Chapter 10 & 11

The Ear and Hearing

acetaminophen ah-seat-ah-MIN-oh-fen Generic drug name Medication that is an analgesic and antipyretic acute ah-KYUT Latin sharp Disease of sudden onset audiology audiologist aw-dee-OL-oh-jee aw-dee-OL-oh-jist S/ R/CF S/ -logy study of audi/o hearing -logist one who studies Study of hearing disorders. Specialist in the evaluation of hearing function bilateral by-LAT-er-al S/ P/ R/ -al pertaining to bi- two -later- side On two sides; e.g., in both ears chronic KRON-ik Greek time A persistent, long-term disease effusion eh-FYU-shun Latin pouring out Collection of fluid that has escaped from blood vessels into a cavity or tissues otitis media oh-TIE-tis ME-dee-ah S/ R/ R/ -itis inflammation ot- ear Latin middle Inflammation of the middle ear otologist otology otorhinolaryngologist oh-TOL-oh-jist oh-TOL-oh-jee oh-toe-rye-no-lah-rin-GOL-oh-jist S/ R/CF S/ R/CF R/CF -logist specialist ot/o- ear -logy study of -rhin/o- nose -laryng/o- larynx Medical specialist in diseases of the ear Diagnosis and treatment of disorders of the ear Ear, nose, and throat medical specialist External Ear (LO 11.6) The external ear comprises several structures that keep it functioning effectively. The auricle or pinna is a wing-shaped structure that directs sound waves into the ear canal through the external auditory meatus. The external auditory canal ends at the very delicate tympanic membrane, otherwise known as the eardrum (Figure 11.26). When using an otoscope to examine the tympanic membrane, the pinna should be pulled up and out to straighten the external auditory canal. ▲ FIGURE 11.26 External Ear. The meatus and canal are lined with skin that contains many modified sweat glands called ceruminous glands, which secrete cerumen. If a foreign body, like a small bead, gets into the auditory canal, or if cerumen becomes impacted in the canal, the result can be hearing loss. Keynotes The external auditory canal is the only skin-lined cul-de-sac in the body. Cerumen combines with dead skin cells to form earwax. Disorders of the External Ear (LO 11.6) Some disorders of the external ear include infections and earwax buildup. Otitis externa (Figure 11.27) is a bacterial or fungal infection of the external auditory canal lining. An otoscopic exam shows a painful, red, swollen ear canal, sometimes with a purulent drainage. Treatment entails thorough cleansing of the ear canal, applying a hydrocortisone topical solution with 2% acetic acid, and using antibiotic drops. Occasionally, a wick is used to help the topical medications penetrate down the canal. ▲ FIGURE 11.27 Otoscopic View of Otitis Externa. Swimmer's ear is a form of otitis externa resulting from swimming, particularly if the water is polluted. Excessive earwax can be removed in your physician's office by ear irrigation or with a curette, a small metal ring at the end of a handle. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION auditory (adj) AW-dih-tor-ee Latin hearing Relating to hearing or the organs of hearing auricle (Note: same as pinna) AW-ri-kul Latin ear The shell-like external ear cerumen ceruminous (adj) seh-ROO-men seh-ROO-mih-nus S/ R/ Latin wax -ous pertaining to cerumin- cerumen Waxy secretion of glands of the external ear Pertaining to cerumen curette curettage (Note: The final "e" of curette is dropped because the suffix -age begins with a vowel) kyu-RET kyu-reh-TAHZH S/ R/ S/ -ette little cur- cleanse, cure -age pertaining to Scoop-shaped instrument for scraping or removal of new growths (or earwax) The use of a curette impacted im-PAK-ted Latin driven in Immovably wedged, as with earwax blocking the external canal irrigation ih-rih-GAY-shun S/ R/ -ation process irrig- to water Use of water; e.g., to remove wax from the external ear canal meatus meatal (adj) me-AY-tus me-AY-tal Latin go through Passage or channel; also the external opening of a passage otoscope otoscopy otoscopic (adj) OH-toe-skope oh-TOS-koh-pee oh-toe-SKOP-ik S/ R/CF S/ S/ -scope instrument for viewing ot/o- ear -scopy to examine -ic pertaining to Instrument for examining the ear Examination of the ear Pertaining to examination with an otoscope pinna pinnae (pl) PIN-ah PIN-ee Latin wing Another name for auricle topical TOP-ih-kal S/ R/ -al pertaining to topic- local Medication applied to the skin to obtain a local effect tympanic tim-PAN-ik S/ R/ -ic pertaining to tympan- eardrum Pertaining to the tympanic membrane (eardrum) or tympanic cavity Middle Ear (LO 11.2 and 11.6) The middle ear has the following four components (Figure 11.28). ▲ FIGURE 11.28 Middle Ear. The tympanic membrane (eardrum) rests at the inner end of the external auditory canal. It vibrates freely as sound waves hit it. It has a good nerve supply and is very sensitive to pain. When examined through the otoscope, it is transparent and reflects light (Figure 11.29). ▲ FIGURE 11.29 Otoscopic View of Normal Tympanic Membrane. The tympanic cavity is immediately behind the tympanic membrane. It is filled with air that enters through the eustachian tube, and the cavity is continuous with the mastoid air cells in the bone behind it. The cavity contains small bones called ossicles. The three ossicles—the malleus, incus, and stapes—work to amplify sounds and are attached to the tympanic cavity wall by tiny ligaments. The malleus is attached to the tympanic membrane and vibrates with the membrane when sound waves hit it. The malleus is also attached to the incus, which vibrates, too, and passes the vibrations onto the stapes. The stapes is attached to the oval window, an opening that transmits the vibrations to the inner ear. The eustachian (auditory) tube connects the middle ear with the nasopharynx (throat), into which it opens near the pharyngeal tonsils (adenoids) (Figure 11.30). In children under 5 years of age, this tube is not fully developed. It is short and horizontal, and valve-like flaps in the throat that protect it are not yet developed. ▲ FIGURE 11.30 Nasopharynx (Throat). Keynote The three ossicles amplify sound so that soft sounds can be heard. The stapes is the smallest bone in the body. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION adenoid ADD-eh-noyd S/ R/ -oid resembling aden- gland Single mass of lymphoid tissue in the midline at the back of the throat eustachian tube (Note: same as auditory tube) you-STAY-shun TYUB Bartolomeo Eustachio, Italian anatomist, 1524-1574 Tube that connects the middle ear to the nasopharynx incus IN-cuss Latin anvil Middle one of the three ossicles in the middle ear; shaped like an anvil malleus MAL-ee-us Latin hammer Outer (lateral) one of the three ossicles in the middle ear; shaped like a hammer mastoid MASS-toyd S/ R/ -oid resembling mast- breast Small bony protrusion immediately behind the ear nasopharynx nasopharyngeal (adj) NAY-zoh-fair-inks NAY-zoh-fair-RIN-jee-al R/CF R/ S/ R/ nas/o- nose -pharynx throat -eal pertaining to -pharyng- pharynx Region of the pharynx at the back of the nose and above the soft palate Pertaining to the nasopharynx ossicle OSS-ih-kel S/ R/CF -cle small oss/i- bone A small bone, particularly relating to the three bones in the middle ear stapes STAY-peez Latin stirrup Inner (medial) one of the three ossicles of the middle ear; shaped like a stirrup Disorders of the Middle Ear (LO 11.6) The middle ear can be susceptible to the disorders outlined below. Acute otitis media (AOM) is the presence of pus in the middle ear with ear pain, fever, and redness of the tympanic membrane. AOM occurs most often in the first 2 to 4 years of age. If the infection is viral, it will go away on its own; if it's bacterial, oral antibiotics may be necessary. Chronic otitis media occurs when the acute infection subsides but the eustachian tube is blocked. The fluid in the middle ear caused by the infection cannot drain, and it gradually becomes stickier. This is called chronic otitis media with effusion (OME) and produces hearing loss because the sticky fluid prevents the ossicles from vibrating. You can see the fluid through the otoscope (Figure 11.31). Dr. Lee was concerned that this had happened to Eddie in his previous ear infection. If the sticky fluid persists, a myringotomy can be performed, and a small, hollow plastic tube may have to be inserted through the tympanic membrane to allow the effusion to drain. These ear tubes have several names: tympanostomy tubes, pressure-equalization tubes, and, most commonly, PE tubes (Figure 11.32). The tubes are inserted under general anesthesia as outpatient surgery. They remain in the ear for 6 to 18 months before they drop out on their own. ▲ FIGURE 11.32 Otoscopic View of PE Tube in Tympanic Membrane. A perforated tympanic membrane (Figure 11.33) can occur in acute otitis media (AOM) and chronic otitis media when pus in the middle ear cannot escape down the eustachian tube. The pus builds up pressure and punctures the eardrum. Most perforations will heal spontaneously in a month, leaving a small scar. Other perforation causes include a Q-tip puncture, an open-handed slap to the ear, or induced pressure as in scuba diving. ▲ FIGURE 11.33 Otoscopic View of Chronic Otitis Media with Perforation. Cholesteatoma is a complication of chronic otitis media with fluid or effusion (OME). Chronically inflamed middle ear cells multiply and collect into a tumor. They damage the ossicles and can spread to the inner ear. Surgical removal is required. Otosclerosis is a middle-ear disease that usually affects people between 18 and 35 years. It can impair one ear or both and produces a gradual hearing loss for low and soft sounds. Its etiology is unknown. Spongy bone forms around the junction of the oval window and stapes, preventing the stapes from conducting sound vibrations to the inner ear. The only treatment is to replace the stapes with a metal or plastic prosthesis. Abbreviations AOM acute otitis media PE tube pressure-equalization tube URI upper respiratory infection Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION cholesteatoma koh-less-tee-ah-TOE-mah S/ R/CF R/ -oma tumor, mass chol/e- bile -steat- fat Yellow, waxy tumor arising in the middle ear coryza (Note: same as acute rhinitis) koh-RYE-zah Greek catarrh Viral inflammation of the mucous membrane of the nose myringotomy mir-in-GOT-oh-me S/ R/CF -tomy surgical incision myring/o- tympanic membrane Incision in the tympanic membrane otosclerosis oh-toe-sklair-OH-sis S/ R/CF R/CF -sis abnormal condition ot/o- ear -scler/o- hard Hardening at the junction of the stapes and oval window that causes loss of hearing perforated perforation PER-foh-ray-ted per-foh-RAY-shun S/ R/ Latin to bore through -ion action perforat- bore through Punctured with one or more holes A hole through the wall of a structure prosthesis PROS-thee-sis Greek addition Manufactured substitute for a missing or diseased part of the body tympanostomy tim-pan-OS-toe-me S/ R/CF -stomy new opening tympan/o- eardrum Surgically created new opening in the tympanic membrane to allow fluid to drain from the middle ear Inner Ear for Hearing (LO 11.6) The inner ear is a labyrinth of complex, intricate passage systems. The passages in the cochlea, a part of the labyrinth (Figure 11.34), contain receptors that convert vibrations into electrical nerve impulses so the brain can interpret them as different sounds. ▲ FIGURE 11.34 Labyrinth of Inner Ear. Sound waves cause the tympanic membrane and the ossicles to vibrate (Figure 11.35). The stapes moves the oval window's membrane to create pressure waves in the fluid inside the inner ear's cochlea. These pressure waves make the basilar membranes in the cochlea vibrate. Hair cells attached to the membrane convert this motion into nerve impulses, which travel via the cochlear nerve to the brain. The excess pressure waves in the cochlea escape to the middle ear through the round window (Figure 11.35). ◀ FIGURE 11.35 Model of the Hearing Process. Keynote Repeated loud noise causes hearing loss in young people. Today, the most common cause of hearing loss is damage to the fine hairs in the cochlea by repeated loud noises—from the work-related use of jackhammers or leaf blowers to the leisure-related exposure to amplified music at concerts, personal listening devices, and motorcycles. This is a sensorineural hearing loss. Hearing aids are becoming more sophisticated and smaller, but they do not help people with cochlear damage. Cochlear implants are used to bypass the damaged hair cells and directly stimulate cochlear nerve endings. A conductive hearing loss occurs when sound is not conducted efficiently through the external auditory canal to the tympanic membrane and the ossicles. Causes of this include: A middle-ear pathology, like acute otitis media, otitis media with effusion, or a perforated eardrum; An infected external auditory canal; or The presence of a foreign body in the external canal. Abbreviations AD right ear AS left ear AU both ears Hearing Test Procedures (LO 11.6) Hearing tests are available to accurately measure just how much, and at what frequencies, a patient is able to hear. Some hearing test procedures are described below. Whispered speech testing: Ask the patient to cover one ear. Stand 2 feet away from the uncovered ear, whisper words, and ask the patient to repeat them. If the patient cannot repeat the words, say the words more loudly. This is a simple, but unmeasured, screening method. Weber test: Place a vibrating tuning fork in the middle of the patient's forehead and ask whether the tone is louder in one ear or equal on both sides. This determines on which side a hearing loss is located. Rinne test: Place a high-frequency tuning fork against the patient's mastoid bone and ask the patient to tell you when the sound is no longer heard. Then, quickly place the tuning fork 1 to 2 cm from the auditory canal on the same side and ask the patient whether he can hear the tuning fork. With normal hearing, air conduction should be greater than bone, and the patient should hear the fork next to the pinna when he can no longer hear it when held against the mastoid. The reverse indicates a conductive hearing loss. Audiometer: After proper training, you may use an audiometer to test for hearing loss. The audiometer is an electronic device that generates sounds in different frequencies and intensities and can print out the patient's responses. In recording the results of hearing testing, AD is shorthand for the right ear, AS for the left ear, and AU for both ears. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION audiometer audiometric (adj) aw-dee-OM-eh-ter AW-dee-oh-MET-rik S/ R/CF S/ -meter measure audi/o- hearing -metric pertaining to measurement Instrument to measure hearing Pertaining to the measurement of hearing basilar BAS-ih-lar S/ R/ -ar pertaining to basil- base, support Pertaining to the base of a structure cochlea cochlear (adj) KOK-lee-ah KOK-lee-ar Latin snail shell An intricate combination of passages; used to describe the inner ear conductive hearing loss kon-DUK-tiv Latin to lead Hearing loss in the outer ear or middle ear implant im-PLANT Latin to plant To insert material into tissues; or the material inserted into tissues labyrinth labyrinthitis LAB-ih-rinth LAB-ih-rin-THI-tis S/ R/ Greek labyrinth -itis inflammation labyrinth -inner ear The inner ear Inflammation of the inner ear Rinne test RIN-eh TEST Friedrich Rinne, German otologist, 1819-1868 Test for conductive hearing loss sensorineural hearing loss SEN-sor-ih-NYUR-al S/ R/CF R/ -al pertaining to sensor/i- sensory -neur- nerve Hearing loss of the inner ear or the auditory nerve Weber test VA-ber TEST Ernst Weber, German physiologist, 1794-1878 Test for sensorineural hearing loss Inner Ear for Equilibrium and Balance (LO 11.6) The inner ear contains the organs in your body responsible for maintaining the true sense of balance. The vestibule and the three semicircular canals (Figures 11.36 and 11.37) in the inner ear maintain an individual's balance. These are the true organs of balance. Inside the fluid-filled vestibule are two raised, flat areas covered with hair cells and a jelly-like material. This gelatinous material contains calcium and protein crystals called otoliths. The position of the head alters the amount of pressure this gelatinous mass applies to the hair cells. The hair cells respond to horizontal and vertical changes and send impulses to the brain relating how the head is tilted. ▲ FIGURE 11.36 Vestibule of the Inner Ear. ▲ FIGURE 11.37 Semicircular Canals. Each of the three fluid-filled semicircular canals has a dilated end called an ampulla. The ampulla contains a mound of hair cells set in a gelatinous material that together are called the crista ampullaris (Figure 11.37). This detects rotational movements of the head that distort the hair cells and lead to stimulation of connected nerve cells. The nerve impulses travel through the vestibular nerve to the brain. From the brain, nerve impulses travel to the muscles to maintain equilibrium and balance. The sensation of spinning or whirling that Mr. Santiago experiences is called vertigo, often described by patients as dizziness. The ringing in his ears is called tinnitus. Both sensations arise in the inner ear. Tinnitus can also sound like hissing, buzzing, roaring, or clicking and may be associated with difficulty hearing, sleeping, or working. Treatment includes hearing aids, sound-masking devices, and learning ways to cope with the problem. Benign paroxysmal positional vertigo (BPPV) is another type of intermittent vertigo caused by fragments of the otoliths in the vestibule migrating into the semicircular canals. The otolith fragments brush against the hair cells, sending conflicting signals to the brain. This produces vertigo. Acute labyrinthitis is an acute viral infection of the labyrinth producing extreme vertigo, nausea, and vomiting. It usually lasts 1 to 2 weeks. Abbreviation BPPV benign paroxysmal positional vertigo Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION ampulla am-PULL-ah Latin two-handled bottle Dilated portion of a canal or duct crista ampullaris KRIS-tah am-PULL-air-is R/ S/ R/ crista crest -aris pertaining to ampull- bottle-shaped Mound of hair cells and gelatinous material in the ampulla of a semicircular canal equilibrium ee-kwi-LIB-ree-um P/ R/ equi- equal -librium balance Being evenly balanced Ménière disease men-YEAR diz-EEZ Prosper Ménière, French physician, 1799-1862 Disorder of the inner ear with acute attacks of tinnitus, vertigo, and hearing loss otolith OH-toe-lith R/CF R/ ot/o- ear -lith stone A calcium particle in the vestibule of the inner ear paroxysmal par-ock-SIZ-mal S/ R/ -al pertaining to paroxysm- sudden, sharp attack Occurring in sharp, spasmodic episodes tinnitus TIN-ih-tus Latin jingle Persistent ringing, whistling, clicking, or booming noise in the ears vertigo VER-tih-go Latin dizziness Sensation of spinning or whirling vestibule vestibular (adj) VES-tih-byul ves-TIB-you-lar S/ R/ Latin entrance chamber -ar pertaining to vestibul- vestibule Space at the entrance to a canal Pertaining to the vestibule

