1. © 2015 Pearson Education, Inc. Lecture Presentation by Lee Ann Frederick University of Texas at Arlington Chapter 16 The Autonomic Nervous System and Higher-Order Functions

2. © 2015 Pearson Education, Inc. An Introduction to the ANS and Higher- Order Functions Learning Outcomes 16-1 Compare the organization of the autonomic nervous system with that of the somatic nervous system. 16-2 Describe the structures and functions of the sympathetic division of the autonomic nervous system. 16-3 Describe the mechanisms of sympathetic neurotransmitter release and their effects on target organs and tissues.

3. © 2015 Pearson Education, Inc. An Introduction to the ANS and Higher- Order Functions Learning Outcomes 16-4 Describe the structures and functions of the parasympathetic division of the autonomic nervous system. 16-5 Describe the mechanisms of parasympathetic neurotransmitter release and their effects on target organs and tissues. 16-6 Discuss the functional significance of dual innervation and autonomic tone. 16-7 Describe the hierarchy of interacting levels of control in the autonomic nervous system, including the significance of visceral reflexes.

4. © 2015 Pearson Education, Inc. An Introduction to the ANS and Higher- Order Functions Learning Outcomes 16-8Explain how memories are created, stored, and recalled, and distinguish among the levels of consciousness and unconsciousness. 16-9Describe some of the ways in which the interactions of neurotransmitters influence brain function. 16-10 Summarize the effects of aging on the nervous system and give examples of interactions between the nervous system and other organ systems.

5. © 2015 Pearson Education, Inc. An Introduction to the ANS and Higher- Order Functions Somatic Nervous System (SNS) Operates under conscious control Seldom affects long-term survival SNS controls skeletal muscles Autonomic Nervous System (ANS) Operates without conscious instruction ANS controls visceral effectors Coordinates system functions Cardiovascular, respiratory, digestive, urinary, reproductive

6. © 2015 Pearson Education, Inc. 16-1 Autonomic Nervous System Organization of the ANS Integrative centers For autonomic activity in hypothalamus Neurons comparable to upper motor neurons in SNS

7. © 2015 Pearson Education, Inc. 16-1 Autonomic Nervous System Organization of the ANS Visceral motor neurons In brain stem and spinal cord, are known as preganglionic neurons Preganglionic fibers Axons of preganglionic neurons Leave CNS and synapse on ganglionic neurons

8. © 2015 Pearson Education, Inc. 16-1 Autonomic Nervous System Visceral Motor Neurons Autonomic ganglia Contain many ganglionic neurons Ganglionic neurons innervate visceral effectors Such as cardiac muscle, smooth muscle, glands, and adipose tissue Postganglionic fibers Axons of ganglionic neurons

9. © 2015 Pearson Education, Inc. Figure 16-1a The Organization of the Somatic and Autonomic Nervous Systems. Brain a Upper motor neurons in primary motor cortex Somatic motor nuclei of brain stem Skeletal muscle Lower motor neurons Skeletal muscle Spinal cord Somatic motor nuclei of spinal cord Somatic nervous system

10. © 2015 Pearson Education, Inc. Figure 16-1b The Organization of the Somatic and Autonomic Nervous Systems. b Visceral motor nuclei in hypothalamus Preganglionic neuron Visceral Effectors Smooth muscle Glands Cardiac muscle Adipocytes Preganglionic neuron Ganglionic neurons Autonomic ganglia Autonomic nuclei in brain stem Spinal cord Autonomic nuclei in spinal cord Brain Autonomic nervous system

11. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS The Autonomic Nervous System Operates largely outside our awareness Has two divisions 1. Sympathetic division Increases alertness, metabolic rate, and muscular abilities 2. Parasympathetic division Reduces metabolic rate and promotes digestion

12. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Sympathetic Division Kicks in only during exertion, stress, or emergency “Fight or flight” Parasympathetic Division Controls during resting conditions “Rest and digest”

13. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Sympathetic and Parasympathetic Division 1.Most often, these two divisions have opposing effects If the sympathetic division causes excitation, the parasympathetic causes inhibition 2.The two divisions may also work independently Only one division innervates some structures 3.The two divisions may work together, with each controlling one stage of a complex process

14. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Sympathetic Division Preganglionic fibers (thoracic and superior lumbar; thoracolumbar) synapse in ganglia near spinal cord Preganglionic fibers are short Postganglionic fibers are long Prepares body for crisis, producing a “fight or flight” response Stimulates tissue metabolism Increases alertness

15. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Seven Responses to Increased Sympathetic Activity 1.Heightened mental alertness 2.Increased metabolic rate 3.Reduced digestive and urinary functions 4.Energy reserves activated 5.Increased respiratory rate and respiratory passageways dilate 6.Increased heart rate and blood pressure 7.Sweat glands activated

16. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Parasympathetic Division Preganglionic fibers originate in brain stem and sacral segments of spinal cord; craniosacral Synapse in ganglia close to (or within) target organs Preganglionic fibers are long Postganglionic fibers are short Parasympathetic division stimulates visceral activity Conserves energy and promotes sedentary activities

17. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Five Responses to Increased Parasympathetic Activity 1.Decreased metabolic rate 2.Decreased heart rate and blood pressure 3.Increased secretion by salivary and digestive glands 4.Increased motility and blood flow in digestive tract 5.Urination and defecation stimulation

18. © 2015 Pearson Education, Inc. Figure 16-2 Overview of the Autonomic Nervous System (Part 1 of 2). Preganglionic fibers Postganglionic fibers KEY “Fight or flight” response Sympathetic activation Most postganglionic fibers release norepinephrine (NE) at neuroeffector junctions. Target Organs Ganglia are located near the spinal cord. Preganglionic fibers release acetylcholine (Ach), stimulating ganglionic neurons. Ganglia Preganglionic Neurons Preganglionic neurons are located in the lateral gray horns of spinal segments T 1 –L 2. Sympathetic Division (Thoracolumbar)

