transmission within a neuron

Cards (30)

  • label the diagram
    A) dendrites
    B) terminal buttons
    C) myelin sheath
    D) soma
    E) axon
  • why do sodium channels open?
    when the threshold of excitation is reached
  • at rest, sodium ions are...
    attracted to the inside of the cell
  • what is a function of the myelin sheath?
    enables action potentials to travel quickly
  • sensory neurons carry information...
    from the body to the CNS
  • motor neurons carry info from the CNS to the muscles
  • how many neurons are in the brain?
    86 billion
  • label the parts on a neuron
    A) dendrites
    B) myelin sheath
    C) axon
    D) soma
    E) terminal buttons
  • dendrite - receives messages from the previous neuron
  • soma (cell body) - contains nucleus
  • axon - carries info from soma to terminal buttons
  • myelin sheath - wraps around axon
  • terminal button - at the end of axon branches
  • glia - the other type of cell that makes up the nervous system
  • astrocytes
    • provide structural support to neurons
    • provide nutrients to neurons. get glucose from capillaries and break it down into lactate
    • surround synapses to limit dispersion of neurotransmitter
  • oligodendrocytes - produce myelin sheath
  • microglia
    • clears dead or dying neurons
    • attack foreign tissue and helps repair damaged cells
  • Transmission withing a neuron is an electrical process. Results from the movement of ions across the cell membrane
  • All cells have electrical charge. More negative on the inside. Result in resting potential (store of energy)
  • ions - charged molecules
  • Cations are positively charged molecules
  • Anions are negatively charged molecules
  • Membrane potential  - difference in electrical potential inside and outside of the cell
  • Intercellular fluid contains potassium ions and anions
  • Extracellular fluid contains chloride ions
  • what is membrane potential balanced by?
    diffusion and electrostatic pressure
  • what is the resting potential of a neuron?
    -70 mV
  • Depolarization - decrease from normal resting potential
  • Hyperpolarization - increase relative to resting potential
  • axons covered by the myelin sheath = fast conduction of AP, less energy required