Unit 24 nerves

• Central Nervous System (CNS):-Brain (brainstem, cerebellum, diencephalon, basalganglia, cortex and hippocampus)-Spinal cord
• Peripheral nervous system: Nerves , ganglia and receptors
• PNS : Sensory and Motor
• Resting membrane potential is -60mv to -70mv
• Once an action potential is initiated, Sodium ions move into the cell and potassium ions move out
• Glia : Nutritional support and protection
• Neuron structure

  
• dendritic spines : small protrusions on dendrites that are covered in receptors and depending on age , different receptors form/ are present
• Axons contain microtubules which are used to transport vesicles containing neurotransmitters
• Components of nerve fibers: axons and envelope ( glial cells : Schwann cells and oligodendrocytes )
• Myelin sheath formation : myelin sheath is formed by Schwann cells, which wrap around axons
• Ranvier Nodes enable saltatory action potential conduction along amyelinated axon.
• Peripheral Nervous System: NERVES and GANGLIA . Central Nervous System: GRAY MATTER and WHITE MATTER
• GANGLIA: Neuronal somas localized outside the CNS
• Synapse : Connection between two neurons: Specialized to transmit specific signals in response to stimulus
• Types of synapses : Axosomatic , axodendritic , axoaxonic
• Neurotransmitters in chemical synapse : Acetylcholine, Norepinephrine, Serotonin , glutamate , GABA
• Astrocytes : A type of glial cell that forms the blood-brain barrier , control of H2O in the extracellular space (aquaporins) , control of increases in K+ after action potential (inward rectifying K+ channels) , uptake of excess of excitatory amino acid
• Microglia : small cells involved in immune response, phagocytosis, and clearing debris
• ependymal cells : form an epithelial monolayer (with cilia) covering the ventricles and the central canal in the spinal cord