis, discoloration & swelling at penis Itching & soreness of anus Rectal bleeding, pain with bowel movement Urine or blood test – diagnoses If left untreated – leads to complications Treatment: antibiotics Prostatectomy: Surgical procedure for partial or complete removal of prostate gland Urethral catheterization: catheter is a flexible tube that collects urine from the bladder and leads to a drainage bag. Testicular tumors: Cells growth, cancer forms when cells develop in the tissue THANK YOU