1st page of notes chapter 11

• Astrocytes


  Star-shaped cells, provide Structural Support to neurons, Regulate Chemical environment of Brain, Play a role in Synaptic transmission (Passing info from 1 neuron to another)
• Microglia


  Immune Cells of (CNS) responsible for immune defense, Scavenging debris, maintaining Brain Health by removing damaged cells and pathogens, Phagocytes
• Ependymal cells


  Line ventricles of Brain and Central canal of the Spinal Cord, Do the production and circulation of Cerebrospinal Fluid which provides Cushioning and Support to the brain and Spinal cord
• Oligodendrocytes


  Produce Myelin, a Fatty Substance that insulates axons in (CNS), allowing for Faster transmission of Nerve impulses
• Schwann cells


  Found in (PNS), Produce myelin Sheaths around axons, helping in Fast transmission of nerve impulses, and providing Structural Support
• Neurons


  Made for transmitting electrical signals, Processing information
• Glial cells


  Support and protect neurons, ensuring proper functioning of the Nervous System
• Myelin


  Speeds up electrical Signals along neurons
• Blood Brain Barrier (BBB)


  Protects Brain by controlling what Substances can enter it From the blood stream, Located in Capillaries of Brain Tissue
• Quick communication in the Nervous System
• Resting membrane potential


  Electrical charge of a neuron when it's not sending signals
• Resting membrane potential


  • Charge mostly negative inside neuron compared to outside
  • Na+ channels closed, keeping Na+ out, while K+ channels mostly open, allowing K+ to leak out, contributing to negative charge inside
  • Creates a balance where inside of neuron is more negative than the outside
• Depolarization and Stimulation


  1. Na+ channels open, letting lots of Na+ in from outside

  2. K+ channels mostly close, letting K+ ions out

  3. Makes inside of neuron more positive
• Repolarization


  1. Na+ channels close

  2. K+ channels open more, letting K+ ions out

  3. Causes an overshoot, making inside more negative than normal resting potential

  4. Restores neuron back to normal resting potential
• Action potential is self-generating because the changes happening inside the neuron open more channels, continuing the process
• Action potential does not need help from outside to continue once it starts