19. © 2015 Pearson Education, Inc. Figure 16-2 Overview of the Autonomic Nervous System (Part 2 of 2). Preganglionic fibers Postganglionic fibers “Rest and digest” response All postganglionic fibers release Ach at neuroeffector junctions. Target Organs Ganglia are in or near the target organ. Preganglionic fibers release acetylcholine (Ach), stimulating ganglionic neurons. Ganglia Preganglionic Neurons Preganglionic neurons in brain stem and in lateral portion of anterior gray horns of S 2 –S 4. Parasympathetic Division (Craniosacral) KEY Parasympathetic stimulation

20. © 2015 Pearson Education, Inc. 16-1 Divisions of the ANS Enteric Nervous System (ENS) Third division of ANS Extensive network in digestive tract walls Complex visceral reflexes coordinated locally Roughly 100 million neurons All neurotransmitters are found in the brain

21. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division The Sympathetic Division Preganglionic neurons located between segments T 1 and L 2 of spinal cord Ganglionic neurons in ganglia near vertebral column Cell bodies of preganglionic neurons in lateral gray horns Axons enter ventral roots of segments

22. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Ganglionic Neurons Occur in three locations 1. Sympathetic chain ganglia 2. Collateral ganglia 3. Adrenal medullae

23. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia On both sides of vertebral column Control effectors: In body wall Inside thoracic cavity In head In limbs

24. © 2015 Pearson Education, Inc. Figure 16-3a Sites of Ganglia in Sympathetic Pathways. Preganglionic neurons Ganglionic neurons KEY Gray ramus Spinal nerve Preganglionic neuron Autonomic ganglion of left sympathetic chain Sympathetic nerve (postganglionic fibers) Innervates visceral organs in thoracic cavity by sympathetic nerves Note: Both innervation patterns occur on each side of the body. Autonomic ganglion of right sympathetic chain Innervates visceral effectors by spinal nerves White ramus Ganglionic neuron SYMPATHETIC CHAIN GANGLIA a

25. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Are anterior to vertebral bodies Contain ganglionic neurons that innervate tissues and organs in abdominopelvic cavity

26. © 2015 Pearson Education, Inc. Figure 16-3b Sites of Ganglia in Sympathetic Pathways. b White ramus COLLATERAL GANGLIA Lateral gray horn Splanchnic nerve (preganglionic fibers) Postganglionic fibers Collateral ganglion Innervates visceral organs in abdominopelvic cavity

27. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Adrenal Medullae (Suprarenal Medullae) Very short axons When stimulated, release neurotransmitters into bloodstream (not at synapse) Function as hormones to affect target cells throughout body

28. © 2015 Pearson Education, Inc. Figure 16-3c Sites of Ganglia in Sympathetic Pathways. c Preganglionic fibers THE ADRENAL MEDULLAE Endocrine cells (specialized ganglionic neurons) Adrenal medullae Secretes neurotransmitters into general circulation

29. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Fibers in Sympathetic Division Preganglionic fibers Are relatively short Ganglia located near spinal cord Postganglionic fibers Are relatively long, except at adrenal medullae

30. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Organization and Anatomy of the Sympathetic Division Ventral roots of spinal segments T 1 –L 2 contain sympathetic preganglionic fibers Give rise to myelinated white ramus Carry myelinated preganglionic fibers into sympathetic chain ganglion May synapse at collateral ganglia or in adrenal medullae

31. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Preganglionic fibers One preganglionic fiber synapses on many ganglionic neurons Fibers interconnect sympathetic chain ganglia Each ganglion innervates particular body segment(s)

32. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Postganglionic Fibers Paths of unmyelinated postganglionic fibers depend on targets

33. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Postganglionic fibers control visceral effectors In body wall, head, neck, or limbs Enter gray ramus Return to spinal nerve for distribution Postganglionic fibers innervate effectors Sweat glands of skin Smooth muscles in superficial blood vessels

34. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Postganglionic fibers innervating structures in thoracic cavity form bundles Sympathetic nerves

35. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Each sympathetic chain ganglia contains: 3 cervical ganglia 10–12 thoracic ganglia 4–5 lumbar ganglia 4–5 sacral ganglia 1 coccygeal ganglion

36. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Preganglionic neurons Limited to spinal cord segments T 1 –L 2 White rami (myelinated preganglionic fibers) Innervate neurons in: Cervical, inferior lumbar, and sacral sympathetic chain ganglia

37. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Chain ganglia provide postganglionic fibers Through gray rami (unmyelinated postganglionic fibers) To cervical, lumbar, and sacral spinal nerves

38. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Only spinal nerves T 1 –L 2 have white rami Every spinal nerve has gray ramus That carries sympathetic postganglionic fibers for distribution in body wall

39. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Chain Ganglia Postganglionic sympathetic fibers In head and neck leave superior cervical sympathetic ganglia Supply the regions and structures innervated by cranial nerves III, VII, IX, X

40. © 2015 Pearson Education, Inc. Figure 16-4 The Distribution of Sympathetic Innervation (Part 1 of 4). T1T1 T2T2 T3T3 Gray rami to spinal nerves Cervical sympathetic ganglia Superior Middle Inferior Pons Preganglionic fibers Postganglionic fibers KEY T1T1 T2T2 T3T3

41. © 2015 Pearson Education, Inc. Figure 16-4 The Distribution of Sympathetic Innervation (Part 2 of 4). Pons Preganglionic fibers Postganglionic fibers KEY T1T1 T2T2 T3T3 T4T4 Lung Heart Sympathetic nerves Cardiac and pulmonary plexuses Eye Salivary glands

