Natural Sciences Grade 9 Human reproduction

A presentation about the Human Reproduction section in Grade 9 Natural Sciences as per CAPS.

1. REPRODUCTIVE SYSTEM + HUMAN REPRODUCTION Grade 9

2. Function of Reproductive System Produces sex cells for the purpose of the continuation of the species. Male sex cells: Sperm Female sex cells: Egg

3. Structure of the reproductive system Male: Testes - male sex organ where sperm cells are produced . Female: Ovaries - female sex organs where egg cells are produced. Uterus - Place where the baby grows.

4. What is the purpose of reproduction? Sexual reproduction is the process that ensures that a species, including the human species will not die out, but will continue to live on. How does sexual reproduction happen? 1 sex cell (gamete - Organism’s reproductive cells) from male and female must join (fuse) together. Male gamete = sperm cell Female gamete = ovum (egg cell)

5. Parts of a sperm

6. Parts of an ovum

7. Puberty It’s the period during adolescence which leads to sexual maturity and reproduction can thus take place. When the pituitary gland near the base of the brain releases certain hormones(chemical messengers) into the bloodstream, which ‘tell’ the testes an ovaries to start working.

8. Hormones Testosterone(Male sex hormone) Oestrogen (Female sex hormone)

9. Secondary Sexual Characteristics Girls Boys There is a growth spurt There is a growth spurt Underarm and pubic hair grows Underarm and pubic hair grows Hips become wider Shoulders become wider Menstruation starts Body and facial hair grows Breasts develop Voice becomes deeper

10. Reproductive organs FEMALE REPRODUCTIVE ORGANS MALE REPRODUCTIVE ORGANS

11. The male reproductive organs Functions 1. Produces sperm cells. 2. Produces male hormones (testosterone) 3. Places sperm into the vagina of the female.

12. The female reproductive organs Functions Produces female hormones (oestrogen and progesterone ). Produces ova (egg cells). Receives sperm from the male. Protects and nourish the unborn baby.

13. MENSTRUATION When a female goes through puberty , one of the changes that will take place is that they will start to menstruate . This is the female body’s way of preparing to reproduce A woman’s reproductive system works on a 28 day cycle This cycle is known as the menstrual cycle

14. MENSTRUATION The blood vessel rich lining of the uterus (endometrium) starts to thicken, preparing for a possible developing embryo to implant if fertilization takes place. If fertilization does NOT take place, the blood vessel lining will break down and be shed through the vagina, we say MENSTRUATION occurs

15. FERTILISATION Sperm cell swims towards and encounters the ovum in the Fallopian tubes The nucleus of one sperm fuses with the nucleus of the ovum The DNA of the sperm and ovum combines Fertilisation has occurred and the fertilised egg cell is called a zygote

16. IMPLANTATION Once fertilization occurs, the fertilized egg cell(zygote) starts to divide, cell division occurs. The embryo develops and attaches to the prepared wall of the uterus – implantation has occurred Implantation