neurons and synapses Flashcards
(27 cards)
what is the function of sensory neurons?
transmit sensory info towards brain and spinal cord
what is the function of relay neurons ?
allow sensory and motor neurons to communicate
what is the function of motor neurons?
controls muscle movements
where are sensory neurons found?
in the peripheral nervous system
where are relay neurons found?
in the CNS - only in the brain and spinal cord
where are motor neurons found?
in the nervous system but their axons reach out into the peripheral nervous system
where do sensory neurons direct info to and from?
from sensory receptors towards the brain and spinal cord
where do relay neurons direct info to and from?
from one neuron to another
where do motor neurons direct info to and from?
from the brain towards effectors ( an organ or cell that acts in response to a stimulus)
what are the differences in structure between relay motor and sensory neurons?
cell body of sensory neurons is in the middle. and they have a myelin sheath
relay neuron do not have myelin sheath and cell body is at the top of neuron
motor neuron has myelin sheath and cell body is at the top
what is the function of an axon?
carries impulses away from the cell body down the length of the neuron.
the electrical impulse is the action potential
what is the function of dendrites?
pick up nerve impulses from other neurons and carry them towards the cell body
what is the function of the cell body ?
contains everything the nerve needs to survive and contains the nulceus
what is the function of the myelin sheath?
protects the axon and speeds up the electrical transmission of the impulse
what is the function of the nodes of ranvier?
speed up transmission of the action potential by forcing it to jump across synapses
what is the function of axon terminals?
the action potential has to travel to the dendrites of another neuron through synaptic transmission
what is an action potential?
electrical signal passed from neurons along their axons
true or false ?sensory neurons recieve information from the outside world.
true
true or false? motor neurons directly or indirectly control muscles
true
what is the reflex arc?
sensory receptors in the sensory neuron detect stimulus. e.g hot temperature
it transmits sensory info towards the relay neuron
the relay neuron allows sensory and motor neurons to communicate
relay neuron takes the information from sensory neuron to the motor neuron
the motor neuron controls muscle movements
the info gets to the brain and towards effectors in muscle that acts in response of stimulus
which results in action e.g moving hand away from a hot item
what is the process of synaptic transmission?
electrical impulses (action potentials) reach the presynaptic terminal
electrical impulses (action potentials) trigger release of neurotransmitters (or named example)
neurotransmitters cross the synapse from vesicles
neurotransmitters combine with receptors on the postsynaptic membrane
stimulation of postsynaptic receptors by neurotransmitters result in either excitation (depolarisation) or inhibition (hyperpolarisation) of the postsynaptic membrane
what are the 2 types of neurotransmitters?
excitatory and inhibitory
what are excitatory neurotransmitters
these excite the nervous system increasing the likelihood that a neuron will fire an action potential
they do this because they are positively charged. they depolarise post synaptic cell and enough of them can generate an action potential
generate excitatory post synaptic potential
what are inhibitory neurotransmitters?
inhibit the nervous system decreasing the likelihood that a neuron will fire an action potential
they do this because they ate negatively charged. they hyperpolarise the post synpatic cell and enough of them can inhibit an action potential
they generate inhibitory post synaptic potential
