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AQAB1a revision
section 1: control and coordination
32
Biology
10th Grade
02/15/2009

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Term
What are the two ways that your body can convey messages between organs?
Definition
By nerves and hormones
Term
Are nerves or hormones better for short behaviours and why?
Definition
Nerves because the messages are fast and short-lived. Hormones are better when a longer-term response is needed.
Term
Where are hormones made?
Definition
In glands
Term
How are hormones transported around your body?
Definition
In the bloodstream
Term
Most hormones affect only a few organs, called the target organs. What hormone has more target hormones than most organs?
Definition
Adrenaline
Term
What S do we call a change in the environment?
Definition
Stimulus
Term
What do we call cells that detect stimuli?
Definition
Receptors
Term
What is an effector?
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.
Term
What is another name for nerve cells?
Definition
Neurones
Term
What is the CNS?
Definition
The central nervous system. This is made up of the brain and the spinal cord.
Term
What do we call neurones that carry information from receptors to the CNS?
Definition
Sensory neurones
Term
What do we call neurones that carry information from the CNS to effectors?
Definition
Motor neurones
Term
What is a transducer and why are receptors transducers?
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.
Term
What is a reflex action?
Definition
A fast, automatic response to a stimulus.
Term
What is a reflex arc and what is the order of events in this pathway?
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.
Term
What is a synapse and how does it work?
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.
Term
Why do we have synapses?
Definition
These allow us to respond in more than one way to the same stimulus when other factors are also involved.
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?
Definition
1) water content
2) ion (salt) content
3) temperature
4) sugar concentration of blood
Term
What organ controls water and ion content of blood?
Definition
The kidney. It varies the amount of water and salt secreted from your body in urine.
Term
What is the name of the hormone that controls blood sugar?
Definition
Insulin
Term
What two organs control blood sugar levels and how do they do this?
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.
Term
What are the three main hormones that control events in the menstrual cycle?
Definition
FSH (follicle-stimulating hormone), oestrogen and LH (luteinising hormone).
Term
Where are FSH, oestrogen and LH made?
Definition
FSH and LH are made in the pituitary gland and oestrogen in the ovaries.
Term
What is menstruation?
Definition
When the uterus lining breaks down and is lost through the vagina.
Term
When in the menstrual cycle does the uterus lining start to build up again?
Definition
After about a week, i.e. day 7 or 8.
Term
When in the menstrual cycle is an egg released?
Definition
Day 14.
Term
What does FSH do?
Definition
It causes an egg to mature and causes the ovary to secrete oestrogen.
Term
What does oestrogen do?
Definition
Stops the pituitary gland from secreting FSH and causes it to secrete LH. Oestrogen also causes the uterus lining to thicken.
Term
What does LH do?
Definition
Causes the mature egg to be released from the ovary.
Term
Why is FSH used as a fertility treatment?
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.
Term
What is IVF and how does it work?
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.
Term
How does an oral contraceptive, such as the pill, work?
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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