Term
| What are the two ways that your body can convey messages between organs? |
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Definition
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Term
| Are nerves or hormones better for short behaviours and why? |
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Definition
| Nerves because the messages are fast and short-lived. Hormones are better when a longer-term response is needed. |
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Definition
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Term
| How are hormones transported around your body? |
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Definition
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Term
| Most hormones affect only a few organs, called the target organs. What hormone has more target hormones than most organs? |
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Definition
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Term
| What S do we call a change in the environment? |
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Definition
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Term
| What do we call cells that detect stimuli? |
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Definition
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Term
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Definition
| An effector is an organ that does something in response to a stimulus. Your muscles are effectors. Glands are also effectors, e.g. salivary glands respond to a stimulus by secreting saliva. |
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Term
| What is another name for nerve cells? |
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Definition
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Term
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Definition
| The central nervous system. This is made up of the brain and the spinal cord. |
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Term
| What do we call neurones that carry information from receptors to the CNS? |
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Definition
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Term
| What do we call neurones that carry information from the CNS to effectors? |
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Definition
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Term
| What is a transducer and why are receptors transducers? |
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Definition
| A transducer converts one form of energy into electrical energy. Receptors transfer energy from a stimulus (such as light energy from receptor cells in your eye) to electrical energy in neurones. |
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Term
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Definition
| A fast, automatic response to a stimulus. |
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Term
| What is a reflex arc and what is the order of events in this pathway? |
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Definition
A reflex arc is the pathway taken by a nerve impulse.
1. A receptor detects a stimulus.
2. A sensory neurone carries an impulse to the spinal cord.
3. A relay neurone carries an impulse to a motor neurone.
4. A motor neurone sends an impulse to an effector. |
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Term
| What is a synapse and how does it work? |
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Definition
A synapse is a small gap between neurones.
Electrical impulses cannot jump over these.
When an impulse gets to a synapse, a chemical is secreted, which diffuses across the gap.
When the chemical reaches the next neurone it starts an electrical impulse. |
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Term
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Definition
| These allow us to respond in more than one way to the same stimulus when other factors are also involved. |
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Term
| What are some important conditions that need to be kept constant in order for chemical reactions to work and the right time and speed in your body? |
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Definition
1) water content
2) ion (salt) content
3) temperature
4) sugar concentration of blood |
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Term
| What organ controls water and ion content of blood? |
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Definition
| The kidney. It varies the amount of water and salt secreted from your body in urine. |
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Term
| What is the name of the hormone that controls blood sugar? |
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Definition
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Term
| What two organs control blood sugar levels and how do they do this? |
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Definition
| The liver and pancreas. The pancreas secretes insulin if glucose levels in your blood are too high. Insulin makes the liver take glucose out of the blood and stores it. If glucose levels get too low, thel liver will release it. |
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Term
| What are the three main hormones that control events in the menstrual cycle? |
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Definition
| FSH (follicle-stimulating hormone), oestrogen and LH (luteinising hormone). |
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Term
| Where are FSH, oestrogen and LH made? |
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Definition
| FSH and LH are made in the pituitary gland and oestrogen in the ovaries. |
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Term
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Definition
| When the uterus lining breaks down and is lost through the vagina. |
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Term
| When in the menstrual cycle does the uterus lining start to build up again? |
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Definition
| After about a week, i.e. day 7 or 8. |
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Term
| When in the menstrual cycle is an egg released? |
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Definition
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Term
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Definition
| It causes an egg to mature and causes the ovary to secrete oestrogen. |
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Term
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Definition
| Stops the pituitary gland from secreting FSH and causes it to secrete LH. Oestrogen also causes the uterus lining to thicken. |
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Term
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Definition
| Causes the mature egg to be released from the ovary. |
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Term
| Why is FSH used as a fertility treatment? |
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Definition
| It causes stimulates a woman’s eggs to mature in her ovaries. Once an egg is released, she can conceive in the normal way. |
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Term
| What is IVF and how does it work? |
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Definition
| In vitro fertilisation. Some of the woman’s eggs are put into a dish with some her partner’s sperm. One of the fertilised eggs is placed in her uterus, where it grows into a baby in the normal way. |
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Term
| How does an oral contraceptive, such as the pill, work? |
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Definition
| The pills contain oestrogen, which stop FSH being produced, so eggs do not mature. The woman can therefore not get pregnant. |
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