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What is a reflex?
rapid automatic responses to certain stimuli that dont involve the conscious part of the brain
What is an example of a reflex?
If a bright light shines in your eyes, your pupils automatically get smaller so less light enters your eyes preventing damage
What is included in the central nervous system (CNS)?
the brain and the spinal chord
What does the nervous system do?
detects and reacts to stimuli (change jn the environment)
What do sensory neurones do?
carry information as electrical impulses from a receptor to a CNS
What does a relay neurone do?
carry impulses from sensory neurones to motor neurons
What does a motor neurone do?
carry instructions from the CNS to the effector
What is an effector?
muscles and glands which respond to the nervous impulses
What are receptors?
cells that detect stimuli
What are effectors?
they respond to nervous impulses and bring about a change
What do the muscles do as effectors?
they contract in response to a nervous impulse
What do glands do as effectors?
Glands secrete hormones in a response to a nervous impulse
What is the order that the nervous system reacts to stimuli?
What is a synapse?
the connection between 2 neurones
How does a synapse work?
the nerve signal is transferred by chemicals which diffuse across the gap, these chemicals then set off a new signal in the next neurone
What is a hormone?
a chemical messenger sent in the blood
What does a hormone do?
control things in the organs and cells that need constant adjustment
Where are hormones produced?
endocrine glands
Where is the pituitary gland located and what does it do?
In the brain and it regulates body conditions
Where is the thyroid gland located and what does it do?
in the throat and it adjusts body temperature, metabolism and heart rate
What does the gland in the pancreas do?
produces insulin which regulates the blood glucose level
What does the gland in the ovaries do?
produces oestrogen, needed for the menstrual cycle
What does the gland in the testes do?
produces testosterone, which controls puberty and sperm production in males
What is the difference between nerves and hormones
Nerves- very fast action, act for a very short time, act on a very precise area
Hormones- slower action, acts for a very long time, act in a more general way
What is stage 1 of menstruation?
menstruation stars- the uterus lining breaks down for about 4 days
What is stage 2 of the menstrual cycle
Note 
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