structure and role of neuron Flashcards

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1
Q

cell body

A

includes a nucleus containing the genetic material of the cell

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2
Q

dendrites

A

branch-like structures sticking out of the cell body, carry impulses from other neurons to the cell body

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3
Q

axon

A

a tube like structure, carries the impulses away from the cell body down the length of the neuron

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4
Q

myelin sheath

A

in many neurones, the axon is covered by a fatty layer formed from special cells
this protects the axon and speeds up transmission of the impulse

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5
Q

nodes of Ranvier

A

gaps in the myelin sheath increase speed by forcing the impulses to ‘jump’ across the gaps along the length of the axon

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6
Q

terminal buttons

A

at the end of axons, not physically connected to the next neuron, but involved in communication across a synapse

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7
Q

sensory neurons

A

carry messages from sensory receptors (e.g., touch and temperature sensitive receptors in the skin) along nerves in the PNS to the CNS

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8
Q

motor neurons

A

carry messages from the central nervous system along nerves in the PNS to effectors such as muscles and glands

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9
Q

relay neurons

A

connect sensory and motor neurons together, and also connect to other relay neurones

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10
Q

function of a neuron

A
  1. when a neuron is in a resting state, the inside of the cell is negatively charged relative to the outside
    but when it is sufficiently activated by a stimulus, the inside of the neurone becomes positively charged for a split second
  2. this rapid switch from negative to positive is depolarisation which creates and electric impulse (action potential) from the axon to the terminal buttons
  3. the action potential is generated once depolarisation reaches a certain threshold and is always the same intensity, regardless of the size of the stimulus that generated it
    if the threshold is not reached there is no action potential - action potential is an all or nothing event
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