Neurons and Synaptic Transmission Flashcards
What are neuron’s?
Cells of the nervous system that process and transmit messages through electrical and chemical signals
What are the electrical impulses called on a neurone?
Action potentials
What is the charge of a neuron in a resting state?
Inside of the cell is negatively charged
What is the charge of a neuron when it is activated by a stimulus?
The inside of the stimulus becomes positively charged
What is the description of a motor neuron?
-Form synapses with muscles and control contractions
-stimulated they bind to receptors on muscle and rigger response muscle movement
Where are motor neurons located?
CNS and project axons outside the CNS to directly/indirectly control muscles
What are the features of a motor neuron?
Short dendrites and long axons
What is the description of a relay neuron?
-Connect with other neurons
-Allow sensory and motor neurons to communicate with each other
-impulses reach they brain they are translated into sensations
What are the features of the relay neuron?
Short dendrites
Short axons
What is the description of sensory neurons?
-Carry messages from sensory receptors via the PNS and CNS
-Sometimes info only travels to spinal cord, allows reflex actions to occur quickly without delay of sending impulses to brain
What are the features of sensory neuron?
Long dendrites
Short axons
Where are relay neurons found?
Brain and spinal cord (CNS)
What do the motor neurone connect the CNS to?
Effectors such as muscles and gland
What is the myelin sheath?
Fatty layer that protects the axon and speeds up electrical transmission of the action potential
What is the cell body?
Control centre of the body
What are dendrites?
Carry nerve impulses from neighbouring neurons or sensory receptors to the cell body
What is the nucleus?
Contains all genetic material of the cell
What are hides of ranvier?
Gaps in the myelin sheath that speed up transmission of the action potential by forcing the impulse to ‘jump’ across the gaps along the axon
What is the axon?
Carries action potentials away from the cell body down the length of the neuron
What are the steps in how the nervous system communicates through neurons?
-stimulus
-sensory receptor
-relay neuron
-motor neuron
-effector
-response
What is the process of synaptic transmission?
-action potential reaches presynaptic terminal
-triggers synaptic vesicles to release neurotransmitters to synaptic gap
-diffuses across the gap
-bind to post-synaptic receptor sites
-stimulate of most-synaptic receptors converts chemical message to electrical impulse
-effects terminated by reuptake
-taken by pre-synaptic neurone stores in vesicles for later
If a neurotransmitter is excitatory what does this cause?
Excitation of the post-synaptic membrane so posit-synaptic neuron is more likely to fire an electrical impulse
If a neurotransmitter is inhibitory what does this cause?
Inhibition of the posy-synaptic membrane so posy-synaptic neuron is less likely to fire an electrical impulse
What can neurotransmitters be classifies as in their action?
Inhibitory or excitatory
Acetylcholine, noradrenaline is a?o
On switch (excitatory)
Serotonin and GABA are?
Off switches (inhibitory)
What is summation?
When the excitatory and inhibitory influences are summed