42. © 2015 Pearson Education, Inc. Figure 16-4 The Distribution of Sympathetic Innervation (Part 3 of 4). T1T1 T2T2 T3T3 T4T4 T5T5 T6T6 T7T7 T8T8 T9T9 T 10 T 11 T 12 L1L1 L2L2 L3L3 L4L4 L5L5 S1S1 S2S2 S3S3 S4S4 S5S5 UterusOvary PenisScrotum Urinary bladder Kidney Adrenal medulla Small intestine Large intestine Pancreas Spleen Stomach Liver and gallbladder Celiac ganglion Inferior mesenteric ganglion Sacral splanchnic nerves Lumbar splanchnic nerves Lesser splanchnic nerve Superior mesenteric ganglion Greater splanchnic nerve Coccygeal ganglia (Co 1 ) fused together (ganglion impar) Preganglionic fibers Postganglionic fibers KEY

43. © 2015 Pearson Education, Inc. Figure 16-4 The Distribution of Sympathetic Innervation (Part 3 of 4). T1T1 T2T2 T3T3 T4T4 T5T5 T6T6 T7T7 T8T8 T9T9 T 10 T 11 T 12 L1L1 L2L2 L3L3 L4L4 L5L5 S1S1 S2S2 S3S3 S4S4 S5S5 UterusOvary PenisScrotum Urinary bladder Kidney Adrenal medulla Small intestine Large intestine Pancreas Spleen Stomach Liver and gallbladder Celiac ganglion Inferior mesenteric ganglion Sacral splanchnic nerves Lumbar splanchnic nerves Lesser splanchnic nerve Superior mesenteric ganglion Greater splanchnic nerve Coccygeal ganglia (Co 1 ) fused together (ganglion impar) Preganglionic fibers Postganglionic fibers KEY

44. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Receive sympathetic innervation via sympathetic preganglionic fibers Splanchnic nerves Formed by preganglionic fibers that innervate collateral ganglia In dorsal wall of abdominal cavity Originate as paired ganglia (left and right) Usually fuse together in adults

45. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Postganglionic fibers Leave collateral ganglia Extend throughout abdominopelvic cavity Innervate variety of visceral tissues and organs Reduction of blood flow and energy by organs not vital to short-term survival Release of stored energy reserves

46. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Preganglionic fibers from seven inferior thoracic segments End at celiac ganglion or superior mesenteric ganglion Ganglia embedded in network of autonomic nerves Preganglionic fibers from lumbar segments Form splanchnic nerves End at inferior mesenteric ganglion

47. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Celiac ganglion Pair of interconnected masses of gray matter May form single mass or many interwoven masses Postganglionic fibers innervate stomach, liver, gallbladder, pancreas, and spleen

48. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Superior mesenteric ganglion Near base of superior mesenteric artery Postganglionic fibers innervate small intestine and proximal 2/3 of large intestine

49. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Collateral Ganglia Inferior mesenteric ganglion Near base of inferior mesenteric artery Postganglionic fibers provide sympathetic innervation to portions of: Large intestine Kidney Urinary bladder Sex organs

50. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Adrenal Medullae Preganglionic fibers entering adrenal gland proceed to center (adrenal medulla) Modified sympathetic ganglion Preganglionic fibers synapse on neuroendocrine cells Specialized neurons secrete hormones into bloodstream

51. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Adrenal Medullae Neuroendocrine cells Secrete neurotransmitters epinephrine (E) and norepinephrine (NE) Epinephrine Also called adrenaline Is 75–80 percent of secretory output Remaining is norepinephrine (NE) Noradrenaline

52. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Adrenal Medullae Bloodstream carries neurotransmitters through body Causing changes in metabolic activities of different cells including cells not innervated by sympathetic postganglionic fibers Effects last longer Hormones continue to diffuse out of bloodstream

53. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Activation Change activities of tissues and organs by: Releasing NE at peripheral synapses Target specific effectors, smooth muscle fibers in blood vessels of skin Are activated in reflexes Do not involve other visceral effectors

54. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Sympathetic Activation Changes activities of tissues and organs by: Distributing E and NE throughout body in bloodstream Entire division responds (sympathetic activation) Are controlled by sympathetic centers in hypothalamus Effects are not limited to peripheral tissues Alters CNS activity

55. © 2015 Pearson Education, Inc. 16-2 The Sympathetic Division Changes Caused by Sympathetic Activation Increased alertness Feelings of energy and euphoria Change in breathing Elevation in muscle tone Mobilization of energy reserves

56. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Stimulation of Sympathetic Preganglionic Neurons Releases ACh at synapses with ganglionic neurons Excitatory effect on ganglionic neurons Ganglionic Neurons Release neurotransmitters at specific target organs

57. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Ganglionic Neurons Axon terminals Form branching networks of telodendria instead of synaptic terminals Telodendria form sympathetic varicosities Resemble string of pearls Swollen segment packed with neurotransmitter vesicles Pass along or near surface of effector cells No specialized postsynaptic membranes Membrane receptors on surfaces of target cells

58. © 2015 Pearson Education, Inc. Figure 16-5 Sympathetic Varicosities. Ganglion Preganglionic fiber (myelinated) Ganglionic neuron Postganglionic fiber (unmyelinated) Vesicles containing norepinephrine (NE) Varicosities Mitochondrion Schwann cell cytoplasm 5 μm Smooth muscle cellsVaricosities

59. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Ganglionic Neurons Axon terminals Release NE at most varicosities Called adrenergic neuron Some ganglionic neurons release ACh instead Are located in body wall, skin, brain, and skeletal muscles Called cholinergic neurons

60. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of NE and E Primarily from interactions of NE and E with two types of adrenergic membrane receptors 1. Alpha receptors (NE more potent) 2. Beta receptors Activates enzymes on inside of cell membrane via G proteins

61. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of NE and E Alpha-1 (  1 ) More common type of alpha receptor Releases intracellular calcium ions from reserves in endoplasmic reticulum Has excitatory effect on target cell

62. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of NE and E Alpha-2 (  2 ) Lowers cAMP levels in cytoplasm Has inhibitory effect on the cell Helps coordinate sympathetic and parasympathetic activities

63. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of NE and E Beta (  ) receptors Affect membranes in many organs (skeletal muscles, lungs, heart, and liver) Trigger metabolic changes in target cell Stimulation increases intracellular cAMP levels

64. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Three Main Types of Beta Receptors 1.Beta-1 (  1 ) Increases metabolic activity 2.Beta-2 (  2 ) Triggers relaxation of smooth muscles along respiratory tract 3.Beta-3 (  3 ) Leads to lipolysis, the breakdown of triglycerides in adipocytes

65. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of ACh and NO Cholinergic (ACh) sympathetic terminals Innervate sweat glands of skin and blood vessels of skeletal muscles and brain Stimulate sweat gland secretion and dilate blood vessels

66. © 2015 Pearson Education, Inc. 16-3 Various Sympathetic Neurotransmitters Sympathetic Stimulation and the Release of ACh and NO Nitroxidergic synapses Release nitric oxide (NO) as neurotransmitter Neurons innervate smooth muscles in walls of blood vessels in skeletal muscles and the brain Produce vasodilation and increased blood flow

67. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Autonomic Nuclei Are contained in the mesencephalon, pons, and medulla oblongata Associated with cranial nerves III, VII, IX, X In lateral gray horns of spinal segments S 2 –S 4

68. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Ganglionic Neurons in Peripheral Ganglia Terminal ganglion Near target organ Usually paired Intramural ganglion Embedded in tissues of target organ Interconnected masses Clusters of ganglion cells

69. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Organization and Anatomy of the Parasympathetic Division Parasympathetic preganglionic fibers leave brain as components of cranial nerves III (oculomotor) VII (facial) IX (glossopharyngeal) X (vagus) Parasympathetic preganglionic fibers leave spinal cord at sacral level

70. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Oculomotor, Facial, and Glossopharyngeal Nerves Control visceral structures in head Synapse in ciliary, pterygopalatine, submandibular, and otic ganglia Short postganglionic fibers continue to their peripheral targets

71. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Vagus Nerve Provides preganglionic parasympathetic innervation to structures in: Neck Thoracic and abdominopelvic cavities as distant as a distal portion of large intestine Provides 75 percent of all parasympathetic outflow Branches intermingle with fibers of sympathetic division

72. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Sacral Segments of Spinal Cord Preganglionic fibers carry sacral parasympathetic output Do not join ventral roots of spinal nerves, instead form pelvic nerves Pelvic nerves innervate intramural ganglia in walls of kidneys, urinary bladder, portions of large intestine, and the sex organs

73. © 2015 Pearson Education, Inc. Figure 16-6 The Distribution of Parasympathetic Innervation (Part 1 of 2). Heart Lungs Pterygopalatine ganglion N III N VII N IX N X (Vagus) Ciliary ganglion Submandibular ganglion Otic ganglion Lacrimal gland Eye Salivary glands Pons

74. © 2015 Pearson Education, Inc. Figure 16-6 The Distribution of Parasympathetic Innervation (Part 2 of 2). Liver and gallbladder Stomach Spleen Pancreas Large intestine Small intestine Rectum Kidney Urinary bladder Scrotum Penis Ovary Uterus Pelvic nerves Spinal cord S2S2 Autonomic plexuses ( see Figure 16-8 ) S3S3 S4S4 Preganglionic fibers Postganglionic fibers KEY Lungs

75. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Parasympathetic Activation Centers on relaxation, food processing, and energy absorption Localized effects, last a few seconds at most

76. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Major Effects of Parasympathetic Division Constriction of the pupils To restrict the amount of light that enters the eyes And focusing of the lenses of the eyes on nearby objects Secretion by digestive glands Including salivary glands, gastric glands, duodenal glands, intestinal glands, the pancreas (exocrine and endocrine), and the liver

77. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Major Effects of Parasympathetic Division Secretion of hormones That promote the absorption and utilization of nutrients by peripheral cells Changes in blood flow and glandular activity Associated with sexual arousal Increase in smooth muscle activity Along the digestive tract

78. © 2015 Pearson Education, Inc. 16-4 The Parasympathetic Division Major Effects of Parasympathetic Division Stimulation and coordination of defecation Contraction of the urinary bladder during urination Constriction of the respiratory passageways Reduction in heart rate and in the force of contraction

79. © 2015 Pearson Education, Inc. 16-5 Parasympathetic Neurons Release ACh Neuromuscular and Neuroglandular Junctions All release ACh as neurotransmitter Small, with narrow synaptic clefts Effects of stimulation are short lived Inactivated by acetylcholinesterase (AChE) at synapse ACh is also inactivated by tissue cholinesterase in surrounding tissues

80. © 2015 Pearson Education, Inc. 16-5 Parasympathetic Neurons Release ACh Membrane Receptors and Responses Nicotinic receptors On surfaces of ganglion cells (sympathetic and parasympathetic) Exposure to ACh causes excitation of ganglionic neuron or muscle fiber

81. © 2015 Pearson Education, Inc. 16-5 Parasympathetic Neurons Release ACh Membrane Receptors and Responses Muscarinic receptors At cholinergic neuromuscular or neuroglandular junctions (parasympathetic) At few cholinergic junctions (sympathetic) G proteins Effects are longer lasting than nicotinic receptors Response reflects activation or inactivation of specific enzymes Can be excitatory or inhibitory

