Lecture 01

• What are neurons also known as?

  Nerve cells
• What can neurons be stimulated to produce?

  Tiny electrical currents
• How do neurons transmit electrical signals?

  Over short or long distances
• What surrounds all living cells, including neurons?

  Plasma membrane
• What is the permeability of the plasma membrane to ions?

  Impermeable to ions
• What is the permeability of the plasma membrane to water?

  Semi-permeable
• What is the extracellular concentration of Sodium (Na+) in neurons?

  140 mM
• What is the intracellular concentration of Potassium (K+) in neurons?

  140 mM
• What does the intracellular environment contain a high concentration of?

  Negatively charged organic anions (A-)
• How is the ionic gradient established in neurons?

  Through active and passive transport
• What do ion pumps use to function?

  ATP hydrolysis
• What do ion pumps do with Sodium (Na+) and Potassium (K+) ions?

  Pumps 3 Na+ out, 2 K+ in

  
• What are ion channels?

  Membrane spanning protein pores
• What is the function of ion channels in cells?

  Allow ions to move in and out

  
• What is gating in ion channels?

  Channel opening and closing
• What determines which ions can pass through an ion channel?

  Channel permeability and selectivity filter
• What activates ligand-gated ion channels?

  Chemicals like ACh
• What type of ion channels are voltage-gated?

  Sodium, potassium, and calcium channels
• What is the characteristic of channel current in ion channels?

  Constant amplitude
• How fast is the opening and closing of ion channels?

  Very fast
• What drives ion movement through a channel?

  Electro-chemical gradient of the ion
• What are leaky channels?

  Special non-gated ion channels
• What do K+ leak channels do?

  Leak potassium ions out of cells
• What is the role of Na+ leak channels?

  Leak sodium ions into cells
• What is the summary of the ionic environment in neurons?

  • An ionic gradient exists across the membrane
  • Generated by ion pumps (membrane proteins)
  • Ion channels allow ions to move down their gradient
  • Activated by chemicals or voltage changes
  • Vital for neuron function