Anatomy of Male Reproductive System Lecture 2 - Level 3 PDF

Anatomy of Male Reproductive System Dr. sally Mohsen Lecture 2 - Level 3 Assistant Professor of Anatomy and Embryology 1 WRITTEN AND COMPILED BY GA...

Anatomy of Male Reproductive System Dr. sally Mohsen Lecture 2 - Level 3 Assistant Professor of Anatomy and Embryology 1 WRITTEN AND COMPILED BY GAD 203 COMMITTEE. Objectives: (‫)أهداف‬ At the end of this lecture, the students will be able to: 1. Describe the structure of the different components and function of the male reproductive system. 2. Describe the adaptation of each system to suit its function. 3. Explain their blood supply and lymphatic drainage. www.vision.edu.sa Components Of Male Reproductive System (‫)مكونات الجهاز التناسلي الذكري‬ Primary Sex Organ: Testis(testes) Reproductive Tract: Epididymis. Vas Deferens. Spermatic cord. Accessory Sex Glands: Prostate gland. Seminal vesicles. Bulbourethral glands. External Genitalia: Penis and scrotum 3 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Testes: (‫)الخصيتين‬ Shape: Paired almond-shaped gonads that are suspended in the scrotum by the spermatic cord. Each testis is surrounded by a tough fibrous capsule, the tunica albuginea. Volume is about 20-25 ml. Length 4 - 5 cm long. Weight (10.5 – 14 g.). Functions: Spermatogenesis (producuction of sperms). Hormone production: (Androgens- testosterone). 4 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Coverings Of The Testis Tunica Vaginalis: Peritoneal covering(serous), formed of parietal and visceral layers. It surrounds testis & epididymis. It allows free movement of testis within the scrotum. Tunica albuginea: It is a whitish fibrous capsule. Tunica Vasculosa It is the vascular layer of the testis, consisting of a plexus of blood vessels, held together by delicate areolar tissue. It clothes the inner surface of the tunica albuginea and the different septa in the interior of the gland.  Internal Structure of The Testis Fibrous septae extend from the capsule, dividing the testis into (200-300) lobules (average 250). Each lobule contains, (1-3) seminiferous tubules. Seminiferous Tubules: (each is a 60 cm coiled tubule). They are the site of spermatogenesis. In between the seminiferous tubules lies the Interstitial cells of Leydig which secret Testosterone. 6 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Internal Structure of The Testis (Continued….) Rete testis: Sperm travels through the testis from the tubules, through a network of ducts called the rete testis, to the epididymis 7 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Cremaster muscles The cremaster muscle is a thin layer of skeletal muscle found in the inguinal canal and scrotum between the external and internal layers of spermatic fascia, surrounding the testis and spermatic cord. Blood supply by the cremasteric artery which is a branch of inferior epigastric artery. Nervous supply The cremaster muscle is innervated from the genital branch of the genitofemoral nerve. Technique: Examiner strokes or pinches the skin in the upper medial thigh. It causes cremasteric muscle contraction. Observation: Rise of the Testicle on same side. Absent: (no Testicle rise), Is Suggestive of Testicular Torsion.  Clinical note: Descent of the Testis(Embryological hint): The testis develops high up on the posterior abdominal wall at level of L2/3 vertebrae and in late fetal life it “descends” behind the peritoneum, dragging its blood supply, nerve supply, and lymphatic drainage after it. Pain from the kidney is often referred to the scrotum and, conversely, testicular pain may radiate to the loin. As the testis enlarges, it also undergoes a caudal migration according to the following timetable 3rd month (of fetal life) reaches the iliac fossa; 7th month traverses the inguinal canal; 8th month reaches the external ring; 9th month descends into the scrotum. Maldescent, in which the testis travels down an abnormal path and fails to reach the scrotum. It may be found in the superficial fascia of the anterior abdominal wall above the inguinal ligament, in front of the pubis, in the perineum, or in the thigh. It is necessary for the testes to leave the abdominal cavity because the temperature there retards the normal process of spermatogenesis. If an incompletely descended testis is brought down into the scrotum by surgery before puberty, it will develop and function normally. www.vision.edu.sa Blood Supply of Testis: (‫)إمداد الدم بالخصية‬ Arterial supply: (‫)توريد الشرايين‬ Testicular artery (branch from abdominal aorta at level of L3 Venous drainage: (‫)التصريف الوريدي‬ Testicular vein (from “Pampiniform plexus” of veins). Right testicular vein drains into IVC (Inferior vena cava) Left testicular vein drains into left renal vein. 10 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Lymphatic drainage: (‫)التصريف اللمفاوي‬ Testicular Lymphatics: End in Lumbar (para-aortic) nodes. Scrotum, Penis and Prepuce: Terminate in Superficial inguinal nodes 11 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Clinical notes A varicocele is a condition in which the veins of the pampiniform plexus are elongated, dilated and tortuous. It is a common disorder in adolescents and young adults, with most occurring on the left side. These varicose vessels, usually visible only when a person is standing, often result from defective valves in the testicular vein. The palpable