The means by which we increase in number and fill the earth. Sexual Reproduction The means by which we increase in number and fill the earth.

Human Reproduction Introduction Puberty Reproductive systems Fertilisation Menstrual cycle Contraception / IVF Sexually Transmitted Diseases Premarital sex and abortion

Introduction One characteristic of living organisms is that they can reproduce. What does ‘reproduce’ mean? to produce young ones or new individuals Why is there a need to reproduce? to replace those that die to ensure that the species does not become extinct What would happen if living thing didn’t reproduce?

(does not involve the fusion of 2 different reproductive cells) Asexual Reproduction (involves the fusion of 2 different reproductive cells) Sexual

Asexual Reproduction In asexual reproduction there is only one parent. All offspring are identical to the parent. They have exactly the same genes. They are called clones.

Sexual Reproduction Involve two parents Have different sex organs Producing gametes

Sexual reproduction involves the fusion of 2 different reproductive cells. What are reproductive cells and where do they come from?

(organs producing reproductive cells or gametes) Gonads (organs producing reproductive cells or gametes) Testes Ovaries produce produce Sperm Ova

In higher animals, the testes and ovaries are borne by different individuals. Hence a mating process is required to allow the meeting of the gametes. Mating occurs only between physically mature individuals.

Fertilisation During sexual reproduction the sperm and the egg join together. This is called fertilisation. A fertilised egg, or zygote, is produced.

Fertilisation External Fertilisation – fertilisation take place outside the body – in water Internal Fertilisation – fertilisation take place inside the body of the female http://www.reef.edu.au/asp_pages/secc.asp?formno=8

When does an individual become physically mature? An individual becomes physically mature when he reaches puberty

Puberty Puberty demo around the age of 11 to 13 the time of active growth in humans and other mammals during which the reproductive organs become functional, i.e. they start producing sex hormones and gametes physical changes develop as a result of the secretion of sex hormones When do girls and boys enter puberty? around the age of 12 to 14 around the age of 11 to 13 Puberty demo

Changes in boys: Changes in girls: 1. physical changes, e.g. (a) growth of hair (i) on certain parts of face (ii) on chest (iii) in armpits (iv) at pubic region (b) “Adam’s apple” appears as the larynx or voice box increases in size, causing the voice to break and deepen testes and penis grow bigger 2. Testes start to produce (i) sperm and (ii) male sex hormones (testosterone) 1. physical changes, e.g. (a) growth of hair (i) in armpits (ii) at pubic region (b) breasts grow bigger hips become wider and rounder 2. Ovaries start to (i) produce female sex hormones (oestrogen and progesterone) and (ii) release mature eggs (ova, singular: ovum) Menstruation starts

Human reproductive organs

The male reproductive system seminal vesicle Cowper’s gland prostate gland seminal vesicle prostate gland sperm duct spermatic cord Cowper’s gland epididymis penis urethra sperm duct urethra testis epididymis scrotum testis penis testis scrotum

Sperm

The Female Reproductive System ovary uterine lining oviduct uterus oviduct cervix ovary uterus uterine lining urethra vagina vagina cervix vulva vulva urethra

Egg /Ovum egg membrane

Comparison of a Sperm and an Ovum Sperm (male gamete ) Ovum (female gamete) 1. Production released by the ovaries produced by the testes released from puberty till menopause produced from puberty onwards 2. Size about 0.01 to 0.05 mm long about 0.10 mm in diameter 3. Quantity only one ovum is released at each ovulation (once in about 28 days) about 500 million sperm are released at each ejaculation during mating 4. Mobility not capable of movement capable of movement by itself, can swim vigorously towards the ovum to fertilise it

Sperm (male gamete ) Ovum (female gamete) 5. Structure divided into 3 parts: spherical , surrounded by a thin membrane and a layer of jelly a) Head - contains large nucleus with little cytoplasm and a sac which contains enzymes that break down part of the egg membrane for penetration during fertilisation has a nucleus and abundant cytoplasm containing stored food b) Middle piece - contains mitochondria that provides energy for the activity of the sperm c) Tail (flagellum) - enables the sperm to swim towards the egg

Comparison of Size

Internal Fertilisation Before fertilisation, mating or sexual intercourse must take place

Erection of penis During sexual intercourse, the erect penis is placed / inserted into the vagina of the female http://www2.hu-berlin.de/sexology/ECE1/foreskin.html

Sexual Intercourse Ejaculation occurs - semen containing sperm (about 500 million are released but only a few hundred reach the oviduct) is deposited / released into the vagina.

