Neurons and Synaptic `Transmission

neuron function

to transmit electrical and chemical signals around the body

sensory neurones

carry impulses toward the brain

relay neuron

connect sensory and motor neurons

motor neurons

carry impulses away for CNS

Myelin Sheath

fatty layer around the axon

speeds up the rate of transmission

role of nodes of ranvier

gaps between the myelin sheath which allow transmission to be even quicker as electrical impulses jump between them

neuron labelles

order of neurons

cell body

contains nucleus which holds genetic info of cell

dendrites

carry impulses from neighbouring neurons to cell body

axonq

the stem which carries impulses away from cell body

synaptic terminal

pass impulse to neighbouring neurons across the gap between neurons

synaptic transmission

-an electrical impulse travels down axon of presynaptic neuron

-when impulse reaches axon terminal it triggers vesicles to move toward presynaptic membrane

-synaptic vesicles release neurotransmitters into the synaptic cleft

-neurotransmitters diffuse across the synaptic cleft

-they bind to receptors of dendrites of the postsynaptic neuron

-this triggers a new action potential in the postsynaptic neuron

neurotransmitters

molecules that neurons use to communicate

-if enough excitation receptors bind- neuron can fire and action potential is repeated

-if enough inhibition receptors bind- neuron cant fire and action potential isn’t repeated

-excitatory and inhibitory influenced summed together to produce action potential(summation)

adrenaline

hormone and neurotransmitter which is an element in stress response

dopamine

released when we experience reward and pleasurable activities

serotonin

involved with emotion mood and sleeping and regulates sleep cycle

what happens to NT in the synapse

-bind to receptors

-reuptake

-diffusion

-enzymes