說明教案成果課件27nervous system

1、PUMC & CAMS Xue Gaou Autonomic Nervous System (ANS)u Instinctual Behavior & Emotionu Electric Activity of Brain u LanguageAutonomic Nervous System (ANS)Examples:u The sweating sunbather lying in the summer sunu The racing heart & “hair-standing-on-end” sensations experienced by your sudd

2、enly frightened in a horror movie p Responses such as these occur as a result of the action of the autonomic portion of the nervous system & take place without conscious actionp Termed as “autonomic nervous system”, -auto (meaning “self”) & nomos (meaning”law”) ANS control visceral activity

3、without participation of CNS ? ANS is entirely independent of CNS ? Absolutely Not !Somatic:u Skeletal muscle u Conscious & Unconscious voluntary actionuFibers do not synapse after leave CNS (Motor neuron directly innervated muscle)u AcetylcholineVisceral:u Smooth & cardiac muscle & glan

4、dsu Unconscious or involuntary activityu Fibers synapse once at a ganglion after they leave CNS (two neuron chain)uAcetycholine or NorepinephrineComparison of autonomic & somatic nervous systemSomatic & Autonomic Nervous SystemANS is subdivided into 3 systems:u Parasympathetic nervous system

5、 u Sympathetic nervous systemu Metasympathetic nervous system - (Enteric nervous system) - An relative independent nervous system responsible for regulation of visceral organ functions - Controlled by sympathetic nerve or arasympathetic nerve, enable organs adapt to the changes from internal & e

6、xternal of body betterAChAchn Sweat Glands,n Sympathetic Vasodilator NerveSkeletalMuscle (SM)AchSomatic Nervous SystemAChAChParasympatheticAChAdrenal MedullaE, NEAdrenal Medulla n Cardiac musclen Smooth musclen Glandsn AChNEAutonomic Nervous SystemSympatheticn Cardiac musclen Smooth musclen Glandsn

7、u Sympathetic nervous system “fight” or “flight” p Increase energy expenditurep Increase cardiac activityp Increase blood flow into skeletal musclep Decrease blood flow to visceral smooth musclesp Digestion is ceasedp Dilatation of the pupilsp Decrease salivary production p Increase sweat p u Parasy

8、mpathetic nervous system “rest” or “digest” p Decrease cardiac activityp Enhancement in digestionp Constriction of the pupilspFunctional Characters of ANSu Sympathetic tone or Parasympathetic toneu Organs double innervated, except vessel in skin & visceral organs only sympathetic nerve innervate

9、du Organic effects depend on the state of organ1. Spinal cordu Micturition reflex & defecation reflexu Baroreceptor reflexu sweating reflexu Central Regulation of Visceral Function2. Medulla oblongatau Vital center for respiratory, cardiovascular activity, et al3. Hypothalamus u Higher center fo

10、r visceral activityu It has at times been labeled as -“head ganglion of the ANS”Central Regulation of Visceral FunctionFunction of Hypothalamusn1. Regulation the activity of ANS n2. Body Temperature n3. Biorhythm: Circannual rhythm Circalunar rhythm Circadian rhythm Function of Hypothalamusn 4. Endo

11、crine functionSuprachiasmatic NucleusGnRHn 5. Instinctual Behaviorn 6. Emotion u Hypothalamic regulatory peptide: GHRH, TRH, GnRH, CRH, PRHu ADH, oxytocinu Instinctual Behavior Basic Instinctual Behavior Survive Ethnic Multiplyp Food intakep Water intakep Sexual Behavior Hypothalamusn Food Intake: u

12、 Feeding Center: or “Hunger center” Lateral Hypothalamus, Increasing food intakeu Satiety Center: Ventromedial Hypothalamus, Decreasing food intake n Food Intake: u Feeding & Satiety center have neurons sensitive to Glucose u Glucose may decrease feeding center discharge & increase satiety c

13、enter discharge, cause food intake decreaseu However, in diabetes, even though the high level of glucose, lower utilization rate of glucose duo to the insufficiency of insulin, feed intake increasep Water intaken Osmoreceptor in hypothalamus Be thirsty to drink Increasing ADH (vasopressin) secret, c

14、ause decreasing water effluence from kidneyn Circulatory blood volume decrease, active RAAS, Ang II: body feeling thirsty to drink Aldosterone: retain Na+ & H2Ou Emotionn Emotion is a mental & physiological state associated with a wide variety of feelings, thoughts & behavior. Emotions a

15、re subjective experiences, often associated with mood, temperament, personality, and disposition uFear & Rage related to the limbic system (including hypothalamus)uDefense reaction (Fight-Flight reaction)Fear & RageFlight & FightLateral part Dorsal part Fight FlightuDefense center in hyp

