Male Reproductive System PDF

MALE REPRODUCTIVE SYSTEM  OUTCOMES Describe the structure and location of the testes and the epididymis. Describe the blood supply and the nerve innervation of the testis. Describe the structure and course of the vas deferens, seminal vesicles and ejaculatory ducts. Describe the macrosco...

MALE REPRODUCTIVE SYSTEM  OUTCOMES Describe the structure and location of the testes and the epididymis. Describe the blood supply and the nerve innervation of the 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. Describe the position of the bulbo-urethral glands. 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 innervation and lymphatic drainage of the prostate. Describe the microscopic structure and functional relationships of the testis, vas deferens and prostate gland. (See Theme 6) Describe the location and structure of the penis. Describe the blood supply, nerve innervation and lymphatic drainage of the penis. Explain the mechanism involved with erection of the penis (see directed self-study). MALE INTERNAL GENITAL ORGANS Testes Epididymes Ductus Deferens Seminal Glands Ejaculatory Ducts Prostate Bulbo-Urethral Glands  DUCTUS DEFERENS Continuation of the Epididymis Thick muscular wall and small lumen Begins at the inferior pole of the testes and ascends posterior to the testis medial to the epididymis Primary component of the spermatic cord Penetrates the anterior abdominal wall via inguinal canal Crosses over the external iliac vessels and enters the pelvis Passes along the lateral wall of pelvis external to parietal peritoneum Ends by joining the duct of the seminal gland to form the ejaculatory duct The ductus deferens enlarges to form the ampulla before its termination  DUCTUS DEFERENS Arterial Supply The artery to the ductus deferens usually arises from a superior vesical artery and terminates by anastomosing with the testicular artery posterior to the testis Venous Drainage Veins from the most of the duct drain into the testicular vein including the distal pampiniform plexus SEMINAL GLANDS Elongated structure that lies between the fundus of the bladder and the rectum Place obliquely superior to the prostate Do NOT store sperm Secretion thick alkaline fluid fructose coagulating agent Superiorly covered with peritoneum and lie posterior to the ureters Separated from the rectum by rectovesical pouch and septum Joins the ductus deferens to form the ejaculatory duct  SEMINAL GLANDS Arterial Supply The arteries to the seminal glands are derived from inferior vesical and middle rectal arteries Venous Drainage Accompany arteries  EJACULATORY DUCTS Formed by the union of the seminal glands and ductus deferens Formed near the neck of the bladder Run through the posterior part of the prostate and along either side of the prostatic utricle Converge to open on the seminal colliculus by tiny apertures Arterial supply are branches of the superior vesical arteries The veins join the prostatic and vesical venous plexus BULBOURETHRAL GLANDS Two pea-sized glands that lie posterolateral to the intermediate part of the urethra largely embedded within the external urethral sphincter The ducts pass through the perineal membrane with the intermediate urethra and open through many apertures in the proximal part of the spongy urethra in the bulb of the penis Mucous like secretion  PROSTATE GLAND Largest accessory gland in the male reproductive system Surrounds the prostatic urethra Two thirds glandular One third fibromuscular Dense neurovascular are surrounded by visceral pelvic fascia forming a fibrous prostatic sheath  PROSTATE GLAND Base Closely related to the base of the bladder Apex In contact with fascia on the superior aspect of the urethral sphincter and deep perineal muscles Anterior Surface Muscular Separated from the pubic symphysis by retroperitoneal fat in the retropubic space Posterior Surface Related to the ampulla of the rectum Inferolateral Surface Related to levator ani m.  PROSTATE GLAND: LOBES Isthmus Historically the anterior lobe Lies anterior to the urethra Fibromuscular representing a superior continuation of the external urethral sphincter muscle to the neck of the bladder Right & left lobes Separated posterior by a central shallow longitudinal furrow Separated anteriorly by the isthmus Each may be subdivided into four indistinct lobules by their relationship to the urethra and ejaculatory ducts  PROSTATE GLAND Lobules of Right and Left Lobe 1. Inferoposterior lobule - Lies posterior to the urethra and inferior to the ejaculatory ducts - Lobule constitutes the aspect of the prostate palpable by digital rectal examination 2. Inferolateral lobule - Lateral to the urethra - Forms major part of the prostate 3. Superomedial lobule - Surrounds the ejaculatory duct - Deep to the inferoposterior lobule 4. Anteromedial lobule - Deep to the inferolateral lobule - Directly lateral to the proximal prostatic urethra PROSTATE ZONES  PROSTATE GLAND Vasculature Prostatic arteries branches of the internal iliac artery, inferior vesical arteries. Internal pudendal arteries and middle rectal arteries Prostatic venous plexus Veins join the prostatic venous plexus drains into the internal iliac veins Between the fibrous capsule of the prostate and prostatic sheath Continuous superiorly with visceral venous plexus Communicates posteriorly with the internal vertebral venous plexus Lymph drainage Drain into the internal iliac nodes and sacral lymph noes EXTERNAL MALE GENITAL ORGANS Distal Urethra Scrotum Penis  SCROTUM Cutaneous sac consisting of two layers: (1) pigmented skin and (2) dartos fascia - Fat free fascial layer with smooth muscle fibers dartos muscle - Responsible for wrinkled appearance of scrotum as dartos muscle attaches to skin Divided internally by the septum of the scrotum - Continuation of the dartos fascia - Demarcated externally by scrotal raphe - Cutaneous ridge marking the line of fusion of the embryonic labioscrotal swellings - Labioscrotal swellings are two cutaneous outpouchings of the anterior abdominal wall that fuse to form the scrotum - Late in the fetal period, the testes and spermatic cord enter the scrotum  INGUINAL CANAL: DEVELOPMENT (MALE) Accounts for the derivatives of the anterolateral abdominal wall layers in the adult scrotum SCROTUM SCROTUM Arterial Supply Posterior scrotal branches of the perineal artery (branch of the internal pudendal artery) Anterior scrotal branches of the deep external pudendal artery (branch of the femoral artery) Cremasteric artery (branch of the inferior epigastric artery) Venous Drainage Accompany the arteries Lymph Drainage Drain into the superficial inguinal lymph nodes  SCROTUM: INNERVATION Branches of the lumbar plexus to the anterolateral surface Branches of the sacral plexus to the posterior and inferior surfaces Genital branch of the genitofemoral nerve (L1, L2) Anterior scrotal nerves Posterior scrotal nerves Perineal branches of the posterior cutaneous nerve of thigh  TESTES Male gonads Paired reproductive glands that produce sperm and male hormones Suspended in the scrotum by the spermatic cords Tunica Vaginalis Surface of each testis is covered by the visceral layer of the tunica vaginalis The parietal layer of the tunica vaginalis is adjacent to the internal spermatic fascia Small amount of fluid separated the visceral and parietal layers Tunica Albaginea Tough fibrous outer surface  PENIS Male copulatory organ Conveys the urethra, the common outlet for urine and semen The penis consists of thin skin, connective tissue, blood vessels, lymphatics, fascia, corpora and the spongy urethra Parts of the Penis - Root of the penis - Body of the penis - Glans of the penis  PENIS: LIGAMENTS Suspensory ligament Condensation of deep fascia Arises from the anterior surface of the pubic symphysis Passes inferiorly and splits Attaches at the junction of the penis root and body Anchors erectile tissue to the pubic symphysis Fundiform ligament Irregular mass of collagen and elastic fibers Descends from the midline of the linea alba anterior to the pubic symphesis Splits to surround the penis Blends with dartos fascia, forming the scrotal septum PENIS: SURFACE ANATOMY Glans Penis Corona of Glans Neck of Glans Skin of Penis Very thin Darkly pigmented relative to adjacent skin Connected to the tunica albuginea with loose connective tissue At the neck of the glans, the skin is prolonged to form a double layer of skin called the prepuce The Frenulum is a median fold that passes from the prepuce to the urethral surface  PENIS: INTERNAL STRUCTURE The penis is composed of three cylindrical cavernous bodies - Paired corpora cavernosa (dorsally) Fused together in the median plane Separate posteriorly to form the crura of the penis - Corpus spongiosum (ventrally) Contains the spongy urethra Cavernous bodies Each covered with fibrous capsule called the tunica albuginea Covered with deep fascia of penis (Buck fascia), a membranous covering binding the bodies together Corpora are separated internally by the septum of the penis ROOT OF THE PENIS Root of the penis consists of: Crura - Erectile tissue - Posterior separation of corpora cavernosa - Each crus is attached to the inferior part of the internal surface of the corresponding ischial ramus anterior to the ischial tuberosity Bulb - Erectile tissue - Enlarged posterior part of corpus spongiosum Ischiocavernosus muscle Bulbospongiosus muscle Located in the superficial perineal pouch PENIS: ARTERIAL SUPPLY Dorsal arteries of the penis - Run on each side of deep dorsal vein in the groove between the corpora cavernosa - Supplies fibrous tissue around the corpora cavernosa, corpus spongiosum, spongy urethra and penile skin Deep arteries of the penis - Pierce corpora proximally and run distaly near the center of the corpora cavernosa supplying erectile tissue Arteries of the bulb of the penis - Supply the posterior bulbous part of the corpus spongiosum and the urethra within it - Bulbourethral gland  PENIS: VENOUS DRAINAGE Blood of the cavernous spaces is drained by the venous plexus that joins the deep dorsal vein of the penis The deep dorsal vein of the penis passes between the laminae of the suspensory ligament of the penis inferior to the inferior pubic ligament and anterior to the perineal membrane and drain into the prostatic venous plexus Blood from the skin and subcutaneous tissue of the penis drains into the superficial dorsal veins, which drain into the superficial external pudendal vein. PENIS: MECHANISM OF AN ERECTION During sexual stimulation, arteriovenous anastomoses by which blood normally bypasses the empty potential spaces are closed Parasympathetic stimulation dilates the luman of helicine arteries, increasing blood flow to the cavernous spaces The bulbospongiosus and ischiocavernosus muscles compress veins egression from the corpora cavernosa Erection occurs as the corpora cavernosa and corpus spongiosum became engorged with blood at the arterial pressure causing the erectile bodies to become turgid elevating the penis  PENIS: MECHANISM OF EJACULATION During emission, semen is delivered to the prostatic urethra through the ejaculatory ducts after peristalsis of the ductus deferentes and seminal glands. Prostatic fluid is added to the seminal fluid. Emission is a sympathetic response (L1-L2). After Ejaculation, the penis returns to its flaccid state of remission.  PENIS: MECHANISM OF EJACULATION Ejaculation results from: 1. Closure of the internal urethral sphincter at the neck of the urinary bladder 2. Contraction of the urethral muscles 3. Contraction of the bulbospongiosus muscles THE END