4.4 THE CONTRIBUTION OF SCIENCE &TECHNOLOGY TO HUMAN REPRODUCTION
LEARNING OUTCOMES• To explain the contribution of science & technology to human reproduction;• To explain some moral issues related to the application of science & technology to human reproduction;• To explain what sexually transmitted diseases are;• To give examples of sexually transmitted diseases.
FAMILY PLANNING• Two main problems 1. Preventing pregnancy 2. Difficulty in having children• To plan families by preventing fertilisation or development of a fertilised egg when they occur at an convenient time.• Enables married couples to choose when to / not to have children.
FAMILY PLANNING• Enables to take steps to prevent pregnancy during that time frame.• Enough children should practise family planning.• Too many pregnancy affected the mother, economic stability can’t be maintained.
Preventing pregnancy / contraception should involve on of the following concepts : a) Stop the ovum from being formed; b) Stop the sperm from reaching the ovum; c) Stop the fertilised ovum from developing in the uterus.
NATURAL METHOD• Depend on an understanding of the female body’s menstrual cycle.• Ovulation – around day 14 of MC.• F ertile period – between day 12 to 16• Avoiding sex during fertile period to prevent conception.• Detect ovulation by measuring her body temperature daily.• Ovulation is accompanied by a rise in body temperature.
M E C H A N IC A L• M E TH O D By using intrauterine device (IUD). – Made of either plastic, copper or stainless steel. – In various shape such as T-shape, loop or coil. – Are inserted into the uterus by doctors preventing the implantation of the embryo.
Using Diaphragm• A dome-shaped structure made up of rubber.• Placed at the cervix to prevent sperms from entering the uterus
Using a condom• A rubber sheath worn by the male to prevent sperms from entering the female reproductive system• Help to prevent the spreading of sexually transmitted diseases (AIDS)
C H E M IC A LM E T By takingD S • H O oral contraceptive pills. – Contain oestrogen & progesterone prevent the formation of follicles in the ovaries, thus preventing conception. – Eaten every day for 21 days, another 7 days the intake is stopped (menstruation) – After menstruation, the intake of the pill is resumed.
By using spermicides• Are chemical applied on the female to kill sperms.• Available in the form of gel, cream, foam, tablets or spray.
SURGICAL METHODS• To prevent conception in a more permanent form.• The effects of sterilisation are not reversible the decision must be well thought out.
Sterilisation of the male • The vas deferens is tied & then cut vasectomy. • Sperms are still being produced by the testes but are unable to reach the urethra. • They disintegrate & are eventually reabsorbed. • Seminal fluid is still produced but does nOt contain sperms.
Sterilisation of the female • Tubal ligation is a method in which the Fallopian tube is ligated & CUT. • SPERMS are unable to reach the ovum no fertilisation.
Moral issues!!!!• Encourage premarital sex.• The use of IUD to prevent implantation of blastocyst, which is considered a new life, is also questionable.
O V E R C O M IN G IN F E R T IL IT Y• Infertility = the failure of a couple to have babies.• Common causes = blocked Fallopian tubes & low sperm count.
SPERM BANK• A special laboratory that is used to store donor sperm in liquid nitrogen at a temperature of -196°C.• These sperms can be used for artificial insemination by couples having sterility problem.• The genetic biodata of the donor is recorded so that a woman wishing to buy the sperm can choose the quality of sperm she desires.• The sperm are chosen & then injected into her Fallopian tube during ovulation.
ARTIFICIAL INSEMINATION• An instrument is used to inject semen into the uterus of a female during her ovulation so that she can conceive.• No copulation is involved.• Enables a female who has no husband / whose husband is sterile, to have a baby, using sperms from other males obtained from the sperm bank enables a female to have a child without having sexual relations with a man.
IN VITRO FERTILISATION (IVF)• ‘In vitro’ = ‘outside the body’.• To overcome sterility caused by blockage in the Fallopian tubes.• The female concerned is given daily injections of hormones to stimulate the production of ova using ultrasound to view the ovary, the egg in the ovary is extracted by the needle fertilisation in the Petri dish & is incubated for a few hours the embryo is implanted into the uterus by using a catheter embryo develop baby born (test tube baby).
SURROGATE MOTHER• A woman who gives birth to a baby for another woman who is unable to conceive.• The female’s ovum is fertilised in vitro using her husband’s sperm. The embryo formed is then implanted into the uterus of the surrogate mother to continue its development.
SEXUALLY TRANSMITTED DISEASES• Known as venereal diseases.• Spread through sexual contact.• Include syphilis, gonorrhoea & acquired immune deficiency syndrome (AIDS).
SYPHILIS• Caused by a type of bacterium (Treponema palladum) which enters the body through sexual intercourse.• Also pass from an infected pregnant mother to the foetus through the placenta, resulting in her baby being born with the disease.• Symptoms : a hard ulcer at the site of infection, fever, enlargement of lymph nodes & lesions throughout the body.• SEVERE CASES = the heart, blood vessels & the nervous system may be damaged.• Penicillin is effective in treating the disease in its early stages.
GONORRHOEA• Caused by a type of bacterium (Neisseria gonorrhoeae).• Symptoms : pain during urination & discharge of pus from the penis or vagina.• SEVERE CASES : sterility & heart problems.• Treatment : antibiotics (sulphonamides, penicillin @ tetracycline) is effective in the early stages.
ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS)• Caused by human immunodeficiency virus (HIV).• Spread through sexual contact, blood transfusion & the sharing of syringes among drug addicts. Can also pass from an expectant mother to her child through the placenta or breast milk.• Check Chapter 1 (Form 5)
DON’ T FORGET TO S T U D Y!!! MAKEYO U R O W NR E V IS IO N !! !
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