Nervous System & Reflex Arc

• central nervous system 


  -integration & command center (where thinking takes place)

  -includes the brain & spinal cord

  stimuli -> receptors -> nervous system -> effectors -> response
• neurones 


  are specialized cells that transmit electrical impulses when stimulated

  • cant be replaced or divided, damage can't fixed it will be permanent
• Synapse

  is a junction between 2 neurones across which electrical signals pass

  1. when an electrical signal reaches the end of a nerve it triggers the release of neurotransmitter molecules from the synaptic vesicles
  2. neurotransmitters diffuse across the synaptic clef & bind with the receptors on the next nerve triggering another electrical signal (impulse)
• peripheral nervous system 


  -consists of nerves & connects to all other parts of the body

  
  

  types: autonomic nervous system & somatic nervous system
• reflex arc 


  -is an involuntary action

  -rapid & automatic moment in response to a stimuli

  -the result of messages sent to & by the spinal cord

  -involuntary action (Ex. sneezing)

  receptor -> sensory neuron -> integration center -> motor neuron -> effector
• types of nervous action

  
  

  voluntary action:

  • requires conscious thought
  • involves skeletal muscles (Ex. raising hand)

  involuntary action:

  • occurs without conscious thought
  • involves smooth muscles, cardiac muscles, or glands (Ex. normalizing blood pressure)
  • involves skeletal muscles (Ex. knee jerk)
• 3 kinds of nerves

  1. motor
  2. sensory
  3. mixed (relay)
• automatic nervous system


  communicates with internal organs & glands

  sympathetic division:

  • responsible for arousing feelings

  parasympathetic division:

  • responsible for calming
• somatic nervous system

  communicates with sense organs & voluntary muscles

  sensory nervous system:

  • deals with sensory input
  • afferent

  motor nervous system:

  • deals with motor input
  • efferent
• synaptic transmission 


  S.T.R.B.R

  
  

  Synthesis:

  • making neurotransmitters(NT) from chemicals

  Transport:

  • vesicles travel down the axon of a nerve to the axon terminal

  Release:

  • an impulse triggers the release of NT into the synaptic gap

  Binding:

  • NT diffuses across the synaptic gap & binds with receptors, continuing the impulse

  Removal:

  • reuptake (recycle NT) + breakdown (into smaller pieces to be used in synthesis)