Structure and Functions of the Nervous System

Structure of the Nervous System (LO 10.2 and 10.4) The nervous system (Figure 10.1) has two major anatomical subdivisions. ▶ FIGURE 10.1 The Nervous System. The central nervous system (CNS), consisting of the brain and spinal cord; and The peripheral nervous system (PNS), consisting of all the neurons and nerves outside the central nervous system. It includes 12 pairs of cranial nerves originating from the brain and 31 pairs of spinal nerves originating from the spinal cord. The peripheral nervous system is further subdivided into: The sensory division, in which sensory nerves (afferent nerves) carry messages toward the spinal cord and brain from sense organs; and The motor division, in which motor nerves (efferent nerves) carry messages away from the brain and spinal cord to muscles and organs. The visceral motor division is called the autonomic nervous system (ANS). It carries signals to glands and to cardiac and smooth muscle. It operates at a subconscious level outside your voluntary control, and it has two subdivisions: The sympathetic division arouses the body for action by increasing the heart and respiratory rates to increase oxygen supply to the brain and muscles. The parasympathetic division calms the body, slowing down the heartbeat but stimulating digestion. The somatic motor division carries signals to the skeletal muscles and is within your voluntary control. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION afferent (Note: Also called sensory; opposite of efferent) efferent (Note: Also called motor; opposite of afferent) AFF-eh-rent EFF-eh-rent Latin to bring to Latin to bring away from Moving toward a center; for example, nerve fibers conducting impulses to the spinal cord and brain Moving away from a center; for example, conducting nerve impulses away from the brain or spinal cord electroencephalogram (EEG) electroencephalograph electroencephalography ee-LEK-troh-en-SEF-ah-low-gram ee-LEK-troh-en-SEF-ah-low-graf ee-LEK-troh-en-SEF-ah-LOG-rah-fee S/ R/CF R/CF S/ S/ -gram recording electr/o- electricity -encephal/o- brain -graph to write, record -graphy process of recording Record of the electrical activity of the brain Device used to record the electrical activity of the brain The process of recording the electrical activity of the brain electroneurodiagnostic (adj) ee-LEK-troh-NYUR-oh-die-ag-NOS-tik S/ R/CF R/CF R/ -ic pertaining to electr/o- electricity -neur/o- nerve -diagnost- decision Pertaining to the use of electricity in the diagnosis of a neurologic disorder epilepsy epileptic (adj) (Note: An epileptic episode is called a seizure.) EP-ih-LEP-see EP-ih-LEP-tik SEE-zhur S/ R/ Greek seizure -ic pertaining to epilept- seizure Chronic brain disorder due to paroxysmal excessive neuronal discharges Pertaining to or suffering from epilepsy motor MOH-tor Latin to move Structures of the nervous system that send impulses out to cause muscles to contract or glands to secrete nerve nervous system NERV NER-vus SIS-tem S/ R/ Latin nerve -ous pertaining to nerv- nerve system, Greek an organized whole A cord of nerve fibers bound together by connective tissue The whole, integrated nerve apparatus neurology neurologist neurologic (adj) neurosurgeon neurosurgery nyu-ROL-oh-jee nyu-ROL-oh-jist NYU-roh-LOJ-ik NYU-roh-SUR-jun NYU-roh-SUR-jer-ee S/ R/CF S/ S/ R/ S/ R/ S/ -logy study of neur/o- nerve -logist one who studies, specialist -ic pertaining to -log- to study -eon one who does -surg- operate -ery process of Medical specialty of disorders of the nervous system Medical specialist in disorders of the nervous system Pertaining to the nervous system One who performs surgery on the nervous system Operating surgically on the nervous system parasympathetic (Note: This term contains two prefixes.) par-ah-sim-pah-THET-ik S/ P/ P/ R/ -ic pertaining to para- beside -sym- together -pathet- suffering Division of the autonomic nervous system; has opposite effects to the sympathetic division sensory SEN-soh-ree S/ R/ -ory having the function of sens- feel Pertaining to sensation; structures of the nervous system that carry impulses to the brain somatic soh-MAT-ik S/ R/ -ic pertaining to somat- body A division of the peripheral nervous system serving the skeletal muscles OR relating to the body in general sympathetic sim-pah-THET-ik S/ P/ R/ -ic pertaining to sym- together -pathet- suffering Division of the autonomic nervous system operating at an unconscious level visceral (adj) viscus viscera (pl) VISS-er-al VISS-kus VISS-er-ah S/ R/ -al pertaining to viscer- internal organs Latin an internal organ Pertaining to the internal organs Any single internal organ Functions of the Nervous System (LO 10.2 and 10.4) Optimal communication between your nervous system and all the cells in your body requires that the following five functions are always working smoothly: Sensory input to the brain comes from receptors all over your body at both the conscious and subconscious levels. You are conscious of external stimuli that you receive from your body as it interacts with your environment. Inside your body, internal stimuli concerning the amount of oxygen and carbon dioxide in your blood, and other homeostatic variables like your body temperature, are being processed continually at the subconscious level. Motor output from your brain stimulates the skeletal muscles to contract, which enables you to move. Your nervous system controls the production of sweat, saliva, and digestive enzymes without active input from you. Evaluation and integration occur in your brain and spinal cord to process the sensory input, initiate a response, and store the event in memory. Homeostasis is maintained by your nervous system taking in internal sensory input and responding to it. For example, the nervous system responds by stimulating the heart to deliver the correct volume of blood to ensure oxygenation of and removal of waste products from cells. Mental activity occurs in your brain so that you can think, feel, understand, respond, and remember. Cells of the Nervous System (LO 10.2 and 10.4) Neurons (nerve cells) receive stimuli and transmit impulses to other neurons or to organ receptors. Each neuron consists of a cell body and two types of processes or extensions, called axons and dendrites (Figure 10.3). ▲ FIGURE 10.3 Neuron. Dendrites are short, multiple, highly branched extensions of the neuron's cell body. They direct impulses toward the cell body. A single axon, or nerve fiber, arises from the cell body, is covered in a fatty myelin sheath, and carries the impulse away from the cell body. Each axon measures a few millimeters to a meter in length. Bundles of axons appear white in color and create the white matter of the brain and spinal cord. Neuron cell bodies, dendrites, and synapses appear gray and create the gray matter. The axon terminates in a network of small branches that ends at a synapse (junction) with a dendrite from another neuron, or with a receptor on a muscle cell or gland cell (Figure 10.4). Neurotransmitters cross the synapse to stimulate or inhibit another neuron or the cell of a muscle or gland. Examples of neurotransmitters are norepinephrine, serotonin, and dopamine. ◀ FIGURE 10.4 Synapse. Groups of cell bodies cluster together to form ganglia, and groups of cell bodies and axons collect together to form nerves. The trillion neurons in the nervous system are outnumbered 50 to 1 by the supportive glial cells (neuroglia). The blood-brain barrier is a physical barrier—composed of glial cells and the capillary blood vessel walls—that prevents foreign substances, toxins, and infections from leaving the bloodstream and affecting the brain cells. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION autonomic awe-toh-NOM-ik S/ P/ R/ -ic pertaining to auto- self -nom- law Self-governing visceral motor division of the peripheral nervous system axon ACK-son Greek axis Single process of a nerve cell carrying nervous impulses away from the cell body dendrite DEN-dright Greek looking like a tree Branched extension of the nerve cell body that receives nervous stimuli dopamine DOH-pah-meen Precursor of norepinephrine Neurotransmitter in some specific small areas of the brain glia glial (adj) neuroglia GLEE-ah GLEE-al nyu-roh-GLEE-ah S/ R/ R/CF Greek glue -al pertaining to -glia glue neur/o- nerve Connective tissue that holds a structure together Pertaining to glia or neuroglia Connective tissue holding nervous tissue together myelin MY-eh-lin S/ R/ -in substance, chemical compound myel- spinal cord Material of the sheath around the axon of a nerve neuron NYUR-on Greek nerve Technical term for a nerve cell; consists of cell body with its dendrites and axons neurotransmitter (Note: Transmit is a word itself, so the prefix trans is in the middle of the overall word.) NYUR-oh-trans-MIT-er S/ R/CF P/ R/ -er agent neur/o- nerve -trans- across -mitt- send Chemical agent that relays messages from one nerve cell to the next parasympathetic (Note: This term contains two prefixes.) par-ah-sim-pah-THET-ik S/ P/ P/ R/ -ic pertaining to para- beside -sym- together -pathet- suffering Division of the autonomic nervous system; has opposite effects to the sympathetic division sympathetic sim-pah-THET-ik S/ P/ R/ -ic pertaining to sym- together -pathet- suffering Division of the autonomic nervous system operating at an unconscious level synapse SIN-aps P/ R/ syn- together -apse clasp Junction between two nerve cells, or a nerve fiber and its target cell, where electrical impulses are transmitted between the cells

