Biology · OCR Paper 1
The Endocrine System
How hormones carry messages in the blood, how the menstrual cycle is controlled, how hormones are used in contraception and to treat infertility, and how plant hormones control growth. Matches OCR GCSE Biology A (Gateway Science) B3.2 (coordination and control: the endocrine system). The lessons on hormones, the menstrual cycle and contraception are for both Combined Science and separate Biology, with Higher tier extras marked. Plant hormones are for separate Biology only.
Lessons
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1
Hormones and the Endocrine System
Hormones are chemical messengers that coordinate the body more slowly than nerves, but with longer-lasting effects. This lesson covers the principles of…
8 terms -
2
The Menstrual Cycle
Hormones control the menstrual cycle and prepare the body for a possible pregnancy. This lesson covers the roles of oestrogen, progesterone, FSH, LH and…
8 terms -
3
Contraception and Fertility Treatment
Hormones can be used to prevent pregnancy and to help people who cannot conceive. This lesson covers hormonal and non-hormonal contraception and how to…
8 terms -
4
Plant Hormones
Plants have no nerves, but they still respond to light, gravity and other stimuli, using hormones. This lesson is for separate Biology. It covers how auxin…
8 terms
Key terms in this chapter
All 32, gathered from every lesson.
- Hormone
- A chemical messenger carried in the blood.
- Endocrine gland
- A gland that releases hormones into the blood.
- Target organ
- An organ with receptors that respond to a particular hormone.
- Pituitary gland
- The master gland that releases hormones controlling other glands.
- Thyroid gland
- The gland in the neck that releases thyroxine.
- Adrenal gland
- A gland above the kidney that releases adrenaline.
- Negative feedback
- A change causes a response that reverses the change (Higher tier).
- Metabolic rate
- The rate of the chemical reactions in the body.
- FSH
- Follicle stimulating hormone, which makes an egg mature in an ovary.
- LH
- Luteinising hormone, which stimulates ovulation.
- Oestrogen
- A hormone from the ovaries that repairs the uterus lining.
- Progesterone
- A hormone that maintains the lining of the uterus.
- Testosterone
- The male sex hormone made by the testes.
- Ovulation
- The release of a mature egg from an ovary.
- Menstruation
- The loss of the lining of the uterus, which is a period.
- Follicle
- The structure in the ovary in which an egg matures.
- Contraception
- A method of preventing pregnancy.
- Combined pill
- A contraceptive pill containing oestrogen and progesterone.
- Implant
- A small rod put under the skin that releases progesterone slowly.
- Condom
- A barrier method that stops sperm reaching an egg and protects against infection.
- IUD
- A small device put in the uterus that prevents pregnancy.
- Infertility
- Difficulty in conceiving a child.
- IVF
- In vitro fertilisation: fertilising an egg with sperm in a laboratory dish (Higher tier).
- Embryo
- A ball of cells that grows from a fertilised egg.
- Plant hormone
- A chemical that regulates plant growth and development.
- Auxin
- A plant hormone made in shoot and root tips that controls growth.
- Phototropism
- Growth of a plant in response to light.
- Gravitropism
- Growth of a plant in response to gravity.
- Gibberellin
- A plant hormone that breaks seed dormancy and stimulates stem growth.
- Ethene
- A plant hormone, a gas, that makes fruit ripen.
- Tropism
- A growth response of a plant to a stimulus in a particular direction.
- Dormancy
- A resting state of a seed, in which it does not germinate.