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Human Reproductive system

Human Reproductive system. INTRODUCTION.

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Human Reproductive system

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  1. Human Reproductive system

  2. INTRODUCTION • The reproductive system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system.Human reproduction takes place as internal fertilization by sexual intercourse. During this process, the erect penis of the male is inserted into the female's vagina until the male ejaculates semen, which contains sperm, into the female's vagina. The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum. Upon successful fertilization and implantation, gestation of the foetus then occurs within the female's uterus for approximately nine months, this process is known as pregnancy in humans. Gestation ends with birth, the process of birth is known as labor. Labor consists of the muscles of the uterus contracting, the cervix dilating, and the baby passing out the vagina. Human's babies and children are nearly helpless and require high levels of parental care for many years. One important type of parental care is the use of the mammary glands in the female breasts to nurse the baby.

  3. MALE REPRODUCTIVE SYSTEM • The male reproductivesystem is a series oforgans located outside of the body and around the pelvic regionof a male that contribute towards the reproductive process. The primary direct function of the male reproductive system is to provide themale gamete or spermatozoafor fertilization of the ovum.

  4. MALE REPRODUCTION CONT

  5. MALE REPRODUCTIVE SYSTEM: FUNCTIONS OF DIFFERENT PARTS • THE TESTES • Contains many coiled seminiferous tubulesin which the male gametes (sperm)are formed. • Produce male hormones for the development of secondary male characteristics. • THE SCROTUM • Accommodates the testesoutside the body. • Ensures that temperature is favourable for production of sperms. • THE EPIDIDYMIS • Store sperm temporarily • Provide a place where the can undergo final maturation.

  6. MALE REPRODUCTIVE SYSTEM CONT. • THE EJACULATORY DUCT • Has a muscular wall to squirt semen through the urethra • THE VAS DEFERENCE • Carries sperms from the epididymis to the ejaculatoryduct. • THE SEMINAL VESICLES • Provide a source of nourishment for the sperm cells. • Provide a fluid mediumin which the sperm are able to move.

  7. MALE REPRODUCTIVE SYSTEM CONT. • THE PROSTATE GLAND • Secretes a fluidwhich stimulates the movement of the maturesperm cells. • Add alkalinity to semen. • THE GLANDS OF COWPER (BULBOURETHRAL GLANDS) • Secrete afluidthat stimulates thespermsto greater motility. • THE PENIS • Transfers the sperm from the male genital system to vagina.

  8. MALE REPRODUCTIVE SYSTEM CONT. • THE CELLS OF SERTOLI • Assist with providing nutrition forspermatozoa • THE INTERSTITIAL CELLS (CELLS OF LEYDIG) • Produce male sex hormone, testosterone, whichcontrols development of secondary male sexual characteristics.

  9. FEMALE REPRODUCTIVE SYSTEM • The female reproductivesystem is a series oforgans primarily located inside of the body and around the pelvic regionof a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which acts as the receptacle for the male's sperm, the uterus, which holds the developing feotus,and the ovaries, which produce the female's ova.

  10. Female reproductive system cont.

  11. THE FEMALE SYSTEM CONSISTS OF THE FOLLOWING PARTS: • OVARIES • There are two ovaries and they produce ova. The ovaries are suspended in the abdominal cavity. Each ovary is held in place by two ligaments, one extends from the ovary to the abdominal wall while the other reaches from the ovary to the outside of the uterus. Each ovary is made up of a covering of germinal epitheliumwith a large number of follicles within it. Thefollicles secrete the female sex hormones. • FALLOPIAN TUBE • Leading away from the ovaries are the oviducts, also called the fallopian tubes. They do not connect directly to theovaries, but have a funnel – shaped opening just a short distance away called the fimbriae. The fallopian tubes transfer an ovumfrom the ovary to the uterus. The lining of each tube is ciliated to create a current that moves the ovum towards theuterus. The sperm fertilizes the ovumas it travels down the fallopian tube.

  12. Parts of reproductive system cont. • UTERUS • The fallopian tubes lead to the uterus or womb. The uterus has very thick walls, made of muscle. The layers are, from the outside, the perimetrium, myometriumand the endometrium. The uterus is about the size of a clenched fist, and is able to stretch a great deal to accommodate the developingfoetus. • CERVIX • At the base of the uterus is a narrow opening, guarded by muscles. This is referred to as the neck or the cervix. The cervixleads to the vagina.

  13. Female parts cont. • VAGINA • The vagina acts as an entrance for the sperm and an exile for the foetus during child – birth. The external opening is called thevulva. The opening from the bladder, called the urethra, runs in front of the vagina, while the rectum is just behind it. The three tubesopen out separately to the outside.

  14. OVULATION, OVARIAN OR MENSTRUAL CYCLE • Ovulation occurs when a ripe egg/ovum is released by the ovary. • MESRUAL CYCLE • The menstrual cycle is a complex series of events occurring each monthin a woman’sreproductive system. It lasts for about 28 daysand is co-ordinated by the sex hormones; oestrogen and progesterone andtwoother hormones made by the pituitary gland. D Sekhukhune 15 & 19 September 2011

  15. Diagram of female menstrual cycle D Sekhukhune 15 & 19 September 2011

  16. MENSTRUAL CYCLE CONT. • TWO IMPORTANT EVENTS OCCUR WHEN: • One ovum developsinside the ovary, and is released. • The thickening of the uterine wallwhich prepares for the implantation of the developing embryo • The pituitary gland secretes FSH (follicle stimulating hormone)and LH(Luteinising hormone). FSH stimulates the ovary to secreteoestrogen and LHstimulates the ovary to secrete progesterone. D Sekhukhune 15 & 19 September 2011