The Ear and Hearing

... Mrs. Carmen Cardenas, who has brought in her 3-year-old son, Eddie. She tells you that Eddie has had a cold for a couple of days. Early this morning, he woke up screaming, felt hot, and was tugging his ears. She gave him acetaminophen with some orange juice, and he threw up. She also tells you this is the third similar episode in the past year, and, since the last time, she is concerned that he is not hearing normally. You see a worried mother and a restless toddler with a green nasal discharge. His oral temperature taken with an electronic digital thermometer is 102.48°F, and his pulse is 100. You tell Mrs. Cardenas that Dr. Lee will be in to see Eddie as soon as possible. Clinical Note. 05/10/14 Examination by Dr. Lee showed that Eddie has a bilateral acute otitis media (BOM) with an upper respiratory infection (URI). Dr. Lee is also concerned that Eddie has a chronic otitis media with effusion (OME) that is causing a hearing loss. She prescribed Amoxicillin 250 mg q.i.d. with acetaminophen 160 mg p.r.n. for 10 days, when she will see Eddie again. If, after the acute infection subsides, there remains an effusion with hearing loss, Dr. Lee may need to refer Eddie to an otologist. I explained this to Mrs. Cardenas. —Luis Guittierez, CMA 1115 hrs. Eddie Cardenas's ear problems began with his eustachian tube. His cold (upper respiratory infection, URI, and coryza) inflamed the mucous membranes of his throat and eustachian tube. Because he is so young, his eustachian tube is short and horizontal and so the inflammation spread easily from his throat into the middle ear, causing his acute otitis media (AOM). The inflammatory process produced fluid (effusion) in the middle ear. His tympanic membrane became inflamed and painful, which you could see through an otoscope (Figure 11.31).

Accessory Structures of the Eye

A beam of light travels to the eye at 186,000 miles per second, or 671 million miles per hour. Before it can reach the eyeball it passes through external accessory structures, which have important functions that support and protect the exposed front surface of the eye. The eyebrows (Figure 11.1) keep sweat from running into the eyes and function in nonverbal -communication to show how you're feeling in response to certain stimuli. ▲ FIGURE 11.1 External Anatomy of the Eye. The eyelids protect the eyes from foreign objects. They blink to move tears across the eyes' surface and sweep debris away. They close in sleep to keep out visual stimuli. They are covered in the body's thinnest layer of skin. The eyelashes are strong hairs that help keep debris out of the eyes. They arise from hair follicles with their sebaceous glands on the edge of the lids. The conjunctiva is a transparent mucous membrane that lines the inside of both eyelids. It moves freely over the eyeball and covers the front of the eye but not the central portion (the cornea). In the conjunctiva, numerous goblet cells secrete a thin film of mucin (a complex protein) that keeps the eyeball moist. It has numerous small blood vessels and is richly supplied with nerve endings that make it very sensitive to pain. The lacrimal apparatus (Figure 11.2) consists of the lacrimal (tear) gland located in the superolateral corner of the orbit. This gland secretes tears, and short ducts carry the tears to the conjunctiva's surface. After washing across the conjunctiva, the tears leave the eye at its medial corner by draining into the lacrimal sac. They then flow into the nasolacrimal duct, which carries the tears into the nose, from where they are swallowed. ▲ FIGURE 11.2 Lacrimal Apparatus. The functions of tears are to: Clean and lubricate the surface of the eyes; Deliver nutrients and oxygen to the conjunctiva; and Prevent infection through bactericidal (bacteria-killing) enzymes. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION conjunctiva conjunctival (adj) conjunctivitis "pink eye" kon-junk-TIE-vah kon-junk-TIE-val kon-junk-tih-VI-tis S/ R/ S/ Latin inner lining of eyelids -al pertaining to conjunctiv- conjunctiva -itis inflammation Lay term for conjunctivitis Inner lining of eyelids Pertaining to the conjunctiva Inflammation of the conjunctiva Conjunctivitis cornea corneal (adj) KOR-nee-ah KOR-nee-al S/ R/ Latin web, tunic -al pertaining to corne- cornea The central, transparent part of the outer coat of the eye covering the iris and pupil lacrimal nasolacrimal duct LAK-rim-al NAY-zoh-LAK-rim-al DUKT S/ R/ R/CF R/ -al pertaining to lacrim- tear nas/o- nose duct to lead Pertaining to tears and the tear apparatus Passage from the lacrimal sac to the nose ophthalmology ophthalmologist ophthalmic (adj) off-thal-MALL-oh-jee off-thal-MALL-oh-jist off-THAL-mik S/ R/CF S/ S/ R/ -logy study of ophthalm/o- eye -logist one who studies, specialist -ic pertaining to ophthalm- eye Diagnosis and treatment of diseases of the eye Medical specialist in ophthalmology Pertaining to the eye orbit orbital (adj) periorbital OR-bit OR-bit-al per-ee-OR-bit-al S/ R/ P/ Latin circle -al pertaining to orbit- orbit peri- around The bony socket that holds the eyeball Pertaining to the orbit Pertaining to tissues around the orbit photophobia photophobic (adj) foh-toe-FOH-bee-ah foh-toe-FOH-bik S/ R/CF R/ S/ -ia condition phot/o- light -phob- fear -ic pertaining to Abnormal sensitivity to light due to pain in the eyes Pertaining to or suffering from photophobia Disorders of the Accessory Glands (LO 11.4) The accessory glands of the eyes can be affected by a number of different disorders, most of which cause noticeable discomfort. Conjunctivitis (Figure 11.3), an inflammation of the conjunctiva, is more commonly viral than bacterial; it can also be caused by irritants like chlorine, soaps, fumes, and smoke. ▲ FIGURE 11.3 Conjunctivitis. Eyelid edema, a generalized swelling of the eyelids, is often produced by an allergic reaction (see Chapter 8) from cosmetics, pollen in the air, or insect stings and bites. A stye or hordeolum is an infection of an eyelash follicle that produces an abscess (Figure 11.4), with localized pain, swelling, redness, and pus at the edge of the eyelid. ▲ FIGURE 11.4 Stye Showing Pus-Filled Cyst. Blepharitis occurs when multiple eyelash follicles become infected. The eyelid's margin shows persistent redness and crusting and may become ulcerated (Figure 11.5). ▲ FIGURE 11.5 Blepharitis of the Lower Lid. Ptosis, in which the upper eyelid is constantly drooped over the eye, is due to paresis of the muscle that raises the upper lid (Figure 11.6). The term blepharoptosis defines the sagging of the eyelids from excess skin. The plastic surgery procedure of blepharoplasty is used to repair the eyelid. ▲ FIGURE 11.6 Ptosis of Right Eyelid. Dry eye disease (dysfunctional tear syndrome) is due to decreased tear production by the lacrimal glands. It leads to ocular discomfort and potential damage to the conjunctiva and cornea. Some cases are due to Sjogren's syndrome, in which the lacrimal glands are affected by autoimmune processes. Dry eye is more common in females and the elderly, and in people who wear contact lenses. Abbreviation q4h Every four hours. Study Hint Note that the term ptosis is a stand-alone term and has a meaning in its own right. It can also function as a suffix specifically relating to the eyelids when it is added to the combining form blephar/o. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION antibiotic AN-tih-bye-OT-ik S/ P/ R/ -tic pertaining to anti- against -bio- life A substance that has the capacity to inhibit the growth of or destroy bacteria and other microorganisms blepharitis blepharoptosis blepharoplasty blef-ah-RYE-tis BLEF-ah-ROP-toe-sis BLEF-ah-roh-plas-tee S/ R/ S/ R/CF S/ -itis inflammation blephar- eyelid -ptosis drooping blephar/o- eyelid -plasty surgical repair Inflammation of the eyelid Drooping of the upper eyelid Surgical repair of the eyelid conjunctivitis contagious kon-TAY-jus S/ R/ -itis inflammation conjunctiv- conjunctiva Latin touch closely Inflammation of the conjunctiva Infection can be transmitted from person to person or from a person to a surface to a person contaminate (verb) contamination (noun) kon-TAM-in-ate KON-tam-ih-NAY-shun S/ P/ R/ S/ -ate composed of, pertaining to con- together -tamin- touch -ation process To cause the presence of an infectious agent to be on any surface The presence of an infectious agent on any surface hordeolum (also called stye) hor-DEE-oh-lum Latin stye in the eye Abscess in an eyelash follicle paresis par-EE-sis Greek paralysis Partial paralysis ptosis (Notes: When a word begins with two consonants, the first is silent. Ptosis can also be used as a suffix.) TOE-sis Greek drooping Drooping down of the upper eyelid or an organ purulent PURE-you-lent S/ R/ -ulent abounding in pur- pus Showing or containing a lot of pus Extrinsic Muscles of the Eye (LO 11.2 and 11.4) Humans have two eyes positioned on the face, one on either side of the nose facing forward, which work closely together. This eye configuration gives us very good three-dimensional perception (stereopsis) and hand-eye coordination. Stereopsis depends on an accurate alignment of the two eyes. Six coordinated extrinsic eye muscles in each eye—attached to the inner wall of the orbit and outer surface of the eyeball—keep the eyes properly aligned, and move the eyes in all directions. When there is a muscle imbalance in one eye, the alignment breaks down and strabismus (Figure 11.7). also known as a "cross-eyed" condition, results. It can be cured by vision therapy or surgery. ▲ FIGURE 11.7 Strabismus. Esotropia is a condition where the eye is turned in toward the nose. In congenital or infantile esotropia, both eyes look in toward the nose—the right eye looks to the left and the left eye looks to the right (Figure 11.8). Children with this condition require surgery. ▲ FIGURE 11.8 Congenital Esotropia (both eyes are affected). Accomodative esotropia is an inward eye turn, usually noticed around age 2 in 1 to 2% of children. Sam Hughes had an accommodative esotropia in one eye. Wearing glasses and perhaps a patch over the stronger eye will help to correct Sam's problem. Exotropia, an outward eye turn, is noticed in children around ages 2 to 4. It will often respond to vision therapy, which includes eye exercises and glasses, from an optometrist. Eye muscle surgery can establish good ocular alignment. Amblyopia, or "lazy eye," occurs in children when vision in one eye has not developed as well as vision in the other. Instead, it occurs because the eye and the brain won't cooperate for the affected eye. Amblyopia is treated with a patch over the stronger eye in order to develop the vision in the weaker eye. Nystagmus is a term to describe fast, uncontrollable movements of the eye that may be side to side (horizontal nystagmus), up and down (vertical nystagmus), or rotary (rotary nystagmus). The condition can be congenital or acquired from head injury, inner ear disorders (see the next section of this chapter), stroke, or drugs, such as excess alcohol, sedatives, or anti-epilepsy drugs (see Chapter 10). There is no cure, but some cases improve spontaneously. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION accommodation (noun) accommodate (verb) accommodative (adj) ah-kom-oh-DAY-shun ah-KOM-oh-date ah-kom-oh-DAY-tiv S/ P/ R/ S/ S/ -ion action ac- toward -commodat- adjust -ate pertaining to, composed of -ive pertaining to The act of adjusting something to make it fit the needs; in this case the lens of the eye adjusts itself To adapt to meet a need Pertaining to accommodation amblyopia am-blee-OH-pee-ah R/ S/ ambly- dull -opia sight Failure or incomplete development of the pathways of vision to the brain esotropia exotropia es-oh-TROH-pee-ah ek-soh-TROH-pee-ah S/ P/ R/ P/ -ia condition eso- inward -trop- turn exo- outward Turning the eye inward toward the nose Turning the eye outward away from the nose extrinsic intrinsic eks-TRIN-sik in-TRIN-sik Latin on the outer side Latin on the inner side Any muscle located entirely on the outside of the structure under consideration; e.g., the eye Any muscle located entirely within (inside) the structure under consideration; e.g., the eye nystagmus nis-TAG-muss Greek nodding Fast, uncontrollable movements of the eyeballs ocular OCK-you-lar S/ R/ -ar pertaining to ocul- eye Pertaining to the eye optometrist optometry op-TOM-eh-trist op-TOM-eh-tree S/ R/CF S/ -metrist skilled in measurement opt/o- vision -metry process of measuring Someone skilled in the measurement of vision but who cannot treat eye diseases or prescribe medication The profession of the measurement of vision rotary ROW-tah-ree Latin to revolve Circular movement stereopsis ster-ee-OP-sis S/ R/ -opsis vision stere- three-dimensional Three-dimensional vision strabismus strah-BIZ-mus S/ R/ -ismus take action strab- squint Turning of an eye away from its normal position

