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CHAPTER 10 NERVOUS SYSTEM 1

CHAPTER 10 NERVOUS SYSTEM 1. FUNCTION. CONTROLS WHAT WE DO AND DETERMINES WHO WE ARE SENSE CHANGES IN HOMEOSTASIS , ANALYZE THE CHANGE AND INITIATE THE CORRECT RESPONSE. COMPOSISTION. NERVOUS TISSUE MOSTLY BLOOD VESSELS CONNECTIVE TISSUE. NERVOUS TISSUE TYPES. NEURONS: NERVE CELLS

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CHAPTER 10 NERVOUS SYSTEM 1

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  1. CHAPTER 10NERVOUS SYSTEM 1

  2. FUNCTION • CONTROLS WHAT WE DO AND DETERMINES WHO WE ARE • SENSE CHANGES IN HOMEOSTASIS , ANALYZE THE CHANGE AND INITIATE THE CORRECT RESPONSE

  3. COMPOSISTION • NERVOUS TISSUE MOSTLY • BLOOD VESSELS • CONNECTIVE TISSUE

  4. NERVOUS TISSUE TYPES • NEURONS: NERVE CELLS • NEUROGLIA

  5. NEURONS • FUNCTIONS: • STIMULATED BY CHEMICAL OR PHYSICAL CHANGES IN THE ENVIRONMENT • PARTS: • DENDRITES • CELL BODY/ SOMA • AXON • NERVE IMPULSE **A NERVE IS A COLLECTION OF NEURONS

  6. NEURON http://vv.carleton.ca/~neil/neural/neuron-a.html http://vv.carleton.ca/~neil/neural/neuron-a.html

  7. PARTS • SYNAPSE • NEUROTRANSMITTERS • CARRY IMPULSE ACROSS SYNAPSE

  8. ORGANS • CENTRAL NERVOUS SYSTEM: CNS • BRAIN • SPINAL CORD • PERIPHERAL NERVOUS SYSTEM: PNS • CRANIAL AND SPINAL NERVES • CONNNECTS CNS TO REST OF BODY • TWO PARTS: • SENSORY • MOTOR: TWO PARTS • SOMATIC NERVOUS SYSTEM • TO SKELETAL MUSCLES • AUTONOMIC NERVOUS SYSTEM • TO SMOOTH AND CARDIAC MUSCLE AND GLANDS

  9. GENERAL FUNCTIONS • RECEIVING INFORMATION: SENSORY • RECEPTORS ON ENDS OF THE PERIPHERAL NEURONS • STIMULATED BY (?) AND FORM IMPULSE OFTEN TO CNS • INTERPRETING INFORMATION: INTEGRATIVE • IMPULSES ARE ANALYZED AND CREATE SENSATIONS, FORM MEMORIES, PRODUCE THOUGHTS; • SUBCONCIOUS OR CONCIOUS DECISIONS MADE • REACTING TO INFORMATION: MOTOR • SUBCONCIOUS OR CONCIOUS DECISIONS ARE CARRIED OUT • EFFECTORS: MUSCLES AND GLANDS • SOMATIC NERVOUS SYSTEM: CONCIOUS; SKELETAL MUSCLES • AUTONOMIC NERVOUS SYSTEM: UNCONCIOUS; SMOOTH, CARDIAC MUSCLE AND GLANDS

  10. PARTS • VARY IN SIZE AND SHAPE; SIZE AND LENGTH OF DENDRITES AND AXONS AND NUMBER OF PROCESSES • CELL BODY: CONTAINS • GRANULAR CYTOPLASM • MITOCHONDRIA • LYSOSOMES • GOLGI APPARATUS • MICROTUBULES • NEUROFIBRILS: EXTEND INTO AXON • NISSL BODIES: CHROMATOPHILIC SUBSTANCE: ROUGH ER (?) • INCLUSIONS • NUCLEUS WITH NUCLEOLUS

  11. NEUROFIBRILS NEUROFIBRILS IN KITTEN NEURONS http://www5.bartleby.com/107/illus629.html

  12. NISSL BODIES SMALL ARROWS http://www.biomedcentral.com/content/figures/1471-2202-6-19-5-l.jpg

  13. DENDRITES • USUALLY BRANCHED • DENDRITIC SPINES: CONTACT POINTS • AXON • AXONAL HILLOCK • CYTOPLASM: • MITOCHONDRIA; MICROTUBULES, NEUROFIBRILS • COLLATERALS • AXON TERMINALS WITH SYNAPTIC KNOB

  14. DENDRITIC SPINES http://www.udel.edu/biology/Wags/histopage/colorpage/cne/cne.htm

  15. AXONAL TRANSPORT • CARRIES MATERIAL MADE IN CELL BODY TO END OF AXON • VESICLES, MITOCHONDRIA, IONS, NUTRIENTS, NEUROTRANSMITTERS

