resting potential Freesciencelessons

• What should you be able to describe by the end of the video on resting potential?


  What's meant by the resting potential and how it is maintained in neurons
• What do neurons transmit?


  Electrical impulses
• What do sensory neurons do?


  They transmit impulses from sensory receptors to the central nervous system
• What is the resting state of a neuron referred to by scientists?


  The res state
• What is the charge of the inside of a resting neuron's membrane compared to the outside?


  Negative
• What does it mean when scientists say the membrane is polarized?


  It means there is a charge difference across the membrane
• What is the value of the resting potential in a neuron?


  Approximately -65 mV
• How is the resting potential produced in a neuron?


  By the unequal distribution of sodium and potassium ions across the membrane
• What happens to the concentration of sodium and potassium ions in a resting neuron?


  Sodium ions are more concentrated outside, and potassium ions are more concentrated inside
• What is the role of the sodium-potassium pump in maintaining resting potential?


  It actively transports sodium ions out and potassium ions into the axon
• How many sodium ions are transported out for every two potassium ions transported in by the sodium-potassium pump?


  Three sodium ions
• What is the effect of the sodium-potassium pump on the charge difference across the membrane?


  It creates a greater number of positive ions outside than inside
• What are electrochemical gradients?


  Concentration gradients of charged ions across the membrane
• How do ions move through the membrane if they cannot diffuse directly through the phospholipid bilayer?


  Through ion channels by facilitated diffusion
• What type of ion channels are mainly closed in a resting neuron?

  Sodium ion channels
• What is the effect of the outward diffusion of potassium ions on the membrane potential?


  It makes the inside of the membrane more negative compared to the outside
• What are the two factors contributing to the resting potential in a neuron?


  • The sodium-potassium pump transfers three sodium ions out for every two potassium ions in
  • The outward movement of potassium ions via facilitated diffusion through ion channels