Ovulation What is ovulation? release of a mature egg from an ovary occurs about once every 28 days the egg enters the funnel-shaped opening of the oviduct which carries it to the uterus fertilisation can occur if the egg meets a sperm in the oviduct

Oviducts (fallopian tubes) Have many tiny hairs (cilia) on inner walls that help to push the ovum along the oviduct as the muscles contract

Fertilisation What is fertilisation? Fertilisation is the fusion of the nuclei of the sperm and the egg. It occurs in the oviduct. to penetrate the egg, the acrosome of the sperm releases an enzyme to break down part of the egg membrane only the head goes in, and the its nucleus fuses with the nucleus of the egg

What happens after fertilisation? when nucleus of egg fuses with nucleus of sperm, the fertilised egg is called a zygote zygote continues journey through the oviduct and divides to form a ball of cells called the embryo embryo enters the uterus and attaches itself to the thick uterus lining from which it gets nourishment and oxygen embryo grows and develops into a fetus

Embryonic Development

Stages of Menstrual Cycle Menstruation Repair and Growth of Uterine Lining Ovulation Further thickening of Uterine Lining

1. Menstruation If no fertilisation occurs after ovulation, ovaries will stop producing hormones ovum disintegrates thick lining of uterus breaks down broken lining, disintegrated egg and some blood flow out through the vagina – menstrual flow - marking the start of menstruation menstruation lasts for about 5 days

2. Repair and Growth of Uterine Lining (after menstruation) after menstruation, ovaries release oestrogen into bloodstream oestrogen causes growth and repair of uterine lining and blood capillaries to form within the thick lining - uterine wall becomes thick and spongy with blood vessels again

3. Ovulation occurs about the 14th day of the menstrual cycle if fertilisation occurs - the female becomes pregnant if no fertilisation occurs - menstruation occurs again 14 days after ovulation for married couples who want to have children, sexual intercourse during period of ovulation is more likely to result in pregnancy

4. Further thickening of Uterine Wall after ovulation, ovary secretes progesterone into bloodstream progesterone causes uterine lining to thicken further and becomes vascularised (contain many blood capillaries) - ready for implantation of embryo if there is no fertilisation, uterine lining breaks down and menstruation starts again

Menstrual Cycle Start Uterine lining grows and thickens Repair and growth of uterine lining Uterine lining thickens further and becomes more vascular, preparing for implantation Uterine lining breaks down and is discharged Start

Contraception refer to birth control due to over-population

Family Planning by a couple refers to limiting the number of children to have and spacing out the arrival of children made possible by practising birth control or contraception which prevents ovulation or fertilisation (sperm and egg cannot meet) or a fertilised egg from being implanted in the uterine lining

The Fertile and Infertile phases an ovum released during ovulation can live for 2 - 3 days before it dies sperm released into the female reproductive system can live for 2 - 3 days time from day 11 to 17 - fertile phase because fertilisation can occur during this period rest of the days in the menstrual cycle - infertile phase because fertilisation is usually not possible during this period

Irregularities in menstrual cycle can be caused by: However, a woman’s menstrual pattern may not be a reliable indicator of her fertility. Irregularities in menstrual cycle can be caused by:  stress  emotional disturbances  mental fatigue  illness  unbalanced diet, malnutrition

Contraceptive Methods Temporary Methods Permanent Methods (couples can have children when they stop using the methods) (couples cannot have any more children in future, very difficult to reverse)

Temporary Contraceptive Methods Use of spermicides chemicals to kill sperm, in form of gels, aerosol foam or tablets, placed in vagina before intercourse, used together with diaphragm or condom prevent fertilisation

2. Use of contraceptive pills contain a hormone (progesterone) prevent ovulation - prescribed by doctor

3. use of contraceptive devices, such as condoms and diaphragms (prevent sperm from meeting the egg and so prevent fertilisation)                            

Condom a rubber tube worn over erect penis to collect the semen, so no sperm can enter vagina can also prevent spread of sexually-transmitted diseases since impermeable to bacteria and viruses

Diaphragm - dome-shaped rubber cap with elastic rim inserted into top of vagina and placed over cervix prevent sperm from entering the uterus - spermicide may be used together with it

3. use of contraceptive intra-uterine devices - a coil or loop of plastic or metal, inserted into uterus - prevents implantation of embryo in the uterine lining - needs to be fitted by a doctor

Permanent Contraceptive Methods vasectomy (male sterilisation)  - a section from the middle of each sperm duct is cut and ends tied - prevents flow of sperm to urethra - semen released contains only fluid from sex glands   

