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16 Neural Integration II: The Autonomic Nervous System and Higher-Order Functions PowerPoint® Lecture Presentations prepared by Jason LaPres Lone Star College—North Harris © 2012 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. © 2012 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. © 2012 Pearson Education, Inc. An Introduction to the ANS and Higher-Order Functions • Learning Outcomes • 16-8 Explain how memories are created, stored, and recalled, and distinguish among the levels of consciousness and unconsciousness. • 16-9 Describe 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. © 2012 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 © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 16-1 An Overview of Neural Integration OVERVIEW OF NEURAL INTEGRATION CHAPTER 16 CHAPTER 15 Sensory processing centers in brain Sensory pathways Conscious and subconscious motor centers in brain © 2012 Pearson Education, Inc. Memory, learning, and intelligence may influence interpretation of sensory information and nature of motor activities Motor pathways Somatic Nervous System (SNS) General sensory receptors Higher-Order Functions Skeletal muscles Autonomic Nervous System (ANS) Visceral effectors (examples: smooth muscle, glands, cardiac muscle, adipocytes) 16-1 Autonomic Nervous System • Organization of the ANS • Integrative centers • For autonomic activity in hypothalamus • Neurons comparable to upper motor neurons in SNS © 2012 Pearson Education, Inc. Figure 16-2a The Organization of the Somatic and Autonomic Nervous Systems Upper motor neurons in primary motor cortex BRAIN Somatic motor nuclei of brain stem Skeletal muscle Lower motor neurons SPINAL CORD Somatic motor nuclei of spinal cord Skeletal muscle Somatic nervous system © 2012 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 • Autonomic ganglia • Contain many ganglionic neurons • Ganglionic neurons innervate visceral effectors • Such as cardiac muscle, smooth muscle, glands, and adipose tissue © 2012 Pearson Education, Inc. Figure 16-2b The Organization of the Somatic and Autonomic Nervous Systems Visceral motor nuclei in hypothalamus BRAIN Preganglionic neuron Visceral Effectors Smooth muscle Glands Cardiac muscle Autonomic ganglia Ganglionic neurons Adipocytes Preganglionic neurons Autonomic nuclei in brain stem SPINAL CORD Autonomic nuclei in spinal cord Autonomic nervous system © 2012 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 © 2012 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” © 2012 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 © 2012 Pearson Education, Inc. 16-1 Divisions of the ANS • Sympathetic Division • Prepares body for crisis, producing a “fight or flight” response • Stimulates tissue metabolism • Increases alertness © 2012 Pearson Education, Inc. • The sympathetic nervous system prepares the body for situations requiring alertness or strength, or situations that arouse fear, anger, excitement, or embarrassment (“fight-or-flight” situations). • In these kinds of situations, the sympathetic nervous system stimulates cardiac muscles to increase the heart rate, causes dilation of the bronchioles of the lungs (increasing oxygen intake), and causes dilation of blood vessels that supply the heart and skeletal muscles (increasing blood supply). • The adrenal medulla is stimulated to release epinephrine (adrenalin) and norepinephrine (noradrenalin), which in turn increases the metabolic rate of cells and stimulates the liver to release glucose into the blood. • Sweat glands are stimulated to produce sweat. • In addition, the sympathetic nervous system reduces the activity of various “tranquil” body functions, such as digestion and kidney functioning. © 2012 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 © 2012 Pearson Education, Inc. 16-2 The Sympathetic Division • Ganglionic Neurons • Occur in three locations 1. Sympathetic chain ganglia (Visceral effectors in thoracic cavity, head, body wall, and limbs) 2. Collateral ganglia (Visceral effectors in abdominopelvic cavity) 3. Adrenal Medulla (Organs and systems throughout body) © 2012 Pearson Education, Inc. Figure 16-3 The Organization of the Sympathetic Division of the ANS Sympathetic Division of ANS Ganglionic Neurons Target Organs Sympathetic chain ganglia Visceral effectors in thoracic cavity, head, body wall, and limbs Preganglionic Neurons Lateral gray horns of spinal segments T1–L2 KEY Preganglionic fibers Postganglionic fibers Hormones released into circulation © 2012 Pearson Education, Inc. Collateral ganglia Visceral effectors in abdominopelvic cavity Adrenal medullae Organs and systems throughout body 16-2 The Sympathetic Division • Adrenal Medullae (Suprarenal Medullae) • When stimulated, release neurotransmitters into bloodstream (not at synapse) • Function as hormones to affect target cells throughout body © 2012 Pearson Education, Inc. Figure 16-4c Sites of Ganglia in Sympathetic Pathways THE ADRENAL MEDULLAE Preganglionic fibers Endocrine cells (specialized ganglionic neurons) Adrenal medullae KEY Preganglionic neurons Ganglionic neurons © 2012 Pearson Education, Inc. Secretes neurotransmitters into general circulation 16-2 The Sympathetic Division • Adrenal Medullae • Neuroendocrine cells • Secrete neurotransmitters epinephrine (E) and norepinephrine (NE) • Epinephrine • Also called adrenaline • Is 75–80% of secretory output • Remaining is norepinephrine (NE) • Noradrenaline © 2012 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 © 2012 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 © 2012 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 © 2012 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 © 2012 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 • Roles in circulation: E reacts