human nervous system Flashcards
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what does the human nervous system consist of?
- central nervous system
- peripheral nervous system
what does the central nervous system contain?
the brain and the spinal cord
what does the peripheral nervous system contain?
all of the nerves in the body
what is information sent through the nervous system as?
electrical impulses
what are electrical impulses?
electrical signals that pass along nerve cells known as neurones
what are neurones?
specialised cells adapted to rapidly carry electrical charges called nerve impulses from one end of the body to the other
what is a bundle of neurones known as?
a nerve
what does the CNS act as?
a central coordinating centre for the impulses that come in or are sent out to any part of the body
what does the CNS coordinate?
all of the nervous responses such as moving or reflexes
where are the nucleus and main organelles found in neurones?
in the cell body
what are axons and dendrites?
cytoplasmic extensions from this cell body
what is the axon?
the main long fibre of the neurone
what is the axon insulated by?
a fatty myelin sheath with small insulated sections along its length (called nodes)
how does the electrical impulse travel down the axon?
it does not travel down the whole axon- it jumps from one node to the next
where do dendrites extend out of?
- the cell body of the neurone
- at the far end of the axon