male reproductive system lecture.pdf
Transcript
The Male Reproductive System The main task of the reproductive system is the production of reproductive cells and the secretion of hormones. The endocrine glands and the nervous system have a direct influence on the work of the reproductive system TESTIS THE TESTIS E...
The Male Reproductive System The main task of the reproductive system is the production of reproductive cells and the secretion of hormones. The endocrine glands and the nervous system have a direct influence on the work of the reproductive system TESTIS THE TESTIS Egg shaped 5 cm long, 3 cm wide, 2.5 cm thick EACH WEIGHS 10–15 g Hang in scrotum Testis produce sperm but also contain endocrine cells secreting hormones such as testosterone, which drives male reproductive physiology. Testosterone is important for spermatogenesis, sexual differentiation during embryonic and fetal development, and control of gonadotropin secretion in the pituitary. SCROTUM Sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis Contains paired testicles separated by a midline septum Its external positioning keeps the testes 3C lower than core body temperature Testis (H+E) Rete testis Tunica albuginea Interlobular septum lobule Tunica albuginea Testis (H+E) Seminiferous tubules Interstitial tissue SEMINIFEROUS TUBULE TESTIS Seminiferous tubule Seminiferous epithelium Interstitial tissue Interstitial cells, or Leydig cells, SPERMATOGENESIS Golgi phase Acrosomal phase Maturation phase SEMINIFEROUS TUBULES SEMINIFEROUS TUBULE BASEMENT MEMBRANE WITH LAMINA PROPRIA SERTOLI CELL SPERMATOGONIA PRIMARY SPERMATOCYTE SECONDARY SPERMATOCYTE SPERMATID SPERMATOZOA LEYDIG CELLS SEMINIFEROUS TUBULES spermatids Secondary spermayocyte SPERM SERTOLI CELLS Primary spermatocyte spermatogonie SPERM Sperm (about 65 µm long) have three major regions HEAD: contains DNA and has a helmet-like acrosome containing hydrolytic enzymes that allow the sperm to penetrate and enter the egg MIDPIECE: contains mitochondria spiraled around the tail filaments TAIL: a typical flagellum produced by a centriole 31 SERTOLI CELLS SEMINIFEROUS TUBULES Interstitial cells Interstitial cells, INTERSTITIAL CELLS, simple RETE TESTIS MEDIASTINUM SEMINIFEROU RETE TESTIS S TUBULES ( SEPTA TESTIS - RETE TESTIS (H+E) SEMINIFEROUS TUBULES RETE TESTIS MEDIASTINUM TESTIS - RETE TESTIS (H+E) simple cuboidal or simple squamous epithelium RETE TESTIS SEMINIFEROUS TUBULES ( MEDIASTINUM RETE TESTIS (IN MEDIASTINUM) SEMINIFEROUS TUBULES EFFERENT DUCT EFFERENS DUCTULUS The epithelium of the efferent duct is irregular in height, causing the lumen to be star-shaped. The epithelium includes ciliated cells (that move sperm toward the epididymis) and shorter non-ciliated cells (to absorb fluid). A thin layer of smooth muscle around the duct provides peristalsis to help transport the sperm. EFFERENT DUCTULES EPIDIDYMIS THE EPIDIDYMIS EFFERENT DUCTULES TESTIS EFFERENT DUCTULES Epididymis EFFERENT DUCTULES EPIDIDYMIS THE EPIDIDYMIS THREE FUNCTIONS OF THE EPIDIDYMIS 1. MONITORS AND ADJUSTS FLUID PRODUCED BY SEMINIFEROUS TUBULES 2. RECYCLES DAMAGED SPERMATOZOA 3. STORES AND PROTECTS SPERMATOZOA FACILITATES FUNCTIONAL MATURATION EPIDIDYMIS HEAD Is proximal to the testis Receives spermatozoa from efferent ductules EPIDIDYMIS BODY From last efferent ductule to posterior margin of testis EPIDIDYMIS TAIL Begins near inferior border of testis where number of coils decreases Re-curves and ascends to connection with ductus deferens Primary storage location of spermatozoa DUCTUS EPIDIDYMIS EPIDIDYMIS Epididymis -ductus epididymis (H+E) Loose connective tissue a layer of smooth muscle sperm pseudostratified columnar epithelium MICROVILLI Sperm (“STEREOCILIA”) BASAL CELL VAS DEFERENS THE DUCTUS DEFERENS (VAS DEFERENS) – Is 40–45 cm long – Begins at tail of the epididymis and, as part of spermatic cord, ascends through inguinal canal – Curves inferiorly along urinary bladder Toward prostate gland and seminal glands – Lumen enlarges into AMPULLA – Wall contains thick layer of smooth muscle DUCTUS (OR VAS) DEFERENS TUNICA MUSCULARIS TUNICA MUCOSA simple or pseudostratified columnar epithelium lamina propria TUNICA ADVENTITIA TUNICA MUCOSA simple or pseudostratified columnar epithelium LAMINA PROPRIA TUNICA MUCOSA TUNICA MUSCULARIS tunica adventitia THE EJACULATORY DUCT –Is a short passageway (2 cm) At junction of ampulla and seminal gland duct –Penetrates wall of prostate gland –Empties into urethra THE ACCESSORY GENITAL GLANDS SEMINAL VESICLE Urinary bladder Seminal vesicle Prostate gland Amuplla of ductus deferens THE SEMINAL GLANDS (SEMINAL VESICLES) –Each gland is about 15 cm long with short side branches from body – Are tubular glands coiled and folded into 5 cm by 2.5 cm mass –Are extremely active secretory glands –Produce about 60% of semen volume (Fructose: provides energy for the sperm, Fibrinogen: helps turn semen into a bolus that can be readily propelled into the vagina, Prostaglandins: decrease cervical mucus viscosity and stimulate reverse peristalsis of the uterus.) SEMINAL VESICLE Parasympathetic ganglion SIMPLE OR PSEUDOSTRATIFIED COLUMNAR EPITHELIUM THE PROSTATE GLAND –Is a small, muscular organ, about 4 cm in diameter –Encircles proximal portion of urethra Below urinary bladder –Consists of 30–50 compound tubuloalveolar glands –Surrounded by smooth muscle fibers Prostate gland The secretory part of gland Simple columnar epithelium lamina propria mucose corpora amylacea Interlobular connective tissue Prostate gland (H+E) CORPORA AMYLACEA Produce alkaline mucus prior to ejaculation that neutralizes traces of acidic urine in the urethra Dellmann H.D., Eurell J.: Textbook of Veterinary Histology. Williams. & Wilkins, Philadelphia 2006 Penis (H+E) EPIDERMIS SKIN DERMIS TUNICA ALBUGINEA TWO CORPORA CAVERNOSA URETHRA CORPUS SPONGIOSUM TUNICA ALBUGINEA CORPORA CAVERNOSA CORPORA SPONGIOSUM URETHERA CORPORA SPONGIOSUM CORPORA SPONGIOSUM
