ANATOMY OF THE REPRODUCTIVE SYSTEM Meditative Rose by

ANATOMY OF THE REPRODUCTIVE SYSTEM Meditative Rose by Salvador Dali Kaan Yücel M. D. , Ph. D. 19. December. 2014 Friday

MALE GENITAL SYSTEM The reproductive system in men has components in the abdomen, pelvis, and perineum. The major components are a testis, epididymis, ductus deferens, and ejaculatory duct on each side, and the urethra and penis in the midline. In addition, three types of accessory glands are associated with the system: Ø a single prostate; Ø a pair of seminal vesicles; and Ø a pair of bulbourethral glands.

SEMINAL GLANDS § Each seminal gland (vesicle) is an elongated structure that lies between the fundus of the bladder and the rectum. § The seminal glands are obliquely placed superior to the prostate and do not store sperms, as the “vesicle” term implies. § They secrete a thick alkaline fluid with fructose (an energy source for sperms) and a coagulating agent that mixes with the sperms as they pass into the ejaculatory ducts and urethra.

EJACULATORY DUCTS Slender tubes Union of ducts of the seminal glands with ductus deferentes

PROSTATE Largest accessory gland of the male reproductive system Firm, walnutsize p Surrounds the prostatic urethra. The glandular part makes up approximately two thirds of the prostate; the other third is fibromuscular.

BULBOURETHRAL GLANDS Ø Lie posterolateral to the intermediate part of the urethra Ø Their ducts open into the proximal part of the penis

SPERMATIC CORD v Contains structures running to and from the testis v Passes through the inguinal canal v Ends in the scrotum at the posterior border of the testis

SCROTUM A cutaneous sac consisting of 2 layers: heavily pigmented skin and the closely related dartos fascia, a fat-free fascial layer including smooth muscle fibers (dartos muscle) responsible for the rugose (wrinkled) appearance of the scrotum. Because the dartos muscle attaches to the skin, its contraction causes the scrotum to wrinkle when cold, and assisting the muscles in holding the testes closer to the body, all of which reduces heat loss. The scrotum is the male homologue of the labia majora in women.

TESTIS (TESTICLES) Male gonads—paired ovoid reproductive glands that produce sperms (spermatozoa) and male hormones, primarily testosterone. Originally develop high on the posterior abdominal wall and then descend, normally before birth, through the inguinal canal in the anterior abdominal wall and into the scrotum of the perineum.

EPIDIDYMIS An elongated structure on the posterior surface of the testis. Efferent ductules of the testis transport newly developed sperms to the epididymis. At the tail of the epididymis, the ductus deferens begins as the continuation of the epididymal duct.

PENIS Ø Suspended from the front and sides of the pubic arch and containing the greater part of the urethra. Ø Consists of a root and body. Ø Body of penis is entirely covered by skin; the tip of the body is covered by the glans penis. Ø The external urethral orifice is a sagittal slit, normally positioned at the tip of the glans.

FEMALE GENITAL SYSTEM The female internal genital organs include the ovaries, uterine tubes, uterus, and vagina.

OVARIES Ø Almond-shaped and -sized female gonads in which the oocytes develop. Lie adjacent to the lateral pelvic wall. Ø Also endocrine glands that produce reproductive hormones. Ø Like the testes in men, the ovaries develop high on the posterior abdominal wall and then descend before birth, bringing with them their vessels, lymphatics, and nerves. Ø Unlike the testes, the ovaries do not migrate through the inguinal canal into the perineum, but stop short and assume a position on the lateral wall of the pelvic cavity.

UTERINE TUBES Ø Conduct the oocyte, discharged monthly from an ovary during childbearing years, from the periovarian peritoneal cavity to the uterine cavity. Ø Provide the usual site of fertilization. Ø Extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries.

The uterine tubes are divisible into four parts, from lateral to medial: Infundibulum: opens into the peritoneal cavity through the abdominal ostium. Ampulla: widest and longest part of the tube, which begins at the medial end of the infundibulum; fertilization of the oocyte usually occurs in the ampulla. Isthmus: thick-walled part of the tube, which enters the uterine horn. Uterine part: short intramural segment, opens via the uterine ostium into uterine cavity at the uterine horn.

UTERUS The uterus (womb) is a thick-walled, pear-shaped, hollow muscular organ. The embryo and fetus develop in the uterus. Its muscular walls adapt to the growth of the fetus and then provide the power for its expulsion during childbirth. The non-gravid (non-pregnant) uterus usually lies in the lesser pelvis, with its body lying on the urinary bladder and its cervix between the urinary bladder and rectum.

Ø The uterus is a very dynamic structure, the size and proportions of which change during the various changes of life. Ø When the bladder is empty, the uterus typically lies in a nearly transverse plane. Ø The position of the uterus changes with the degree of fullness of the bladder and rectum, and stage of pregnancy.

Ø The uterus is divisible into two main parts: the body and cervix. Ø The uterine horns (L. cornua) are the superolateral regions of the uterine cavity, where the uterine tubes enter. The wall of the body of the uterus consists of three coats, or layers: 1. Perimetrium 2. Myometrium 3. Endometrium

VAGINA A distensible musculomembranous tube, extends from the middle cervix of the uterus to the vaginal orifice, the opening at the inferior end of the vagina.

Ø The vagina lies posterior to the urinary bladder and urethra, the latter projecting into its inferior anterior wall. Ø It lies anterior to the rectum.

EXTERNAL PART OF THE FEMALE GENITAL SYSTEM Ø In women, the clitoris and vestibular apparatus, together with a number of skin and tissue folds, form the vulva. Ø On either side of the midline are two thin folds of skin termed the labia minora.

Ø Lateral to the labia minora are two broad folds, the labia majora, majora which unite anteriorly to form the mons pubis. Ø The mons pubis overlies the inferior aspect of the pubic symphysis and is anterior to the vestibule and the clitoris.

VESSELS OF THE UROGENITAL SYSTEM

SYMPATHETIC FIBERS § innervate blood vessels; § cause contraction of smooth muscle in the internal urethral sphincter in men and the internal anal sphincters in both men and women; § cause smooth muscle contraction associated with the reproductive tract and with the accessory glands of the reproductive system; and § are important in moving secretions from the epididymis and associated glands into the urethra to form semen during ejaculation.

PARASYMPATHETIC FIBERS enter the pelvic plexus in pelvic splanchnic nerves that originate from spinal cord levels S 2 to S 4. They: § § generally vasodilatory; stimulate bladder contraction; stimulate erection; and modulate activity of the enteric nervous system of the colon distal to the left colic flexure (in addition to pelvic viscera, some of the fibers from the pelvic plexus course superiorly in the prevertebral plexus, or as separate nerves, and pass into the inferior mesenteric plexus of the abdomen).