with both α- and β receptors, causing vasoconstriction and vasodilation, respectively. Although α receptors are less sensitive to E, when activated, they override the vasodilation mediated by βreceptors. The result is that high levels of circulating E cause vasoconstriction. At lower levels of circulating epinephrine, β receptor stimulation dominates, producing an overall vasodilation. NE increases blood pressure through α- receptor activation. © 2012 Pearson Education, Inc. 16-1 Divisions of the ANS • Parasympathetic Division • Parasympathetic division stimulates visceral activity • Conserves energy and promotes sedentary activities © 2012 Pearson Education, Inc. • The parasympathetic nervous system is active during periods of digestion and rest. • It stimulates the production of digestive enzymes and stimulates the processes of digestion, urination, and defecation. • It reduces blood pressure and heart and respiratory rates and conserves energy through relaxation and rest. © 2012 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 © 2012 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 © 2012 Pearson Education, Inc. Figure 16-7 The Organization of the Parasympathetic Division of the ANS Parasympathetic Division of ANS Preganglionic Neurons Nuclei in brain stem Ganglionic Neurons Target Organs Ciliary ganglion Intrinsic eye muscles (pupil and lens shape) Pterygopalatine and submandibular ganglia Nasal glands, tear glands, and salivary glands Otic ganglion Parotid salivary gland Intramural ganglia Visceral organs of neck, thoracic cavity, and most of abdominal cavity Intramural ganglia Visceral organs in inferior portion of abdominopelvic cavity N III N VII N IX NX KEY Preganglionic fibers Postganglionic fibers © 2012 Pearson Education, Inc. Nuclei in spinal cord segments S2–S4 Pelvic nerves 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 © 2012 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 © 2012 Pearson Education, Inc. Figure 16-8 The Distribution of Parasympathetic Innervation Pterygopalatine ganglion N III Lacrimal gland Eye Ciliary ganglion PONS N VII N IX Submandibular ganglion Salivary glands Otic ganglion N X (Vagus) Heart KEY Preganglionic neurons Ganglionic neurons © 2012 Pearson Education, Inc. Lungs Figure 16-8 The Distribution of Parasympathetic Innervation KEY Preganglionic neurons Ganglionic neurons Lungs Autonomic plexuses (see Figure 16-10) Liver and gallbladder Stomach Spleen Pancreas Large intestine Small intestine Rectum Pelvic nerves Spinal cord Kidney S2 S3 S4 Uterus Ovary © 2012 Pearson Education, Inc. Penis Scrotum Urinary bladder 16-4 The Parasympathetic Division • Parasympathetic Activation • Centers on relaxation, food processing, and energy absorption • Localized effects, last a few seconds at most © 2012 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 © 2012 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 © 2012 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 © 2012 Pearson Education, Inc. 16-8 Higher-Order Functions • Memory • Fact memories • Are specific bits of information • Skill memories • Learned motor behaviors • Short-term memories • Information that can be recalled immediately • 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 © 2012 Pearson Education, Inc. Figure 16-13 Memory Storage Repetition promotes retention Sensory input Short-term Memory Long-term Memory Consolidation Secondary Memory Tertiary Memory • Cerebral cortex (fact memory) • Cerebral cortex and cerebellar cortex (skill memory) Temporary loss Permanent loss due to neural fatigue, shock, interference by other stimuli © 2012 Pearson Education, Inc. Permanent loss 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” © 2012 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 © 2012 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 © 2012 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 © 2012 Pearson Education, Inc. 16-8 Higher-Order Functions • Cellular Mechanisms of Memory Formation and Storage • Drugs stimulate CNS • NMDA (N-methyl D-aspartate) Receptors • Chemically gated calcium channels • Activated by neurotransmitter glutamate • Gates open, calcium enters cell • Blocking NMDA receptors in hippocampus prevents long-term memory formation © 2012 Pearson Education, Inc. 16-9 Brain Chemistry • Brain Chemistry • Changes in normal balance between two or more neurotransmitters can profoundly affect brain function © 2012 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 © 2012 Pearson Education, Inc. 16-9 Brain Chemistry • Lysergic Acid Diethylamide (LSD) • Powerful hallucinogenic drug • Activates serotonin receptors in brain stem, hypothalamus, and limbic system © 2012 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 © 2012 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 © 2012 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 © 2012 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% of people over age 65 have changes in mental performance and CNS function © 2012 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 © 2012 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 © 2012 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 © 2012 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 © 2012 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 © 2012 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 © 2012 Pearson Education, Inc. 16-10 Effects of Aging on the Nervous System • Incapacitation • 85% of elderly population develops changes that do not interfere with abilities • Some individuals become incapacitated by progressive CNS changes © 2012 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 © 2012 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 © 2012 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 © 2012 Pearson Education, Inc.