  17. MENSRUAL CYCLE CONT. • LET US NOW LOOK AT WHAT OCCURS IN THE OVARY: • The germinal epitheliumproduces a primary folliclewhich develops into a Graafiaan follicle or ovarian follicle. In the Graafiaan follicle anovum develops. • FSH (follicle stimulating hormone) is secreted by the Pituitary Gland and this stimulates the ovary to secrete oestrogen. The hormone oestrogen prepares the lining of the uterus for the attachment of the embryo.Theendometrium becomesthicker and its blood supply increases. When the Graafiaan follicleis matured it ruptures and releases the egg. This is known as ovulation. The releasedeggis captured by thefimbriae and moves along the fallopian tube. D Sekhukhune 15 & 19 September 2011

  18. MENSTRUAL CYCLE CONT. • Oestrogen causes ovulation and repair of the uterus lining after menstruation. The concentration is high at days 12 to 13. Progesterone maintains the thickness of the uterus and prevents development of a new follicle in the ovary. D Sekhukhune 15 & 19 September 2011

  19. MENSRUAL CYCLE CONT. • Ovulation usually occurs in the middle of a cycle, if the cycle is 28 days, then ovulation is on day 14.LH (Luteinising hormone)which is secreted by the pituitary glandand stimulates the ovary to secrete progesterone changes the ruptured follicle into a corpus luteum. Progesterone prepares the uterine wallfor implantation of the embryo. If the ovum is not fertilised,the corpus luteum gradually becomes smaller and stops producing progesterone.This then allows menstruation to start and a new follicledevelops. D Sekhukhune 15 & 19 September 2011

  20. FERTILIZATION AND DEVELOPMENT OF FOETUS • Fertilization occurs in the upper portion of the fallopian tube. Many sperms are deposited into the vagina, using their tails swim up through the cervix through the uterus and into the fallopian tube. Only one sperm enters the egg. Only the head of the sperm goes in, the tail is left outside. The nucleus of the sperm (n) fuses with the nucleus of the egg (n) is forming a zygote (2n). This is called fertilization. As soon as the successful sperm enters the egg, the egg membrane becomes impenetrable, so that no other sperm can get in. The unsuccessful sperm will all die. D Sekhukhune 15 & 19 September 2011

  21. THE PROCESS OF FERTILISATION

  22. DEVELOPING FOETUS IN EMBRYO • Once the female is pregnant, the pregnant mother needs to make regular monthly visits to the clinic or gynaecologist. The length of the time between fertilization and birth is called the gestation period. A few weeks before birth the foetus usually turns over in the uterus, so that it is lying head downwards. The process of birth is known as parturition. Birth begins when the muscular layer in the wall of the uterus contracts. This is called labour. D Sekhukhune 15 & 19 September 2011

  23. DEVELOPING FOETUS CONT. D Sekhukhune 15 & 19 September 2011

  24. DEVELOPING FOETUS CONT. • There are three stages in labour: • FIRST STAGE: • This stage covers the time from the onset of labour until the cervix is completely dilated. This is the longest stage, lasting about – 12 hours for the first baby and 6 – hours for the second baby. After several hours the cervix is wide enough for the head of the baby to pass through. • SECOND STAGE: • The cervix is now completely dilated and lasts until the baby is delivered. This stage lasts about 30 minutes to 2 hours. • THIRD STAGE: • This stage begins after birth of the baby and ends after the delivery of the placenta or after birth. The duration of this stage is about 5 – 20 minutes. D Sekhukhune 15 & 19 September 2011

  25. Developing foetus cont. Two types of deliveries • Normal delivery Is a natural birth. D Sekhukhune 15 & 19 September 2011

  26. Birth control(contraception) and termination of pregnancy • Contraception or birth control is when couples want to remove the possibility of conception. It is achieved by preventing the egg and sperms from meeting or by preventing implantation. D Sekhukhune 15 & 19 September 2011

  27. DIFFERENT METHOD OF Contraception • Contraceptive pill – Contains hormones which prevent ovulation. D Sekhukhune 15 & 19 September 2011

  28. Contraception method cont. • Cap (diaphragm) – blocks path of sperm at cervix. • Coil (intra uterine device) – fitted in uterus prevents implantation D Sekhukhune 15 & 19 September 2011

  29. Contraception method cont. • Condom- rubber sleeve, retains semen D Sekhukhune 15 & 19 September 2011

  30. Contraception method cont. • Withdrawal- penis withdrawn from the vagina before ejaculation • Rhythm Method- avoidance of sexualintercourse around the of ovulation D Sekhukhune 15 & 19 September 2011

  31. Contraception method cont. • Sterilisation - male: sperm ducts surgically cut (vasectomy) D Sekhukhune 15 & 19 September 2011

  32. Contraception method cont. • Female: female oviducts surgically cut. D Sekhukhune 15 & 19 September 2011

  33. conclution • Human Reproductive system helps to increases learners knowledge about life because it is based more in natural things that are currently happening in the world. Majority of parents are afraid to face their children to talk with them about the dangerous of sexual intercourse at young stage. Knowing about Reproductive system for learners will help to decrease the rate of teenage pregnancy in all schools. Learners will know how to prevent themselves and the consequences of being in a sexual relationship at young stage. The government should hire more counsellors to go all around the world in different schools to teach all learners about sexual education. D Sekhukhune 15 & 19 September 2011

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