KIN 3304 1nd Edition Lecture 11 Outline of Last Lecture I Neural Tissue II CNS III PNS IV Afferent PNS V Efferent PNS VI Components of Efferent Division VII Astrocytes VIII Controlling Interstitial Environment IX Maintaining BBB X Creates 3D framework for CNS XI Repairs Damaged Neural Tissue XII Oligodendrocytes XIII Myelin Sheath XIV Schwann Cells XV Neurotransmitter XVI Signaling XVII Receptors XVIII Neural Regeneration Outline of Current Lecture I Neural Regeneration cont II Rate of Nerve Impulse III Types of Processing IV Aging and Nervous System V Changes in Aged VI Subdivisions of ANS VII Sympathetic Stimulation VIII When Activation Occurs Current Lecture I Neural Regeneration cont a Schwann cells release growth factors i Promote axonal regrowth These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute ii If axon cut new axons may emerge at cut within hours iii Most likely at site of injury axon dies regenerates 1 New axonal segments sprout 1 week later 2 As neuron recovers axon grows II Rate of Nerve Impulse a Depends on proportion of the axon b 1 Presence of myelin sheath i Myelinated axon conducts 5 7x faster c 2 Diameter of axon i large diameter more rapid impulse ii 140 m s 300 mph III Types of Processing KNOW THIS a Divergence info spreads from one to multiple b Serial Processing occurs as sensory information is relayed from one center to another in the brain c Parallel Processing occurs when several neurons or pools process same information at the same time i Allows for reflexes d Reverberation allows neurons to remain active once they are stimulated i Once active will continue until synaptic fatigue or inhibitory stimuli breaks cycle 1 Think of breathing must inhibit this from occurring TQ FIGURE 16 6 the exact picture Know the white part IV Aging and Nervous System a Reduced in brain weight size b Reduced in neurons c Decreased blood flow to brain d Changes in synaptic organization of brain e Cellular changes in CNS neurons V Changes in Aged a Reduced in brain weight size i Results primarily from decrease in volume at cerebral cortex b Reduced in number of neurons i Reduced brain size linked to loss of cortical neurons c Decreased blood flow to brain i Fatty deposits occur in walls of blood vessels ii This decreases articular flow 1 Increases stroke risk iii Called atherosclerosis d Changes in synaptic organization of brain i Number of dendric branches and interconnections decrease ii As synaptic connections lost rate of neurotransmitter production declines e Intracellular extracellular changes in CNS neurons i Neurons in brain accumulate abnormal deposits ii Plaques form extracellularly 1 Amyloid fibrillar protein 2 Surrounded by abnormal dendrites axons iii Neurofibrillary tangles 1 Mass of neurofibrils 2 Form dense mats inside soma KNOW Fig 17 1 how things flow on the left VI VII VIII Subdivisions of ANS a 2 Major Subdivisions i Sympathetic and Parasympathetic ii In general 1 Parasympathetic dominates at rest 2 Sympathetic dominates during stress iii Excitation and inhibition respectively iv But not always 1 Divisions may work independently 2 May work together Sympathetic Stimulation a Can change organ tissue activities by releasing catecholamines epi norepi in blood stream b Activated in reflexes that do not involve other effectors c Sympathetic activation entire division response controlled by sympathetic centers in hypothalamus When Activation Occurs a Increase alertness stimulation of reticular activating system now on edge b Insensitive to painful stimuli increase energy c Increase cardiovascular and respiratory center activity i Increase in strength HR BP respiration rate depth ii Hyperventilating d Increase muscle tone looks tense shivers e Mobilization of energy reserves i Increase breakdown of glycogen
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