Permanent Contraceptive Methods ligation (female sterilisation) - mid-portion of each oviduct is cut and ends tied - prevents released egg from travelling through oviduct to reach uterus

Sexually Transmitted Diseases (STDs) diseases passed on from an infected person to another person through sexual intercourse dangerous - because infected person usually feels and looks healthy during early stage of infection babies born to infected mothers may be infected too

Gonorrhoea Syphilis AIDS Sexually Transmitted Diseases (STDs) (Acquired Immune Deficiency Syndrome)

1. Gonorrhoea caused by a type of bacteria can be passed on by an infected person - to his or her partner, during sexual intercourse - to a baby during birth baby can become blind if bacteria enter eyes during birth

Signs and Symptoms of Gonorrhoea pain when passing urine for men - a discharge of pus from the penis for women - lower abdominal pain from infection of the oviducts which can lead to sterility - no symptoms in women in early stages can lead to sterility in men and women if not treated

Gonorrhoea

Gonorrhoea blind due to gonorrhoea

Treatment of Gonorrhoea can be cured by a course of antibiotics such as penicillin

2. Syphilis caused by a type of bacteria spread by an infected person to his or her partner, during sexual intercourse disease can be passed on from an infected woman to her fetus during pregnancy - baby born with congenital syphilis, may suffer from deafness and eye defects, have abnormal teeth, bones and joints

Signs and Symptoms of Syphilis Earlier stage - painless sores (on lips, tongue, penis, vagina, cervix- usually heals in a week or two, even without treatment) - non-itchy skin rash Later stages - heart failure - blindness - bone / joint deformity - paralysis, insanity and even death

Syphilis

Syphilis

Syphilis

Syphilis

Treatment of Syphilis can be cured by a course of antibiotics such as penicillin

Treatment for Gonorrhoea and Syphilis full course of antibiotics, such as penicillin infected person to refrain from sexual intercourse tracing contacts whom the patient has had intercourse and treating them

Prevention and Control of Gonorrhoea and Syphilis - male to wear condom - discourage promiscuous sexual behaviour and keep to one sex partner

3. Acquired Immune Deficiency Syndrome (AIDS) caused by a virus, Human Immuno-deficiency Virus (HIV) destroys body’s immune system so infections which are normally mild may prove to be fatal

Ways in which HIV can be transmitted - sexual intercourse with an infected person - sharing of HIV-contaminated needles when abusing drugs - transfusion of blood contaminate with HIV - during pregnancy or childbirth, when a HIV-positive mother passes the virus to her child

Signs and Symptoms - no symptoms at first but - after a few months may develop symptoms such as - tiredness - loss of appetite - loss of weight - prolonged fever - night sweats - skin rash - swollen lymph glands - persistent diarrhoea - lowered resistance to infections - after several years, immune system weakens

AIDS (final stage of HIV infection) - within 8-10 years for half of those infected complete breakdown of body’s immune system against infections diseases include - pneumonia - Kaposi’s sarcoma (cancer of the blood vessels) - persistent diarrhoea - brain infection - tuberculosis

AIDS

Prevention and control - keep to one sex partner male to wear condoms to reduce the risk of infection avoid sharing items that are likely to break the skin and be contaminated with blood - go to reliable operators for acupucture, ear-piercing or tattooing, making sure instruments are sterilised or insist on using disposable instruments

Educating the public Never share needle Avoid sex with prostitutes / Stay with one STD-free partner Always use a condom Destroy all contaminated blood

Treatment of AIDS drug AZT can slow down the course of the disease there is no cure for AIDS Chemical Name: Azidothymidine Generic Name: Zidovudine Nick Name: AZT Brand Name: Retrovir ® (Retrovis ®) Manufacturer: Glaxo-SmithKline http://www.virusmyth.net/aids/index/azt.htm

Premarital Sex and Abortion Premarital sex is having sexual intercourse before marriage Abortion is the deliberate ending / termination of pregnancy through a medical procedure and involves the removal of the foetus from the mother’s uterus

http://www.freerepublic.com/~tame/

Abortion is safer and easier if it is done in the first 3 months of pregnancy Termination of a pregnancy can be risky if it is not performed by trained medical personnel, under safe and proper conditions http://www.wrtl.org/multimedia.htm

http://www.carmical.net/features/abortionisprolife.html

Main medical reasons for abortion · The baby may be born deformed, with inherited diseases or mental abnormality. · The pregnancy may affect the mother’s health. The baby may be infected with sex transmitted diseases. · The pregnancy may be the results from contraceptive failure or rape.

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