1. http://www.youtube.com/watch?v=Q4uh2r1djWw The Nervous System

2. - General organization - The basic units- the cells - Neurophysiology - Neural interactions Brain, Spinal cord, Neuronal pathways, Special senses

3. The Central Nervous System (CNS) The Peripheral Nervous System (PNS) The Human Nervous System

4. The Nervous System Monitors changes Processes and interprets Causes a response PNSCNS

5. Peripheral Nervous system Central Nervous system sensorymotor Autonomic Smooth and cardiac muscles; Glands Somatic Skeletal muscles Motor (Efferent) Sensory (Afferent) Somatic (skin, skeletal muscle and joints) Visceral (internal organs)

6. “As the entomologist chasing butterflies of bright colors, my attention was seeking in the garden of gray matter, those cells of delicate and elegant forms, the mysterious butterflies of the soul, whose fluttering wings would someday—who knows?— enlighten the secret of mental life” Santiago Ramón y Cajal (1852-1934) Neurons “The Mysterious Butterflies of the Soul”

7. Neurons “The Mysterious Butterflies of the Soul” Santiago Ramón y Cajal Nobel prize in physiology and medicine 1906

8. The neuron Axon Cell body Dendrites Telodendria Nissl bodies

9. Most of our wiring is insulated Myelin sheath

10. Whitish, fatty (protein-lipoid), segmented sheath around most long (NOT ALL) axons It functions to: - Protect the axon - Electrically insulate fibers from one another - Increase the speed of nerve impulse transmission Myelin sheath

11. Formed by Schwann cells in the PNS A Schwann cell: - Envelopes an axon in a trough - Has concentric layers of membrane that make up the myelin sheath Myelin sheath

12. Axons are bundled together to form fascicles CNS: axon bundles form tracts PNS: axon bundles form nerves

13. Neurons are not alone

14. Neurons are Not Alone: The supporting neuroglia CNS

15. Astrocytes - Support and brace neurons - Anchor neurons to their nutrient supplies - Guide migration of young neurons - Control the chemical environment

16. Microglia The “Immune System” of the CNS - Small, ovoid cells with spiny processes - Turn into phagocytes upon inflammation (monitor the health of neurons, in the absence of macrophages, due to the BBB)

17. Ependymal cells - Ciliated epithelial cells lining the central cavities of the brain and spinal column - Forming a permeable barrier between the CSF and nervous tissue - Beating cilia helps circulating the CSF CSF (cerebrospinal fluid)

18. Banizs et al. Development (2005) What could happen in B? B A -Beating cilia helps circulating the CSF

19. Neurons are Not Alone: The supporting neuroglia CNS

20. Oligodendrocytes - Insulators of the thick neurons of the CNS - A single oligodendrocyte can form myelin sheaths around several axons

21. The supporting neuroglia in the CNS

22. The supporting neuroglia in the PNS - Schwann cells surround and insulate axons (the “oligodendrocytes” of the PNS) -Satellite cells Support an nourish cell bodies (“astrocytes” of the PNS)

23. Summary Peripheral Nervous system Central Nervous system sensorymotor Autonomic Smooth and cardiac muscles; Glands Somatic Skeletal muscles Motor (Efferent) Sensory (Afferent) Somatic (skin, skeletal muscle and joints) Visceral (internal organs)

24. Summary Not all neurons look like that

25. Neurophysiology Opposite electrical charges attract each other In case negative and positive charges are separated from each other, their coming together liberates energy Thus, separated opposing electrical charges carry a potential energy - - - - - - - - ++ + ++ ++ inside outside

26. Voltage (V) measure of differences in electrical potential energy generated by separated charges Current (I) the flow of electrical charge between two points Resistance (R) hindrance to charge flow Neurophysiology - - - - - - - - ++ + ++ ++ inside outside

27. Ohm’s law

28. --- - - - - - ++ + ++ ++ inside outside + + + - Current: ions Resistance: membrane permeability Voltage: potential across the membrane

29. --- - - - - - ++ + ++ ++ inside outside + + + - Resistance: membrane permeability How can ions move across the membrane?