Neurons

• Neurons


  Nerve cells that process & transmit messages via electrical impulses.
• Motor neurons 


  Carry information away from the brain and tell our muscles to move. They have a myelin sheath.
• Sensory neurons

  Pick up sensory info from sensory receptors and transmit info towards the brain. They form synapses with sensory receptors. Its cell body sticks out the axon and the axon is covered with a myelin sheath. They also have a receptor cell instead of dendrites.
• Relay neurons


  Connect sensory neurons to motor neurons.

  Dont have a myelin sheath
• Structure of neurons

  Axon: carries impulse.

  Myelin sheath: fatty layer that protects and insulates the axon and speeds up electrical transmission.

  Nodes of ranvier: Speeds up transmission by forcing it to jump across the gaps in an axon.
• Synaptic Transmission


  The pre-synaptic neuron has synaptic vesicles that contain neurotransmitters. A nerve impulse causes the vesicles to travel down the pre-synaptic terminal where the vesicle fuses with the membrane, causing the neurotransmitters to be released into the synaptic cleft where they diffuse and move toward the post-synaptic terminal, where the neurotransmitters bind to the receptor cells. Once neurotransmitters are binded to the receptors cells they are unbounded and reuptaken by the reuptake proteins into the pre-synaptic neuron.
• Neurotransmitters can be either excitatory or inhibitory.

  Excitatory: Allow positively charged particles to enter post-synaptic neurons. They also create Epsp which makes nerve impulses more likely to occur.

  Inhibitory: allows negatively charged particles to enter which creates IPSPS which makes nerve impulses less likely to occur.