enlargement, which feels like a bundle of worms, usually disappears when the person lies down. Malignant Tumor of the testis spreads upward via the lymph vessels to the lumbar (para- aortic) lymph nodes at the level of the first lumbar vertebra. It is only later, when the tumor spreads locally to involve the tissues and skin of the scrotum, that the superficial inguinal lymph nodes are involved. Ligation of testicular artery is not followed by atrophy of the testis as there is anastomosis between testicular artery and artery of Vas www.vision.edu.sa Epididymis: It is a single coiled tubule. Length: 6 Meters long. Site: located on the superior and posterior margins of the testis. Parts: It is divided into 3 parts: Head, Body and Tail. The Head receives (rete testis) efferent ductules from the testis. The Tail is continuous with Vas Deferens. 13 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Epididymis (Continued…) Functions: 1. Secretes and absorbs the nourishing fluid. 2. Recycles damaged spermatozoa. 3. Stores spermatozoa up to 2 weeks to allow for physiological maturation of sperms. 14 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Scrotum: The Scrotum is a cutaneous pouch of loose skin & superficial fascia, which contains the testes, epididymis and parts of the spermatic cords. Skin is thin, wrinkled and is divided on its surface into two lateral portions by a ridge or raphe The fat-free fascial layer including smooth muscle fibers (dartos muscle) responsible for the rugose (wrinkled) appearance of the scrotum. The Left scrotum is slightly lower than the right Functions: (‫)المهام‬ Houses and protects the testis. Regulates testicular temperature. 15 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Clinical note Normal spermatogenesis can occur only if the testes are at a temperature lower than that of the abdominal cavity. When they are located in the scrotum, they are at a temperature about 3°C lower than the abdominal temperature. The control of testicular temperature in the scrotum is not fully understood, but the surface area of the scrotal skin can be changed reflexly by the contraction of the dartos and cremaster muscles. It is now recognized that the testicular veins in the spermatic cord that form the pampiniform plexus—together with the branches of the testicular arteries, which lie close to the veins—probably assist in stabilizing the temperature of the testes by a countercurrent heat exchange mechanism. www.vision.edu.sa Vas Deferens: It is a muscular tube 45 cm long. Carries sperms from the epididymis to pelvic cavity. Passes through the inguinal canal as one of the contents of the spermatic cord. It joins the duct of the seminal vesicle to form ejaculatory duct which opens into the prostatic urethra. 17 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Clinical note Bilateral vasectomy is a simple operation performed to produce infertility( sterilization of male). Under local anesthesia, a small incision is made in the upper part of the scrotal wall, and the vas deferens is divided between ligatures. Spermatozoa may be present in the first few postoperative ejaculations, but that is simply an emptying process. Unexpelled sperms degenerate in epididymis and proximal part of vas. Now only the secretions of the seminal vesicles and prostate constitute the seminal fluid, which can be ejaculated as before. www.vision.edu.sa Accessory Glands: (‫)الغدد الملحقة‬ I. Seminal vesicle. II. Prostate. III. Bulbourethral or Cooper’s glands Functions: 1. Secretion of seminal fluid. 2. Nourishing and activation of sperms. 3. Protection of sperms. 19 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Seminal vesicle The seminal vesicles are two lobulated organs about 2 in. (5 cm) long lying on the posterior surface of the bladder. On the medial side of each vesicle lies the terminal part of the vas deferens. Posteriorly, the seminal vesicles are related to the rectum. Inferiorly, each seminal vesicle narrows and joins the vas deferens of the same side to form the ejaculatory duct. The function of the seminal vesicles is to produce a secretion that is added to the seminal fluid(60% of seminal fluid). The secretions nourish the spermatozoa. During ejaculation, the seminal vesicles contract and expel their contents into the ejaculatory ducts, thus washing the spermatozoa out of the urethra www.vision.edu.sa Ejaculatory ducts The two ejaculatory ducts are each (2.5 cm) long and are formed by the union of the vas deferens and the duct of the seminal vesicle. The ejaculatory ducts pierce the posterior surface of the prostate and open into the prostatic part of the urethra, close to the margins of the prostatic utricle; Their function is to drain the seminal fluid into the prostatic urethra www.vision.edu.sa www.vision.edu.sa  Prostate Gland (‫)غدة البروستات‬ The Largest male accessory gland. It is a fibromuscular glandular tissue. It has a dense fibrous capsule that incorporates the prostatic plexuses of nerves and veins. Size: It is a walnut size. Site: It is located at the neck of bladder. It is traversed by the prostatic urethra. It secretes (20-30% of seminal fluid.) Shape: Conical. 