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The Nervous System: Organization and Tissues. Chapter 11. Functions of the Nervous System. Organization of the Nervous System. Histology of the Nervous System. Neuroglial cells Neurons. Neuroglial Cells of the Central Nervous System. Neuroglial Cells of the Peripheral Nervous System.
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Histology of theNervous System • Neuroglial cells • Neurons
Neurons • Characteristics • Excitable • Longevity • High Metabolic Rate • Sometimes Large • Amitotic • May Regenerate
Neurophysiology • Electrical currents correspond to the flow ions across cellular membranes • Ion channels allow the flow of ions into and out of the cell • Passive, or leakage, channels • Active, or gated, channels
Location of Channels Leakage Channels Chemical Channels Voltage Channels
The Synapse Presynaptic neurons versus Postsynaptic neurons
Classes of Neurotransmitters • Acetylcholine: excitatory (skeletal muscle) • Biogenic amines • Dopamine, Norepinephrine, and epinephrine (feel good catecholamines) • Serotonin: mood, sleep, appetite & anger (inhibitory) • Histamine • Amino acids • GABA (gamma-aminobutyric acid) (inhibitory) • Glutamate: excitatory • Peptides • Endorphins and enkephalins: inhibitory (opioids)