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Hormones

FSH - Produced in the pituitary gland

Oestrogen - produced in the ovaries

LH - produced in the pituitary gland

Progesterone - produced in the ovary after ovulation

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Controlling fertility

Oestrogen can be used to prevent the release of an egg - so it can be used as a method of contraception.

The contraceptive pill contains oestrogen and progesterone.

there is also a progesterone only pill - it has fewer side effects than the pill, and is just as effective.

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Cotraceptives

The contraceptive patch contains oestrogen and progesterone, its a small patch that is stuck to skin.

The contraceptive implant is inserted under the skin of the arm, it releases a continuous amount progesterone.

The contaceptive injection also contains progesterone.

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Questions

What effect does oestrogen have on the release of FSH?  It inhibits it

Give one drawback to using hormones ti increase fertility.  It doesn't always work, it is expensive

Name three forms of contraception that reduce fertility using progesterone.  Progesterone only pill, contraceptive implant, contraceptive injection.

What is the role of oestrogen?  It repairs the lining of the uterus

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Diffusion

Diffusion is the gradual movement of particles from places where there is a high concentration to a lower concentration.

The larger the surcafe area of the membrane, the faster the diffusion rate because more particles can pass through at once.

Only small molecules can diffuse through cell membranes, oxygen, glucose, amino acids and water.

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Osmosis

Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

partially-permeable membrane is a membrane that allows small particles such as water molecules through it, but not larger particles such as sugar molecules and ions from salts.

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Questions

Simple diffusion is...  Molecules from areas of higher concentration to areas of lower concentration 

The rate of diffusion is affected by...   Temperature Size of molecules Steepness of the concentration gradient

Other than diffusion, by what two processes do substances move across exchange surfaces?  Osmosis and active transport

Osmosis is a special case of diffusion through a selectively permeable membrane for which type of molecule? Water

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