Medical Terminology A WordBuilding Approach Seventh Edition CHAPTER

Medical Terminology A Word-Building Approach Seventh Edition CHAPTER 14 Nervous System Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Learning Outcomes • Describe the nervous system. • State the description and primary functions of the organs/structures of the nervous system. • List the major divisions of the brain and their functions. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Learning Outcomes • Analyze, build, spell, and pronounce medical words. • Comprehend the drugs highlighted in this chapter. • Describe diagnostic and laboratory tests related to the nervous system. • Identify and define selected abbreviations. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Multimedia Directory Slide 12 Slide 21 Slide 26 Slide 27 Slide 28 Slide 32 Slide 33 Slide 34 Slide 37 Slide 40 Slide 41 Slide 68 Slide 69 Neuron Structure Animation Neuron Type Animation Nerve Type Animation 1 Nerve Type Animation 2 Nerve Impulse Transmission Animation Dendrite Animation Neural Reflex Arc Animation Neurosynapse Animation Central Nervous System Animation Brain Anatomy Animation 1 Brain Anatomy Animation 2 Corpus Callosum Animation Brain Lobes Animation Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Multimedia Directory Slide 70 Slide 71 Slide 99 Slide 101 Slide 113 Slide 114 Slide 115 Slide 116 Slide 117 Slide 136 Slide 142 Slide 161 Language Areas Animation Cerebral Cortex Animation Autonomic Nervous System Animation Alzheimer’s Disease Video Epilepsy Video Epileptic Seizure Animation 1 Epileptic Seizure Animation 2 Epileptic Seizure Animation 3 Epidural Hematoma Animation Multiple Sclerosis Animation Parkinson’s Disease Video PET Scan Animation Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Anatomy and Physiology Overview • The nervous system is usually described as having two interconnected divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). • CNS: – Includes the brain and spinal cord. – Is enclosed by bones of the skull and spinal column. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Anatomy and Physiology Overview • PNS: – Network of nerves and neural tissues branching throughout the body from 12 pairs of cranial nerves and 31 pairs of spinal nerves. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 1 The nervous system is described as having two interconnected divisions: the central nervous system (CNS) consisting of the brain and spinal cord and the peripheral nervous system (PNS) consisting of peripheral nerves. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

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Tissues of the Nervous System • Two principal tissue types of the nervous system: – neurons (nerve cells) § the structural and functional units of the nervous system § specialized conductors of impulses – neuroglia (supporting tissues) Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Neuron Structure Animation Click on the screenshot to view an animation showing the structure of the neuron. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • There are several types of neurons, three of which are: – Motor neurons – Sensory neurons – Interneurons Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 2 Two main types of nerve cells. Medical Terminology: A Word-Building Approach,

Tissues of the Nervous System • Motor neurons – Cause contractions in muscles and secretions from glands and organs. – Inhibit the actions of glands and organs, thereby controlling most of the body’s functions. – Transmit impulses away from neural cell body to muscles or organs to be innervated. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • Motor neurons – Consist of a nucleated cell body with protoplasmic processes (axon and dendrites) extending away from it in several directions. – Axons: Long and covered with a fatty substance, the myelin sheath, which acts as an insulator and increases the transmission velocity of the nerve fiber it surrounds. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • Motor neurons – Axons may be as long as several feet and reach from the cell body to the area to be activated. – Dendrites: Resemble the branches of a tree, are short, or unsheathed, and transmit impulses to the cell body. • Neurons usually have several dendrites and only one axon. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • Sensory neurons – Differ in structure from motor neurons because they do not have true dendrites. – Peripheral processes § transmit sensory information to the cell bodies of sensory neurons. § are sheathed and resemble axons. § are attached to sensory receptors and transmit impulses to the central nervous system (CNS). Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • Sensory neurons – The CNS can stimulate motor neurons in response to sensory information. – Sensory neurons are referred to as afferent nerves because they carry impulses from sensory receptors to synaptic endings in the CNS. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Tissues of the Nervous System • Interneurons – Are called central or associative neurons. – Located entirely within the central nervous system. – They function to mediate impulses between sensory and motor neurons. