1. Slide 1 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Bear: Neuroscience: Exploring the Brain 3e Chapter 02: Neurons and Glia

2. Slide 2 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Introduction “Neurophilosophy” Brain is the origin of mental abilities Glia and Neurons Glia: Insulates, supports, and nourishes neurons Neurons Process information Sense environmental changes Communicate changes to other neurons Command body response

3. Slide 3 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Neuron Doctrine Histology Study of tissue structure The Nissl Stain Facilitates the study of cytoarchitecture in the CNS

4. Slide 4 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Neuron Doctrine Golgi-stain shows two parts of neurons: Soma and perikaryon Neurites: Axons and dendrites

5. Slide 5 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Neuron Doctrine Cajal’s Contribution Neural circuitry Neurons communicate by contact, not continuity Neuron doctrine Neurons adhere to cell theory

6. Slide 6 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron Neuronal membrane The Soma Cytosol: Watery fluid inside the cell Organelles: Membrane-enclosed structures within the soma Cytoplasm: Contents within a cell membrane (e.g., organelles, excluding the nucleus)

7. Slide 7 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Soma Gene expression Protein synthesis RNA splicing Molecular biology

8. Slide 8 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Soma Rough Endoplasmic Reticulum (ER) Major site for protein synthesis Free ribosomes Polyribosomes

9. Slide 9 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Soma Rough ER Protein synthesis in neurons

10. Slide 10 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Soma Smooth ER and Golgi Apparatus Sites for preparing/sorting proteins for delivery to different cell regions (trafficking) and regulating substances

11. Slide 11 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Soma Mitochondrion Site of cellular respiration (inhale and exhale) Krebs cycle ATP- cell’s energy source

12. Slide 12 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Neuronal Membrane Barrier that encloses cytoplasm ~5 nm thick Protein concentration in membrane varies Structure of discrete membrane regions influences neuronal function

13. Slide 13 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Cytoskeleton Not static Internal scaffolding of neuronal membrane Three “bones” Microtubules Microfilaments Neurofilaments

14. Slide 14 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Axon Axon hillock (beginning) Axon proper (middle) Axon terminal (end) Differences between axon and soma ER does not extend into axon Protein composition: Unique

15. Slide 15 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Axon The Axon Terminal Differences between the cytoplasm of axon terminal and axon No microtubules in terminal Presence of synaptic vesicles Abundance of membrane proteins Large number of mitochondria

16. Slide 16 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Axon Synapse Synaptic transmission Electrical-to- chemical-to-electrical transformation Synaptic transmission dysfunction Mental disorders

17. Slide 17 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron The Axon Axoplasmic transport Anterograde (soma to terminal) vs. Retrograde (terminal to soma) transport

18. Slide 18 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins The Prototypical Neuron Dendrites “Antennae” of neurons Dendritic tree Synapse - receptors Dendritic spines Postsynaptic (receives signals from axon terminal)

19. Slide 19 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Classifying Neurons Classification Based on the Number of Neurites Single neurite Unipolar Two or more neurites Bipolar- two Multipolar- more than two

20. Slide 20 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Classifying Neurons Classification Based on Dendritic and Somatic Morphologies Stellate cells (star- shaped) and pyramidal cells (pyramid-shaped) Spiny or aspinous

21. Slide 21 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Classifying Neurons Further Classification By connections within the CNS Primary sensory neurons, motor neurons, interneurons Based on axonal length Golgi Type I Golgi Type II Based on neurotransmitter type e.g., – Cholinergic = Acetycholine at synapses

22. Slide 22 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Glia Function of Glia Supports neuronal functions Astrocytes Most numerous glia in the brain Fill spaces between neurons Influence neurite growth

23. Slide 23 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Glia Myelinating Glia Oligodendroglia (in CNS) and Schwann cells (in PNS) Insulate axons Node of Ranvier Region where the axonal membrane is exposed

24. Slide 24 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Glia Myelinating Glia (Cont’d) Oligodendroglial cells Node of Ranvier Other Non- Neuronal Cells Microglia as phagocytes (immune)

25. Slide 25 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Concluding Remarks Structural characteristics of a neuron tell us about its function NEURONS Soma Axons Dendrites Synapse Elaborate structure of dendritic tree = receiver e.g., Dense Nissl stain = protein; suggests specialization Structure Correlates with Function

26. Slide 26 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins End of Presentation