Neurons and Synaptic Transmission

• Structure of a neuron

  A) Dendrite

  B) Nucleus

  C) Axon

  D) Myelin sheath

  E) Node of ranvier

  F) Terminal buttons

  
• Sensory neuron- activated by sensory input from the environment; send signals to the brain, parietal lobe translates the impulses into the senses; mainly found in eyes, ears, tongue and skin

  A) Sensory neuron

  
• Relay neuron- connect sensory neurons and spinal motor neurons and transfer signals between; communicate with each other to form circuits; have the ability for limited movement eg. reflex arc

  
• Motor neuron- part of the central nervous system; transmit impulses directly from the spinal cord to skeletal and smooth muscles to directly control muscle movement; 2 types:

  Lower motor neurons- travel from spinal cord to muscle

  Upper motor neurons- travel between brain and spinal cord

  
• Synaptic transmission

  A) Pre-synaptic neuron

  B) Post-synaptic neuron

  C) Synapse

  D) Receptor

  E) Neurotransmitter

  F) Terminal button

  G) Vesicles

  
• Neuron- a specialised cell transmitting nerve impulses
• Cell body- the spherical part of the neuron that contains the nucleus
• Dendrites- short, branched extension of a nerve cell, where impulses received from other cells at synapses are transmitted to the cell body
• Axon- the long thread-like part of a nerve cell along which impulses are conducted from the cell body to other cells
• Nodes of Ranvier- gaps in the myelin sheath of a nerve, where the axons are left uncovered
• Terminal buttons- the small knobs at the end of an axon are left uncovered
• Action potential- a rapid sequence of changes in the voltage across a membrane
• Synaptic gap- the space in between the axon of one neuron and the dendrites of another, and is where the electrical signal translates to a chemical signal that can be perceived by the next neuron
• Receptors- a cell or group of cells that receive stimuli
• Pre-synaptic neuron- the neuron that transmits the signal towards the synapse
• Post-synaptic neuron- the neuron that transmits the signal away from the synapse
• Lock and key system- a neurotransmitter will only bind to a specific receptor
• Excitatory neurotransmission- generates a signal called an action potential in the receiving neuron
• Inhibitory neurotransmission- prevents an action potential in the receiving neuron
• Summation- the process of adding things together
• Myelin sheath- an insulating layer that forms around nerves
• Vesicles- small, liquid-filled sac formed by a membrane