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Neuron Type Animation Click on the screenshot to view an animation showing the three types of neurons. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Fibers, Nerves, and Tracts • Used to describe neuronal processes conducting impulses from one location to another. • Nerve fibers – Nerve fibers of the PNS are wrapped by protective membranes called sheaths. § Myelinated fibers have an inner sheath of myelin, a thick fatty substance, and an outer sheath or neurilemma composed of Schwann cells. § Unmyelinated fibers lack myelin and are sheathed only by the neurilemma. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Fibers, Nerves, and Tracts • Nerve fibers – Nerve fibers of the CNS do not contain Schwann cells. – Damage to fibers of the CNS is permanent. – Damage to a peripheral nerve can be reversible. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Fibers, Nerves, and Tracts • Nerves – A nerve is a collection of nerve fibers, outside the CNS. – Afferent: Sensory nerves that conduct to the CNS. – Efferent: Motor nerves that conduct away from the CNS to muscles, organs, and glands. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Fibers, Nerves, and Tracts • Tracts – Groups of nerve fibers within the CNS that have the same origin, function, and termination. – Spinal cord contains afferent sensory tracts ascending to the brain, and efferent motor tracts descending from the brain. – Brain itself contains numerous tracts; largest is the corpus callosum joining the left and right hemispheres. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Type Animation 1 Click on the screenshot to view an animation on the different types of nerves. The animation may take a moment before playing. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Type Animation 2 Click on the screenshot to view an animation on the different types of nerves. The animation may take a moment before playing. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Nerve Impulse Transmission Animation Click on the screenshot to view an animation showing the transmission of nerve impulses. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Transmission of Nerve Impulses • Stimulation of a nerve occurs at a receptor. • Sensory receptors – Specialized to specific types of stimulation such as heat, cold, light, pressure, or pain. – React by initiating a chemical change or impulse. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Transmission of Nerve Impulses • All-or-none principle – Means that no transmission occurs until stimulus reaches a set minimum strength, which can vary for different receptors. – Once the minimum stimulus or threshold is reached, a maximum impulse is produced. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Transmission of Nerve Impulses • All-or-none principle – Impulse is transmitted via a synapse, a specialized knoblike branch ending, with the help of chemical agents (neurotransmitters), across a synaptic cleft. – Synaptic cleft separates the axon’s end knobs from dendrites of the next neuron or from a motor end plate attached to a muscle. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Dendrite Animation Click on the screenshot to view an animation showing how dendrites act as receptors. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Neural Reflex Arc Animation Click on the screenshot to view an animation showing the steps involved in a neural reflex arc. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Neurosynapse Animation Click on the screenshot to view an animation showing a neurosynapse. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Central Nervous System • Consists of the brain and spinal cord. • CNS – receives impulses from throughout the body – processes the information – responds with an appropriate action • Brain and spinal cord can be divided into: – gray matter (unsheathed cell bodies and true dendrites) – white matter (myelinated nerve fibers) Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Central Nervous System • In the spinal cord: – An H-shaped core of gray cell bodies is surrounded by tracts of nerve fibers interconnected to the brain. • In the brain: – The surface layer or cortex is gray matter and most of the internal structures are white matter. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Central Nervous System Animation Click on the screenshot to view an animation on the central nervous system. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Life Span Considerations • At 3– 4 weeks of embryonic life, neural tube development, which becomes the central nervous system, occurs. • At 6 weeks, brain waves are measurable. • At 28 weeks, the fetal nervous system begins some regulatory functions. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Life Span Considerations • By 32 weeks, the fetal nervous system is capable of sustaining rhythmic respirations and regulating body temperature. • Growth rate of brain and nerve cells is at its most rapid pace up to about 4 years of age. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain Anatomy Animation 1 Click on the screenshot to view an animation showing the brain stem, the two hemispheres of the brain, and the structure of the brain. