ELAINE N. MARIEB EIGHTH EDITION 7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY PART A The Nervous System

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  Sensory input – gathering information  To monitor changes inside and outside body  Changes = stimuli  Integration  To process and interpret sensory input and decide if action is needed  Motor output  A response to integrated stimuli  The response activates muscles or glands

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of the Nervous System  Central nervous system (CNS)  Brain  Spinal cord  Peripheral nervous system (PNS)  Nerves outside the brain and spinal cord

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.1 Peripheral Nervous System  Sensory (afferent) division  Nerves carry information TO CNS  Motor (efferent) division  Nerves carry information AWAY from CNS Somatic Nervous System – voluntary Autonomic Nervous System - involuntary

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons  Carry impulses from the sensory receptors  Cutaneous sense organs (skin)  Proprioceptors – detect stretch or tension  Motor (efferent) neurons  Carry impulses from the central nervous system to muscles, glands  Interneurons (association neurons)  Connect sensory and motor neurons

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Anatomy  Neurons = nerve cells Parts of a neuron:  Cell body – where nucleus is located  Processes – fibers that extend from cell body (dendrites, axons)  Dendrites –impulses toward the cell body  Axons – conduct impulses away from cell body Figure 7.4a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings How Neurons Communicate at Synapses Figure 7.10  Axonal terminals contain vesicles with neurotransmitters  Axonal terminals are separated from the next neuron by a gap  Synaptic cleft – gap between adjacent neurons  Synapse – junction between nerves

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.3e Nervous Tissue: Support Cells  Schwann cells  Form myelin sheath in the peripheral nervous system

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Fiber Coverings  Schwann cells – produce myelin sheaths in jelly-roll like fashion  Nodes of Ranvier – gaps in myelin sheath along the axon Figure 7.5

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Cell Body Location  Most are found in the central nervous system  Gray matter – cell bodies and unmylenated fibers  White matter – mylenated nerves  Nuclei – clusters of cell bodies within the white matter of the central nervous system  Ganglia – collections of cell bodies outside the central nervous system

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functional Properties of Neurons  Irritability – ability to respond to stimuli  Conductivity – ability to transmit an impulse  An impulse is conducted through polarization and repolarization of the nerve cell membranes.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Continuation of the Nerve Impulse between Neurons  Impulses are able to cross the synapse from one nerve to another nerve  Neurotransmitter is released from a nerve’s axon terminal  The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter  An action potential is started in the dendrite and the impulse is sent

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings How Neurons Communicate at Synapses Figure 7.10

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc  Reflex – rapid, predictable, and involuntary responses to stimuli  Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector Figure 7.11a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b–c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Reflexes and Regulation  Autonomic reflexes  Smooth muscle regulation  Heart and blood pressure regulation  Regulation of glands  Digestive system regulation  Somatic reflexes  Activation of skeletal muscles (tap knee)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain 4 Regions of the Brain:  Cerebrum/ Cerebral hemispheres (mushroom top)  Diencephalon  Brain stem  Cerebellum Figure 7.12b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cerebral Hemispheres (Cerebrum) Cerebral Hemispheres- Cerebrum  Paired (left and right) superior parts of the brain. Left brain controls right side of body, and vice-versa.  The surface is made of ridges (gyri) and grooves (sulci) Figure 7.13a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lobes of the Cerebrum  Fissures (deep grooves) divide the cerebrum into lobes  4 main lobes of the cerebrum  Frontal lobe, Parietal lobe, Occipital lobe and Temporal lobe  Somatic sensory area – receives impulses from the body’s sensory receptors  Primary motor area – sends impulses to skeletal muscles  Broca’s area – involved in our ability to speak

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Specialized Areas of the Cerebrum  Cerebral areas involved in special senses  Gustatory area (taste)  Visual area (seeing)  Auditory area (hearing)  Olfactory area (nose/smell)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Specialized Areas of the Cerebrum Figure 7.13c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Cerebrum  Corpus callosum connects left and right hemispheres Figure 7.13a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diencephalon Figure 7.15

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diencephalon  Diencephalon: sits on brain stem  Thalamus: relay station for sensory impulses  Hypothalamus: autonomic center  Helps regulate body temperature  Controls water balance  Regulates metabolism  An important part of the limbic system (emotions)  The pituitary gland is attached to the hypothalamus

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Brain Stem  Brain Stem attaches to the spinal cord:  Midbrain  Pons  Medulla oblongata: c ontains important control centers  Heart rate control  Blood pressure regulation  Breathing  Swallowing  Vomiting

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cerebellum  Cerebellum  Two hemispheres with convoluted surfaces  Provides involuntary coordination of body movements

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protection of the Central Nervous System  Meninges: cushion/protects brain and nerves.  Double folded membrane between brain/spinal cord and surrounding bone  Cerebrospinal fluid: circulates brain and spinal cord. Figure 7.16a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Traumatic Brain Injuries  Concussion  Slight brain injury, no permanent damage  Contusion  Destruction of nervous tissue, no regeneration  Cerebral edema  Swelling from the inflammatory response  Stroke  Ruptured blood vessel supplying part of brain  Lack of oxygen causes brain tissue to die.  Alzheimer’s Disease  Abnormal protein deposits in brain causes memory loss, confusion, agitation, irritability

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Autonomic Functioning  Sympathetic Nervous system: “fight-or- flight”  Response to unusual stimulus  Takes over to increase activities  Remember Es= exercise, excitement, emergency, and embarrassment  Parasympathetic – housekeeping activities  Conserves energy  Maintains daily necessary body functions  Remember D= division, digestion