Year 7 Human Reproduction

Key Words

Asexual reproduction
Sexual reproduction
Gestation
Puberty
Fertilisation
Foetus
Menstrual cycle
Ovum
Sperm
Fallopian tube
Uterus
Oestrogen
Progesterone
LH
FSH
Implantation
Zygote
Placenta

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Sexual and Asexual Reproduction

Asexual reproduction

•1 parent only (doesn’t require gametes)

•Offspring are genetically identical to the parent •No genetic variation (all offspring are clones of the parent) – susceptible to same diseases.

Sexual reproduction

•2 parents (and gametes) needed - offspring inherit their genes from both parents (half from each parent)

•Offspring are not genetically identical to either parent – there’s more genetic variation

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Puberty

•The time during which adolescents reach sexual maturity and become capable of reproduction. •Changes occur during puberty due to hormones.

Oestrogen - produced by the ovaries

-controls the development of female secondary sexual characteristics

Testosterone - produced by the testes (male reproductive parts)

- controls the development of male secondary sexual characteristics

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Secondary Sexual Characteristics (Girls)

Voice deepens gradually
Hips get wider
Breasts develop
Ovaries start to get egg cells (menstruation starts)
Pubic hair grows
Under arm hair grows
Sexual organs grow and develop

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Secondary Sexual Characteristics (Boys)

Voice breaks
Hair grows on face and body
Body becomes more muscular
Testes start to produce sperm cells
Pubic hair grows
Under arm hair grows
Sexual organs grow and develop

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Function of The Placenta

•To supply oxygen to the foetus •To supply nutrients (glucose, amino acids) to the foetus •To remove waste products from the foetus (e.g. CO2) •To produce hormones •To provide temporary immunity (from disease/infections)

The amniotic fluid protects the developing baby from bumps and knocks and allows the baby to move

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Changes through pregnancy

•The mother’s placenta will develop and grow throughout the pregnancy in order to supply enough oxygen and nutrients to the growing baby. •This is because as the foetus develops and gets bigger, it will need more oxygen and more nutrients from the mother (through the placenta). •The mother’s blood volume will also increase throughout pregnancy, so it’s important that she has enough iron in her diet. Iron is needed to make red blood cells.

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Effects of drugs on the foetus

•The mother’s lifestyle can affect the developing foetus.
•Smoking reduces the amount of oxygen in the bloodstream, so the baby would get less oxygen. This can lead to low birth weight and premature birth (when a baby is born too soon).
•Drinking alcohol during pregnancy can harm the developing foetus’ nervous system, especially its brain.

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