Disorders of the Eye and Ophthalmic Procedures

Disorders of the Anterior Eyeball (LO 11.5) Conjunctivitis is the infectious, contagious, "bloodshot eyes"-causing condition that Mrs. Jenny Hughes had in the opening Case Report of this chapter. It can be caused by viruses and bacteria, and by organisms that cause sexually transmitted diseases (STDs) (Chapter 15). Four other types of conjunctivitis are: Allergic conjunctivitis, which can be part of seasonal hay fever or produced by year-round allergens like animal dander and dust mites (Chapter 8); Irritant conjunctivitis, which can be caused by air pollutants (smoke and fumes), chemicals like chlorine, and some ingredients found in soaps and cosmetics; and Neonatal conjunctivitis (ophthalmia neonatorum), which is specific to babies and can be caused by a blocked tear duct, by the antibiotic eye drops given routinely at birth, or by sexually transmitted bacteria from an infected mother's birth canal. Keratoconjunctivitis is a combined inflammation of the cornea and conjunctiva. It can be viral, bacterial, or allergic in origin. Corneal abrasions are caused by foreign bodies, by direct trauma (like being poked by a fingernail), or by ill-fitting contact lenses. An abrasion can grow into an ulcer. This ulcer or lesion can be stained with drops of the dye fluorescein to make it more easily visible on examination (Figure 11.14). If the cornea is scarred by trauma or infection and vision is impaired, a corneal transplant or graft (keratoplasty) from a deceased donor can be performed. ▲ FIGURE 11.14 Fluorescein-Stained Corneal Ulcer. Scleritis is an inflammation of the sclera (the white outer covering of the eyeball) that can affect one or both eyes. Glaucoma results if fluid from inside the eyeball cannot escape from the eye into the bloodstream. The fluid continues to be produced and pressure builds up inside the eye. This pressure interferes with the blood supply to the retina, causing retinal cells to die and damage to the optic nerve fibers. Glaucoma is a major cause of blindness (Figure 11.15), and it's treated with a lifelong use of eye drops, which help to prevent the condition from worsening. ▲ FIGURE 11.15 Vision with Glaucoma. A cataract is a cloudy or opaque area in the lens (Figure 11.16). It is caused by aging and may be associated with diabetes and cigarette smoke. Symptoms include blurred vision and photosensitivity. A cataract may also be discovered during a routine eye exam. It is another major cause of blindness. ▲ FIGURE 11.16 Cataract. Congenital (present at birth) cataracts occur in less than 0.5% of newborns and can be unilateral (present in one eye) or bilateral (present in both eyes). They are treated in the same way as any other cataract. When a cataract interferes with a patient's vision (Figure 11.17), the lens needs to be removed and replaced with an artificial intraocular lens, which becomes a permanent part of the eye. The lens is removed by phacoemulsification, a process in which the lens is fragmented with an ultrasonic handpiece and aspirated from the eye. ▲ FIGURE 11.17 Vision with Cataract. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION cataract KAT-ah-ract Latin to break down Complete or partial opacity of the lens fluorescein flor-ESS-ee-in P/ R/ fluo- fluorine -rescein resin Dye that produces a vivid green color under a blue light to diagnose corneal abrasions and foreign bodies glaucoma glau-KOH-mah S/ R/ -oma mass, tumor glauc- lens opacity Loss of vision due to increased intraocular pressure intraocular in-trah-OCK-you-lar S/ P/ R/ -ar pertaining to intra- inside -ocul- eye Pertaining to the inside of the eye keratoplasty keratoconjunctivitis KER-ah-toh-PLAS-tee KER-ah-toh-con-junk-tih-VI-tis S/ R/ S/ R/ -plasty repair kerat/o cornea -itis inflammation -conjunctiv- conjunctiva Corneal transplant or graft Combined inflammation of the cornea and conjunctiva ophthalmia neonatorum off-THAL-me-ah ne-oh-nay-TOR-um S/ R/ S/ P/ R/ -ia condition ophthalm- eye -orum function of neo- new -nat- born Conjunctivitis of the newborn phacoemulsification FAKE-oh-ee-MUL sih-fih-KAY-shun S/ P/ R/ -ation process phaco- lens -emulsific- to milk out Technique used to fragment the lens into very tiny pieces and suck them out of the eye photosensitivity photosensitive (adj) FOH-toe-sen-sih-TIV-ih-tee foh-toe-SEN-sih-tiv S/ R/CF R/ -ity condition phot/o- light -sensitiv- feeling When light produces pain in the eye pollution pollutant poh-LOO-shun poh-LOO-tant S/ R/ Latin to defile -ant pertaining to pollut- unclean Condition that is unclean, impure, and a danger to health Substance that makes an environment unclean or impure Disorders of the Retina (LO 11.5) An impaired retina affects your ability to see in the same way that an injured leg affects your ability to walk. In either case, your level of functioning in normal, daily life is limited. Macular Degeneration (LO 11.5) Degeneration of the central macula results in a loss of visual acuity or sharpness, with a dark blurry area of vision loss in the center of the visual field (Figure 11.18). Photoreceptor cell loss and bleeding with capillary proliferation and scar formation (Figure 11.19) also occur. Macular degeneration can progress to blindness. Most cases occur in people over 55. Although there is currently no known cure, laser photocoagulation may be used to destroy abnormal capillaries, which slows the pace of vision loss. ▲ FIGURE 11.18 Vision with Macular Degeneration. ▲ FIGURE 11.19 Ophthalmoscopic View of Macular Degeneration. Retinal Detachment (LO 11.5) In retinal detachment, the retina may separate partially or completely from its underlying choroid layer, creating a retinal tear or hole. This detachment—visible on an ophthalmoscopic exam—can happen suddenly, without pain, but is considered a surgical emergency. The patient sees a dark shadow invading his or her peripheral vision. Laser surgery is used to treat the small lesions and to "weld" the retina back into place. Diabetic Retinopathy (LO 11.5) Some 50% of diabetics have retinopathy. Patients may experience hemorrhages (bleeding), which can lead to the destruction of the photoreceptor cells (rods and cones) and visual difficulties. An ophthalmoscopic examination shows the disease (Figure 11.20), and fluorescein angiography with pictures taken as the dye passes through the retina reveals more details. ▲ FIGURE 11.20 Ophthalmoscopic View of Diabetic Retinopathy Showing Areas of Hemorrhage. Laser photocoagulation is often effective in controlling the lesions, but once vision is lost from an area of the retina, it usually doesn't return (Figure 11.21). ▲ FIGURE 11.21 Vision with Diabetic Retinopathy. Cancer of the Eye (LO 11.5) Tumors of the skin of the eyelids include the squamous cell and basal cell carcinomas and melanoma described in Chapter 3. Retinoblastoma is the most common cancer in children and is diagnosed most frequently around 18 months of age. Of those children affected, 20% have the cancer in both eyes. This condition can be hereditary. With early detection and aggressive chemotherapy and laser surgery treatment, 90% of these cases can be cured. In adults, the most common eye cancers are metastases to the eye from lung cancer in men and breast cancer in women. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION angiography angiogram an-jee-OG-rah-fee AN-jee-oh-gram S/ R/CF S/ -graphy process of recording angi/o- blood vessel -gram a record X-ray visualization of vessels after injection of contrast material X-ray images obtained after injection of radiopaque material into blood vessels laser surgery LAY-zer SUR-jer-ee S/ R/ Light Amplification by Simulated Emission of Radiation -ery process of surg- operate Use of a concentrated, intense narrow beam of electromagnetic radiation for surgery ophthalmoscope ophthalmoscopy ophthalmoscopic (adj) off-THAL-moh-skope OFF-thal-MOS-koh-pee OFF-thal-moh-SCOP-ik S/ R/CF S/ S/ -scope instrument for viewing ophthalm/o- eye -scopy to view, examine -ic pertaining to Instrument for viewing the retina The process of viewing the retina Pertaining to the use of an ophthalmoscope photocoagulation foh-toe-koh-ag-you-LAY-shun S/ R/CF R/ -ation process phot/o- light -coagul- clotting Using light (laser beam) to form a clot retinoblastoma retinopathy RET-in-oh-blas-TOE-mah ret-ih-NOP-ah-thee S/ R/CF R/ S/ -oma tumor, mass retin/o- retina -blast- immature cell -pathy disease Malignant neoplasm of primitive retinal cells Degenerative disease of the retina Ophthalmic Diagnostic Procedures (LO 11.2 and 11.5) A number of procedures, which are detailed in the following paragraphs, can be used to effectively examine the eye for various purposes. Examination of the Retina (LO 11.5) A fundoscopy examines the retina with an ophthalmoscope to identify the optic disc (Figure 11.22), where the optic nerve leaves the back of the eye. The optic disc has no receptor cells and, as mentioned earlier in this chapter, it produces a "blind spot" in the visual field of each eye. In the middle of the optic disc, a retinal artery enters to supply the intraocular structures, and a retinal vein leaves the eye. ▲ FIGURE 11.22 Anatomy of the Fundus. Color Vision (LO 11.5) The Ishihara color system is used to test color vision. In the example in Figure 11.23, people with red-green color blindness would not be able to see the number 16 among the colored dots. ▲ FIGURE 11.23 Test for Color Blindness.Reproduced with permission from Ishihara's Tests for Color Deficiency, published by Kanehara Trading Inc., Tokyo, Japan. Tests for color deficiency cannot be conducted with this figure. For accurate testing, the original plates should be used. Distance Vision (LO 11.5) The Snellen letter chart is used to test distance vision (Figure 11.24a). The results are recorded as a fraction. For example, when the chart is viewed from 20 feet, line 8 is the smallest line a person with standard vision can read. This is recorded as 20/20. If the patient using her or his left eye misses two letters on line 8, this is documented as OS 20/20-2. The right eye is documented as OD, the left eye as OS, and the use of both eyes is noted as OU. ▲ FIGURE 11.24 Visual Acuity Tests.(a) Snellen letter chart for distant vision. (b) Jaeger reading card for near vision. Near Vision (LO 11.5) Near vision is measured using handheld charts or Jaeger reading cards with printed paragraphs of different sizes of print (Figure 11.24b). Visual Fields (LO 11.5) Visual fields are tested in the following way: Sit 2 feet in front of your patient, and instruct the patient to cover one eye. Next, cover your own opposite eye. Now, bring a pencil into the horizontal and vertical fields to compare the patient's peripheral vision with your own. Intraocular Pressure (LO 11.5) Intraocular pressure is measured with a tonometer, which determines the eyeball's resistance to indentation or tension. Increased intraocular pressure indicates glaucoma. Abbreviations OD right eye OS left eye OU both eyes Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION fundus fundoscopy fundoscopic (adj) FUN-dus fun-DOS-koh-pee fun-doh-SKOP-ik S/ R/CF S/ Latin bottom -scopy to examine fund/o- fundus -ic pertaining to Part farthest from the opening of a hollow organ Examination of the fundus (retina) of the eye Pertaining to fundoscopy Ishihara color system ish-ee-HAR-ah Shinobu Ishihara, Japanese ophthalmologist, 1879-1963 Test for color vision defects Jaeger reading cards YA-ger Eduard Jaeger, Austrian ophthalmologist, 1818-1884 Type of different sizes for testing near vision peripheral peripheral vision peh-RIF-er-al peh-RIF-er-al VIZH-un S/ R/ S/ R/ -al pertaining to peripher- external boundary -ion action, condition vis- sight Pertaining to the periphery or external boundary Ability to see objects as they come into the outer edges of the visual field Snellen letter chart SNEL-en Hermann Snellen, Dutch ophthalmologist, 1834-1908 Test for acuity of distant vision tonometer tonometry toe-NOM-eh-ter toe-NOM-eh-tree S/ R/CF S/ -meter measure ton/o- pressure, tension -metry process of measuring Instrument for determining intraocular pressure The measurement of intraocular pressure Ophthalmic Pharmacology (LO 11.4 and 11.5) Fluorescein eye drops are used extensively as a tool for the diagnosis of corneal abrasions, corneal ulcers, and herpetic corneal infections. Ocular local (topical) anesthetics are used in the initial assessment of minor trauma and for removal of conjunctival and corneal foreign bodies. The most commonly used agent is lidocaine hydrochloride. Injected ocular anesthetics are used in ocular surgery, most commonly in cataract removal. The injections can be given subconjunctivally, or through the lower lid, or into the space between the conjunctiva and the lens. Lidocaine or tetracaine are most frequently used. Hydrocortisone (corticosteroid) drops and eye ointment are used following surgery and for allergic and inflammatory conditions, but not for infections. Bacterial conjunctivitis (a form of "pink eye") is often treated empirically without a culture using drops or ointments containing such antibiotics as trimethoprim, polymyxin, and bacitracin. Ophthalmia neonatorum, which is caused by acquiring gonorrhea or chlamydia infection during passage down the birth canal of an infected mother, is prevented by routinely giving 0.5% erythromycin eye drops to all newborns within two hours of birth. Untreated, the infections can cause blindness. Dry eye syndrome and irritable eyes can be treated with more than 20 over-the-counter (OTC) drops or ointments. Herpetic keratoconjunctivitis requires acyclovir in eye ointment or drops. Mydriatics, agents to dilate the pupils of the eye, are used to examine the interior of the eye, to determine refractive error in children, and to treat amblyopia. Atropine and homatropine are mydriatics. The opiate class drugs—heroin, codeine, morphine, and methadone—contract (miosis) the pupils. Anesthetics used prior to cataract surgery can be injected by the intracameral route. After the surgery, antibiotics can be given by the same route to prevent endophthalmitis. Glaucoma treatment can start with prostaglandin eye drops, which increase the outflow of the aqueous humor fluid in the eye to reduce the pressure. Medications such as beta blockers or alpha-adrenergic agonists reduce the production of fluid in the eye. If eye drops are insufficient to bring down the intraocular pressure, an oral medication such as a carbonic anhydrase inhibitor can be added. If medication is insufficient, surgery involving laser treatment or surgery to the eye can help reduce the pressure. The surgery does not reverse vision loss. Medications to treat diabetic retinopathy that are in clinical practice and in clinical trials are given by intravitreal injection. They include the synthetic corticosteroid triamcinalone and monoclonal antibodies such as Avastin and Lucentis, but these medications have not achieved as robust an effect as focal laser treatment. Surgical therapeutic interventions have been described previously with each disorder of the different elements of the eye. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION endophthalmitis EN-dof-thal-MY-tis S/ P/ R/ -itis inflammation end- inside -ophthalm- eye Inflammation of tissues inside the eye fluorescein flor-ESS-ee-in P/ R/ fluo- fluorine -rescein resin Dye that produces a vivid green color under blue light to diagnose corneal abrasions and foreign bodies in the eye graft GRAFT French transplant The transplanted tissue or the act of transplantation of tissue intracameral in-trah-CAM-er-al S/ P/ R/ -al pertaining to intra- inside -camer- chamber Introduction of an anesthetic agent into the anterior chamber of the eye during surgery intravitreal in-trah-VIT-ree-al S/ P/ R/ -eal pertaining to intra- inside -vitr- glass Injection of various agents into the vitreous body of the eye to treat retinal disorders miosis miotic my-OH-sis my-OT-ik S/ R/ Greek a lessening -ic pertaining to miot- a lessening Contraction of the pupil An agent that contracts the pupil mydriasis mydriatic mih-DRY-ah-sis mih-dree-AT-ik S/ R/ Greek to dilate -ic pertaining to mydriat- dilate Dilation of the pupil An agent that dilates the pupil prostaglandin PROSS-tah-GLAN-din S/ R/ R/ -in chemical prosta- prostate -gland- gland Hormone present in many tissues; first isolated in the prostate gland transplant transplantation TRANZ-plant TRANZ-plan-TAY-shun P/ R/ S/ trans- across -plant plant -ation process Tissue or organ used, or the act of transferring tissue from one person to another The process of moving tissue from one person or place to another

