1 / 29

The Nervous System

This article provides an overview of the general organization of the nervous system, the structure and function of neurons, and the anatomy of the brain. It also discusses the supporting cells of the nervous system and the protection mechanisms of the brain.

gwaltney
Download Presentation

The Nervous System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Nervous System

  2. I. General organization of nervous system • CNS 1. brain 2. spinal cord B. PNS 1. sensory 2. motor a. Somatic b. ANS -sympathetic -parasympathetic

  3. II. Nervous Supporting Cells - neuroglia • Astrocytes • Connect to capillaries • Mopping up chemical environment of brain as far as potassium ions and neurotransmitters

  4. B. Microglia • 1. spider-like phagocytes • 2. debris, dead brain cells, bacteria

  5. C. Ependymal cells • 1. lines cavities in CNS • 2. beating of cilia moves cerebrospinal fluid • 3. fluid nourishes and cushions CNS

  6. D. Oligodendrocytes • 1. wrap axons of nerve cells with fatty layer • 2. produces myelin sheath • 3. speeds conduction

  7. E. Glia cells in general • 1. resemble neurons • 2. not excitable • 3. supportive cells • 4. capable of repeated mitosis • 5. gliomas-glial tumors

  8. III. NeuronsA. Structure • 1. cell body • 2. nissl bodies-rer • 3. dendrites • 4. axon • 5. axon hillock • 6. axon collateral • 7. axon terminals • 8. neurotransmitters • 9. synaptic cleft

  9. B. Myelin sheath • 1. functions • 2. PNS-Schwann cell • 3. Node of Ranvier • 4. Can form a pathway for regrowth of damaged axon • 5. multiple sclerosis

  10. C. Neurons classified by function • 1. afferent • 2. interneuron • 3. efferent • 4. ganglia • 5. nuclei

  11. D. Neurons classified by structure • 1. multipolar • 2. bipolar • 3. unipolar

  12. IV. Neuron physiology • A. Resting membrane potential • B. Action potential-nerve impulse

  13. C. Propagation of action potential • 1. diagram on board • 2. a lot like dominoes • 3. http://www.youtube.com/watch?v=7tBWl4GE8rk&NR=1

  14. D. Anatomy of a synapse • 1. presynaptic membrane • 2. synaptic cleft • 3. postsynaptic membrane • 4. synaptic vesicles • 5. receptor sites for transmitter substance

  15. E. Physiology of synapse • 1. action potential arrives • 2. Calcium ion channels open • 3. synaptic vesicles fuse with membrane • 4. transmitter substance released • 5. diffusion of transmitter substance • 6. binding to receptors • 7. creates a graded potential • 8. may bring postsynaptic membrane to threshold • 9. nerve gas-blocks cholinesterase

  16. F. You tube of synaptic events • http://www.youtube.com/watch?v=z3F5dfmQ3hk

  17. V. Functional Anatomy of the Brain A. Introduction • 1. difficult to talk about • 2. two fistfuls of pinkish/gray • 3. wrinkled • 4. consistency of cold oatmeal • 5. three pounds • 6. hugely complex • 7. four basic regions • a. Cerebral hemispheres • b. Diencephalon • c. Brain stem • d. cerebellum

  18. B. Cerebral hemispheres • 1. most important part • 2. overshadows diencephalon and brain stem • 3. mushroom cap covers top of stalk • 4. gyri • 5. sulci • 6. fissures-ie longitudinal cerebral fissure

  19. 7. Lobes of cerebrum • a. Frontal lobe controls mainly motor function • b. Primary motor area is on the precentralgyrus -governs conscious motor control which can be mapped

  20. Motor homunculus

  21. c. Motor homunculus • -specific regions of the precentralgyrus control specific body parts • -finer the movements, the more brain area needed to control those movements

  22. d. Premotor area • -learned repetitive tasks • Typing, playing piano • Athletes learn tasks by visualizing motions • Ingrained in this area

  23. e. Broca’s area • speech center • Usually located left cerebral hemisphere • Damage here causes inability to speak

  24. 8. Other important areas of cerebral hemispheres • a. Primary somatic sensory area • b. Visual area in occipital lobe • c. Complex memory in the temporal lobe • d. Note close proximity to olfactory area • e. Anterior association area-higher intellectual reasoning and socially acceptable behavior

  25. 9. Sensory homunculus

  26. C. Diencephalon • Thalamus a. Encloses third vent. b. Screens incoming sensory messages • Hypothalamus a. ANS center for body temperature and water balance b. Regulates pituitary • Epithalamus a. Pineal gland b. Choroid plexus

  27. D. Brain stem • 1. size of thumb • 2. midbrain • 3. pons • 4. medulla • 5. interchange for sensory and motor paths • 6. nuclei for respiratory, blood pressure, heart rate, RAS

  28. E. Cerebellum • Cauliflower shape • Controls balance and equilibrium • Produces smooth and coordinated muscular contractions

  29. VI. Protection of the brain • A. Meninges • 1. dura mater • 2. arachnoid • 3. pia mater • B. CSF • 1. produced choroid plexi • 2. flow • 3. functions • 4. hydrocephalus

More Related