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Neuron structure and Function - Coggle Diagram
Neuron structure and Function
Neurons and electrical transmission
types of neuron
Sensory neurons PNS to CNS. Long dendrites, Short axons (LS). Relay neurons: Sensory neurons to motor neurons. Short dendrites. Short axons (SS), Motor neurons. CNS to muscles and glands. Short dendrites, Long axons (SL).
Structure of neurons
Cell body: Nucleus with genetic material (DNA). Axon: Carries signals from the cell body down the neuron, covered in myelin sheath. Myelin sheath: Fatty layer acts as insulation and gaps (nodes of Ranvier) speed up signal. Terminal button End of axon (part of synapse)
What are neurons
Nerve cells send electrical and chemical signals There are 100 billion of them in the human body
Electrical transmission
Resting state: Inside has a negative charge compared to outside When it fires: Changes to a positive charge which causes an action potential
Synapses and chemical transmission
Reuptake of neurotransmitters
Neurotransmitters attach themselves to the next neuron at postsynaptic receptor sites. The chemical message is turned back to an electrical impulse. Neurotransmitters in synaptic cleft broken down by enzymes, reabsorbed by presynaptic neuron,
Excitation and inhibition
Excitatory neurotransmitters increase the postsynaptic neuron's positive charge and make it more likely to fire Inhibitory neurotransmitters increase the postsynaptic neuron's negative charge and make it less likely to fire
Release of neurotransmitters
Neurotransmitters stored in vesicles at terminal buttons of presynaptic neuron. Electrical signal releases neurotransmitters into the synaptic cleft
The synapse
Neurons communicate using neurotransmitters, released from presynaptic to postsynaptic neuron across the synaptic cleft.
Summation
Summation occurs if there are more excitatory signals than inhibitory signals. Makes neuron fire, causing an electrical impulse