Disorders of the Brain, Cranial Nerves, and Meninges

Disorders of the Brain (LO 10.2 and 10.5) Dementia (LO 10.2 and 10.5) Your empathy allowed Mr. Rood to talk comfortably without interruption. His condition made clear again the specific symptoms of dementia. These include an irreversible short-term memory loss, the inability to solve problems, and confusion. Inappropriate behavior, like wandering away, and impaired intellectual function that interferes with normal activities and relationships are also key signs of dementia. Dementia requires a lot of sympathy from family and caregivers. Senile dementia is not a normal part of aging and is not a specific disease. It is a term used for a collection of symptoms that can be caused by a number of disorders affecting the brain. Alzheimer disease (Figure 10.10)—the most common form of dementia—affects 10% of the population over 65, and 50% of the population over 85. Nerve cells in the areas of the brain associated with memory and cognition are replaced by abnormal protein clumps and tangles. ▲ FIGURE 10.10 Brain Sections. (a) MRI scan, normal brain. (b) MRI scan of Alzheimer disease, showing cerebral atrophy (yellow). Vascular dementia—the second most common form of dementia—can come on gradually when arteries supplying the brain become arteriosclerotic (narrowed or blocked), depriving the brain of oxygen. It can also occur suddenly after a stroke (see later in this chapter). Frontotemporal dementia (FTD) is caused by progressive cell degeneration in the brain's frontal and temporal lobes, which control planning and judgment, emotions, speaking and understanding speech, and certain types of movement. It accounts for 10% to 15% of all dementias, but it is more common in those younger than 65. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION Alzheimer disease AWLZ-high-mer diz-EEZ Dr. Alois Alzheimer, German physician, 1864-1915 Common form of dementia cognition kog-NIH-shun Latin knowledge Process of acquiring knowledge through thinking, learning, and memory confusion kon-FEW-zhun S/ R/ -ion condition, action confus- bewildered Mental state in which environmental stimuli are not processed appropriately delirium de-LIR-ee-um S/ R/ -um structure deliri- disorientation, confusion Acute altered state of consciousness with agitation and disorientation dementia dee-MEN-she-ah S/ P/ R/ -ia condition de- removal, without -ment- mind Chronic, progressive, irreversible loss of the mind's cognitive, and intellectual functions empathy sympathy EM-pah-thee SIM-pah-thee P/ S/ P/ S/ em- into -pathy emotion, disease sym- together -pathy emotion, disease Ability to place yourself into the feelings, emotions, and reactions of another person Appreciation and concern for another person's mental and emotional state sedative sedation SED-ah-tiv seh-DAY-shun S/ R/ S/ -ive pertaining to, quality of sedat- to calm -ion condition, action Agent that calms nervous excitement State of being calmed senile SEE-nile S/ R/ -ile pertaining to sen- old age Characteristic of old age stroke (same as cerebrovascular accident, CVA) STROHK Old English to strike Acute clinical event caused by impaired cerebral circulation Other conditions causing dementia include reactions to medications, like sedatives and antiarthritics; depression in the elderly; and infections, such as AIDS or encephalitis. Confusion is used to describe people who cannot process information normally. They cannot answer questions appropriately, understand where they are, or remember important facts, like their name and address. Delirium is an altered mental state (AMS), characterized by the sudden onset of disorientation, an inability to think clearly or pay attention. The level of consciousness varies from increased wakefulness to drowsiness. It is not a disease, it is reversible, and it can be part of dementia or a stroke. Epilepsy (LO 10.5) Epilepsy is a chronic disorder in which clusters of neurons (nerve cells) discharge their electrical signals in an abnormal rhythm. This disturbed electrical activity (a seizure or a convulsion) can cause strange sensations and behavior, convulsions, and loss of consciousness. The causes of epilepsy are numerous, from abnormal brain development to brain damage. The International League Against Epilepsy created the following classification system for seizures: Partial seizures occur when the epileptic activity is in one localized area of the brain only, causing, for example, involuntary jerking movements of a single limb. Generalized seizures can be categorized into one of the following three types: Absence seizures, previously known as "petit mal," which begin between ages 5 and 10. The child stares vacantly for a few seconds and may be accused of daydreaming. Tonic-clonic seizures, previously called "grand mal," which are dramatic. The person experiences a loss of consciousness (LOC), breathing stops, the eyes roll up, and the jaw is clenched. This "tonic" phase lasts for 30 to 60 seconds. It is followed by the "clonic" phase, in which the whole body shakes with a series of violent, rhythmic jerkings of the limbs. The seizures last for a couple of minutes, and then consciousness returns. Febrile seizures, which are triggered by a fever in infants and toddlers aged 6 months to 5 years. Very few of these children go on to develop epilepsy. Status epilepticus is considered to be a medical emergency. It is defined as having one continuous seizure or recurrent seizures without regaining consciousness for 30 minutes or more. Any seizure may be followed by a period of diminished function in the area of the brain surrounding the seizure's main origin. This temporary neurologic deficit is called a postictal state. Tourette syndrome and other tic disorders are characterized by episodes of involuntary, rapid, repetitive, fixed movements of individual muscle groups in the face or the limbs. They are associated with meaningless vocal sounds or meaningful words and phrases. The tics may be genetic. Narcolepsy is a chronic disorder in which patients fall asleep during the day—from a few seconds up to an hour. There is no cure. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION grand mal GRAHN MAL R/ R/ grand big mal bad Previous name for generalized tonic-clonic seizure narcolepsy NAR-koh-lep-see S/ R/CF -lepsy seizure narc/o- stupor Involuntary falling asleep petit mal peh-TEE MAL R/ R/ petit small mal bad Previous name for absence seizures postictal (adj) ictal (adj) post-IK-tal IK-tal S/ P/ R/ S/ -al pertaining to post- after -ict- seizure -al pertaining to Transient neurologic deficit after a seizure Pertaining to, or a condition caused by, a stroke or epilepsy tic TIK French tic Sudden, involuntary, repeated contraction of muscles tonic tonic-clonic seizure TON-ik TON-ik-KLON-ik SEE-zhur S/ R/ R/ S/ R/ -ic pertaining to ton- pressure, tension clon- tumult -ure process seiz- to grab State of muscular contraction The body alternates between excessive muscular rigidity (tonic) and jerking muscular contractions (clonic) Tourette syndrome tur-ET SIN-drome Gilles de la Tourette, French neurologist, 1857-1904 Disorder of multiple motor and vocal tics Cerebrovascular Accidents (CVAs) or Strokes (LO 10.3 and 10.5) A stroke (also known as a cerebrovascular accident or CVA) occurs when the blood supply to a part of the brain is suddenly interrupted, depriving the brain cells of oxygen. Some cells die; others are badly damaged. With timely treatment, the damaged cells can be saved. There are two types of stroke: Ischemic strokes account for 90% of all strokes and are caused by: Atherosclerosis: Plaque in the wall of a cerebral artery (Figure 10.11a); or ◀ FIGURE 10.11 Causes of Ischemic Strokes. (a) Atherosclerosis in a cerebral artery, leaving a small, residual lumen. (b) Embolus blocking an artery. Healthy tissue is on the left (pink) and blood-starved tissue is on the right (blue). Embolism: A blood clot in a cerebral artery originating from elsewhere in the body (Figure 10.11b). Treatment of ischemic strokes is by thrombolysis together with clot busters like tissue plasminogen activator (tPA). This must occur within 3½ hours of the stroke, using supportive measures followed by rehabilitation. Hemorrhagic strokes (intracranial hemorrhage) occur when a blood vessel in the brain bursts or when a cerebral aneurysm ruptures. Cerebral arteriography can determine the site of bleeding in hemorrhagic stroke. A surgical procedure can be performed to stop the bleed or clip off the aneurysm. Transient Ischemic Attack (TIA) (LO 10.3 and 10.5) Transient ischemic attacks (TIAs) are small, short-term strokes with symptoms lasting for less than 24 hours. If neurologic symptoms persist for more than 24 hours, the condition is a full-blown stroke with brain cell damage and death. The most frequent cause of TIAs is a small embolus that occludes (blocks) a small artery in the brain. Often, the embolus arises from a clot in the atrium in atrial fibrillation or from an atherosclerotic plaque in a carotid artery. Treatment is directed at the underlying cause. A carotid endarterectomy may be necessary if a carotid artery is significantly blocked with plaque. Other Brain Disorders (LO 10.3 and 10.5) Parkinson disease is caused by the degeneration of neurons in the basal ganglia that produce a neurotransmitter called dopamine. Motor symptoms of abnormal movements, tremor of the hands, rigidity, a shuffling gait, and weak voice appear, and gradually become more and more severe. There is no cure. Creutzfeld-Jakob disease (CJD) produces a rapid deterioration of mental function, with difficulty in muscle movement coordination. Some cases are linked to the consumption of beef from cattle with mad cow disease (bovine spongiform encephalopathy, BSE). Syncope (fainting or passing out) is a temporary loss of consciousness and posture. It is usually due to hypotension and the associated deficient oxygen supply (hypoxia) to the brain. Keynotes Risk factors for ischemic strokes are hypertension, diabetes mellitus, high cholesterol levels, cigarettes, and obesity. Risk factors for hemorrhagic strokes are hypertension, cerebral arteriovenous malformations, and cerebral aneurysms. One-third of people with TIAs have subsequent TIAs, and