nervous system

• what is nervous tissue?

  the term for groups of organised cells in the nervous system
• what are the three functions of nervous tissue?

  1. controls the body's movement
  2. sends and carries signals
  3. has a role in controlling bodily functions
• what are the two main types of nervous tissue?


  neurons and glial cells
• what are neurons?

  electrically excitable cells that function to process and transmit information
• what are the main components of the nervous system in mammals?

  • brain
  • spinal cord
  • peripheral nerves
• what are neurons typically composed of?


  • soma (cell body)
  • dendrite
  • axon
• label this neutron

  A) dendrite

  B) cell body

  C) node of ranvier

  D) axon terminal

  E) schwann cell

  F) myelin sheath

  G) axon

  H) nucleus

  
• what is the function of the soma/cell body?

  contains genetic information,

  maintains the neurons structure,

  provides energy to drive activities
• what is the function of dendrites?

  receive information from other neurons, called pre-synaptic neurons, from the environment
• what is the function of the axon?

  transmits information between neurons and away from muscles and glands
• what is the function of the axon terminal?

  allows the neurons to conduct electrical impulses down to another neuron or another type of cell, by the release of signals into the synapse
• what is the function of the myelin sheath?

  allows electrical impulses to transmit quickly and efficiently along the nerve cells
• what is the function of the node of ranvier?

  allows ion exchange for regenerating action potentials and facilitates faster signal transmission
• what is the function of the Schwann cells?

  produce and maintain the myelin sheath, aiding in signal conduction and axonal repair
• what is the function of the nucleus?

  controls cell functions and contains genetic information
• what are the three types of glial cells?


  1. astrocytes
  2. oligodendrocytes
  3. microglia
• astrocytes :

  • provide structural and metabolic support
  • maintain blood brain barrier
  • regulate ion balance
  • promote maturation and stability of connection between neurons
• oligodendrocytes:

  • speed up electrical signalling through myelin production
  • supports neurons which stabilises axons.
  • regulates signal transmission, maintaining proper myelination
  • promotes natural repair, remyelinates axons
• microglia:

  • primary immune cells detect and respond to pathogens
  • phagocytosis which removes debris, dead cells and engulfs
  • releases inflammatory mediators in response to infection
  • monitor for injury or disease, maintaining homeostasis
• what are the three parts of a synapse?

  1. presynaptic neuron
  2. synaptic cleft
  3. postsynaptic cleft
• what are the two types of synapses?

  chemical and electrical
• what are the parts of the CNS?


  the brain and the spinal cord
• the peripheral nervous system involves parasympathetic nerves, the central nervous system involves sympathetic nerves
• what functions does the brain oversee?


  • sensory input
  • decision making
  • coordinating responses
• what is the function of sensory/afferent nerves?


  carrying information from the body to the CNS
• what is the function of motor/efferent nerves?


  transmitting responses back to muscles and glands
• what is the function of the sympathetic division?

  triggers a fight or flight response during stress
• increased heart rate, expanding airways and redirecting blood flow to muscles are all 'fight or flight' responses
• what is the function of the parasympathetic division?

  encourages rest and digest functions
• slowing heart rate, enhancing digestion and promoting energy storage are all 'rest and digest' functions
• what are receptors?

  specialised cells that detect changes in the environment and convert them into electrical signals
• voluntary reactions are controlled by out conscious thought, such as moving a limb or deciding to walk
• non voluntary reactions include reflexes and automatic responses, they are fast and protective, bypassing conscious processing
• what are the stages of a reaction?

  1. stimulus detected by receptors
  2. transmission to the CNS via sensory nerves
  3. CNS processing and decision making
  4. response via motor nerves