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Figure 15-1 An Overview of Neural Integration OVERVIEW OF NEURAL INTEGRATION CHAPTER 15 Sensory processing centers in brain Sensory pathways CHAPTER 16 Conscious and subconscious motor centers in brain Motor pathways Somatic Nervous System (SNS) General sensory receptors © 2012 Pearson Education, Inc. Skeletal muscles Higher-Order Functions Memory, learning, and intelligence may influence interpretation of sensory information and nature of motor activities Autonomic Nervous System (ANS) Visceral effectors (examples: smooth muscles, glands, cardiac muscle, adipocytes) 15-1 Sensory Information • Sensory Receptors • Specialized cells that monitor specific conditions • In the body or external environment • When stimulated, a receptor passes information to the CNS • In the form of action potentials along the axon of a sensory neuron © 2012 Pearson Education, Inc. 15-1 Sensory Information • Sensory Pathways • Deliver somatic and visceral sensory information to their final destinations inside the CNS using: • Nerves • Nuclei • Tracts © 2012 Pearson Education, Inc. 15-1 Sensory Information • Somatic Motor Portion of the Efferent Division • Controls peripheral effectors • Somatic Motor Commands • Travel from motor centers in the brain along somatic motor pathways of: • Motor nuclei • Tracts • Nerves © 2012 Pearson Education, Inc. 15-1 Sensory Information • Somatic Nervous System (SNS) • Motor neurons and pathways that control skeletal muscles © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • General Senses • Describe our sensitivity to: • Temperature • Pain • Touch • Pressure • Vibration • Proprioception © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • Sensation • The arriving information from these senses • Perception • Conscious awareness of a sensation © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • Special Senses • Olfaction (smell) • Vision (sight) • Gustation (taste) • Equilibrium (balance) • Hearing © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • The Special Senses • Are provided by special sensory receptors • Special Sensory Receptors • Are located in sense organs such as the eye or ear • Are protected by surrounding tissues © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • The Interpretation of Sensory Information • Arriving stimulus reaches cortical neurons via labeled line • Takes many forms (modalities) • Physical force (such as pressure) • Dissolved chemical • Sound • Light © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • The Interpretation of Sensory Information • Sensations • Taste, hearing, equilibrium, and vision provided by specialized receptor cells • Communicate with sensory neurons across chemical synapses © 2012 Pearson Education, Inc. 15-2 Sensory Receptors • Adaptation • Reduction in sensitivity of a constant stimulus • Your nervous system quickly adapts to stimuli that are painless and constant © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Classifying Sensory Receptors • Exteroceptors provide information about the external environment • Proprioceptors report the positions of skeletal muscles and joints • Interoceptors monitor visceral organs and functions © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Proprioceptors • Provide a purely somatic sensation • No proprioceptors in the visceral organs of the thoracic and abdominopelvic cavities • You cannot tell where your spleen, appendix, or pancreas is at the moment © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • General Sensory Receptors • Are divided into four types by the nature of the stimulus that excites them 1. Nociceptors (pain) 2. Thermoreceptors (temperature) 3. Mechanoreceptors (physical distortion) 4. Chemoreceptors (chemical concentration) © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Nociceptors (Pain Receptors) • Are common • In the superficial portions of the skin, in joint capsules • Within the periostea of bones,around the walls of blood vessels • Carry sensations of fast pain, or prickling pain, such as that caused by an injection or a deep cut • Carry sensations of slow pain, or burning and aching pain © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Nociceptors • May be sensitive to: 1. Temperature extremes 2. Mechanical damage 3. Dissolved chemicals, such as chemicals released by injured cells © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Thermoreceptors • Also called temperature receptors • Conducted along the same pathways that carry pain sensations • Are free nerve endings located in: • The dermis • Skeletal muscles • The liver • The hypothalamus © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Mechanoreceptors • Sensitive to stimuli that distort their plasma membranes (Tactile, Baroreceptors, Proprioceptors) • Contain mechanically gated ion channels whose gates open or close in response to: • Stretching • Compression • Twisting • Other distortions of the membrane © 2012 Pearson Education, Inc. 15-3 Classifying Sensory Receptors • Chemoreceptors • Respond only to water-soluble and lipid-soluble substances dissolved in surrounding fluid • Receptors exhibit peripheral adaptation over period of seconds • Central adaptation may also occur © 2012 Pearson Education, Inc. 15-4 Sensory Pathways • Somatic Sensory Pathways • Carry sensory information from the skin and musculature of the body wall, head, neck, and limbs • Three major somatic sensory pathways 1. The spinothalamic pathway 2. The posterior column pathway 3. The spinocerebellar pathway © 2012 Pearson Education, Inc. Figure 15-5 Somatic Sensory Pathways SPINOTHALAMIC PATHWAY KEY Axon of firstorder neuron Second-order neuron Third-order neuron Midbrain The anterior spinothalamic tracts of the spinothalamic pathway carry crude touch and pressure sensations. Medulla oblongata Anterior spinothalamic tract Crude touch and pressure sensations from right side of body © 2012 Pearson Education, Inc. Figure 15-5 Somatic Sensory Pathways SPINOTHALAMIC PATHWAY KEY Axon of firstorder neuron Second-order neuron Third-order neuron Midbrain Medulla oblongata Spinal cord The lateral spinothalamic tracts of the spinothalamic pathway carry pain and temperature