NEURONS AND SYNAPTIC TRANSMISSION Flashcards
what % of neurons are located in the brain?
80%
what do neurons do?
they transmit signals electrically and chemically
what are the three types of neurons?
sensory
relay
motor
what are sensory neurons?
messages from the PNS t the CNS
how are snesory neurons adpted for ther function?
long dendrites and short axons
what are relay neurons?
connect the sensory neurons to motor or other neruons
how are relay neurons adapted for their function?
short dendrites
short axons
what are motor neurons?
connect CNS to effectors e.g. muscles or glands
how are motor neurons adpted for their function?
short dendrites
long axons
what is the basic structure of a neuron?
- cell body with nucleus
- dendrites extending from body carrying nerves impulses away from neighbouring neurons to cell body
- axon carrying impulse away from cell body down neuron
- axon covered w/ myelin sheath protect axon and speed up elec impulse
- nodes of ranvier ensure that impulses have speed as it is a gap
- terminal buttons communicate with next neuron across synapse
what is step 1 in the structure of a neuron?
1.cell body with nuclues
what is step 2 in the structure of the neuron?
dendrites carry nerve impulses away from neighbouring neurons to cell body
what is step 3 in the structure of a neuron?
axon carrying impulse away from cell body down neuron
what is step 4 in the structure of a neuron?
axon covered w/ myelin sheath protect axon and speed up elec impulse
what is step 5 in the structure of a neuron?
nodes of ranvier ensure that impulses have speed as it is a gap
what is step 6 in the structure of a neuron?
terminal buttons communicate with next neuron across synapse
when a neuron is in it’s resting state it is… until it is activated with a stimulus
negative
when a neuron becomes positively charged for a split second, this causes an …..
action potential creating electrical impulse that travels down the axon towards the end of the neuron
define synaptic transmission
process where neighbouring neurons communicate with each other through chemical messages across the synaptic cleft
what are the 6 steps of synaptic transmission?
- info passed down axon, called action potential needing to transferred to another neuron
- needs to cross through synaptic cleft between pre-syn neuron and post-syn neuron
- in the axon terminal located at end of neuron is synaptic vesicles containing neurotransmitters
- action potential reaches synaptic vesicles, open up calcium channels which move vesicles to membrane to release into synaptic cleft
- neurotransmitters carry signals across syn cleft, binding to receptor sites of post-syn cell
- neurotransmitter either has has an excitatory or inhibitory effect
what is step 1 in synaptic transmission?
info passed down axon, called action potential needing to transferred to another neuron
what is step 2 in synaptic transmission?
needs to cross through synaptic cleft between pre-syn neuron and post-syn neuron
what is step 3 in synaptic transmission?
in the axon terminal located at end of neuron is synaptic vesicles containing neurotransmitters
what is step 4 in synaptic transmission?
action potential reaches synaptic vesicles, open up calcium channels which move vesicles to membrane to release into synaptic cleft
what is step 5 in synaptic transmissiion?
neurotransmitters carry signals across syn cleft, binding to receptor sites of post-syn cell
what is step 6 in synaptic transmission?
neurotransmitter either has has an excitatory or inhibitory effect
what is an excitatory and inhibitory neurotransmitter?
excitatory - increase positive charge, increase action potential and more likely to fire e.g. adrenaline
inhibitory - negative charge, decrease action potential, less likely to fire e.g. serotonin
