Everything Psychology

But what does a neuron look like?..

• Firstly, they vary in size but all have the same basic structure.
• The cell body(or soma if you want to use those smart words) has a nucleus(inc. genetic material of the cell)
• Dendrites(they look like branches) protrude from the cell body. What do they do? They carry nerve impulses from neighbouring neurons towards the cell body
• The axon... this carries impulses away from the cell body down the length of the neuron. It's covered in a fatty layer of myelin sheath(one of my favourite terms in psychology and I don't know why) but it protects the axon while speeding up electrical transmission of the impulse
• Important to note that the myelin sheath is not continuous else it would just slow down the electrical transmission. It's segmented by nodes of Ranvier(where do they even get these names from?) - this speeds up transmission because the impulse is forced to "jump" across the gaps. 
• At the end of the axon - terminal buttons which communicate with the next neuron in the chain across a gap known as the synapse. 

The inside of the cell is negatively charged unlike the outside when a neuron is in its resting state but when it's activated by a stimulus, the inside becomes positively charged for a very small amount of time. This causes an action potential to happen - creating an electrical impulse which travels down the axon towards the end of the neuron.

Synaptic transmission

Firstly, chemical transmissions and synapses...

Neural networks: Groups in which neurons communicate(Neuron group chat, lol)

Synapse: What keeps each neuron separated - synaptic cleft, pre synaptic terminal and post synaptic receptor site

IMPORTANT: Signals within neurons are transmitted electrically. Signals between neurons are transmitted chemically(synaptic transmission)

When the electrical impulse reaches the end of the pre synaptic terminal, it triggers the release of neurotransmitter from the synaptic vesicles(or tiny sacs)

But, what is a neurotransmitter?..

Chemicals that diffuse across the synapse to the next neuron in the chain.

- Once it crosses gap, it is taken up by the post synaptic receptor sites - the chemical message is converted back into an electrical impulse - the process of transmission begins again

- Each neurotransmitter has its own specific molecular structure which fits perfectly into a post synaptic receptor site(like a lock and key) 

- Neurotransmitters also have specialist functions

Excitation and inhibition

- Serotonin causes inhibition in the receiving neuron - neuron is more negatively charged - less likely to fire

- Adrenaline causes excitation of the post synaptic neuron - increases positive charge - more likely to fire