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain Anatomy Animation 2 Click on the screenshot to view an animation showing the brain stem, the two hemispheres of the brain, and the structure of the brain. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Its nervous tissue consists of millions of nerve cells and fibers. • It is the largest mass of nervous tissue in the body. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • The brain is enclosed by three membranes known collectively as the meninges: – dura mater – arachnoid – pia mater Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • The major structures are the: – cerebrum – cerebellum – diencephalon – brainstem § midbrain § pons § medulla oblongata Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 3 The meninges from the outside in: dura mater, arachnoid, and pia mater. Also showing the subarachnoid space and superior sagittal sinus. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 4 Major structures of the brain. Medical Terminology: A Word-Building Approach, Seventh

Life Span Considerations • A baby’s brain has three main structural parts: – cerebrum § control center that receives, processes, and acts on information. – cerebellum § helps coordinate muscle activities and maintains posture and balance. – brainstem § maintains vital body functions, such as heartbeat, blood pressure, digestion, and swallowing. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Life Span Considerations • In an infant, the right and left hemispheres of the brain have yet to develop their own specific tasks. • By the time a child is 3 years old, the two sides of the brain are well on their way to becoming specialized for different tasks. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebrum – Represents 7/8 of brain’s total weight. – Contains nerve centers that evaluate and control all sensory and motor activity, including: § sensory perception § emotions § consciousness § memory § voluntary movements Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

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Table 14. 2 (continued) Major Divisions of the Brain and Their Functions Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebrum – Divided by the longitudinal fissure into two cerebral hemispheres, the right and left, that are joined by large fiber tracts (corpus callosum) that allow information to pass from one hemisphere to the other. – Gyrus or convolution: Each bulge of the cerebrum. – Sulcus: Each shallow furrow of the cerebrum. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebrum – Cerebral cortex § Surface of the cerebrum, composed of gray, unmyelinated cell bodies. § Divided into lobes that correspond to overlying bones of the skull: frontal, parietal, temporal, and occipital lobes. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebrum – Frontal lobe: § Brain’s major motor area. § Site for personality and speech. – Parietal lobe: § Contains centers for sensory input from all parts of the body. § Known as the somesthetic area. § Site for interpretation of language. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebrum – Parietal lobe § Temperature, pressure, touch, and an awareness of muscle control are some of the sensory activities localized in this area. – Temporal lobe § Contains centers for hearing, smell, and language input. – Occipital lobe § Primary interpretive processing area for vision. § Directly posterior to the temporal lobe. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebellum – Second largest part of the brain. – Occupies a space in back of skull, inferior to cerebrum and dorsal to pons and medulla oblongata. – Oval in shape and divided into lobes by deep fissures. – Has a cortex of gray cell bodies, and its interior contains nerve fibers and white matter connecting it to every part of the CNS. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Cerebellum – Plays an important part in coordination of voluntary and involuntary complex patterns of movement and adjusts muscles to maintain posture. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Diencephalon – Means second portion of the brain and refers to the thalamus and hypothalamus. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Thalamus – Two large masses of gray cell bodies joined by a third or intermediate mass. – Serves as a relay center for all sensory impulses (except olfactory) being transmitted to the sensory areas of the cortex. – Relays motor impulses from the cerebellum and the basal ganglia to motor areas of the cortex. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Thalamus – Some impulses related to emotional behavior are also passed from the hypothalamus, through the thalamus, to the cerebral cortex. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Hypothalamus – Lies beneath the thalamus. – Is a principal regulator of autonomic nervous activity that is associated with behavior and emotional expression. – It also produces neurosecretions for the control of water balance, sugar and fat metabolism, regulation of body temperature, and other metabolic activities. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Hypothalamus – Pituitary gland is attached to the hypothalamus by a narrow stalk, the infundibulum. