1. Cells of the Nervous System

2. Two Broad Classes of Cells in the Nervous System 1. Nerve cells (neurons) 2. Support cells (glia) Neurons come in many different varieties based on size, shape, chemistry, etc. Glia also come in different varieties. Different varieties allow for optimizing specialized functions of both neurons and glia. Five to ten times as many glia as neurons in the CNS

5. 4. Transmit information to target cell (neuron, muscle, gland) Four Functions of Neurons 1. Receive and integrate inputs 2. Generate a nerve impulse (action potential) 3. Conduct the action potential dendrites, soma axon hillock axon nerve terminals

6. Dendrites and cell body Receive and integrate inputs Axon hillock and initial segment Generate action potentials Axon Conducts action potential Terminals Synaptic transmission

7. Receive and integrate inputs Conducts action potential Axon hillock Generates action potential Transmits to target cell receives and integrates inputs

8. Synaptosome

11. Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity

12. Classifications of Neurons 1. Function a. sensory neurons b. motoneurons c. interneurons

13. Classifications of Neurons 1. Function 2. Structure a. unipolar b. bipolar c. multipolar

17. 100μm B A

18. Classifications of Neurons 1. Function 2. Structure 3. Shape e.g., pyramidal, stellate, basket, granule, etc.

21. Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect a. excitatory neurons b. inhibitory neurons

22. Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length a. projection neurons (Golgi Type I) b. local neurons (Golgi Type II)

23. Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity e.g., cholinergic, dopaminergic, GABAergic, etc.

24. Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity

25. Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia 4. Schwann cells

26. Types of glial cells 1.Astrocytes a. mechanical support b. metabolic support transport nutrients and wastes c. encapsulate synapses d. regulate chemical and ionic environment e. form scar tissue f. act as phagocytes

28. Types of glial cells 1.Astrocytes 2.Microglia a. act as phagocytes b. part of brain’s immune system

30. Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia myelinate axons of central nervous system

33. Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia 4. Schwann cells myelinate axons of peripheral nervous system