Chapter 3 Human Reproduction

1 . What are the male reproductive organs?

    It includes a pair of testes along with accessory ducts, glands and the external genitalia.

2.Explain male reproductive system

•     The male reproductive system is located in the pelvis region. It includes a pair of testes along with accessory ducts, glands and the external genitalia.

•     The testes are situated outside the abdominal cavity within a pouch called scrotum. The scrotum helps in maintaining the low temperature of the testes (2–2.5o C )lower than the normal internal body temperature) necessary for spermatogenesis. 

•     In adults, each testis is oval in shape, with a length of about 4 to 5 cm and a width of about 2 to 3 cm. The testis is covered by a dense covering. Each testis has about 250 compartments called testicular lobules.

•     Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced. Each seminiferous tubule is lined on its inside by two types of cells called male germ cells

(spermatogonia) and Sertoli cells.

•     The regions outside the seminiferous tubules called interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells.

•     The male sex accessory ducts include rete testis, vasa efferentia, epididymis and vas deferens . The seminiferous tubules of the testis open into the vasa efferentia through rete testis. The vasa efferentia leave the testis and open into epididymis located along the posterior surface of each testis

•     The epididymis leads to vas deferens that ascends to the abdomen and loops over the urinary bladder. 

•     It receives a duct from seminal vesicle and opens into urethra as the ejaculatory duct. These ducts store and transport the sperms from the testis to the outside through urethra. The urethra originates from the urinary bladder and extends through the penis to its external opening called urethral meatus.

•     The male accessory glands  include paired seminal vesicles, a prostate and paired bulbourethral glands. Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain enzymes. The secretions of bulbourethral glands also helps in lubrication of penis


3.    What are female reproductive organs ?

                  The female reproductive system consists of a pair of ovaries along with a pair of oviducts, uterus, cervix, vagina and the external genitalia located in pelvic region

4.    Explain female reproductive system?

•     The female reproductive system consists of a pair of ovaries along with a pair of oviducts, uterus, cervix, vagina and the external genitalia located in pelvic region. 

•     These parts of the system along with a pair of the mammary glands are integrated structurally and functionally to support the processes of ovulation, fertilisation, pregnancy, birth and child care.

•     Each ovary is about 2 to 4 cm in length and is connected to the pelvic wall and uterus by ligaments. Each ovary is covered by a thin epithelium which encloses the ovarian stroma. The stroma is divided into two zones – a peripheral cortex and an inner medulla.

•     The oviducts (fallopian tubes), uterus and vagina constitute the female accessory ducts. Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the uterus,  the part close to the ovary is the funnel-shaped infundibulum.

•     The edges of the infundibulum possess finger-like projections called fimbriae

•     The infundibulum leads to a wider part of the oviduct called ampulla. The last part of the oviduct, isthmus has a narrow lumen and it joins the uterus.

•     The cavity of the cervix is called cervical canal  which along with vagina forms the birth canal. The wall of the uterus has three layers of tissue.

•     The external thin membranous perimetrium, middle thick layer of smooth muscle, myometrium and inner glandular layer called endometrium that lines the uterine cavity.

•     The female external genitalia include mons pubis, labia major, labiaminora, hymen and clitoris . Mons pubis is a cushion of fatty tissue covered by skin and pubic hair.

•     The labia majors are fleshy folds of tissue, which extend down from the mons pubis and surround the vaginal opening.

•     The labia minora are paired folds of tissue under the labia majora.

•     The opening of the vagina is often covered partially by a membrane called

•     hymen. The clitoris is a tiny finger-like structure which lies at the upper junction of the two labia minora above the urethral opening

•     The glandular tissue of each breast is divided into 15-20 mammary lobes containing clusters of cells called alveoli .The cells of alveoli secrete milk, which is stored in the cavities (lumens) of alveoli. The alveoli open into mammary tubules. • The tubules of each lobe join to form a mammary duct. Several mammary ducts join to form a wider mammary ampulla which is connected to lactiferous duct through which milk is sucked out. 

          


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