82. © 2015 Pearson Education, Inc. 16-5 Parasympathetic Neurons Release ACh Dangerous Environmental Toxins Produce exaggerated, uncontrolled responses Nicotine Binds to nicotinic receptors Targets autonomic ganglia and skeletal neuromuscular junctions 50 mg ingested or absorbed through skin Signs and symptoms: Vomiting, diarrhea, high blood pressure, rapid heart rate, sweating, profuse salivation, convulsions May result in coma or death

83. © 2015 Pearson Education, Inc. 16-5 Parasympathetic Neurons Release ACh Dangerous Environmental Toxins Produce exaggerated, uncontrolled responses Muscarine Binds to muscarinic receptors Targets parasympathetic neuromuscular or neuroglandular junctions Signs and symptoms: Salivation, nausea, vomiting, diarrhea, constriction of respiratory passages, low blood pressure, slow heart rate (bradycardia)

84. © 2015 Pearson Education, Inc. Table 16-1 Adrenergic and Cholinergic Receptors of the ANS.

85. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Sympathetic Division Widespread impact Reaches organs and tissues throughout body Parasympathetic Division Innervates only specific visceral structures Sympathetic and Parasympathetic Division Most vital organs receive instructions from both sympathetic and parasympathetic divisions Two divisions commonly have opposing effects

86. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Anatomy of Dual Innervation Parasympathetic postganglionic fibers accompany cranial nerves to peripheral destinations Sympathetic innervation reaches same structures By traveling directly from superior cervical ganglia of sympathetic chain

87. © 2015 Pearson Education, Inc. Figure 16-7 Summary: The Anatomical Differences between the Sympathetic and Parasympathetic Divisions. Bloodstream Sympathetic ganglion PNS CNS Sympathetic Parasympathetic Preganglionic neuron Preganglionic fiber Ganglionic neurons Postganglionic fiber TARGET Parasympathetic ganglion KEY Neurotransmitters Acetylcholine Norepinephrine Epinephrine or

88. © 2015 Pearson Education, Inc. Table 16-2 A Structural Comparison of the Sympathetic and Parasympathetic Divisions of the ANS.

89. © 2015 Pearson Education, Inc. Table 16-3 A Functional Comparison of the Sympathetic and Parasympathetic Divisions of the ANS (Part 1 of 4).

90. © 2015 Pearson Education, Inc. Table 16-3 A Functional Comparison of the Sympathetic and Parasympathetic Divisions of the ANS (Part 2 of 4).

91. © 2015 Pearson Education, Inc. Table 16-3 A Functional Comparison of the Sympathetic and Parasympathetic Divisions of the ANS (Part 3 of 4).

92. © 2015 Pearson Education, Inc. Table 16-3 A Functional Comparison of the Sympathetic and Parasympathetic Divisions of the ANS (Part 4 of 4).

93. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Anatomy of Dual Innervation Autonomic plexuses Nerve networks in the thoracic and abdominopelvic cavities Are formed by mingled sympathetic postganglionic fibers and parasympathetic preganglionic fibers Travel with blood and lymphatic vessels that supply visceral organs

94. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Anatomy of Dual Innervation Cardiac plexus Pulmonary plexus Esophageal plexus Celiac plexus Inferior mesenteric plexus Hypogastric plexus

95. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Cardiac and Pulmonary Plexuses Autonomic fibers entering thoracic cavity intersect Contain: Sympathetic and parasympathetic fibers for heart and lungs Parasympathetic ganglia whose output affects those organs

96. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Esophageal Plexus Contains: Descending branches of vagus nerves Splanchnic nerves leaving sympathetic chain Parasympathetic preganglionic fibers of vagus nerve enter abdominopelvic cavity with esophagus Fibers enter celiac plexus (solar plexus)

97. © 2015 Pearson Education, Inc. Figure 16-8 The Autonomic Plexuses and Ganglia (Part 1 of 2). Aortic arch Right vagus nerve Autonomic Plexuses and Ganglia Cardiac plexus Pulmonary plexus Thoracic sympathetic chain ganglia Esophageal plexus Celiac plexus and ganglion Inferior mesenteric plexus and ganglia Hypogastric plexus Pelvic sympathetic chain Superior mesenteric ganglion

98. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Celiac Plexus Associated with smaller plexuses, such as inferior mesenteric plexus Innervates viscera within abdominal cavity

99. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Hypogastric Plexus Contains: Parasympathetic outflow of pelvic nerves Sympathetic postganglionic fibers from inferior mesenteric ganglion Splanchnic nerves from sacral sympathetic chain Innervates digestive, urinary, and reproductive organs of pelvic cavity

100. © 2015 Pearson Education, Inc. Figure 16-8 The Autonomic Plexuses and Ganglia (Part 2 of 2). Trachea Left vagus nerve Thoracic spinal nerves Esophagus Splanchnic nerves Diaphragm Superior mesenteric artery Inferior mesenteric artery

101. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Autonomic Tone Is an important aspect of ANS function If nerve is inactive under normal conditions, can only increase activity If nerve maintains background level of activity, can increase or decrease activity

102. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Autonomic Tone Autonomic motor neurons Maintain resting level of spontaneous activity Background level of activation determines autonomic tone

103. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Autonomic Tone Significant where dual innervation occurs Two divisions have opposing effects More important when dual innervation does not occur

104. © 2015 Pearson Education, Inc. 16-6 Dual Innervation The Heart Receives Dual Innervation Two divisions have opposing effects on heart function 1.Parasympathetic division Acetylcholine released by postganglionic fibers slows heart rate 2.Sympathetic division NE released by varicosities accelerates heart rate Balance between two divisions Autonomic tone is present Releases small amounts of both neurotransmitters continuously

