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Ch. 7 nervous system

Ch. 7 nervous system. ORGANIZATION-SUPPORTING CELLS. NERVOUS SYSTEM. MASTER CONTROLLING & COMMUNICATION SYSTEM OF BODY. NERVOUS SYSTEM FUNCTIONS. SENSORY INPUT - MONITOR CHANGES IN/OUTSIDE OF BODY (STIMULI) --- GATHERS INFORMATION

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Ch. 7 nervous system

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  1. Ch. 7 nervous system ORGANIZATION-SUPPORTING CELLS

  2. NERVOUS SYSTEM • MASTER CONTROLLING & COMMUNICATION SYSTEM OF BODY

  3. NERVOUS SYSTEM FUNCTIONS • SENSORY INPUT - MONITOR CHANGES IN/OUTSIDE OF BODY (STIMULI) --- GATHERS INFORMATION • INTEGRATION -PROCESSES & INTERPRETS INPUT, MAKES CHANGES • MOTOR OUTPUT - A RESPONSE BY MUSCLE/GLAND ACTIVATION

  4. NERVOUS SYSTEM FUNCTIONS

  5. NERVOUS SYSTEM FUNCTIONS • WORKS WITH ENDOCRINE SYSTEM • PRODUCES HORMONES RELEASED INTO BLOOD

  6. STRUCTURAL CLASSIFICATION • 2 SUBDIVISIONS: • CENTRAL NERVOUS SYSTEM • BRAIN AND SPINAL CORD • INTERPRET INCOMING INFORMATION • PERIPHERAL NERVOUS SYSTEM • OUTSIDE OF CNS • NERVES EXTENDING FROM BRAIN & S.C. • SPINAL NERVES-TO/FROM S.C. • CRANIAL NERVES-TO/FROM BRAIN

  7. FUNCTIONAL CLASSIFICATION • ONLY PNS • 2 SUBDIVISIONS OF PNS • SENSORY (AFFERENT) • CARRY INFO TO CNS FROM SENSORY RECEPTORS • MOTOR (EFFERENT) • CARRY INFO FROM CNS TO MUSCLES/GLANDS

  8. FUNCTIONAL CLASSIFICATION • THE MOTOR DIVISION HAS 2 SUBDIVISIONS: • SOMATIC NERVOUS SYSTEM • CONSCIOUS, VOLUNTARY CONTROL (NOT REFLEXES) • AUTONOMIC NERVOUS SYSTEM • INVOLUNTARY; SMOOTH/CARDIACE MUSCLE & GLANDS

  9. FUNCTIONAL CLASSIFICATION • INVOLUNTARY (ANS)HAS 2 SUBDIVISIONS: • SYMPATHETIC BRING • PARASYMPATHETIC OPPOSITE EFFECTS *WILL BE DISCUSSED LATER

  10. FUNCTIONAL CLASSIFICATION TO SUMMARIZE: CENTRAL N.S. MOTOR SENSORY SOMATIC AUTONOMIC SYMPATH. PARASYM.

  11. FUNCTIONAL CLASSIFICATION

  12. STOP DAY 1

  13. NERVOUS TISSUE pg. 204 • SUPPORTING CELLS • “NEUROGLIA” – NERVE GLUE (GLIA) • FUNCTION-SUPPORT, INSULATE, PROTECT THE NEURON • 4 SUPPORTING CELLS OF CNS: • ASTROCYTES, MICROGLIA, EPENDYMAL, OLIGODENDROCYTES

  14. SUPPORTING CELLS • ASTROCYTES • ½ OF NEURAL TISSUE; STAR SHAPED; BARRIER B/T CAPILLARIES & NEURONS; PROTECT NEURON; CONTROL CHEMICAL ENVIRONMENT

  15. SUPPORTING CELLS 2. MICROGLIA • SPIDERLIKE PHAGOCYTE; DISPOSE OF DEBRIS (DEAD BRAIN CELLS, BACTERIA)

  16. SUPPORTING CELLS 3. EPENDYMAL • LINE CAVITIES OF BRAIN & SPINAL CORD; CIRCULATE CEREBROSPINAL FLUID; CUSHION CNS

  17. SUPPORTING CELLS 4. OLIGODENDROCYTES • WRAP EXTENSIONS AROUND NERVE FIBERS; FATTY INSULATING COVERS - MYELIN SHEATHS

  18. SUPPORTING CELLS • SUPPORTING CELLS OF PNS (PERIPHERAL NERVOUS SYSTEM) • SCHWANN CELLS • FORM MYELIN SHEATHS AROUND NERVE FIBERS IN PNS • SATELLITE CELLS • PROTECTIVE CUSHIONING CELLS OF PNS

