14-1 Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Chapter 14 Lecture Outline *

14-2 Chapter 14 Integration of Nervous System Functions

14-3 Sensation Senses: Means by which brain receives information about environment and body –General: Distributed over large part of body Somatic: Touch, pressure, temperature, proprioception, pain Visceral: Internal organs and consist mostly of pain and pressure –Special senses: Smell, taste, sight, hearing, balance Sensation or perception: Conscious awareness of stimuli received by sensory receptors

14-4 Types of Sensory Receptors Mechanoreceptors: Compression, bending, stretching of cells Chemoreceptors: Smell and taste Thermoreceptors: Temperature Photoreceptors: Light as vision Nociceptors: Pain Exteroreceptors: Associated with skin Visceroreceptors: Associated with organs Proprioceptors: Associated with joints, tendons

14-5 Sensory Nerve Endings Free nerve endings: Cold receptors and warm Merkel’s disk: Light touch, superficial pressure Hair follicle receptor: Light touch, bending of hair Pacinian corpuscle: Deep cutaneous pressure, vibration and proprioception Meissner’s corpuscle: Two-point discrimination Ruffini’s end organ: Continuous touch or pressure Muscle spindle: Proprioception as to muscle stretch and control of muscle tone Golgi tendon organ: Important in muscle contraction and tendon stretch proprioception

14-6 Sensory Nerve Endings in Skin

14-7 Two-Point Discrimination

14-8 Muscle Spindle and Golgi Tendon Organ

14-9 Responses of Sensory Receptors Receptor: Interaction of stimulus with sensory receptor produces a local potential –Primary: Have axons that conduct action potential in response to receptor potential –Secondary: Have no axons and receptor potentials produced do not result in action potentials but cause release of neurotransmitters Accommodation or adaptation: Decreased sensitivity to a continued stimulus Proprioceptors –Tonic: Example is know where little finger is without looking –Phasic: Example is you know where hand is as it moves

14-10 Sensory Nerve Tracts Transmit action potentials from periphery to brain Each pathway involved with specific modalities First half of word indicates origin, second half indicates termination

14-11 Spinothalamic System Conveys cutaneous sensory information to brain Unable to localize source of stimulus Divisions –Lateral for pain and temperature –Anterior for light touch, pressure, tickle, itch

14-12 Dorsal-Column/ Medial-Lemniscal System Carries sensations of – Two-point discrimination – Proprioception – Pressure – Vibration Tracts –Fasciculus gracilis –Fasciculus cuneatus

14-13 Spinocerebellar System Carry proprioceptive information to cerebellum Actual movements can be monitored and compared to cerebral information representing intended movement Tracts –Posterior –Anterior

14-14 Sensory Areas of Cerebral Cortex

14-15 Pain Types –Referred: Sensation in one region of body that is not source of stimulus –Phantom: Occurs in people who have appendage amputated or structure removed as tooth –Chronic: Not a response to immediate direct tissue injury

14-16 Somatic Sensory Cortex

14-17 Primary Motor Cortex

14-18 Descending Spinal Pathways Direct –Control muscle tone and conscious skilled movements –Direct synapse of upper motor neurons of cerebral cortex with lower motor neurons in brainstem or spinal cord –Tracts Corticospinal Lateral Anterior corticobulbar

14-19 Descending Spinal Pathways Indirect –Synapse in some intermediate nucleus rather than directly with lower motor neurons –Tracts Rubrospinal Vestibulospinal Reticulospinal

14-20 Cerebellar Comparator Function

14-21 Speech Speech area normally in left cerebral cortex –Wernicke’s area: Sensory speech –Broca’s area: Motor speech Aphasia: Absent or defective speech or language comprehension

14-22 Brain Waves and Sleep Electroencephalogram (EEG): Record of brain’s electrical activity Brain wave patterns –Alpha: Resting state with eyes closed –Beta: During intense mental activity –Theta: Occur in children but also in adults experiencing frustration or brain disorders –Delta: Occur in deep sleep, infancy, and severe brain disorders

14-23 Memory Sensory –Very short-term retention of sensory input Short-term –Information retained for few seconds to minutes Long-term –Explicit or declarative Retention of facts Accessed by hippocampus and amygdaloid (emotional) –Implicit or procedural Development of skills as riding a bicycle

14-24 Long-Term Potentiation

14-25 General CNS Disorders Infections –Encephalitis: Inflammation of the brain –Rabies: Viral disease transmitted by bite of infected animal –Multiple sclerosis: Possibly involves autoimmune response to viral infection Other disorders –Stroke: CVA or cerebrovascular accident caused by hemorrhage, thrombosis, embolism –Aneurysm: Dilation or ballooning of an artery –Alzheimer’s disease: Severe type of dementia –Epilepsy: Group of brain disorders that have seizures

14-26 Effects of Aging on Nervous System Gradual decline in sensory and motor function Reflexes slow Size and weight of brain decrease –Decreased short-term memory in most people –Long-term memory unaffected or improved