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Chapter 16

Chapter 16. Neural Integration II: The Autonomic Nervous System and Higher-Order Functions. Sensory. Motor. General (15). Somatic (15). Special (17). Autonomic (16). fig. 15-1. fig. 16-1. Autonomic Nervous System (ANS). regulate homeostasis works independent of consciousness.

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Chapter 16

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  1. Chapter 16 Neural Integration II: The Autonomic Nervous System and Higher-Order Functions

  2. Sensory Motor General (15) Somatic (15) Special (17) Autonomic (16)

  3. fig. 15-1

  4. fig. 16-1

  5. Autonomic Nervous System (ANS) regulate homeostasis works independent of consciousness

  6. Autonomic Nervous System (ANS) compared to Somatic NS

  7. fig. 16-2

  8. fig. 16-3

  9. Sympathetic prepare body for heightened levels of somatic activity “fight or flight” response • increased mental alertness • increase metabolic rate • reduced digestive/urinary fn • activation of energy reserves • increase respiration rate • increase heart rate, bp • activation of sweat glands

  10. fig. 16-7

  11. parasympathetic stimulates visceral activity “rest and repose” conserve energy promote sedentary activities • decrease metabolic rate • decrease heart rate, bp • increase secretion-digestion • more blood to digestive system • stimulate urination/defecation

  12. sympathetic parasympathetic ENS enteric nervous system complex visceral reflexes

  13. sympathetic nervous system preganglionic neurons T1 to L2 lateral horn of spinal cord lots of divergence (1 to many) project to ganglia (3) sympathetic chain ganglia collateral ganglia adrenal medulla

  14. fig. 16-4

  15. fig. 16-5 sympathetic nervous system

  16. collateral ganglia • celiac • stomach, liver, gall bladder • pancreas and spleen • superior mesenteric • small intestine • proximal 2/3’s of large intestine • inferior mesenteric • large intestine, kidneys, bladder • reproductive organs

  17. fig. 16-4b

  18. Adrenal medulla receives preganglionic sympathetic input synapse on neuroendocrine cells of medulla cells secrete E or NE into blood epinephrine norepinephrine adrenaline noradrenaline

  19. fig. 16-4c

  20. CRISIS sympathetic activation controlled by centers in the hypothalamus • increased alertness RAS • feelings of energy and euphoria • (disregard for danger, insensitivity to pain) • Increase heart and lung activity • (controlled by pons and medulla) • Elevation of muscle tone • Mobilization of energy reserves

  21. sympathetic neurotransmitters preganglionic neurons use ACh (cholinergic) postganglionic neurons release NE (adrenergic) postganglionic cells have varicosities instead of axon terminals

  22. fig. 16-6

  23. sympathetic neurotransmitters affect is longer lasting than at a neuromuscular jn (Ach; 20 msec) NE affects its targets until it is reabsorbed or broken down (seconds) NE adrenal medulla lasts even longer (minutes)

  24. sympathetic neurotransmitters Most of the NE released is reabsorbed by the neruon (50-80%) reabsorbed NE is re-used or broken down by MAO (monoamine oxidase) the rest diffuses away and is broken down by COMT in the tissues

  25. sympathetic neurotransmitters receptors for NE Two classes alpha beta both are G-proteins (second messengers; 12)

  26. neurotransmitters and neuromodulators How do they work? 1. direct effect on membrane potential 2. indirect effect on membrane potential 3. diffusion into cell

  27. 2. fig 12-17 fig. 12-17

  28. sympathetic neurotransmitters alpha receptors a-1 a -2 more common release intracellular Ca2+ stimulates target cell lowers cAMP levels in cell (inhibitory on target cell) found on parasympathetic cells

  29. sympathetic neurotransmitters beta receptors in membranes of many organs heart, lungs, liver, muscle, … changes metabolic activity of target cells (intracellular cAMP)

  30. sympathetic neurotransmitters beta receptors b-1 b -2 • increased metabolic activity • skeletal muscle • cardiac output • inhibitory • relax smooth m. in resp. tract • easier to breath (asthma)

  31. sympathetic neurotransmitters beta receptors b-3 found in adipose tissue causes lipolysis release fatty acids for metabolism

  32. sympathetic neurotransmitters other transmitters ACh NO (nitric oxide) sweat glands in skin (secretion) blood vessels to brain and muscle (dilation of vessels) vasodilation in brain and muscle

  33. to here 3/16/07 lec# 27

  34. sympathetic summary • uses sympathetic chain • collateral ganglia • adrenal medulla • short preganglionic, long postgang. • excessive divergence (2 doz +) • pregang. cells release ACh • Most postgang. cells release NE • a few use ACh, NO • Response depends on receptors (a,b)

  35. a b a a b b b sympathetic summary neurotransmitters and receptors: pre- ACh post- NE ACh NO receptors most common- stimulatory inhibitory increase skel. muscle cardiac output inhibitory (airways) fat cells lipolysis

  36. Parasympathetic nervous system

  37. fig. 16-7

  38. Parasympathetic nervous system preganglionic cells in nuclei in: midbrain pons medulla oblongata spinal cord travel with: CN III, VII, IX, X pelvic nerves S2 to S4

  39. Parasympathetic nervous system preganglionic cells: less divergence than sym. (6-8) postganglionic cells: in terminal ganglia (near organ) or intramural (in organ) effects more localized and specific

  40. CN III VII IX X pelvic fig. 16-8

  41. Parasympathetic nervous system CN III, VII, IX control visceral structures in the head CN X neck, thoracic and abdominal cavities (75% of parasympathetics)

  42. Parasympathetic activation constrict pupils close vision stimulate digestion secretions secretion of hormones-cellular nutrient use sexual arousal changes increase smooth m. activity - digestive sys. stimulate/coordinate defecation contract urinary bladder for urination constrict airways reduce heart activity

  43. Parasympathetic neurotransmitters ACh fast acting inactivated quickly by AChE localized effects

  44. Parasympathetic neurotransmitters Receptors two types: nicotinic muscarinic on ganglion cells most muscles (SNS) lead to epsp parasym. muscle, glands G proteins epsp or ipsp longer lasting

  45. Parasympathetic neurotransmitters Receptors nicotinic muscarinic nicotine poisoning (50 mg): vomiting, diarrhea, high bp rapid heart rate, sweating,… nausea, vomitting, diarrhea, constriction of airways, low bp low heart rate

  46. 100 keys (pg. 530) “The preganglionic neurons of the autonomic nervous system release acetylcholine (ACh) as a neurotransmitter. The ganglionic neurons of the sympathetic division primarily release norepinephrine as a neurotransmitter (and both NE and E as hormones at the adrenal medulla). The ganglionic neurons of the parasympathetic division release ACh as a neurotransmitter.

  47. Table 16-2

  48. fig. 16-9

  49. summary and interactions sympathetic widespread distribution parasympathetic visceral structures served by CN or in abdominopelvic cavity most organs receive input from both (dual innervation) actions are usually opposite

  50. anatomy of dual innervation • head • parasympathetics with CN • sympathetic via superior cevical ganglion • thorax and abdomen • sympathetics and parasympathetics mix • autonomic plexuses • cardiac • pulmonary • esophageal • celiac • hypogastric

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