16、othalamusSham Rage:u Hypothalamus loss the inhibitory control from cortex, exhibit a over-defense response Pleasure & Agonyn Self Stimulation to localize the centern Reward system or Approach system (Pleasure): Located in external & ventral medial of hypothalamus Relate to the dopaminergic p

17、athwayn Punishment system or Avoidance system (Agony)： Located from midbrain to hypothalamusPleasure & Agony Electric Activity of Brainu Brain function involves continuous electrical activityu Patterns of brain (neuronal) electrical activity recorded are called Brain Waveu Brain waves change wit

18、h body state, e.g. Sleep, Wakefulness, disease such as Epilepsy, PsychosisOrigin of Brain Wavesu Discharge of a single neuron in the brain can never be recorded from the surface of the brainu Many thousands or even millions of neurons must fire synchronously, then myriad postsynaptic potentials summ

19、ate enough to be recorded all the way through the skullu Spontaneous Electric Activity of Brain u Evoked Cortical Potential Electric Activity of Brainp Electroencephalogram (EEG): Record of Spontaneous Electric Activity of Brainl Some pathologic state, e.g. Epilepsy can be discerned distinct pattern

20、 Evoked Cortical Potentialu Somatosensory evoked potentialu Auditory evoked potentialu Visual evoked potentialEEG in Normal Healthy people Voltage Frequency 50mV 813 Hz520mV 1430Hz100150mV 47Hz20200mV 3.5 Hzu waves: Occur when a person is awake, relaxed with eyes closedAlpha Waves(Alpha rhythm)n Def

21、inition: Replacement of the alpha rhythm by an asynchronous, low-voltage beta rhythm whenopening the eyesAlpha Block(Arousal response)n waves (Fast waves): Higher-frequency but lower-voltage waves produced by visual stimuli & mental activity & in “fast wave sleep” n Indicating the excited st

22、ate of cerebral cortex Beta Wavesn waves: More regular with higher-voltage but lower-frequencyn Normally occurred in children & some adult with emotional stress, disappointment or frustratedn Main waves indicating the person in sleepy state Theta Wavesu waves (Slow waves): High-amplitude but low

23、-frequency waves u Occur during very deep sleep in adult & awake infant u If occurred in awake adults, indicating a very serious organic brain disease Delta Wavesn Synchronous: The neurons activity of cerebral cortex is in step, represent a kind of low frequency but high voltage waves Indicating

24、 the further suppressionn Asynchronous: The neurons activity of cerebral cortex is out of step, represent a kind of high frequency but low voltage waves Indicating the further excitation Synchronous & AsynchronousClinical Correlateu Epilepsyu Definition: Epilepsy also called seizures, is charact

25、erized by uncontrolled excess activity of either part or all of the central nervous systemu Classified into three types: p Grand mal epilepsyp Petit mal epilepsyp Focal epilepsyn Grand mal epilepsy: Characterized by extreme neuronal discharges in all areas of the brain, last from a few seconds to 3

26、to 4 minutesu Neuronal discharge transmitted all the way into the spinal cord cause tonic seizures of the entire body u Then followed by spasmodic muscle contraction“Tonic-Clonic Seizures”Grand mal epilepsy“Tonic-Clonic Seizures”EEG: u High Frequency u High Voltage What initiated a grand mal attack

27、?n Strong emotional stimulin Alcohon Overbreathing (Alkalosis Neuronal Overactivity)n Drugn Fevern Loud noise or flashing lightsWhat stop the grand mal attack ?n Neuronal fatigue (Fatigue of synaptic transmit)n Active inhibitory neurons“Absence Epilepsy” “Absence Seizures”n Petit mal epilepsy: Chara

28、cterized by 3 to 30 seconds of unconsciousness or diminished consciousness during which the person has several twitch-like contractions of the muscle, usually in the head region, especially blinking the eyesn First appear during late childhood & may disappear by the age of 30EGG: u spike-and-dom

29、e pattern Petit mal epilepsyFocal Epilepsyu Focal Epilepsy: Result from some localized organic lesion or functional abnormalityp Scar tissue in the brain p Tumoru Lesion area can promote extremely rapid discharge in the local areap Synchronous discharge result from lesion area gradually recruit adja

30、cent area of the cortex into the epilepsy discharge area u When such a wave of excitation spreads over the motor cortex, it cause progressive “march” of muscle contraction throughout the opposite side of the bodyu At the beginning, contraction in the mouth region & marching progressively downward to the opposite side of leg Focal Epilepsy“Jacksonian Epilepsy”u Another syndrome of focal epilepsy is: p A short period of amnesiap Sudden anxiety, discomfort, fear et alp A moment of incoherent