Biology - B3 - Organism Level Systems

What do hormonal contraceptives (signals throughout the body that prevent pregnancy) do?

They contain hormones (messenger signals in the body) to stop FSH (a hormone that makes eggs grow) so no eggs grow.

What is in the combined pill?

Oestrogen (hormone that controls monthly changes) and progesterone (hormone that helps the body stay ready for pregnancy in case). It is used to prevent pregnancy daily.

How does oestrogen prevent pregnancy?

It stops FSH (hormone that makes egg grow) so no egg is released or grows.

How does progesterone prevent pregnancy?

It stops egg release and makes thick cervical mucus (sticky fluid in the uterus (womb)) that blocks sperm.

What is the mini-pill?

Progesterone only pill (fewer side effects)

How do implants/injections/patches work?

It slowly releases progesterone (vital to release eggs) so it stops egg release for months/years

Why are implants/patches better than the combined pill?

You don’t have to remember every day.

What are IUDs? (intrauterine device)

It’s a small device in the uterus that stop the embryo from installing.

What does a plastic IUD do?

Releases progesterone and makes a thick mucus which blocks sperm.

How do barrier methods work?

It stops sperm from reaching the egg.

What is a condom?

It is a rubber sheath worn on the penis which catches sperm and protects against STIs,

What is a femidom?

Rubber sheath inside the vagina which blocks sperm.

What is a diaphragm?

Rubber cap covering uterus, often used with spermicide (chemical that kills sperm)

What is abstinence?

Deciding to not have sexual intercourse - only 100% efficient method.

What is natural family planning?

Avoiding to have sex during ovulation (egg release) days by tracking : cycle, body temperature and cervical mucus rates.

What is vasectomy?

When sperm ducts (tubes) are cut → so no sperm in semen.

What is female sterilisation?

Oviducts (tubes carrying eggs) are cut, so the egg cannot meet the sperm.

What are factors to consider in contraception?

Reliability (success rate), side effects (unwanted effects), human error (mistakes), invasiveness (how medical procedure feels), frequency (how often needed), STI protection.

Which method protects against STIs?

Condoms

What hormones are used for fertility (the ability to have babies) treatment?

FSH (grows eggs) + LH (luteinising hormone = triggers ovulation/egg release).

What risk comes with FSH + LH treatment?

Several eggs released → multiple births (twins/triplets).

What is IVF (in vitro fertilisation = “fertilisation in glass”)?

Eggs collected → fertilised with sperm in dish → embryos (early baby cells) placed in uterus.

Risks of IVF?

Expensive, not always successful, multiple births possible (twins or triplets)