nervous system

Nota:

• Complex network of the cells that carry informations.

1. central nervous system (CNS)

   Nota:

   • Coordinate and influences the activities. Processes and integrates the incoming informations.
   1. stimulus

      Nota:

      • Something that initiate the reaction.
      1. sensor

         Nota:

         • Simulated by environmental information (stimuli)
         1. sensory neursons

            Nota:

            • Transmit impulses to the spinal cord and the brain.
            1. motor neursons

               Nota:

               • Further impulses then pass back.
               1. reaction

                  Nota:

                  • Our body reacts to the received stimulus.
2. peripheral nervous system (PNS)

   Nota:

   • Connect the CNS with the body. Consists of nerve cells outside the brain.
   1. voluntary nervous system (VNS)

      Nota:

      • It controls the body.
   2. automatic nervous system (ANS)

      Nota:

      • Influences regulate organs.
      1. sympathetic nervous system

         Nota:

         • "fight or run" -situation. The body can react quickly.
      2. parasympathetic nervous system

         Nota:

         • "rest and digest" -situation. The body can rest.
3. neurons
   1. cell body (soma)

      Nota:

      • Includes the nucleus and other organelles. atahe electrical impuls travels through it.
      1. extensions
         1. dendrites

            Nota:

            • Are highly branched. Receive signals from other neurons.
         2. axon

            Nota:

            • They Transmits signals. Mnay of them are enclosed by an isulation sheath.
            1. axon hillock

               Nota:

               • The region where the signals that travel down the axon are generated.
            2. saltatory conduction

               Nota:

               • Increases the conduction speed of action potential. ´jumps´along the axon. Vertebrates motor neurons has an insulating sheath.
            3. continuous conduction

               Nota:

               • 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.
         3. synaptic terminal

            Nota:

            • It´s an important part for communicating with other cells.
            1. synapses

               Nota:

               • The region where the communicating between the synaptic terminal and other cells takes place.
               1. A.

                  Nota:

                  • An electrical impulse (action potential) reaches the synaptic terminal and causes the synaptic vescicles to fuse with the cell membrane.
                  1. B.

                     Nota:

                     • The synaptic vesicles release neurotransmitter into the synaptic cleft.
                     1. C.

                        Nota:

                        • The neurotransmitter binds to the receptor on the target cell (other neurons).
                        1. D.

                           Nota:

                           • This causes an electrical impulse in the dendrite of the target cell
                           1. E.

                              Nota:

                              • The neurotransmitter is degreaded and recycled in the synaptic terminal.
               2. Neurotoxin
                  1. Black widow spider bite

                     Nota:

                     • It is in the synaptic cleft. they give you a permanent signal and you get a muscle cramp that leads to the Death.
                  2. Toxin of the fly agaric

                     Nota:

                     • 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.
                  3. Nicotine

                     Nota:

                     • The toxin works on the receptors just like neurotransmites. So they can´t recycled and degraded and it inreases the blood pressure ans pulse.
                  4. botox

                     Nota:

                     • In the synaptic cleft. The effects are that the blocks release of neurotransmites and the muscle cannot be contracted.