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Reproduction is the formation of new individuals of the same species.
Sexual reproduction is the only method of reproduction in our species.
Sexual reproduction involves the fusion of specialised haploid sex cells.
The fusion of sperm and egg cell is called fertilisation .
Fertilisation results in the formation of a diploid zygote from which a new individual develops.

Sperm
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Sperm is really just a haploid nucleus with a
 flagellum that propels it towards the egg cell.
The middle piece or neck contains mitochondria producing the ATP to supply energy for propulsion.
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The head contains the nucleus with the genetic material.
It also has a large digestive enzyme sac, called the acrosome.
The digestive enzymes help the sperm to make their way to the surface of the egg cell.

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These are the features that distinguish the sexually mature individual from the immature.
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They appear at puberty as a result of new higher levels of oestrogen in females and testosterone in males.
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Primary Sexual Characteristics are the basic forms that distinguish between male and female i.e. the presence or absence of a penis!

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Hair growth on the face, underarm, chest and pubic region
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Enlarged larynx producing a deeper voice
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Wider shoulders
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Greater skeletal musculature
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Taller

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Hair growth in the pubic region and underarm
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Enlarged breasts
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Wide hips
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Greater fat deposits under the skin
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Taller

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The menstrual cycle is the repeating series of changes in the uterine lining of a fertile female if fertilisation and implantation does not happen.
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This cycle ranges from 24 to 35 days, commonly
28 days.

Day 1 to day 5
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Day 1 is the first day of menstruation.
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The corpus luteum of the previous cycle has disintegrated.
The levels of oestrogen and progesterone declined greatly.
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Low progesterone level leads to the menstruation.
Menstruation is the breakdown and discharge of the outer layer of the uterine lining.
Low oestrogen and progesterone levels permit the secretion of FSH (follicle stimulating hormone) by the pituitary gland.

Day 6 to day 13
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FSH stimulated the formation and maturation of a Graafian follicle.
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The maturing follicle secretes oestrogen.
Oestrogen inhibits FSH secretion preventing other follicles maturing.
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Oestrogen also stimulates repair of the uterine lining.
Oestrogen brings about a surge of LH
(luteinising hormone) just before ovulation.

Day 14
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The surge of LH stimulates ovulation.
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Ovulation is the release of the egg cell from the mature Graafian follicle at the ovary’s surface.
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The egg cell is drawn into the Fallopian tube.

Day 15 to day 26
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A corpus luteum (yellow body) develops from the
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‘empty’ Graafian follicle.
The corpus luteum secretes progesterone and oestrogen.
These hormones stimulate the final maturation
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High levels of theses hormones also inhibit FSH and LH secretion from the pituitary.
If implantation does not take place by day 26 the corpus luteum disintegrates.

Day 26 to day 28
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The degeneration of the corpus luteum causes he levels of oestrogen and progesterone to decline rapidly.
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The degenerated corpus luteum becomes a small scar in the ovary.

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Fertilisation is the fusion of the male gamete
(sperm cell) and the female gamete (egg) to form a diploid zygote.
Fertilisation occurs in the Fallopian Tube usually.
Only one sperm cell can fertilise an egg and a chemical change occurs in the membrane of egg once fertilisation has taken place.
The most motile sperm will reach the egg first!

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The usual first sign that pregnancy has occurred is that menstruation does not happen.
Implantation is the embedding of the blastocyst
(early developing embryo) into the uterine lining (endometrium).
Implantation occurs about six days after fertilisation.
The developing embryo releases a hormone into the mother’s blood.
This hormone maintains the corpus luteum.
The surviving corpus luteum continues to secrete progesterone and oestrogen.
As a result the endometrium (uterine lining) does not break down and the pregnancy continues.
Conception is fertilisation followed by successful implantation.

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Lactation is breastfeeding the baby with milk.
The placenta produced very high levels of oestrogen and progesterone.
After the birth of the baby these hormone levels fall rapidly.
This decline allows the pituitary to secrete prolactin hormone.
Prolactin stimulates the glands in the breasts to produce milk.
The suckling of a baby at the breast also stimulates the mother’s pituitary to release prolactin.
The regular presence of prolactin maintains milk production.
Suckling also stimulates the pituitary to secrete oxytocin .
Oxytocin causes the milk ducts to contract ejecting
the milk from the breast.

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Family planning is a conscious action to control the number of and interval between children.
Contraception is the deliberate prevention of fertilisation or implantation.
Natural Methods
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Abstinence: no sexual intercourse. 0% failure rate.
Temporary abstinence: no sexual intercourse during the most fertile period of the menstrual cycle: 24% failure rate.
Withdrawal: penis is removed from the vagina before ejaculation: 25% failure rate.

Male Contraceptive Methods
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Condom: a thin impermeable sheath covering the penis; semen cannot be deposited in the vagina:
10% failure rate.
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Vasectomy: cutting, sealing or tying off the sperm ducts; sperm will not be in the semen:
0.4% failure.

Female Contraceptive Methods
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Cervix Barriers: diaphragm or cap – prevents
 sperm entering the uterus: 15% failure rate.
Intrauterine Devices (IUD): these are plastic or metal loops or coils, prevents implantation: 5% failure rate.
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Oral contraceptive pill: prevents ovulation as the follicles do not mature 6% failure rate.
Spermicides: these chemicals are placed in the vagina to kill sperm: 20% failure rate.
Tubal ligation: the Fallopian tubes are cut and sealed preventing sperm and egg cells meeting:
0.4% failure rate.