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27 Cards in this Set
- Front
- Back
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What is a Hormone? |
A chemical that is released into the blood stream by glands and creates a long, slow action general effect in a targeted area |
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Give three examples of hormones |
Oestrogen Testosterone Adrenaline |
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Describe how Hormones are involved in the Menstrual Cycle |
FSH is produced by the pituitary gland and this causes an egg to mature in the ovaries and stimulates the ovaries to produce Oestrogen. Which, in turn prohibits FSH and causes LH to be produced by the pituitary gland. LH then causes the Ovaries to release an egg. |
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when is the egg released during the Menstrual Cycle? |
Day 14 |
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Name all 5 sense organs and their stimuli |
Eyes Light Ears Sound Nose Smell Tongue Chemicals in food - Taste Skin Touch, Heat |
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Name and describe the parts of a Neurone |
The 'head' is the Dendrite and the 'Tail' is the Axon The axon of one Neurone attaches itself to the dendrite of another |
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Describe what is involved in a Reflex action |
A sense organ gives an electrical signal to a sersory neuron, which transmits the signal to a relay neuron in the spine, which transmits it onto a motor neurone which transmits it to an effector |
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What is an effector? |
The end output of a reflex action, most often a muscle |
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What is a synapse? |
A synapse is the gap between two nuerons |
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What crosses a Synapse |
A Chemical called a Neurotransmitter, this transmits an electrical signal between Nuerons |
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How do painkillers such as Paracetamol work? |
They slow down the transmission of Neurotransmitters across a synapse so that the electrical signals reach your brain slowly rather than all at once |
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How can Oestrogen be used as a contraceptive?
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Oestrogen prohibits the production of FSH, so if injections of Oestrogen are given, no FSH is produced, meaning that no eggs mature in the ovaries, preventing pregnancy
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How can Progesterone be used as a contraceptive?
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Progesterone Stimulates the production of cervical mucus, meaning that sperm cells cannot reach the egg
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What is 'the pill' also known as?
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The combined oral contraceptive pill
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What hormones are in 'the pill'
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Oestrogen and Progesterone
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How effective is the pill?
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It works in 99% of cases, however it has side effects such as blood clotting and does not protect against STDs
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Why can women with naturally low levels of FSH not get pregnant?
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FSH causes eggs to mature in the ovaries, without the correct levels of this hormone, no eggs will mature and a pregnancy cannot then occur.
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What hormones can be injected to increase fertility?
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Injections of FSH and LH can increase fertility as this will cause more eggs to mature and more to be released, however this can result in multiple pregnancies
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What does IVF stand for?
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In Vitro Fertilisation
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What is IVF?
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When an egg is removed from the mother and fertilised with the fathers sperm in a lab. then these are implanted back into the mother. FSH and LH are given before this process
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Name a plant hormone
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Auxin
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What effect does Auxin have on roots and shoots?
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it causes growth at their tips
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What happens when there is extra Auxin in an area of a shoot?
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Growth is promoted in that area
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What happens when there is extra Auxin in an area of a root?
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Growth is inhibited in that area
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What is it called when plants grow in relation to gravity?
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Gravitropism - Caused by Auxin imbalance
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What is it called when plant shoots grow in relation to light?
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Phototropism - Caused by Auxin accumulating in shade
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What is it called when plant roots grow relative to the level of moisture in the ground?
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Hydrotropism - caused by Auxin accumulating near to moisture
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