sensations. Lateral spinothalamic tract Pain and temperature sensations from right side of body © 2012 Pearson Education, Inc. Figure 15-5 Somatic Sensory Pathways POSTERIOR COLUMN PATHWAY Ventral nuclei in thalamus Midbrain Nucleus gracilis and nucleus cuneatus Medial lemniscus Medulla oblongata Fasciculus gracilis and fasciculus cuneatus Dorsal root ganglion Fine-touch, vibration, pressure, and proprioception sensations from right side of body © 2012 Pearson Education, Inc. Figure 15-5 Somatic Sensory Pathways SPINOCEREBELLAR PATHWAY PONS Cerebellum Medulla oblongata Spinocerebellar pathway Spinal cord Posterior spinocerebellar tract Anterior spinocerebellar tract Proprioceptive input from Golgi tendon organs, muscle spindles, and joint capsules © 2012 Pearson Education, Inc. 15-4 Sensory Pathways • Sensory Information • Most somatic sensory information • Is relayed to the thalamus for processing • A small fraction of the arriving information • Is projected to the cerebral cortex and reaches our awareness © 2012 Pearson Education, Inc. 15-4 Sensory Pathways • Visceral Sensory Pathways • Collected by interoceptors monitoring visceral tissues and organs, primarily within the thoracic and abdominopelvic cavities • These interoceptors are not as numerous as in somatic tissues © 2012 Pearson Education, Inc. 15-4 Sensory Pathways • Visceral Sensory Pathways • Interoceptors include: • Nociceptors • Thermoreceptors • Tactile receptors • Baroreceptors • Chemoreceptors © 2012 Pearson Education, Inc. 15-4 Sensory Pathways • Visceral Sensory Pathways • Cranial Nerves V, VII, IX, and X • Carry visceral sensory information from mouth, palate, pharynx, larynx, trachea, esophagus, and associated vessels and glands © 2012 Pearson Education, Inc. 15-5 Somatic Motor Pathways • The Somatic Nervous System (SNS) • Also called the somatic motor system • Controls contractions of skeletal muscles (discussed next) • The Autonomic Nervous System (ANS) • Also called the visceral motor system • Controls visceral effectors, such as smooth muscle, cardiac muscle, and glands (Ch. 16) © 2012 Pearson Education, Inc. 15-5 Somatic Motor Pathways • Somatic Motor Pathways • Always involve at least two motor neurons 1. Upper motor neuron 2. Lower motor neuron © 2012 Pearson Education, Inc. 15-5 Somatic Motor Pathways • Upper Motor Neuron • Cell body lies in a CNS processing center • Synapses on the lower motor neuron • Innervates a single motor unit in a skeletal muscle • Activity in upper motor neuron may facilitate or inhibit lower motor neuron © 2012 Pearson Education, Inc. 15-5 Somatic Motor Pathways • Lower Motor Neuron • Cell body lies in a nucleus of the brain stem or spinal cord • Triggers a contraction in innervated muscle • Only axon of lower motor neuron extends outside CNS • Destruction of or damage to lower motor neuron eliminates voluntary and reflex control over innervated motor unit © 2012 Pearson Education, Inc. 15-5 Somatic Motor Pathways • Levels of Processing and Motor Control • Integrative centers in the brain • Perform more elaborate processing • As we move from medulla oblongata to cerebral cortex, motor patterns become increasingly complex and variable • Primary motor cortex • Most complex and variable motor activities are directed by primary motor cortex of cerebral hemispheres © 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. 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 • 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 © 2012 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 © 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. 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 • 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 © 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. 16-1 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 © 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. Figure 16-5 The Distribution of Sympathetic Innervation PONS Superior Cervical sympathetic ganglia Middle Inferior T1 Gray rami to spinal nerves KEY Preganglionic neurons Ganglionic neurons © 2012 Pearson Education, Inc. T1 Figure 16-5 The Distribution of Sympathetic Innervation Eye PONS Salivary glands Sympathetic nerves Heart Cardiac and pulmonary plexuses (see Figure 16-10) T1 KEY Preganglionic neurons Ganglionic neurons © 2012 Pearson Education, Inc. Lung Figure 16-5 The Distribution of Sympathetic Innervation T1 Greater splanchnic nerve KEY Preganglionic neurons Ganglionic neurons Celiac ganglion Superior mesenteric ganglion Liver and gallbladder Stomach Splanchnic nerves Spleen Pancreas Inferior mesenteric ganglion L2 Large intestine Small intestine Adrenal medulla Kidney Coccygeal ganglia (Co1) fused together © 2012 Pearson Education, Inc. Uterus Ovary Penis Scrotum Urinary bladder Figure 16-5 The Distribution of Sympathetic Innervation Postganglionic fibers to spinal nerves (innervating skin, blood vessels, sweat glands, arrector pili muscles, adipose tissue) Sympathetic chain ganglia L2 Spinal cord KEY Preganglionic neurons Ganglionic neurons © 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. 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. 16-6 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 © 2012 Pearson Education, Inc. Figure 16-9 Summary: The Anatomical Differences between the Sympathetic and Parasympathetic Divisions Sympathetic CNS Parasympathetic Preganglionic neuron PNS Preganglionic fiber Sympathetic ganglion KEY Neurotransmitters Acetylcholine Norepinephrine or Epinephrine Ganglionic neurons Circulatory system Postganglionic fiber TARGET © 2012 Pearson Education, Inc. Parasympathetic ganglion 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 © 2012 Pearson Education, Inc. Figure 16-12 A Comparison of Somatic and Autonomic Function Central Nervous System Cerebral cortex Limbic system Thalamus Hypothalamus Somatic sensory Visceral sensory Relay and processing centers in brain stem Long reflexes Somatic reflexes Peripheral Nervous SNS System Lower motor neuron Sensory pathways Preganglionic neuron ANS Short reflexes Ganglionic neuron Skeletal muscles © 2012 Pearson Education, Inc. Sensory receptors Visceral effectors 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