Nervouse Systems

• two main parts of nervouse system:

  • Central, Peripheral
  • CNS: brain, spinal cord
  • PNS: autonomic, somatic
• Autonomic:

  • subconscious systems
  • sympathetic (fight or flight) and parasympathetic (rest)
• Parasympathetic NS:

  • seeks to return body to normal levels of arousal (rest and digest)
  • functions: pupils constrict, salavation, airways constrict, HR slows
• Sympathetic NS:

  • emergency arousal systems that activates when danger is percived (fight or flight)
  • functions: pupils dialate, saliva inhibited, airways dialate, HR increases
• Neurons:

  • basic building blocks of the nerve system to transport info around the body
• what are neurons made of:

  • dendrite, soma, nucleus, axon, mylon sheeth, axon terminals, synapse
• Cell body:

  • produces all proteins for dendrites, axons and synaptic terminals
• Axons:

  • main conductor of neurons, capable of conveying electrocal signals along distances
• Dendrites:

  • branch out, receive signals from other nerve cells like antena
• Myelin Sheath:

  • wraps around certain nerve axons, insulates nerves, speeds up electrical impulses
• Synapse:

  • structure than permits neuron to pass on electrical or chemical signal
• Neurotransmitters:

  • chemical substance relesed at end of nerve fiber by arrival of nerve impulse and by diffusing across synapse or junction.
  • NTs enable neural transmission
• Sensory Neurons:

  • proccess sensory info from organs/receptors and carry senses to the spinal cord
• Motor Neurons:

  • carry motor messages from the spinal cord to the muscles, glands and organs of the body
• Interneurons:

  • act as connection between sensory and motor neurons and transfer messages from sensory neurons to motor neurons within CNS
  • found in spinal cord
• Spinal Cord:

  • long thin bundle of nerve fibres that extend from the base of the brain to the lower back
• 2 major functions of the spinal cord:

  • recive sensory info from body and send to brain
  • recive sensory info from brain and send to relevant part of body
• Somatic NS:

  • voluntary, muscles, movement
  • sensory - from CNS (afferent nerves)
  • motor - to CNS (efferent nerves)
• Direction of neurotransmission:

  • dendrite to axon terminal
• Electro-chemical signal:

  • Neurons can be explained as carrying electro-chemical signals, as an electrical nerve impulse (aciton potential) travels through neuron and neurotransmitters travel between the synapse of communicating neurons.
• Axon Terminals:

  • the enlarged end points of axon branches that store neurotransmitters and relese them into the synaptic cleft.