  19. Ch. 7 nervous system NEURON ANATOMY-CLASSIFICATION

  20. NEURON ANATOMYpg. 207 • NEURON – NERVE CELL • HIGHLY SPECIALIZED TO TRANSMIT NERVE IMPULSES • COMMON FEATURES: • CELL BODY • PROCESSES – CELL EXTENSIONS

  21. NEURON ANATOMY

  22. NEURON ANATOMYpg. 207 1. CELL BODY • METABOLIC CENTER OF THE NEURON • CONTAIN USUAL ORGANELLES • NISSL SUBSTANCE– ROUGH E.R. – CELL SHAPE • NEUROFIBRILS- FILAMENTS – CELL SHAPE

  23. NEURON ANATOMYpg. 207 2. PROCESSESS/FIBERS: • VARY IN LENGTH • LONGEST=LUMBAR SPINE TO BIG TOE • CONVEY MESSAGES: • DENDRITES-INCOMING TOWARD CELL BODY • AXONS-CONDUCT IMPULSES AWAY FROM CELL BODY

  24. NEURON ANATOMYpg. 207 • AXON TERMINALS-END OF AXON • CONTAIN NEUROTRANSMITTERS; RELEASED INTO EXTRACELLULAR SPACE • SYNAPTIC CLEFT-TINY GAP IN AXON TERMINALS SEPARATING EACH NEURON • SYNAPSE-A JUNCTION OF 2 NEURONS

  25. NEURON ANATOMYpg. 207

  26. NEURON ANATOMYpg. 207 3. MYELIN- WHITISH, FATTY MATERIAL, WAXY APPEARANCE • PROTECTS/INSULATES THE NERVE FIBER • INCREASES TRANSMISSION RATE • MYELIN SHEATH-TIGHT COIL OF WRAPPED MEMBRANES; ENCLOSE THE AXON

  27. NEURON ANATOMYpg. 207

  28. NEURON ANATOMYpg. 207 4. SCHWANN CELLS-MYELINATE AXONS OUTSIDE OF THE CNS; PRODUCE MYELIN IN JELLY-ROLL FASHION 5. NODES OF RANVIER-GAPS IN MYELIN IN MYELIN SHEATH ALONG THE AXON 6. NEURILEMMA-EXTERNAL TO MYELIN SHEATH; “NEURON HUSK”;

  29. NEURON ANATOMYpg. 207 7. WHITE MATTER • MYELINATED FIBERS (TRACTS – CNS) 8. GRAY MATTER • UNMYLINATED FIBERS AND CELL BODIES

  30. NEURON ANATOMYpg. 207

  31. STOP DAY 2

  32. NEURON CLASSIFICATION pg. 208 • FUNCTIONAL OR STRUCTURAL • FUNCTIONAL- ACCORDING TO DIRECTION OF NERVE IMPULSE RELATIVE TO CNS

  33. FUNCTIONAL CLASSIFICATION pg. 208 • FUNCTIONAL- ACCORDING TO DIRECTION OF NERVE IMPULSE RELATIVE TO CNS • SENSORY • MOTOR • INTERNEURONS

  34. FUNCTIONAL CLASSIFICATION pg. 208 • SENSORY (AFFERENT) NEURONS: • IMPULSES FROM SENSORY RECEPTORS TO THE CNS • DENDRITE ENDINGS ASSOCIATED WITH SPECIAL RECEPTORS: • CUTANEOUS SENSE ORGANS – SKIN • PROPRIOCEPTORS- DETECT STRETCH/TENSION IN MUSCLES/TENDONS

  35. FUNCTIONAL CLASSIFICATION pg. 208 • MOTOR (EFFERENT) NEURONS • IMPULSES FROM CNS TO MUSCLES AND GLANDS • INTERNEURONS (ASSOCIATION) • IN NEURAL PATHWAYS IN CNS • CONNECT SENSORY & MOTOR NEURONS

