MedicalTerminology_AWord-BuildingApproach7thEditionrice_ch14

1、a word-building approach copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricechapter seventh editionnervous system14 copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building appro

2、ach, seventh editionjane rice 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. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-b

3、uilding approach, seventh editionjane rice 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. copyright 2012 by pearson education, in

4、c.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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

5、 by bones of the skull and spinal column. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice pns: network of nerves and neural tissues branching throughout the body from 12 pairs of cranial nerves and 31 pairs of spina

6、l nerves. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricefigure 14.1the nervous system is described as having two interconnected divisions: the central nervous system (cns) consisting of the brain and spinal cord an

7、d the peripheral nervous system (pns) consisting of peripheral nerves. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane riceinsert table 14-1 copyright 2012 by pearson education, inc.all rights reserved.medical terminolog

8、y: a word-building approach, seventh editionjane riceinsert table 14-1 copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice two principal tissue types of the nervous system: neurons (nerve cells) the structural and funct

9、ional units of the nervous system specialized conductors of impulses neuroglia (supporting tissues) copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice there are several types of neurons, three of which are: motor neuro

10、ns sensory neurons interneurons copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricefigure 14.2two main types of nerve cells. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-build

11、ing approach, seventh editionjane rice motor neurons cause contractions in muscles and secretions from glands and organs. inhibit the actions of glands and organs, thereby controlling most of the bodys functions. transmit impulses away from neural cell body to muscles or organs to be innervated. cop

12、yright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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

13、 a fatty substance, the myelin sheath, which acts as an insulator and increases the transmission velocity of the nerve fiber it surrounds. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice motor neurons axons may be a

14、s 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. copyright 2012 by pearson education, inc.all rights

15、 reserved.medical terminology: a word-building approach, seventh editionjane rice 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.

16、are attached to sensory receptors and transmit impulses to the central nervous system (cns). copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice sensory neurons the cns can stimulate motor neurons in response to sensory

17、 information. sensory neurons are referred to as afferent nerves because they carry impulses from sensory receptors to synaptic endings in the cns. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice interneurons are ca

18、lled central or associative neurons. located entirely within the central nervous system. they function to mediate impulses between sensory and motor neurons. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice used to d

19、escribe 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

20、. unmyelinated fibers lack myelin and are sheathed only by the neurilemma. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice nerve fibers nerve fibers of the cns do not contain schwann cells. damage to fibers of the c

21、ns is permanent. damage to a peripheral nerve can be reversible. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice nerves a nerve is a collection of nerve fibers, outside the cns. afferent: sensory nerves that conduct

22、 to the cns. efferent: motor nerves that conduct away from the cns to muscles, organs, and glands. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice tracts groups of nerve fibers within the cns that have the same orig

23、in, 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. copyright 2012 by pearson education,

24、inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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.

25、copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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 stimulu

26、s or threshold is reached, a maximum impulse is produced. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice all-or-none principle impulse is transmitted via a synapse, a specialized knoblike branch ending, with the he

27、lp of chemical agents (neurotransmitters), across a synaptic cleft. synaptic cleft separates the axons end knobs from dendrites of the next neuron or from a motor end plate attached to a muscle. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approac

28、h, seventh editionjane rice 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

29、nerve fibers) copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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 l

30、ayer or cortex is gray matter and most of the internal structures are white matter. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice at 34 weeks of embryonic life, neural tube development, which becomes the central n

31、ervous system, occurs. at 6 weeks, brain waves are measurable. at 28 weeks, the fetal nervous system begins some regulatory functions. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice by 32 weeks, the fetal nervous s

32、ystem 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. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh edition

33、jane rice its nervous tissue consists of millions of nerve cells and fibers. it is the largest mass of nervous tissue in the body. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice the brain is enclosed by three membr

34、anes known collectively as the meninges: dura mater arachnoid pia mater copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice the major structures are the: cerebrum cerebellum diencephalon brainstem midbrain pons medulla

35、oblongata copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricefigure 14.3the meninges from the outside in: dura mater, arachnoid, and pia mater. also showing the subarachnoid space and superior sagittal sinus. copyright

36、2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricefigure 14.4major structures of the brain. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice a b

37、abys 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 swallowi

38、ng. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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 br

39、ain are well on their way to becoming specialized for different tasks. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice cerebrum represents 7/8 of brains total weight. contains nerve centers that evaluate and control

40、 all sensory and motor activity, including: sensory perception emotions consciousness memory voluntary movements copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane riceinsert table 14-2 copyright 2012 by pearson education,

41、inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane ricetable 14.2 (continued)major divisions of the brain and their functions copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice c

42、erebrum 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

43、 cerebrum. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice cerebrum cerebral cortex surface of the cerebrum, composed of gray, unmyelinated cell bodies. divided into lobes that correspond to overlying bones of the s

44、kull: frontal, parietal, temporal, and occipital lobes. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice cerebrum frontal lobe: brains major motor area. site for personality and speech. parietal lobe: contains center

45、s for sensory input from all parts of the body. known as the somesthetic area. site for interpretation of language. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice cerebrum parietal lobe: temperature, pressure, touc

46、h, 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. copyright 2012 by pearson e

47、ducation, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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 fissur

48、es. has a cortex of gray cell bodies, and its interior contains nerve fibers and white matter connecting it to every part of the cns. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice cerebellum plays an important par

49、t in coordination of voluntary and involuntary complex patterns of movement and adjusts muscles to maintain posture. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice diencephalon means second portion of the brain and

50、 refers to the thalamus and hypothalamus. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice thalamus two large masses of gray-cell bodies joined by a third or intermediate mass. serves as a relay center for all sensor

51、y 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. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editio

52、njane rice thalamus some impulses related to emotional behavior are also passed from the hypothalamus, through the thalamus, to the cerebral cortex. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice hypothalamus lies

53、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. copyrig

54、ht 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice hypothalamus pituitary gland is attached to the hypothalamus by a narrow stalk, the infundibulum. copyright 2012 by pearson education, inc.all rights reserved.medical termino

55、logy: a word-building approach, seventh editionjane rice 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 copyright 2012 by pearson education, inc

56、.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice 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

57、 regulating the sleep cycle. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice brainstem midbrain located below the cerebrum and above the pons. has four small masses of gray cells known collectively as the corpora qu

58、adrigemina. 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. copyright 2012 by pearson education, inc.all rights reserved.medica

59、l terminology: a word-building approach, seventh editionjane rice 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 som

60、atic and visceral motor control. copyright 2012 by pearson education, inc.all rights reserved.medical terminology: a word-building approach, seventh editionjane rice brainstem medulla oblongata connects the pons and the rest of the brain to the spinal cord. all afferent and efferent tracts from the