Human Reproductive System: The Human Reproductive System mainly consists of: The Male Reproductive System: The male reproductive system is positioned in the pelvis region and comprises a pair of testes in addition to the accessory glands, ducts, and the external genitalia. A pouch-like structure known as scrotum encloses the testes located outside the abdominal cavity Each testis has close to 250 testicular lobules(compartments). These lobules comprise 1-3 seminiferous tubules wherein the sperms are produced. the lining of these tubules consists of two types of cells -male germ cells and sertoli cells The exterior of these tubules consist of spaces containing blood vessels and Leydig cells Male sex. accessory ducts comprises rete testis, vasa effrentia, epididymis and vas deferens The urethra opens externally to the urethral meatus The male external genitalia, the penis is covered by foreskin which is a loose fold of skin. Ejaculatory duct---- Bulbourethral gland ---M--...__ Crus of penis ----r-- Epididymis Testis The female Reproductive System: The female reproductive system is made up of the internal and external sex. organs, which consists of a pair of ovaries and oviducts, cervix., uterus, vagina and the external genitalia situated in the pelvic region. Along with the mammary glands, these femo.le reproductive organs o.re combined both structurally and functionally in order to support the complete processes of reproduction including ovulation, fertilization, pregnancy, and the birth of o. child. The femo.le accessory ducts are constituted by the oviducts, vo.gino. o.nd uterus The section closer to the ovary is funnel-shaped infundibulum tho.t possesses the fimbriae -finger-like projections facilitating the assimilation of ovum post ovulation The infundibulum directs to o. wider section of oviduct known as ampulla. The last section of the oviduct, isthmus, has a narrow lumen joining the uterus. Uterus is o.lso known o.s the womb The cervical co.vity is known o.s the cervical cano.I which goes onto form the birth co.nal along with the vagino. femo.le ex.terno.l genitalia comprises - mons pubis, labio. minora, lo.bio. mo.joro., clitoris o.nd hymen Both the mo.le and femo.le reproductive systems plo.y o.n important role in the process of reproduction. Other than these reproductive organs, there are sex. hormones which are produced by the respective glo.nds and o.re mainly involved in the development of secondary sex.uo.l characteristics o.nd proper functioning of the reproductive tracts. Uterine fundus Uterine cavity ----Isthmus Fallopian tube Infundibulum Gametogenesis: The process of formation of male gametogenesis. and female gametes in testes and ovary respectively is called It is of two types: • • Spermatogenesis in males Oogenesis in females Spermatogenesis: In testes immature, male germ cells (spermatogonia) produce sperm puberty. by spermatogenesis that begin at The spermatogonia present at the inner side of seminiferous tubules multiply by mitotic division and increase in number. Each spematogonium contain 46 chromosomes. Spermatogonia forms spermatocyte that undergo meiotic division to reproduce secondary spermatocytes having 23 chromosomes. The spermatids are transformed into spermatozoa by the process called spermiogenesis. The sperm heads remain embedded in sertoli cells and are released from seminiferous tubules by the process of spermiation. Spermatogonia At Puberty I Mitosis � differentiation Primary spermatocytes I� 1st meiotic division Secondary spermatocytes I 2nd meiotic .!, division Spermatids ! Differentiation Spermatozoa Hormonal control of spermatogenesis: Spermo.togenesis initiated due to increase in secretion of gono.dotropin releasing hormone by hypothalamus. Increase in GnRH o.ct on anterior pituitary and stimulate secretion of two gono.dotropins, LH o.nd fSH. LH acts on Leydig cells and stimulates them to secrete androgens. fSH acts on Sertoli cells, stimulates secretion of some fo.ctors which help in spermiogenesis. Structure of sperm: Sperm is o. microscopic structure composed of o. head, neck, o. middle piece o.nd o. to.ii. The sperm head contain elongated haploid nucleus, anterior portion of which is covered by cap like structure o.crosome. Human mo.le ejaculates about 200-300 million sperms during o. coitus. The seminal plasma along with the sperms constitutes the semen. The function of mo.le sex secondary ducts o.nd glands o.re maintained by androgen hormones. Plasma �-membrane Head �- Nucleus containing chromosomal material .,.....�-- Middle piece ,.i:ia.-____,a� Mi lochondria (energy source for swimming) Oogenesis: The process of formation of mature female go.metes is co.lied oogenesis. It started during embryonic development stage when millions of ogonia (go.mete mother cells) o.re formed in each feto.l ovary. The gametes mother cells start division and enter into prophase-I of meiotic division and get temporally arrested o.t that stage co.lied primary oocytes. Each primary oocyte get surrounded by o. layer of gro.nuloso. cell than it is co.lied the primary follicle. At puberty, about 60,000- 80,000 primary follicles o.re left in each ovary.