one-third have a subsequent full-blown stroke. Abbreviations ASD autism spectrum disorder BSE bovine spongiform encephalopathy CJD Creutzfeldt-Jakob disease CVA cerebrovascular accident TIA transient ischemic attack tPA tissue plasminogen activator Migraine produces an intense throbbing, pulsating pain in one area of the head, often with nausea and vomiting. It can be preceded by an aura, visual disturbances like flashing lights, or temporary loss of vision. Prevention is difficult. Encephalitis, an inflammation of the parenchyma (tissue) of the brain, is often caused by a virus such as HIV, West Nile virus, herpes simplex, or childhood measles, mumps, chickenpox, and rubella. Brain abscess is usually a direct spread of infection from sinusitis, otitis media (middle ear infection), or mastoiditis (an infection in the skull bone behind the ear). It can also result from blood-borne pathogens arising from lung or dental infections. Brain tumors are often secondary tumors that have metastasized from cancers in the lung, breast, skin, or kidney. Primary brain tumors arise from any of the glial cells and are called gliomas. In Case Report 10.1, Ms. Gaston has a glioma. Autism spectrum disorder (ASD) is a range of complex developmental disorders characterized by communication difficulties, impaired social interactions, and rigid or repetitive patterns of behavior. It is estimated that more than 1% of children aged eight will have an ASD, and it is four times as likely to occur in males than females. It occurs in all ethnic and socioeconomic groups. Twenty to 30% of children with an ASD develop epilepsy before reaching adulthood. Treatment is with highly structured educational and behavioral interventions. Medications can be used to treat autism-related symptoms, such as depression and seizures. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION aneurysm AN-yur-izm Greek dilation Small, circumscribed dilation of an artery or cardiac chamber arteriography ar-teer-ee-OG-rah-fee S/ R/CF -graphy recording arteri/o- artery X-ray visualization of an artery after injection of contrast material autism autistic AWE-tizm awe-TIS-tik S/ R/ Greek self -tic pertaining to autis- autism A disorder with severely abnormal social and communication skills Pertaining to autism bovine spongiform encephalopathy (BSE) BO-vine SPON-jee-form en-sef-ah-LOP-ah-thee S/ R/ S/ R/CF S/ R/CF -ine pertaining to bov- cattle -form appearance of spong/i- sponge -pathy disease encephal/o- head Disease of cattle ("mad cow disease") that can be transmitted to humans, causing Creutzfeldt-Jakob disease carotid endarterectomy kah-ROT-id END-ar-ter-EK-toe-me S/ P/ R/ carotid, Greek large neck artery -ectomy surgical excision end- inside -arter- artery Surgical removal of diseased lining from the carotid artery to leave a smooth lining and restore blood flow Creutzfeldt-Jakob disease (CJD) KROITS-felt YAK-op DIZ-eez Hans Creutzfeldt, 1885-1964, and Alfons Jakob, 1884-1931, German psychiatrists Progressive, incurable, neurologic disease caused by infectious prions encephalitis en-SEF-ah-LIE-tis S/ R/ -itis inflammation encephal- brain Inflammation of brain cells and tissues migraine MY-grain P/ R/ mi- derived from hemi, half -graine head pain Paroxysmal severe headache confined to one side of the head Parkinson disease PAR-kin-son diz-EEZ James Parkinson, British physician, 1755-1824 Disease of muscular rigidity, tremors, and a masklike facial expression prion PREE-on Latin protein Small, infectious protein particle syncope SIN-koh-pee Greek cutting short Temporary loss of consciousness and postural tone due to diminished cerebral blood flow tremor TREM-or Latin to shake Small, shaking, involuntary, repetitive movements of hands, extremities, neck, or jaw Traumatic Brain Injury (TBI) (LO 10.3 and 10.5) Traumatic brain injury (TBI) results from any one of many types of injuries to the head, from a bad fall on a hard surface to a car accident to war injuries. Every year, physicians treat over 1 million patients who have experienced TBI; as many as 10% of these have long-term damage affecting their normal activities of daily living (ADLs). Imagine driving your car along the highway at 50 miles per hour. Suddenly, you are hit head-on by another driver. Your brain goes from 50 miles per hour to zero—instantly. Your soft brain is propelled forward and squished against the front of your hard skull (coup). Next, you rebound backward, and your brain slams against the back of your skull (contrecoup). Your brain now has at least one bruise or contusion, if not worse damage. A mild head injury (concussion) may leave you feeling dazed, confused, or unable to recall the event that caused your concussion. Repeated concussions, like those experienced by famous boxer Muhammad Ali, have a cumulative effect, leading to a reduced mental ability and reaction time, and/or trauma-induced Parkinson's disease. A severe injury may include torn blood vessels that bleed into the brain. The brain may also tear, or swell within the hard, inflexible skull, cutting off important signals and connections. Shaken baby syndrome (SBS) is a type of TBI produced when a baby is violently shaken. A baby has weak neck muscles and a heavy head. Shaking makes the brain bounce back and forth in the skull, leading to severe brain damage. Posttraumatic stress disorder is discussed later in this chapter, in Lesson 10.5 Mental Health. Disorders of the Meninges (LO 10.5) Meningitis is an inflammation of the membranes (meninges) covering the brain and spinal cord. Viral meningitis—the most common form—can occur at any age. Bacterial meningitis predominantly affects the very young or very old. Meningococcal meningitis is contagious, transmitted through a simple cough or sneeze. It is most commonly passed among people who live in close quarters—such as students in college dormitories. Vaccines are available to prevent most types of meningitis. A subdural hematoma is bleeding into the subdural space below the dura mater, which is frequently associated with closed-head injuries and bleeding from broken veins caused by violent head rotations. An epidural hematoma is a pooling of blood in the epidural space between the skull and the dura mater, often associated with a fractured skull and bleeding from an artery within the meninges. Disorders of the Cranial Nerves (LO 10.5) Bell palsy is a facial nerve (vii) disorder characterized by a sudden weakness or paralysis of muscles on one side of the face. The inability to smile or whistle, the uncontrollable drooping of the mouth and drooling of saliva, and an inability to close the eye (Figure 10.12) are common symptoms. The use of steroids in the early stages can prevent the paralysis from becoming permanent. Trigeminal neuralgia (TN), tic douloureux, is an extremely painful chronic disorder of the trigeminal (v) cranial nerve caused by nerve injury or compression of the nerve by a blood vessel. The facial pain can be constant or sporadic and is very intense. The anticonvulsant carbamazepine (Tegretol) is the first-line treatment, and opiates can be prescribed for pain. The evidence for a good result from surgical treatment is poor. An acoustic neuroma is a benign, slow-growing tumor on the vestibulocochlear (viii) nerve that causes hearing loss, tinnitus, and dizziness. Treatment is with surgery and/or radiation. Pain Management (LO 10.5) It's estimated that more than 6 million Americans are affected by the acute or chronic pain of fibromyalgia, 5 million are disabled by back pain, and 40 million suffer from recurrent headaches. Interventional procedures (such as nerve blocks or trigger point injections) can target the tissue or the organ causing pain, and physical medicine and rehabilitation (physiatry) can use physical techniques such as heat, electrotherapy, therapeutic exercises, and biofeedback techniques. Pain management practitioners include anesthesiologists, physiatrists, physiotherapists, occupational therapists, and chiropractors. Medications prescribed based on the severity of the pain include: Analgesics (such as acetaminophen) and nonsteroidal anti-inflammatory drugs (NSAIDs) for mild pain; Opiates (codeine, hydrocodone, and oxycodone) in combination with analgesics for moderate pain; and Higher doses of opiates for severe pain. These are often used on their own, and include morphine and fentanyl. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION acoustic ah-KYU-stik Greek hearing Pertaining to hearing analgesia analgesic (adj) an-al-JEE-zee-ah an-al-JEE-zik S/ P/ R/ S/ -ia condition an- without -alges- sensation of pain -ic pertaining to State in which pain is reduced Substance that produces analgesia Bell palsy BELL PAWL-zee Charles Bell, Scottish -surgeon, 1774-1842 Paresis, or paralysis, of one side of the face concussion kon-KUSH-un S/ R/ -ion action, condition concuss- shake or jar violently Mild brain injury contrecoup KON-treh-koo French counterblow Injury to the brain at a point directly opposite the point of contact contusion kon-TOO-zhun S/ R/ -ion action, condition contus- bruise Hemorrhage into a tissue (bruising), including the brain coup KOO French a blow Injury to the brain directly under the skull at the point of contact fibromyalgia fie-broh-my-AL-jee-ah S/ R/CF R/ -algia pain fibr/o- fiber -my- muscle Pain in the muscle fibers meningococcal meh-nin-goh-KOK-al S/ R/CF R/ -al pertaining to mening/o- meninges -cocc- round bacterium Pertaining to the meningococcus bacterium neuroma nyu-ROH-mah S/ R/ -oma tumor neur- nerve Any tumor arising from cells in the nervous system subdural space sub-DYU-ral SPASE S/ P/ R/ -al pertaining to sub- below -dur- dura, hard Space between the arachnoid and dura mater layers of the meninges trauma traumatic TRAW-mah traw-MAT-ik S/ R/ Greek wound -tic pertaining to trauma- injury A physical or mental injury Pertaining to or caused by trauma trigeminal neuralgia try-GEM-in-al nyu-RAL-jee-ah S/ P/ R/ S/ R/ -al pertaining to tri- three -gemin- double -algia pain neur- nerve Fifth (v) cranial nerve with three branches supplying the face Trigeminal neuralgia; painful facial muscles supplied by the trigeminal nerve tic douloureux TIK duh-luh-RUE douloureux French painful tic Synonym for trigeminal neuralgia

