1. Neural Tissue The nervous system includes all the neural tissue in the body.

2. Structure of the nervous system

3. The Nervous System Central Nervous System Peripheral Nervous System Brain Spinal Cord Sympathetic Parasympathet ic SomaticAutonomic AfferentEfferent

4. Peripheral Nervous System Afferent - bring sensory Efferent - carry commands

5. Efferent Division ✴S✴S omatic - skeletal muscle contractions (voluntary) & involuntary reflexes ✴A✴A utonomic (visceral motor system) - Involuntary (smooth muscles, cardiac muscle & glandular secretions)

6. Autonomic Nervous System Parasympathetic - nonstressful rest & digest Sympathetic – stressful fight or flight

7. Neuron Functional & Structural unit of the nervous system

8. dendrites Nissl bodies nucleusnucleolus neurofilaments Initial segment of axon axon mitochondria dendritic spines synaptic terminals telodendria Golgi apparatus axon hillock telodendria axon nucleus perikaryon dendrites Multipolar Neuron

9. Vocabulary ✴ dendrites - typically highly branched, carry messages ✴ axon - propagates an electrical impulse away from the cell body ✴ initial segment - base of an axon

10. Vocabulary cont. ✴ axon hillock - thickened region ✴ soma - cell body, houses organelles but lack centioles ✴ telodendria - fine extensions off the axon ✴ synaptic terminal - ends of the telodendria

11. Structural Classification of Neurons anaxonic neuron bipolar neuron unipolar neuron multipolar neuron

12. Functional Classification of Neurons ✴S✴S ensory neurons (afferent) - from sensory receptors to CNS somatic sensory neurons - monitor the outside world & our position in it visceral sensory neurons - monitor internal conditions & the status of the organs

13. Sensory receptors proprioceptors interoceptors exteroceptors

14. Sensory Receptors Further broken down into Mechanoreceptor s Thermoreceptors Nociceptors Chemoreceptors Osmoreceptors Photoreceptors

15. Functional Classification of Neurons ✴M✴M otor Neurons (efferent) - carry instructions from the CNS to peripheral effectors

16. Functional Classification of Neurons ✴ Interneurons (association) - outnumber all other types mostly in brain & spinal cord situated between sensory & motor neurons

17. Ependymal Cells line the central canal & ventricles which house the brain & spinal cord, creates a barrier between the Cerebral Spinal Fluid (CSF) and the brain & spinal cord

18. Neuroglial Cells

19. Astrocytes ✴ Maintain the blood-brain barrier ✴ Create a 3-D framework for the CNS ✴ Repair damaged nerve tissue ✴ Guide neuron development ✴ Control the interstitial environment

20. Oligodendrocytes Form the myelin sheath along the length of the axon ✴ myelin - increases the speed of the action potential along the axon ✴ myelin sheath - membrane wrapping around the axon ✴ internodes - area of the axon wrapped myelin (1 - 2 mm in length) ✴ nodes - small gaps (few micrometers) between internodes with no myelin ✴ white matter - CNS, areas with myelinated axons, high lipid content ✴ gray matter - areas containing neuron cell bodies, dendrites & unmyelinated axons

21. The Myelinated Axon

22. Microglia least numerous cleanup by engulfing cellular debris, waste products & pathogens