nervous system

nervous system

1. central nervous system (CNS)

   • Coordinate and influences the activities. Processes and integrates the incoming informations.
   • stimulus
     • Something that initiate the reaction.
     • sensor
       • Simulated by environmental information (stimuli)
       • sensory neursons
         • Transmit impulses to the spinal cord and the brain.
         • motor neursons
           • Further impulses then pass back.
           • reaction
             • Our body reacts to the received stimulus.

2. peripheral nervous system (PNS)

   • Connect the CNS with the body. Consists of nerve cells outside the brain.
   • voluntary nervous system (VNS)
     • It controls the body.
   • automatic nervous system (ANS)
     • Influences regulate organs.
     • sympathetic nervous system
       • "fight or run" -situation. The body can react quickly.
     • parasympathetic nervous system
       • "rest and digest" -situation. The body can rest.

3. neurons

   • cell body (soma)
     • Includes the nucleus and other organelles. atahe electrical impuls travels through it.
     • extensions
       • dendrites
         • Are highly branched. Receive signals from other neurons.
       • axon
         • They Transmits signals. Mnay of them are enclosed by an isulation sheath.
         • axon hillock
           • The region where the signals that travel down the axon are generated.
         • saltatory conduction
           • Increases the conduction speed of action potential. ´jumps´along the axon. Vertebrates motor neurons has an insulating sheath.
         • continuous conduction
           • Action potential develops over and over again along the axon section by section. Axons without an insulating sheath have a low conduction speed and the thickness is important.
       • synaptic terminal
         • It´s an important part for communicating with other cells.
         • synapses
           • The region where the communicating between the synaptic terminal and other cells takes place.
           • A.
             • An electrical impulse (action potential) reaches the synaptic terminal and causes the synaptic vescicles to fuse with the cell membrane.
             • B.
               • The synaptic vesicles release neurotransmitter into the synaptic cleft.
               • C.
                 • The neurotransmitter binds to the receptor on the target cell (other neurons).
                 • D.
                   • This causes an electrical impulse in the dendrite of the target cell
                   • E.
                     • The neurotransmitter is degreaded and recycled in the synaptic terminal.
           • Neurotoxin
             • Black widow spider bite
               • It is in the synaptic cleft. they give you a permanent signal and you get a muscle cramp that leads to the Death.
             • Toxin of the fly agaric
               • The toxin works on the targed cells. The effects are hat the neurotransmites doesn´t work anymore and you can result in more sweating and increasing heart beat.
             • Nicotine
               • The toxin works on the receptors just like neurotransmites. So they can´t recycled and degraded and it inreases the blood pressure ans pulse.
             • botox
               • In the synaptic cleft. The effects are that the blocks release of neurotransmites and the muscle cannot be contracted.

Images and files in the map

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• Function of Neurotransmitters (Embed)