Disorders of the Spinal Cord and Peripheral Nerves

Disorders of the Myelin Sheath of Nerve Fibers (LO 10.5) When the myelin sheath surrounding nerve fibers is damaged, nerves do not conduct impulses normally. In newborns, many of their nerves have immature myelin sheaths, which is why some of their movements are jerky and uncoordinated. Demyelination, the destruction of an area of the myelin sheath, can occur in the PNS and be caused by inflammation, vitamin B12 deficiency, poisons, and some medications. Multiple sclerosis (MS), a chronic, progressive disorder, is the most common condition in which demyelination of nerve fibers in the brain, spinal cord, and optic nerves can occur (Figure 10.13). Intermittent myelin damage and scarring slow nerve impulses. This leads to muscle weakness, pain, abnormal sensations (paresthesias), numbness, and vision loss. Because different nerve fibers are affected at different times, MS symptoms often worsen (exacerbations) or show partial or complete reduction (remissions). Suzanne Kalish is now in an exacerbation. ▲ FIGURE 10.13 Multiple Sclerosis of the Spinal Cord. Areas of demyelination are arrowed and shown in red. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION demyelination dee-MY-eh-lin-A-shun S/ P/ R/ -ation process de- without -myelin- myelin Process of losing the myelin sheath of a nerve fiber exacerbation (contrast remission) ek-zas-er-BAY-shun S/ R/ -ation process exacerbat- increase, aggravate Period when there is an increase in the severity of a disease intermittent IN-ter-MIT-ent S/ P/ R/ -ent end result inter- between -mitt- send Alternately ceasing and beginning again modify MOD-ih-fie Latin to limit Change the form or qualities of something; here, the pathology of MS paresthesia paresthesias (pl) (Note: the "a" following the "r" in para is dropped for ease of pronunciation.) par-es-THEE-ze-ah S/ P/ R/ -ia condition par(a)- abnormal -esthes- sensation Abnormal sensation; e.g., tingling, burning, pricking remission (contrast exacerbation) ree-MISH-un S/ P/ R/ -ion condition, action re- back -miss- send Period when there is a lessening or absence of the symptoms of a disease sclerosis skleh-ROH-sis S/ R/CF -sis abnormal condition scler/o- hardness Thickening and hardening of a tissue; in the nervous system, hardening of nervous tissue by fibrous and glial connective tissue Disorders of the Spinal Cord (LO 10.5) Trauma (LO 10.5) The spinal cord can be injured in three ways: Severed, by a fractured vertebra (Figure 10.14a); ▼ FIGURE 10.14 Spinal Cord Injuries. (a) Severed spinal cord from fracture-dislocation of vertebra. (b) Compressed spinal cord with vertebral fracture. Contused, as in a sudden, violent jolt to the spine; and Compressed, by a dislocated vertebra, bleeding, or swelling (Figure 10.14b). Because of its anatomy—with nerve fibers and tracts going up and down, to and from the brain—a spinal cord injury results in a loss of function below the injury site. For example, if the cord is injured in the thoracic region, the arms function normally but the legs can be paralyzed. Both muscle control and sensation are lost. Paresis is partial paralysis. If the spinal cord is severed, the loss of function is permanent. Contusions can cause temporary loss, lasting days, weeks, or months. Compression of the cord can also occur from a tumor in the cord or spine or from a herniated disc. The intervertebral disc (see Lesson 4.2 of Chapter 4) can move out of place (herniate, slip) or break open (rupture) from injury or strain. This causes pressure on the spinal nerves leading to pain, numbness, and/or weakness. Cancer or osteoporosis can cause a vertebra to collapse and also compress the cord. Other Disorders of the Spinal Cord (LO 10.5) Acute transverse myelitis is a localized spinal cord disorder that blocks the transmission of impulses up and down the spinal cord. Subacute combined degeneration of the spinal cord is due to a deficiency of vitamin B12. The spinal cord's sensory nerve fibers degenerate, producing weakness, clumsiness, tingling, and a sensory loss as to the position of the limbs. Treatment involves vitamin B12 injections. In syringomyelia, fluid-filled cavities form in the spinal cord and compress nerves that detect pain and temperature. There is no specific cure. Poliomyelitis (POLIO) is an acute infectious disease, occurring mostly in children, due to the poliovirus. The virus destroys motor neurons. It is preventable by vaccination and has almost been eradicated worldwide. Postpolio syndrome (PPS) is when people develop tired, painful, and weak muscles many years after recovery from polio. Amyotrophic lateral sclerosis (ALS), or "Lou Gehrig's disease," occurs when motor nerves in the spinal cord progressively deteriorate. There is no cure. Disorders of Peripheral Nerves (LO 10.5) Peripheral neuropathy is used here as any disorder affecting one or more peripheral nerves. Mononeuropathy is damage to a single peripheral nerve. Examples are: Carpal tunnel syndrome, in which the median nerve at the wrist is compressed between the wrist bones and a strong overlying ligament. Ulnar nerve palsy, which results from nerve damage as the forearm's ulnar nerve crosses close to the surface over the humerus at the back of the elbow. Peroneal nerve palsy, which arises from nerve damage as the peroneal or lower leg bone nerve passes close to the surface near the back of the knee. Compression of this nerve occurs in people who are bedridden or strapped in a wheelchair. Polyneuropathy is damage to, and the simultaneous malfunction of, many motor and/or sensory peripheral nerves throughout the body. There are many causes of peripheral polyneuropathy; diabetes is a common cause. Symptoms include numbness, pain, tingling sensations, and weakness. Treatment is aimed at the underlying problem and pain reduction. Herpes zoster, or shingles, is an infection of peripheral nerves arising from a reactivation of the dormant childhood chickenpox (varicella) virus. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION amyotrophic a-my-oh-TROH-fik S/ P/ R/CF R/ -ic pertaining to a- without -my/o- muscle -troph- nourishment, development Pertaining to muscular atrophy compression kom-PRESH-un S/ P/ R/ -ion action, condition com- together -press- squeeze Squeeze together to increase density and/or decrease a dimension of a structure herniation hernia (noun) herniate (verb) her-nee-AY-shun HER-nee-ah HER-nee-ate S/ R/ S/ -ation process herni- rupture -ate composed of Protrusion of an anatomical structure from its normal location Protrusion of a structure through the tissue that normally contains it myelitis MY-eh-LIE-tis S/ R/ -itis inflammation myel- spinal cord Inflammation of the spinal cord neuropathy mononeuropathy polyneuropathy nyu-ROP-ah-thee MON-oh-nyu-ROP-ah-thee POL-ee-nyu-ROP-ah-thee S/ R/CF P/ P/ -pathy disease neur/o- nerve mono- one poly- many Any disorder of the nervous system Disorder affecting a single nerve Disorder affecting many nerves paralyze (verb) paralysis (noun) paralytic (adj) PAR-ah-lyze pah-RAL-ih-sis par-ah-LYT-ik P/ R/ R/ S/ R/ para- beside, abnormal -lyze destroy -lysis destruction -ic pertaining to -lyt- destroy To make incapable of movement Loss of voluntary movement Suffering from paralysis paresis hemiparesis par-EE-sis HEM-ee-pah-REE-sis P/ R/ Greek weakness hemi- half -paresis weakness Partial paralysis (weakness) Weakness of one side of the body poliomyelitis (Note: abbreviated as polio) postpolio syndrome (PPS) POE-lee-oh-MY-eh-lie-tis post-POE-lee-oh SIN-drome S/ R/ R/ P/ R/ P/ R/ -itis inflammation polio- gray matter -myel- spinal cord post- after -polio gray matter syn- together -drome running Inflammation of the gray matter of the spinal cord, leading to paralysis of the limbs and muscles of respiration Progressive muscle weakness in a person previously affected by polio syringomyelia sih-RING-oh-my-EE-lee-ah S R/CF R/ -ia condition syring/o- tube, pipe -myel- spinal cord Abnormal longitudinal cavities in the spinal cord that cause paresthesias and muscle weakness trauma traumatic TRAW-mah traw-MAT-ik S/ R/ Greek wound -tic pertaining to trauma- injury A physical or mental injury Pertaining to or caused by trauma Some of the most devastating congenital neurologic abnormalities develop in the first 8 to 10 weeks of pregnancy, when the nervous system is in its early stages of formation. These malformations can be detected using ultrasonography and amniocentesis (see Chapter 15). Many of these can be prevented by the mother taking 4 mg/day of folic acid before conception and during early pregnancy. A teratogen is an agent that can cause anomalies of an embryo or fetus (see Chapter 15). It can be a chemical, a virus, or radiation. Some teratogens found in the workplace include textile dyes, photographic chemicals, semiconductor materials, and the metals lead, mercury, and cadmium. Anencephaly is the absence of the cerebral hemispheres and is incompatible with life. Microcephaly, decreased head size, is associated with small cerebral hemispheres and moderate to severe motor and mental retardation. Hydrocephalus (Figure 10.15) is ventricular enlargement in the cerebral hemispheres with excessive CSF; it is usually due to a blockage that prevents the CSF from exiting the ventricles to circulate around the spinal cord. Treatment involves placing a tube (shunt) into the ventricle to divert the excess fluid into the abdominal cavity or a neck vein. ▲ FIGURE 10.15 Infant with Hydrocephalus. Spina bifida (neural tube defect) occurs mostly in the lumbar and sacral regions. It is variable in its presentation and symptoms. Spina bifida occulta has a small partial defect in the vertebral arch. The spinal cord or meninges do not protrude. Often the only sign is a tuft of hair on the skin overlying the defect. Abbreviations CP cerebral palsy FAS fetal alcohol syndrome In spina bifida cystica there is no vertebral arch formed. The spinal cord and meninges protrude through the opening and may or may not be covered with a thin layer of skin (Figure 10.16a and b). Protrusion of only the meninges is called a meningocele. Protrusion of the meninges and spinal cord is called a meningomyelocele (myelomeningomyelocele). The lower limbs may be paralyzed. ▲ FIGURE 10.16 Spina Bifida Cystica. (a) Cross section of a spinal meningocele. (b) Child with spina bifida cystica. Fetal alcohol syndrome (FAS) can occur when a pregnant woman drinks alcohol. A child born with FAS has a small head, narrow eyes, and a flat face and nose. Intellect and growth are impaired. FAS is the third most common cause of mental retardation in newborns. Cerebral Palsy (LO 10.5) Cerebral palsy (CP) is the term used to describe the motor impairment resulting from brain damage in an infant or young child. It is not hereditary. In congenital CP, the cause is often unknown but can be a brain malformation or maternal use of cocaine. CP developed at birth or in the neonatal period is usually related to an incident causing hypoxia of the brain. Cerebral palsy causes delay in the development of normal milestones in infancy and childhood. The affected limbs can be spastic (muscles are tight and resistant to stretch) and may show athetoid movements, where the limbs involuntarily writhe and constantly move. A poor sense of balance and coordination may also be present, leading to ataxia. A rehabilitation program focused on function is the key component in treatment of cerebral palsy. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION anencephaly microcephaly AN-en-SEF-ah-lee MY-kroh-SEF-ah-lee S/ P/ R/ P/ R/ -aly condition an- without -enceph- brain micro- small -ceph- head Born without cerebral hemispheres An abnormally small head ataxia ataxic (adj) a-TAK-see-ah a-TAK-sik S/ P/ R/ S/ -ia condition a- without -tax- coordination -ic pertaining to Inability to coordinate muscle activity, leading to jerky movements Pertaining to or suffering from ataxia athetosis athetoid (adj) ath-eh-TOE-sis ATH-eh-toyd S/ R/ S/ -osis condition athet- without position, uncontrolled -oid resembling Slow, writhing involuntary movements Resembling or suffering from athetosis hemiplegia hemiplegic (adj) hemiparesis hem-ee-PLEE-jee-ah hem-ee-PLEE-jik HEM-ee-pah-REE-sis S/ P/ R/ S/ R/ -ia condition hemi- half -pleg- paralysis -ic pertaining to -paresis weakness Paralysis of one side of the body Pertaining to or suffering from hemiplegia Weakness of one side of the body meningocele meningomyelocele meh-NIN-goh-seal meh-nin-goh-MY-el-oh-seal S/ R/CF S/ R/CF -cele hernia mening/o- meninges -cele hernia -myel/o- spinal cord Protrusion of the meninges from the spinal cord or brain through a defect in the vertebral column or cranium Protrusion of the spinal cord and meninges through a defect in the vertebral arch of one or more vertebrae monoplegia monoplegic (adj) MON-oh-PLEE-jee-ah MON-oh-PLEE-jik S/ P/ R/ S/ -ia condition mono- one -pleg- paralysis -ic pertaining to Paralysis of one limb Pertaining to or suffering from monoplegia palsy PAWL-zee Latin paralysis Paralysis or paresis from brain damage paraplegia paraplegic (adj) par-ah-PLEE-jee-ah par-ah-PLEE-jik S/ P/ R/ S/ -ia condition para- abnormal -pleg- paralysis -ic pertaining to Paralysis of both lower extremities Pertaining to or suffering from paraplegia quadriplegia quadriplegic (adj) kwad-rih-PLEE-jee-ah kwad-rih-PLEE-jik S/ P/ R/ S/ -ia condition quadri- four -pleg- paralysis -ic pertaining to Paralysis of all four limbs Pertaining to or suffering from quadriplegia spina bifida spina bifida cystica spina bifida occulta SPY-nah BIH-fih-dah SIS-tik-ah OH-kul-tah R/CF P/ R/ S/ R/ R/CF spin/a spine bi- two -fida split -ica pertaining to cyst- cyst occult/a hidden Failure of one or more vertebral arches to close during fetal development Meninges and spinal cord protruding through the absent vertebral arch and having the appearance of a cyst The deformity of the vertebral arch is not apparent from the surface teratogen TER-ah-toe-gen S/ R/CF -gen create, produce terat/o- monster, malformed fetus Agent that produces fetal deformities Lumbar puncture (LP or spinal tap) enables laboratory examination of the CSF to be made and helps diagnose meningitis, damage to the spinal cord, and brain hemorrhage. Electroencephalography (EEG) records the brain's electrical activity to help identify epilepsy, sleep disturbances, degenerative brain disease, and brain damage (Figure 10.17). ▲ FIGURE 10.17 Four Classes of Brain Waves on EEG. Computed tomography (CT scan) generates images of slices of the brain to detect tumors, tissue damage, and birth defects. Magnetic resonance imaging (MRI) produces highly detailed anatomical images of most neurologic disorders (Figure 10.18). ▲ FIGURE 10.18 MRI Scans of Brain Sections. (a) Colored MRI scan of a Section of Normal Brain. (b) Colored MRI Scan of Brain Section showing Cerebral Atrophy (in yellow) in a Patient with Alzheimer Disease. Cerebral angiography involves an injection of radiopaque dye into the blood vessels of the neck and brain to detect partial or complete blockages of blood vessels and aneurysms. Color Doppler ultrasonography uses high-frequency sound (ultrasound) waves to evaluate the rates of blood flow through arteries of the neck or base of the brain. Positron emission tomography (PET scan) involves attaching radioactive molecules to glucose to look at brain function (Figure 10.19). ▲ FIGURE 10.19 PET Scan of the Brain Showing the Motor Cortex. Evoked responses are a procedure in which stimuli for vision, sound, and touch are used to activate areas of the brain, and their responses are measured with EEG or PET scans. They are used to give information about how a specific area of the brain is functioning. Electromyography involves placing small needles into a muscle to record its electrical activity at rest and during contraction. Nerve conduction studies measure the speed at which sensory and motor nerves conduct impulses to focus on the function of peripheral nerves. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION angiography an-jee-OG-rah-fee S/ R/CF -graphy process of recording angi/o- blood vessel X-ray visualization of blood vessels after injection of contrast material electromyography ee-LEK-troh-my-OG-rah-fee S/ R/CF R/CF -graphy process of recording electr/o- electricity -my/o- muscle Recording of electrical activity in muscle neuromuscular NYUR-oh-MUSS-kyu-lar S/ R/CF R/ -ar pertaining to neur/o- nerve -muscul- muscle Pertaining to both nerves and muscles ultrasonography UL-trah-son-NOG-rah-fee S/ P/ R/CF -graphy process of recording ultra- beyond -son/o- sound Imaging using ultrasound that detects direction, velocity, and turbulence of blood flow