105. © 2015 Pearson Education, Inc. 16-6 Dual Innervation The Heart Receives Dual Innervation Parasympathetic innervation dominates under resting conditions Crisis accelerates heart rate by: Stimulation of sympathetic innervation Inhibition of parasympathetic innervation

106. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Autonomic Tone Blood vessel dilates and blood flow increases Blood vessel constricts and blood flow is reduced Sympathetic postganglionic fibers release NE Innervate smooth muscle cells in walls of peripheral vessels

107. © 2015 Pearson Education, Inc. 16-6 Dual Innervation Autonomic Tone Background sympathetic tone keeps muscles partially contracted To increase blood flow: Rate of NE release decreases Sympathetic cholinergic fibers are stimulated Smooth muscle cells relax Vessels dilate and blood flow increases

108. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Somatic Motor Control Centers in all portions of CNS Lowest level regulatory control Lower motor neurons of cranial and spinal visceral reflex arcs Highest level Pyramidal motor neurons of primary motor cortex Operating with feedback from cerebellum and basal nuclei

109. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Visceral Reflexes Provide automatic motor responses Can be modified, facilitated, or inhibited by higher centers, especially hypothalamus Visceral reflex arc Receptor Sensory neuron Processing center (one or more interneurons) All polysynaptic Two visceral motor neurons

110. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Visceral Reflexes Long reflexes Autonomic equivalents of polysynaptic reflexes Visceral sensory neurons deliver information to CNS along dorsal roots of spinal nerves Within sensory branches of cranial nerves Within autonomic nerves that innervate visceral effectors ANS carries motor commands to visceral effectors Coordinate activities of entire organ

111. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Visceral Reflexes Short reflexes Bypass CNS Involve sensory neurons and interneurons located within autonomic ganglia Interneurons synapse on ganglionic neurons Motor commands distributed by postganglionic fibers Control simple motor responses with localized effects One small part of target organ

112. © 2015 Pearson Education, Inc. Figure 16-9 Visceral Reflexes. Stimulus Receptors in peripheral tissue Afferent (sensory) fibers CENTRAL NERVOUS SYSTEM Long reflex Processing center in spinal cord Preganglionic neuron Autonomic ganglion (sympathetic or parasympathetic) Postganglionic neuron Peripheral effector Short reflex Response

113. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Visceral Reflexes Regulating visceral activity Most organs Long reflexes most important Digestive tract Short reflexes provide most control and coordination

114. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Visceral Reflexes Enteric nervous system Ganglia in the walls of digestive tract contain cell bodies of: Visceral sensory neurons Interneurons Visceral motor neurons Axons form extensive nerve nets Control digestive functions independent of CNS

115. © 2015 Pearson Education, Inc. Table 16-4 Representative Visceral Reflexes (Part 1 of 2).

116. © 2015 Pearson Education, Inc. Table 16-4 Representative Visceral Reflexes (Part 2 of 2).

117. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS Higher Levels of Autonomic Control Simple reflexes from spinal cord provide rapid and automatic responses Complex reflexes coordinated in medulla oblongata Contains centers and nuclei involved in: Salivation Swallowing Digestive secretions Peristalsis Urinary function Regulated by hypothalamus

118. © 2015 Pearson Education, Inc. 16-7 Visceral Reflexes Regulate the ANS The Integration of SNS and ANS Activities Many parallels in organization and function Integration at brain stem Both systems under control of higher centers

119. © 2015 Pearson Education, Inc. Figure 16-10 A Comparison of Somatic and Autonomic Function. Thalamus Central Nervous System Cerebral cortex Limbic system Hypothalamus Visceral sensory Long reflexes Preganglionic neuron ANS Short reflexes Ganglionic neuron Visceral effectors Sensory receptors Skeletal muscles SNS Sensory pathways Lower motor neuron Somatic reflexes Relay and processing centers in brain stem Somatic sensory Peripheral Nervous System

120. © 2015 Pearson Education, Inc. Table 16-5 A Comparison of the ANS and SNS.

121. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Higher-Order Functions Share Three Characteristics 1.Require the cerebral cortex 2.Involve conscious and unconscious information processing 3.Are not part of programmed “wiring” of brain Can adjust over time

122. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Memory Fact memories Are specific bits of information Skill memories Learned motor behaviors Incorporated at unconscious level with repetition Programmed behaviors stored in appropriate area of brain stem Complex skill memories are stored and involve motor patterns in the basal nuclei, cerebral cortex, and cerebellum

123. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Memory Short-term memories Information that can be recalled immediately Contain small bits of information Primary memories

124. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Memory Long-term memories Memory consolidation – conversion from short- term to long-term memory Two types of long-term memory 1. Secondary memories fade and require effort to recall 2. Tertiary memories are with you for life

125. © 2015 Pearson Education, Inc. Figure 16-11 Memory Storage. Consolidation Repetition promotes retention Sensory input Short-Term Memory Long-Term Memory Secondary Memory Tertiary Memory Cerebral cortex ( fact memory ) Cerebral cortex and cerebellar cortex ( skill memory ) Temporary loss Permanent loss Permanent loss due to neural fatigue, shock, interference by other stimuli

126. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Brain Regions Involved in Memory Consolidation and Access Amygdaloid body and hippocampus Nucleus basalis Cerebral cortex

127. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Amygdaloid Body and Hippocampus Are essential to memory consolidation Damage may cause: Inability to convert short-term memories to new long-term memories Existing long-term memories remain intact and accessible

128. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Nucleus Basalis Cerebral nucleus near diencephalon Plays uncertain role in memory storage and retrieval Tracts connect with hippocampus, amygdaloid body, and cerebral cortex Damage changes emotional states, memory, and intellectual functions

129. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cerebral Cortex Stores long-term memories Conscious motor and sensory memories referred to association areas Occipital and temporal lobes Special portions crucial to memories of faces, voices, and words A specific neuron may be activated by combination of sensory stimuli associated with particular individual; called “grandmother cells”

130. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cerebral Cortex Visual association area Auditory association area Speech center Frontal lobes Related information stored in other locations If storage area is damaged, memory will be incomplete

131. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cellular Mechanisms of Memory Formation and Storage Involves anatomical and physiological changes in neurons and synapses Increased neurotransmitter release Facilitation at synapses Formation of additional synaptic connections

132. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Increased Neurotransmitter Release Frequently active synapse increases the amount of neurotransmitter it stores Releases more on each stimulation The more neurotransmitter released, the greater effect on postsynaptic neuron

133. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Facilitation at Synapses Neural circuit repeatedly activated Synaptic terminals begin continuously releasing neurotransmitter Neurotransmitter binds to receptors on postsynaptic membrane Produces graded depolarization Brings membrane closer to threshold Facilitation results affect all neurons in circuit

134. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Formation of Additional Synaptic Connections Neurons repeatedly communicating Axon tip branches and forms additional synapses on postsynaptic neuron Presynaptic neuron has greater effect on transmembrane potential of postsynaptic neuron

135. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cellular Mechanisms of Memory Formation and Storage Basis of memory storage Processes create anatomical changes Facilitate communication along specific neural circuit Memory Engram Single circuit corresponds to single memory Forms as result of experience and repetition

136. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cellular Mechanisms of Memory Formation and Storage Efficient conversion of short-term memory Takes at least 1 hour Repetition crucial Factors of conversion Nature, intensity, and frequency of original stimulus Strong, repeated, and exceedingly pleasant or unpleasant events likely converted to long-term memories

137. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cellular Mechanisms of Memory Formation and Storage Drugs stimulate CNS Caffeine and nicotine are examples Enhance memory consolidation through facilitation

138. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Cellular Mechanisms of Memory Formation and Storage Drugs stimulate CNS NMDA (N-methyl D-aspartate) Receptors Linked to consolidation Chemically gated calcium channels Activated by neurotransmitter glutamate Gates open, calcium enters cell Blocking NMDA receptors in hippocampus prevents long-term memory formation

139. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions States of Consciousness Many gradations of states Degree of wakefulness indicates level of ongoing CNS activity When abnormal or depressed, state of wakefulness is affected

140. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions States of Consciousness Deep sleep Also called slow-wave or Non-REM (NREM) sleep Entire body relaxes Cerebral cortex activity minimal Heart rate, blood pressure, respiratory rate, and energy utilization decline up to 30 percent

141. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions States of Consciousness Rapid eye movement (REM) sleep Active dreaming occurs Changes in blood pressure and respiratory rate Less receptive to outside stimuli than in deep sleep Muscle tone decreases markedly Intense inhibition of somatic motor neurons Eyes move rapidly as dream events unfold

142. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions States of Consciousness Nighttime sleep pattern Alternates between levels Begins in deep sleep REM periods average 5 minutes in length; increase to 20 minutes over 8 hours

143. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Sleep Has important impact on CNS Produces only minor changes in physiological activities of organs and systems Protein synthesis in neurons increases during sleep Extended periods without sleep lead to disturbances in mental function 25 percent of the U.S. population experiences sleep disorders

144. © 2015 Pearson Education, Inc. Figure 16-12a States of Sleep. Awake a REM sleep Deep (slow wave) sleep An EEG of the various sleep states. The EEG pattern during REM sleep resembles the alpha waves typical of awake adults.

145. © 2015 Pearson Education, Inc. Figure 16-12b States of Sleep. b Transition period Deep sleep Awake REM sleep 10:00 P. M.Midnight Time 2:00 A. M.4:00 A. M. 6:00 A. M. Typical pattern of sleep stages in a healthy young adult during a single night’s sleep.

146. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions States of Consciousness Arousal and the reticular activating system (RAS) Awakening from sleep Function of reticular formation Extensive interconnections with sensory, motor, integrative nuclei, and pathways along brain stem Determined by complex interactions between reticular formation and cerebral cortex

147. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Reticular Activating System (RAS) Important brain stem component Diffuse network in reticular formation Extends from medulla oblongata to midbrain Output of RAS projects to thalamic nuclei that influence large areas of cerebral cortex When RAS inactive, so is cerebral cortex Stimulation of RAS produces widespread activation of cerebral cortex

148. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Arousal and the Reticular Activating System Ending sleep Any stimulus activates reticular formation and RAS Arousal occurs rapidly Effects of single stimulation of RAS last less than a minute

149. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Arousal and the Reticular Activating System Maintaining consciousness Activity in cerebral cortex, basal nuclei, and sensory and motor pathways continue to stimulate RAS After many hours, reticular formation becomes less responsive to stimulation Individual becomes less alert and more lethargic Neural fatigue reduces RAS activity

150. © 2015 Pearson Education, Inc. 16-8 Higher-Order Functions Arousal and the Reticular Activating System Regulation of sleep–wake cycles Involves interplay between brain stem nuclei that use different neurotransmitters Group of nuclei stimulates RAS with NE and maintains awake, alert state Other group promotes deep sleep by depressing RAS activity with serotonin “Dueling” nuclei located in brain stem

151. © 2015 Pearson Education, Inc. Figure 16-13 The Reticular Activating System. RAS N II N VIII Reticular formation Special sensory input General cranial or spinal nerve input

152. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Brain Chemistry Changes in normal balance between two or more neurotransmitters can profoundly affect brain function

153. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Huntington’s Disease Destruction of ACh-secreting and GABA-secreting neurons in basal nuclei Symptoms appear as basal nuclei and frontal lobes slowly degenerate Difficulty controlling movements Intellectual abilities gradually decline

154. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Lysergic Acid Diethylamide (LSD) Powerful hallucinogenic drug Activates serotonin receptors in brain stem, hypothalamus, and limbic system

155. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Serotonin Compounds that enhance effects also produce hallucinations (LSD) Compounds that inhibit or block action cause severe depression and anxiety Variations in levels affect sensory interpretation and emotional states

156. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Serotonin Fluoxetine (Prozac) Slows removal of serotonin at synapses Increases serotonin concentrations at postsynaptic membrane Classified as selective serotonin reuptake inhibitors (SSRIs) Other SSRIs Celexa, Luvox, Paxil, and Zoloft

157. © 2015 Pearson Education, Inc. 16-9 Brain Chemistry Parkinson’s Disease Inadequate dopamine production causes motor problems Dopamine Secretion stimulated by amphetamines, or “speed” Large doses can produce symptoms resembling schizophrenia Important in nuclei that control intentional movements Important in other centers of diencephalon and cerebrum

158. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Effects of Aging Anatomical and physiological changes begin after maturity (age 30) Accumulate over time 85 percent of people over age 65 have changes in mental performance and CNS function

159. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Common Age-related Anatomical Changes in the Nervous System Reduction in Brain Size and Weight Reduction in Number of Neurons Decrease in Blood Flow to Brain Changes in Synaptic Organization of Brain Intracellular and Extracellular Changes in CNS Neurons

160. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Reduction in Brain Size and Weight Decrease in volume of cerebral cortex Narrower gyri and wider sulci Larger subarachnoid space Reduction in Number of Neurons Brain shrinkage linked to loss of cortical neurons No neuronal loss in brain stem nuclei

161. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Decrease in Blood Flow to Brain Arteriosclerosis Fatty deposits in walls of blood vessels Reduces blood flow through arteries Increases chances of rupture Cerebrovascular accident (CVA), or stroke May damage surrounding neural tissue

162. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Changes in Synaptic Organization of Brain Number of dendritic branches, spines, and interconnections decreases Synaptic connections lost Rate of neurotransmitter production declines

163. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Intracellular and Extracellular Changes in CNS Neurons Neurons in brain accumulate abnormal intracellular deposits Lipofuscin Granular pigment with no known function Neurofibrillary tangles Masses of neurofibrils form dense mats inside cell body and axon

164. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Intracellular and Extracellular Changes in CNS Neurons Plaques Extracellular accumulations of fibrillar proteins Surrounded by abnormal dendrites and axons

165. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Intracellular and Extracellular Changes in CNS Neurons Plaques and tangles Contain deposits of several peptides Primarily two forms of amyloid ß (Aß) protein Appear in brain regions specifically associated with memory processing

166. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Anatomical Changes Linked to functional changes Neural processing becomes less efficient with age Memory consolidation more difficult Secondary memories harder to access

167. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Sensory Systems Hearing, balance, vision, smell, and taste become less acute Reaction times slowed Reflexes weaken or disappear Motor Control Precision decreases Takes longer to perform

168. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Incapacitation 85 percent of elderly population develops changes that do not interfere with abilities Some individuals become incapacitated by progressive CNS changes

169. © 2015 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System Senility Also called senile dementia Degenerative changes Memory loss Anterograde amnesia (lose ability to store new memories) Emotional disturbances Alzheimer’s disease is most common

170. © 2015 Pearson Education, Inc. 16-10 Nervous System Integration The Nervous System Monitors all other systems Issues commands that adjust their activities Like conductor of orchestra

171. © 2015 Pearson Education, Inc. 16-10 Nervous System Integration Neural Tissue Extremely delicate Extracellular environment must maintain homeostatic limits If regulatory mechanisms break down, neurological disorders appear

172. © 2015 Pearson Education, Inc. Figure 16-14 diagrams the functional relationships between the nervous system and other body systems we have studied so far. SYSTEM INTEGRATOR The Nervous System Body SystemNervous System Provides sensations of touch, pressure, pain, vibration, and temperature; hair provides some protection and insulation for skull and brain; protects peripheral nerves Nervous SystemBody System Provides calcium ions for neural function; protects brain and spinal cord Facial muscles express emotional state; intrinsic laryngeal muscles permit communication; muscle spindles provide proprioceptive sensations Controls skeletal muscle contractions; coordinates respiratory and cardiovascular activities Controls skeletal muscle contractions that results in bone thickening and maintenance and determine bone position Controls contraction of arrector pili muscles and secretion of sweat glands The nervous system is closely integrated with other body systems. Every moment of your life, billions of neurons in your nervous system are exchanging information across trillions of synapses and performing the most complex integrative functions in the body. As part of this process, the nervous system monitors all other systems and issues commands that adjust their activities. However, the significance and impact of these commands varies greatly from one system to another. The normal functions of the muscular system, for example, simply cannot be performed without instructions from the nervous system. By contrast, the cardiovascular system is relatively independent—the nervous system merely coordinates and adjusts cardiovascular activities to meet the circulatory demands of other systems. In the final analysis, the nervous system is like the conductor of an orchestra, directing the rhythm and balancing the performances of each section to produce a symphony, instead of simply a very loud noise. Integumentary Skeletal Muscular Skeletal Integumentary Page 174 Page 285 Page 380 Endocrine Page 647 Cardiovascular Page 776 Lymphatic Page 824 Respiratory Page 874 Digestive Page 929 Page 1010 Urinary Reproductive Page 1090