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Brainstem – Lower part of brain. – Provides the main motor and sensory innervation to the face and neck via the cranial nerves. – Consists of three structures: § mesencephalon or midbrain § pons § medulla oblongata Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Brainstem – Processes visual, auditory, and sensory information. – Plays an important role in the regulation of cardiac and respiratory function. – Regulates the CNS and is pivotal in maintaining consciousness and regulating the sleep cycle. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Brainstem – Midbrain § Located below the cerebrum and above the pons. § Has four small masses of gray cells known collectively as the corpora quadrigemina. – The upper two of these masses, called the superior colliculi, are associated with visual reflexes, such as the tracking movements of the eyes. – The lower two, or inferior colliculi, are involved with the sense of hearing. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Brainstem – Pons § Broad band of white matter located anterior to the cerebellum and between the midbrain and the medulla oblongata. § Composed of fiber tracts linking the cerebellum and medulla to higher cortical areas. § Plays a role in somatic and visceral motor control. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain • Brainstem – Medulla Oblongata § Connects the pons and the rest of the brain to the spinal cord. § All afferent and efferent tracts from the spinal cord either pass through or terminate in the medulla oblongata. § Contains nerve centers for regulation and control of breathing, swallowing, coughing, sneezing, vomiting, the heartbeat, and blood pressure. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Corpus Callosum Animation Click on the screenshot to view an animation showing the corpus callosum. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Brain Lobes Animation Click on the screenshot to view an animation showing the lobes of the brain. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Language Areas Animation Click on the screenshot to view an animation on the specific language areas of the brain. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Cerebral Cortex Animation Click on the screenshot to view an animation showing the cerebral cortex. Back to Directory Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Spinal Cord • Has an H-shaped gray area of cell bodies encircled by an outer region of white matter. • White matter consists of nerve tracts and fibers that: – provide sensory input to the brain – conduct motor impulses from the brain to spinal neurons Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 5 Brain, spinal cord, and spinal nerves with an expanded view of a spinal nerve. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Spinal Cord • Conus medullaris – The region between the 12 th thoracic and L 1, where the spinal cord becomes conically tapered. • Filum terminale – Terminal thread of fibrous tissue that extends from the conus medullaris to the second sacral vertebra. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Spinal Cord • Cauda equina (known as the horse’s tail) – Terminal portion of the spinal cord that forms the nerve fibers that are the lumbar, sacral, and coccygeal spinal nerves. • Functions of the spinal cord: – Conduct sensory impulses to the brain. – Conduct motor impulses from the brain. – Serve as a reflex center for impulses entering and leaving the spinal cord without direct involvement of the brain. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Cerebrospinal Fluid • CSF is a colorless fluid that surrounds the brain and spinal cord. • Produced as a filtrate of blood by the choroid plexuses within the ventricles of the brain. • Circulates through the ventricles, the central canal, and the subarachnoid space. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Cerebrospinal Fluid • Arachnoid Villi – Small projections of the arachnoid membrane that penetrate the dura mater. – Remove CSF from circulation. – Allow the fluid to drain into the superior sagittal sinus. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Cerebrospinal Fluid • Serves to cushion the brain and spinal cord from shocks that could cause injury. • Helps support the brain by allowing it to float within the supporting liquid. • Carries neurotransmitters. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Peripheral Nervous System • The network of nerves branching throughout the body from the brain and the spinal cord is known as the peripheral nervous system (PNS). • 12 pairs of cranial nerves attach to the brain. • 31 pairs of spinal nerves connect to the spinal cord. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Peripheral Nervous System • Cranial Nerves – Provide sensory input, motor control, or a combination of these functions. – Arranged symmetrically, 12 to each side of the brain. – Generally are named for the area or function they serve. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.

Figure 14. 6 Relationship of the 12 cranial nerves to specific regions of the brain. Medical Terminology: A Word-Building Approach, Seventh Edition Jane Rice Copyright © 2012 by Pearson Education, Inc. All rights reserved.