  36. FUNCTIONAL CLASSIFICATION pg. 209

  37. STRUCTURAL CLASSIFICATION pg. 210 • BASED ON # OF PROCESSES EXTENDING FROM THE CELL BODY • MULTIPOLAR-MANY EXTENSIONS; MOST COMMON; ALL MOTOR & ASSOCIATION NEURONS

  38. STRUCTURAL CLASSIFICATION pg. 210 2. BIPOLAR-2 PROCESSES; 1 AXON & 1 DENDRITE; RARE IN ADULTS; SPECIAL SENSE ORGANS (EAR/EYE); ACT AS SENSORY RECEPTORS

  39. STRUCTURAL CLASSIFICATION pg. 210 • UNIPOLAR NEURONS HAVE A SINGLE PROCESS EMERGING FROM THE CELL BODY • VERY SHORT • DIVIDE INTO 2 FIBERS: CENTRAL & DISTAL

  40. STOP DAY 3

  41. NEURON PHYSIOLOGY pg 211 • 2 MAJOR FUNCTIONS OF A NEURON 1. IRRITABILITY – RESPONSE TO STIMULI 2. CONDUCTIVITY – TRANSMIT AN IMPULSE TO OTHER NEURONS, MUSCLES, GLANDS

  42. NEURON PHYSIOLOGY pg 211 POLARIZATION • POLARIZED: • WHEN PLASMA MEMBRANE IS @ REST (INACTIVE) • FEWER + IONS INSIDE NEURON THAN OUTSIDE • + IONS INSIDE ARE POTASSIUM (K+) • + IONS OUTSIDE ARE SODIUM (Na+) IF INSIDE REMAINS MORE NEGATIVE THAN OUTSIDE --->NEURON WILL REMAIN INACTIVE

  43. NEURON PHYSIOLOGY pg 211 EXCITABILITY OF A NEURON: • LIGHT ---> EYE RECEPTORS • SOUND ---> EAR RECEPTORS • NEUROTRANSMITTERS ---> RELEASED BY NEURONS EXCITE OTHER NEURONS • RESULT OF ANY STIMULUS = “SODIUM GATES” IN MEMBRANE OPEN --->INWARD RUSH OF Na+ • (SODIUM IONS)

  44. NEURON PHYSIOLOGY pg 211 DEPOLARIZATION – RESULTS FROM INWARD RUSH OF Na+  POLARITY IS CHANGED • INSIDE IS MORE + / OUTSIDE IS LESS + • IF STIMULUS IS STRONG ENOUGH, DEPOLARIZATION ACTIVATES THE NEURON TO INITIATE & TRANSMIT AN ACTION POTENTIAL (NERVE IMPULSE) IN THE NEURON

  45. NEURON PHYSIOLOGY pg 211 “ALL OR NONE” – RESPONSE OVER THE ENTIRE AXON OR NOT AT ALL

  46. NEURON PHYSIOLOGY pg 211 IMMEDIATELY AFTER Na+ RUSH INTO NEURON – MEMBRANE PERMEABILITY CHANGES TO IMPERMEABLE TO Na+ BUT PERMEABLE TO K+

  47. NEURON PHYSIOLOGY pg 211 REPOLARIZATION- OUTFLOW OF + IONS FROM THE CELL RESTORES ELECTRICAL CONDITIONS AT THE MEMBRANE TO A POLARIZED (RESTING) STATE • UNTIL REPOLARIZATION OCCURS A NEURON CANNOT CONDUCT ANOTHER IMPULSE

  48. NEURON PHYSIOLOGY pg 211 REFRACTORY PERIOD: PERIOD OF REPOLARIZATION OF THE NEURON --->NEURON CANNOT RESPOND TO A SECOND STIMULUS

  49. NEURON PHYSIOLOGY pg 211 SODIUM/POTASSIUM PUMP RESTORES THE ORIGINAL CONFIGURATION OF Na AND K IONS INSIDE & OUTSIDE THE NEURON • REQUIRES ATP (CELLULAR ENERGY)

  50. Nerve Impulse Video http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

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