  16. http://www.lookfordiagnosis.com/mesh_info.php?term=axonal+transport&lang=1http://www.lookfordiagnosis.com/mesh_info.php?term=axonal+transport&lang=1

  17. SCHWANN CELLS www.mc.vanderbilt.edu/histology/slide.php?image_name=myelin&slide_file=images/histology/nervous_tissue/display/schwann3.jpg&image_id=1058

  18. MYELINATED NEURONS • HAVE SCHWANN CELLS (PNS) OR OLIGODENDROCYTES (CNS) • WHITE MATTER • INCREASE SPEED OF TRANSMISSION • UNMYELINATED • NO MYELIN • GRAY MATTER

  19. CLASSIFICATION OF NEURONS • STRUCTURAL • MULTIPOLAR • MOST NEURONS • WITH CELL BODIES • IN CNS • BIPOLAR • SPECIALIZED • STRUCTURES (EYES) • UNIPOLAR • SOME HAVE • GANGLIA http://library.thinkquest.org/C0126536/main.php?currentchap=1&currentsect=neuron.htm

  20. FUNCTIONAL CLASSIFICATION • SENSORY NEURONS/ AFFERENT • TO CNS • SENSES/ RECEPTORS • MOST UNIPOLAR (SOME BIPOLAR) • INTERNEURONS/ASSOCIATION/ • INTERNUNCIAL • IN CNS • MULTIPOLAR • TRANSFER IMPULSES TO BE INTERPRETED • MOTOR NEURONS/ EFFERENT • MULTIPOLAR • FROM CNS TO EFFECTORS • SOME VOLUNTARY/ SOME INVOLUNTARY

  21. NEUROGLIA • FUNCTION: • SCAFFOLDING; CONTROL SITES OF NEURONAL CONTACT; EMBRYONIC: GUIDE DEVELOPMENT, PLACEMENT AND SPECIALIZATION OF NEURONS; • PRODUCE GROWTH FACTORS THAT NOURISH NEURONS; REMOVE ACCUMULATING IONS AND NEUROTRANSMITTERS BETWEEN NEURONS; HELP FORMATION AND MAINTAINENCE OF SYNAPSES

  22. CLASSIFICATION OF NEUROGLIACNS • ASTROCYTES • STAR SHAPED • LOCATED BETWEEN BLOOD VESSELS AND NEURONS • SUPPOSRT NEURONS, AID METABOLISM OF SUBSTANCES (GLUCOSE); REGULATE ION CONCENTRATIONS; FORM SCAR TISSUE; MOVEMENT OF SUBSTANCES FROM BLOOD; RELEASE GROWTH FACTORS; PART OF BLOOD BRAIN BARRIER; • GAP JUNCTIONS http://medcell.med.yale.edu/ systems_cell_biology/nervous/ neuroglia.php

  23. OLIGODENDROCYTES • SIMILAR SHAPE BUT SMALLER • FORM MYELIN BUT ONLY PROCESS WRAP AROUND NEURONS SO COVER MANY CELLS BUT NO NEURILEMMA

  24. MICROGLIA • SMALL WITH FEWER PROCESSES • THROUGH OUT CNS • PHAGOCYTIZE BACTERIA • PROLIFERATE WHEN INJURY OCCURS • EPENDYMA • CUBOIDAL, COLUMNAR MAY BE CILIATED • FORM INNER LINING OF CENTRAL CANAL OF SPINAL CORD AND VENTRICLES AND CHOROID PLEXUSES • GAP JUNCTIONS: ALLOWING MOVEMENT BETWEEN CEREBROSPINAL FLIUD AND INTERSTITIAL FLUID OF BRAIN

  25. http://www.google.com/imgres?q=satellite+cells+pns+function&hlhttp://www.google.com/imgres?q=satellite+cells+pns+function&hl

  26. ABNORMAL NEUROGLIA • BRAIN TUMORS • ALS • HUNTINGTON’S DISEASES

  27. PNS • SCWHANN CELLS • SATELLITE CELLS • SUPPORT GANGLIA NOT SURE OF S[PECIFIC FUNCTION • FORM AN ENVELOPE AROUND EACH CELL BODY IN GANGLIA

