Transmission within neurons

• What is the function of neurons?

  carry out all info processing and transmission
• What are sensory neurons?

  neurons that carry info from the senses
• What are interneurons?

  neurons that link sensory and motor neurons
• What are motot neurons?

  neurons that carry info to parts of the nbody like muscles
• What is a soma?

  a cell body of a neuron, contains nucleus
• What is an axon?

  A long, slender projection of a nerve cell that conducts electrical impulses from the cell body to terminal buttons
• What are terminal buttons?

  Endings of axon branches
• What are dendrites?

  Branch-like structures on a neuron that receive signals from other neurons
• What is the myelin sheath?

  Insulating layer around axon
• What are ghlial cells?

  Supporting cells in the nervous system
• What are the 3 types of ghlial cells?

  astrocytes, oligodendrocytes, microglia
• What are astrocytes?

  Glial cells in the central nervous system that support and protect neurons
• What are oligodendrocytes?

  Glial cells that produce myelin in the central nervous system.
• What are microglia?

  ghlial cells that clear dead parts of neurons, acting like the nerves' immune system
• Cells are more _____ on the inside than outside, creating resting potential

  negative
• What kind of membrane surrounds cells?

  phospholipid bilayer
• What are ions?

  Charged particles
• What charge do cations have?

  Positive
• what charge do anions have?

  Negative
• The intracellular fluid contains...

  potassium ions and anions
• The extracellular fluid contains....

  sodium and chloride ions
• What is the membrane potential?

  The difference in electric charge between the inside and outside of a cell membrane
• How is membrane potential balanced?

  diffusion of ions and electrostatic pressure
• Where are organic ions?

  inside cell as cant cross membrane
• Where are potassium ions?

  concentrated inside cell, they want to diffuse out but electrostatic pressure attracts them inside, forces balance so K+ doesnt move
• Where are chloride ions?

  more concentrated outside cell, they want to diffuse into cell but electrostatic pressure repels them from inside, forces balance so Cl- doesnt move
• Where are sodium ions?

  more concentrated outside cell, they want to diffuse into cell and electrostatic pressure attracts them inside, both force Na+ into cell
• How are sodium ions controlled?

  using sodium-potassium pumps, 3 Na+ out as 2 K+ in
• What is resting potential of a neuron?

  -70mV, inside of neuron is negative and outside is positive
• Why is it imporant to maintain a resting potential?

  Allows neuron to respond rapidly to a stimulus
• What is an action potential?

  a rapid change in membrane potential
• Action potential are what kind of process?

  all or nothing
• Action potential stay the same____ throughout transmission

  size
• What is depolarisation?

  decrease from resting potential (less negative)
• What is hyperpolarisation?

  increase from resting potential (more negative)
• Action potential has to reach what to fire?

  threshold of excitation
• 1st stage of action potential..

  when threshold is reached, Na+ channels open and sodium ions begin to enter cell
• 2nd stage of action potential...

  K+ channels open and potassium ions begin to leave cell (start of depolarisation)
• 3rd stage of action potential...

  Na+ channels become refractory (close) so no more sodium ions can enter cell (end of depolarisation)
• 4th stage of action potential...

  K+ continues to leave cell, membrane begins returning to resting potential