23 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE. Prostate Gland (Continued …) The prostate has A base (superior aspect) that is closely related to the neck of the bladder An apex (inferior aspect) that is in contact with fascia on the superior aspect of the urethral sphincter and deep perineal muscles A muscular anterior surface that features mostly transversely oriented muscle fibers forming a vertical trough-like hemisphincter (rhabdosphincter), which is part of the urethral sphincter, separated from the pubic symphysis by retroperitoneal fat in the retropubic space A posterior surface that is related to the ampulla of the rectum Inferolateral surfaces that are related to the levator ani Function: It secretes enzymes which has the following functions: 1. Aid in activating sperm motility 2. Mucus degradation 3. Neutralize the acidity of female reproductive tract (Alkaline fluid). 24 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Prostatic Lobes It is divided into 5 lobes according to their relation to the urethra: Anterior lobe, (isthmus): Lies anterior to the urethra. It is fibromuscular. Posterior lobe: Posterior to the urethra and inferior to the ejaculatory ducts. Two lateral lobes: On each side of the urethra. Middle (median): Between the urethra and ejaculatory ducts & closely related to neck of urinary bladder. Usually it projects into lumen of the bladder distorting the internal urethral sphincter, after the age of 40 years. The median & the 2 lateral lobes are rich in glandular tissue.  Blood Supply & Lymph Drainage Arterial Supply: Inferior vesical artery from Internal Iliac Artery. Prostatic venous plexus: Lies between the prostatic fibrous capsule and the prostatic sheath. It drains into the internal iliac veins. It is continuous superiorly with the vesical venous plexus of the urinary bladder and posteriorly to the internal vertebral venous plexus. Lymph drainage: Internal iliac lymph nodes.  Clinical notes Benign enlargement or benign hypertrophy of the prostate (BHP) is common in men older than 50 years. An enlarged prostate projects into the urinary bladder and impedes urination by distorting the prostatic urethra. The middle lobule usually enlarges the most and obstructs the internal urethral orifice. The patient experiences difficulty in passing urine and the stream is weak. Back-pressure effects on the ureters and both kidneys are a common complication. The stagnant urine frequently becomes infected, and the inflamed bladder (cystitis) adds to the patient’s symptoms. Prostatic cancer is common in men older than 55 years of age. In most cases, the cancer develops in the posterolateral region. This may be palpated during a digital rectal examination. A malignant prostate feels hard and often irregular. In advanced stages, cancer cells metastasize (spread) to the iliac and sacral lymph nodes and later to distant nodes and bone. The prostatic plexus, closely associated with the prostatic sheath, gives passage to parasympathetic fibers, which give rise to the cavernous nerves that convey the fibers that cause penile erection. A major concern regarding prostatectomy is that impotency may be a consequence. www.vision.edu.sa In all operations on the prostate, the surgeon regards the prostatic venous plexus with respect. The veins have thin walls, are valveless, and are drained by several large trunks directly into the internal iliac veins. Damage to these veins can result in a severe hemorrhage. Also many connections between the prostatic venous plexus and the vertebral veins exist. During coughing and sneezing or abdominal straining, it is possible for prostatic venous blood to flow in a reverse direction and enter the vertebral veins. This explains the frequent occurrence of skeletal metastases in the lower vertebral column and pelvic bones of patients with carcinoma of the prostate or even Cancer cells may enter the skull All or part of the prostate, or just the hypertrophied part, is removed (transurethral resection of the prostate [TURP]) www.vision.edu.sa  Prostatic Urethra Structures seen on the posterior wall of the prostatic urethra: Urethral crest: A longitudinal elevated ridge. Prostatic sinus: A groove on each side of the crest. The prostatic gland opens into the prostatic sinus. Prostatic utricle : A depression on the summit of the urethral crest. The ejaculatory ducts open on the sides of the utricle. Seminal colliculus: a rounded eminence that opens into the prostatic utricle. Bulbourethral (Cooper’s Gland) Number: Small paired glands. Site: Located at the base of the penis. Function: Secrete alkaline mucus for: Neutralization of urinary acids Lubrication. Penis: A Copulatory & Excretory organ. Excretory: Penile urethra transmits urine & seminal fluid. Copulatory: Has (3) cylindrical masses of erectile tissue Two Corpora Cavernosa One Corpus Spongiosum 31 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.  Corpora Cavernosa Two superior (right & left) masses of Primary erectile tissue. They Provide the majority of rigidity & length of penis. Their posterior expansions, forms the 2 Crurae (anchor” tissue) against pelvic bone  Corpus Spongiosum The single inferior mass (Secondary erectile tissue) It is traversed by the penile urethra. Its Anterior expansion forms the Glans penis. Its posterior expansion forms the bulb of the penis. Prepuce or foreskin: Fold of skin covering glans penis (before circumcision) Reference Book: (‫)كتاب مرجعي‬ SNELL’S CLINICAL ANATOMY BY REGIONS by Dr. LAWRENCE E. WINESKI PhD (Author)10th Edition 2019 ISBN 978-1496345646 34 www.vision.edu.sa 35 WRITTEN AND COMPILED BY GAD 231 www.vision.edu.sa COMMITTEE.