  28. A: Satellite cells B: Schwann cells http://www.google.com/imgres?q=satellite+cells+pns+function&hl=en&sa

  29. NEURON REPAIR • INJURY TO CELL BODY = DEATH; NOT REPLACED UNLESS A STEM CELL IS STIMULATED • PNS: AXON MAY REGENERATE: • INJURY: • DISTAL PORTION DIES • MACROPHAGES REMOVE DEBRIES • PROXIMAL END DEVELOPS SPROUTS • NEUROGLIA RELEASE GROWTH FACTORS WHICH STIMULATE ONE SPROUT TO GROW INTO A TUBE FORMED BY BASEMENT MEMBRANE AND CONNECTIVE TISSUE • SCHWANN CELLS PROLIFERATE FORMING NEW MYELIN • GROWS 3-4MM/DAY; MAY NOT GROW TO PROPER POSITION

  30. NEURON REPAIR • CNS: • INJURY: • DISTAL PORTION DIES SLOWLY • OLIGODENDROCYTES DON’T FORM A NEURILEMMAE AND DON’T PROLIFERATE SO SPROUT USUALLY ISN’T DIRECTED TO GROW PROPERLY physproject-2011.wikispaces.com

  31. SYNAPTIC TRANSMISSION • PRESYNAPTIC NEURON STIMULATES OR INHIBITS THE POST SYNAPTIC NEURON • IMPULSE REACHES THE AXON TERMINAL AND THE CHANGE IN THE MEMBRANE OPENS THE CALCIUM CHANNELS AND CALCIUM DIFFUSES IN • CAUSING THE SYNAPTIC VESSICLES TO FUSE WITH THE CELL MEMBRANE AND RELEASE THE NEUROTRANSMITTERS BY EXOCYTOSIS • THE NEUROTRANSMITTER ATTACHES TO A RECEPTOR ON THE POST SYNAPTIC NEURON AND STIMULATES OR INHIBITS THE NEURON • THE EFFECT DEPENDS ON THE INPUT FROM 1 TO 100,000+ PRESYNAPTIC NEURONS AND THEIR INPUT

  32. http://www.ucl.ac.uk/~sjjgsca/NerveSynapse.html

  33. http://scienceaid.co.uk/biology/humans/nerves.html

  34. RESTING CELL MEMBRANE POTENTIAL • USUALLY POLARIZED: THE INSIDE IS MORE NEGATIVE THAN THE OUTSIDE BECAUSE OF THE SODIUM/POTASSIUM PUMP AND THE GATED CHANNELS ARE NOT OPEN • THE MEMBRANE IS MORE PERMEABLE TO POTASSIUM THAN SODIUM, SO POTASSIUM DIFFUSES OUT MORE READILY THAN SODIUM DIFFUSES IN • THERE ARE CELL FORMED ANIONS (PHOSPHATE, SULFATE AND PROTEINS) THAT CAN NOT DIFFUSE OUT OF THE CELL • SO THE OUTSIDE IS MORE POSITIVE AND THE INSIDE IS MORE NEGATIVE • THIS DIFFERENCE IS MEASURED IN MILLIVOLTS; THIS RESTING POTENTIAL IS -70 MILLIVOLTS • THIS NEGATIVE POTENTIAL ALLOWS SODIUM TO DIFFUSE INTO THE CELL BUT INHIBITS THE DIFFUSION OF POTASSIUM OUT OF THE CELL (ABOUT 3Na TO 2 K) WHICH THE PUMP REPLACES (3Na OUT TO 2 K IN)

  35. http://tle.westone.wa.gov.au/content/items/969144ed-0d3b-fa04-2e88-8b23de2a630c/1/human_bio_science_3b.zip/content/002_nervous_control/media/cc2_g015a.gifhttp://tle.westone.wa.gov.au/content/items/969144ed-0d3b-fa04-2e88-8b23de2a630c/1/human_bio_science_3b.zip/content/002_nervous_control/media/cc2_g015a.gif

  36. LOCAL MEMBRANE POTENTIAL CHANGES • NEURONS ARE HIGHLY EXCITABLE: RESPOND TO CHANGES • USUALLY OPENS A GATED ION CHANNEL • IF INSIDE BECOMES MORE NEGATIVE= HYPERPOLARIZED • IF INSIDE IS LESS NEGATIVE= DEPOLARIZED • CHANGES ARE GRADED= GREATER THE STIMULATION/ GREATER THE HYPERPOLARIZATION OR DEPOLARIZATION • IF DEPOLARIZATION REACHES -55MILLIVOLTS = THRESHOLD STIMULATION AND STARTS AN ACTION POTENTIAL= IMPULSE

  37. HYPERPOLARIZATION http://www.jci.org/articles/view/29063/figure/2

  38. DEPOLARIZATION

  39. ACTION POTENTIAL/IMPULSE • AT AXONAL HILLOCK MEMBRANE IS MOST LIKELY TO BE STIMULATED TO THRESHOLD = TRIGGER ZONE, CONTAINS LOTS OF VOLTAGE-GATED SODIUM CHANNELS • WHEN THRESHOLD IS REACHED THE CHANNELS OPEN AND Na DIFFUSES IN CHANGING POTENTIAL TO +30mV • Na CHANNELS CLOSE AND K CHANNELS OPEN AND K DIFFUSES OUT MAKING INSIDE NEGATIVE AGAIN= REPOLARIZATION • K CHANNELS CLOSE AND RESTING POTENTIAL IS REFORMED • ACTION POTENTIAL AT TRIGGER ZONE CUSES AN ELECTRICAL STIMULTION A SHORT DISTANCE ON THE MEMBRANE CAUSING ANOTHER ACTION POTENTIAL AND SO FORTH ALONG THE WHOLE AXON = IMPULSE • SODIUM IS PUMPED OUT, POTASSIUM IS PUMPED IN RESTORING THE RESTING POTENTIAL

  40. http://web.lemoyne.edu/~hevern/psy340_10S/graphics/action_potential.jpghttp://web.lemoyne.edu/~hevern/psy340_10S/graphics/action_potential.jpg

  41. http://www.google.com/imgres?imgurl=http://www.millerandlevine.com/chapter/35/figure35-7.jpg&imgrefurl=http://http://www.google.com/imgres?imgurl=http://www.millerandlevine.com/chapter/35/figure35-7.jpg&imgrefurl=http://

  42. HOW THE IMPUPLSE FORMS AND TRAVELS • http://www.youtube.com/watch?v=9euDb4TN3b0 • http://www.youtube.com/watch?feature=endscreen&v=7EyhsOewnH4&NR=1 • http://www.youtube.com/watch?NR=1&v=rWrnz-CiM7A&feature=fvwp http://www.youtube.com/watch?feature=endscreen&v=7EyhsOewnH4&NR=1

  43. ALL OR NONE • IF THRESHOLD IS REACHED THE AXON RESPONDS COMPLETELY • A GREATER STIMULUS RESULTS IN MORE IMPULSES PER SECOND NOT A STRONGER IMPULSE

  44. REFRACTORY PERIOD • ABSOLUTE • 1/2500 OF A SECOND • SODIUM PERMEABILITY • IS CHANGING/ CAN’T • RESPOND • RELATIVE • CLOSE TO RESTING POTENTIAL • RESPONDS TO A STRONGER STIMULUS TAKES 10-30 MILLISECONDS COULD HAVE UP TO 700 IMPULSES PER SECOND BUT USUALLY ONLY ABOUT 100 http://scienceaid.co.uk/biology/humans/nerves.html

  45. IMPULSE CONDUCTION • MYELINATED NEURON: • SALTATORY CONDUCTION • FASTER • UNMYELINATED • WHOLE AXON: SLOWER • LARGE AXON DIAMETER • FASTER • SMALL DIAMETER • SLOWER • THICK MYELINATED: • 120 M/S • THIN UNMYELINATED: • .5 M/S

  46. SYNAPTIC POTENTIALS • NEUROTRANSMITTERS OPEN OR CLOSE CHEMICALLY-GATED CHANNELS WHEN ATTACH TO RECEPTORS • LOCAL POTENTIALS = SYNAPTIC POTENTIALS • EXCITATORY POSTSYNAPTIC POTENTIAL • OPENS SODIUM CHANNELS = DEPOLARIZES • 15 MILLISECONDS • INHIBITORY POSTSYNAPTIC POTENTIAL • OPENS POTASSIUM OR CHLORIDE CHANNELS = HYPERPOLARIZED • INTEGRATED SUM OF EPSPS AND IPSPS DETERMINES RESPONSE • THE TRIGGER ZONE OR IN SOME THE DISTAL PERIPHERAL PROCESS IS MOST SENSITIVE SO THE DECISION-MAKING PART

  47. NEUROTRANSMITTERS • 30 – 50; FINDING NEW ONES • SOME NEURONS RELEASE ONLY 1; SOME 2 OR MORE • TYPES: • Ach • SKELETAL MUSCLES • MONOAMINES/BIOGENIC AMINES/MODIFIED AMINO ACIDS • NOREPINEPHRINE; DOPAMINE; SROTONIN; HISTAMINE • UNMODIFIED AMINO ACIDS • GLYCINE; ASPARTIC ACID; GABA; GLUTAMATE • NEUROPEPTIDES • ENKEPHALIN; ENDORPHIN; SUBSTANCE P • GASES • NITRIC OXIDE

  48. NEUROTRANSMITTER PRODUCTION • PEPTIDES: • ROUGH ER OF CELL BODY AND TRANSPORTED TO AXON TERMINAL • OTHERS • FORMED IN CYTOPLASM OF TERMINALS AND PACKAGED THE MORE CALCIUM THAT ENTERS THE MORE NEUROTRANSMITTERS RELEASED

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