Mental Health

Mental Health Definitions (LO 10.7 and 10.8) Mental health is defined by the World Health Organization (WHO) as "a state of wellbeing in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to the community." Psychology is the scientific study of behavior—talking, reading, sleeping, interacting with others—and mental processes—thinking, feeling, remembering, and dreaming. Psychiatry is the medical specialty concerned with the origin, diagnosis, prevention, and treatment of mental, emotional, and behavioral disorders. Mental health disorders are of different types and will be considered in this chapter under the headings Psychosis and Schizophrenia, Mood Disorders, Anxiety Disorders, Personality Disorders, and Substance Abuse and Chemical Dependence. Psychosis and Schizophrenia (LO 10.7) Psychosis is an abnormal mental state in which the individual has a loss of contact with reality. People suffering from psychosis are described as psychotic. Schizophrenia is a form of psychosis in which the individual loses contact with reality. People with schizophrenia do not have a "split personality," but their perceptions are separated from reality, their words are separated from their meanings, and their behaviors are separated from their thought processes. They perceive things without stimulation (hallucinations). They suffer from mistaken beliefs that are contrary to facts (delusions). The delusions can be paranoid, with pervasive distrust and suspicion of others. Their speech is disorganized and can be incoherent, and they may refuse or be unable to speak (mute) (Figure 10.20). In the Case Report above, Mr. Costello showed all of these symptoms. ◀ FIGURE 10.20 Homeless Schizophrenic Man on the Street. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION affect AFF-ekt Latin state of mind External display of feelings, emotions, and thoughts congruent KON-gru-ent S/ P/ R/ -ent end result con- with -gru- to move Coinciding or agreeing with delusion dee-LOO-zhun S/ R/ -ion condition delus- deceive Fixed, unyielding false belief despite strong evidence to the contrary hallucination hah-loo-sih-NAY-shun S/ R/ -ation condition hallucin- imagination Perception of an object or event when there is no such thing present mute MYUT Latin silent Unable or unwilling to speak paranoia paranoid par-ah-NOY-ah PAR-ah-noyd P/ R/ S/ para- abnormal -noia to think -oid resembling Presence of persecutory delusions Having persecutory delusions psychiatry psychiatrist sigh-KIGH-ah-tree sigh-KIGH-ah-trist S/ R/ S/ iatry- treatment psych- mind -iatrist one who treats Diagnosis and treatment of mental disorders Licensed medical specialist in psychiatry psychology psychologist sigh-KOL-oh-jee sigh-KOL-oh-jist S/ R/CF S/ -logy study of psych/o- mind -logist one who treats Science concerned with the behavior of the human mind Licensed specialist in psychology psychosis psychotic sigh-KOH-sis sigh-KOT-ik S/ R/ S/ R/CF -osis condition psych- mind -tic pertaining to psych/o- mind Disorder with loss of contact with reality Affected by psychosis schizophrenia schizophrenic skitz-oh-FREE-nee-ah skitz-oh-FREN-ik S/ R/CF R/ S/ -ia condition schiz/o- to split -phren- mind -ic pertaining to Disorder of perception and behavior with loss of reality Suffering from schizophrenia suicide suicidal SOO-ih-side SOO-ih-SIGH-dal R/CF R/CF S/ su/i- self -cid/e kill -al pertaining to The act of killing oneself Wanting to kill oneself Major depression, also called unipolar disorder (Figure 10.21), occurs when a person is deeply sad, despairing, and hopeless for at least two weeks; sees nothing but sorrow and despair in the future; and may not want to live anymore. Moderate exercise has been shown to reduce the symptoms of depression by 47%, and medication will ease the symptoms (see later). Electroconvulsive therapy (ECT) is used in severe depression that has not responded to other treatment. ▲ FIGURE 10.21 Depressed Woman at a Window. Bipolar disorder, which used to be called manic-depressive disorder, is the alternation of major episodes of depression with periods of excessive overexcitement, impulsive behavior, insomnia, and lack of fatigue, called mania. Untreated mixed (manic and depressive) episodes usually last around four to five months. Dysphoric mania combines the frenetic energy of mania with dark thoughts and paranoid delusions. It may be the cause of some mass shootings. Seasonal affective disorder (SAD) has episodes of depression that occur in the fall and winter months. It appears to be related to a lack of sunshine causing increased melatonin production by the pineal gland (see Chapter 12). It can be helped by phototherapy with bright white fluorescent lights and by antidepressant medications. Anxiety Disorders (LO 10.2, 10.3, and 10.7) Anxiety disorders are the most common category of mental disorder found in the United States. They are characterized by an unreasonable anxiety and fear so intense and persistent that it disrupts the person's life. There are five categories of anxiety disorders: Generalized anxiety disorder (GAD) consists of uncontrollable anxiety not focused on one situation or event that has lasted for six months or more. People with the disorder develop physical fear reactions, including palpitations, insomnia, difficulty concentrating, and irritability. Posttraumatic stress disorder (PTSD) affects about 7.7 million American adults. It arises after significant trauma, such as a life-threatening incident, loss of a loved one, abuse, torture or combat in war, or a high level of stress in daily life (Figure 10.22). Symptoms include flashbacks of the traumatic event, nightmares, intense physical reactions to reminders of the event, feeling emotionally numb, irritability, outbursts of anger, and difficulty concentrating. Alcohol and drug abuse are common. Treatment is with cognitive behavioral therapy (CBT), in which the traumatic experiences are relived and worked through; cognitive processing therapy (CPT), in which the thoughts and beliefs generated by the trauma are explored and reframed; and antidepressants. ▲ FIGURE 10.22 The remains of an American Humvee, one of four that were disabled by massive IEDs, lies on a dirt road on August 4, 2007, in Hawr Rajab, Iraq. Panic disorder is characterized by sudden, brief attacks of intense fear that cause physical symptoms, occur often for no reason, and peak in 10 minutes or less. Treatment is with CBT and medication with benzodiazepines or selective serotonin reuptake inhibitors (SSRI) (see later in this lesson). Phobias differ from panic attacks in that a specific situation or event brings on the strong fear response. There are two categories of phobias: Situational phobias involve a fear of specific situations. Examples are acrophobia (fear of heights), agoraphobia (fear of crowded places), and claustrophobia (fear of confined spaces). Social phobias involve a fear of being embarrassed in social situations. The most common are fear of public speaking and fear of eating in public. In obsessive-compulsive disorder (OCD), most patients have both obsessions and compulsions. Obsessions are recurrent thoughts, fears, doubts, images, or impulses. Compulsions are recurrent, irresistible impulses to perform actions such as counting, hand washing, checking, and systematically arranging things. Treatment is with CBT and/or an SSRI. Psychosomatic disorder is a real physical illness in which anxiety and stress play a causative role. Examples are tension headaches and low back pain. Treatment is with biofeedback and relaxation techniques (Figure 10.23). ▲ FIGURE 10.23 Person Undergoing Biofeedback. A person called a hypochondriac has hypochondriasis and interprets some minor symptom such as a cough or a bruise as a sign of serious disease, and cannot believe normal physical examinations and reassurances. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION acrophobia ak-roh-FOH-be-ah S/ R/CF -phobia fear acr/o- peak, highest point Pathologic fear of heights agoraphobia ah-gor-ah-FOH-be-ah S/ R/CF -phobia fear agor/a- marketplace Pathologic fear of being trapped in a public place anxiety ang-ZI-eh-tee Greek distress, anxiety Distress caused by fear biofeedback (Note: This term has no prefix or suffix.) bi-oh-FEED-back R/CF R/ R/ bi/o- life -feed- to give food, nourish -back back, return Training techniques to achieve voluntary control of responses to stimuli bipolar disorder bi-POH-lar dis-OR-der S/ P/ R/ -ar pertaining to bi- two -pol- pole A mood disorder with alternating episodes of depression and mania claustrophobia cognitive klaw-stroh-FOH-be-ah KOG-nih-tiv S/ R/CF S/ R/ -phobia fear claustr/o- confined space -ive quality of cognit- thinking Pathologic fear of being trapped in a confined space Pertaining to the mental activities of thinking and learning cognitive behavioral therapy (CBT) (Note: Behavioral has two suffixes to make the word flow.) KOG-nih-tiv be-HAYV-yur-al THAIR-ah-pee S/ R/ S/ S/ R/ R/ -ive quality of cognit- thinking -al pertaining to -ior- pertaining to behav- mental activity therapy medical treatment Psychotherapy that emphasizes thoughts and attitudes in one's behavior cognitive processing therapy (CPT) KOG-nih-tiv PROS-es-ing THAIR-ah-pee S/ R/ S/ P/ R/ -ive quality of cognit- thinking -ing doing pro- before -cess- going forward Psychotherapy to build skills to deal with effects of trauma in other areas of life compulsion compulsive (adj) kom-PULL-shun kom-PULL-siv S/ R/ S/ -ion action, condition compuls- drive, compel -ive nature of, quality of Uncontrollable impulses to perform an act repetitively Possessing uncontrollable impulses to perform an act repetitively depression de-PRESH-un S/ R/ -ion condition, process depress- press down Mental disorder with feelings of deep sadness and despair electroconvulsive therapy ee-LEK-troh-kon-VUL-siv THAIR-ah-pee S/ R/CF P/ R/ -ive quality of electr/o- electricity -con- with -vuls- tear, pull Passage of electric current through the brain to produce convulsions and treat persistent depression, mania, and other disorders hypochondriac hypochondriasis high-poh-KON-dree-ack HIGH-poh-kon-DRY-ah-sis S/ P/ R/ S/ -iac pertaining to hypo- below -chondr- cartilage -iasis condition, state of A person who exaggerates the significance of symptoms Belief that a minor symptom indicates a severe disease insomnia in-SOM-nee-ah S/ P/ R/ -ia condition in- not -somn- sleep Inability to sleep mania manic manic-depressive disorder MAY-nee-ah MAN-ik MAN-ik-de-PRESS-iv dis-OR-der S/ R/ S/ R/ Greek frenzy -ic pertaining to man- mania -ive quality of depress- press down Mood disorder with hyperactivity, irritability, and rapid speech Pertaining to or characterized by mania An outdated name for bipolar disorder obsession obsessive (adj) ob-SESH-un ob-SES-iv S/ R/ S/ -ion action, Condition obsess- besieged by thoughts -ive nature of, quality of Persistent, recurrent, uncontrollable thoughts or impulses Possessing persistent, recurrent, uncontrollable thoughts or impulses phobia FOH-be-ah Greek fear Pathologic fear or dread posttraumatic post-traw-MAT-ik S/ P/ R/ -ic pertaining to post- after -traumat- wound Occurring after and caused by trauma psychosomatic sigh-koh-soh-MAT-ik S/ R/CF R/ -tic pertaining to psych/o- mind -soma- body Pertaining to disorders of the body usually resulting from disturbances of the mind unipolar disorder you-nih-POLE-ar dis-OR-der S/ P/ R/ -ar pertaining to uni- one -pol- pole (at the pole of depression) Depression Personality is defined as an individual's unique and stable patterns of thoughts, feelings, and behaviors. When these patterns become rigid and inflexible in response to different situations, they can cause impairment of the individual's ability to deal with other people (i.e., to function socially). Borderline personality disorder (BPD) is a frequent diagnosis in people who are impulsive, unstable in mood, and manipulative. They can be exciting, charming, and friendly one moment and angry, irritable, and sarcastic the next. Their identity is fragile and insecure, their self-worth low. They can be promiscuous and self-destructive; for example, with self-mutilation (self-injury) (Figure 10.24) or suicide. People with narcissistic personality disorder have an exaggerated sense of self-importance and seek constant attention. ▲ FIGURE 10.24 Self-Mutilated Arm. Antisocial personality disorder, used interchangeably with the terms sociopath and psychopath, describes people who lie, cheat, steal, and have no sense of responsibility and no anxiety or guilt about their behavior. Psychopaths have these characteristics but tend to be more violent and anger easily. Schizoid and paranoid personality disorders describe people who are absorbed with themselves, untrusting, and fearful of closeness with others. Treatment for personality disorders is not successful. Dissociative Disorders (LO 10.3 and 10.7) Dissociative disorders involve a disassociation (splitting apart) of past experiences from present memory or consciousness. The development of distinctly separate personalities is called dissociative identity disorder (DID). It was formerly called multiple personality disorder (MPD). Two or more distinct personalities, each with its own memories and behaviors, inhabit the same person at the same time (Figure 10.25). The basic origin of all these disorders is the need to escape, usually from extreme trauma, and most often from sexual, emotional, or physical abuse in childhood. Treatment is with psychotherapy. ▲ FIGURE 10.25 Dissociative Identity Disorder (Multiple Personality Disorder). Impulse Control Disorders (LO 10.3 and 10.7) Impulse control disorders involve an inability to resist an impulse to perform an action that is harmful to the individual or to others. These disorders include: Kleptomania, which is characterized by stealing—not for gain but to satisfy an irresistible urge to steal. Behavior therapy can help, and SSRIs appear to be of value. Trichotillomania (TTM), which is characterized by the repeated urge to pull out one's own scalp, beard, pubic, and other body hair. Pyromania, which is repeated fire setting with no motive other than a fascination with fire and fire engines. Some pyromaniacs end up as volunteer firefighters. Treatment with behavior therapy is sometimes successful. Substance Abuse and Chemical Dependence (LO 10.3 and 10.7) Substance abuse involves a person's continued use of psychoactive drugs, including alcohol and illicit drugs, despite having significant problems or distress related to their use. This continued use can lead to a dependence syndrome, which includes the strong need to take the drug, persistence in its use despite harmful consequences to the user and others, daily priority given to drug use, and increased tolerance. Tolerance is the process by which the body continually adapts to a substance and requires increasingly larger amounts to achieve the original effects. Addiction includes dependence syndrome, but it refers to not only psychoactive drugs but also such entities as exercise addiction, food addiction, computer addiction, and gambling. The patterns of behavior and habits of use associated with an addiction are characterized by immediate gratification coupled with the long-term harmful effects, which include changes in the structure and function of the brain. Abused substances include tobacco, alcohol, marijuana, cocaine, heroin, methamphetamines, Ecstasy, LSD, and PCP. In addition, prescription drug abuse is increasing dramatically. The three classes of prescription drugs being abused are: Opioids, which include oxycodone (Oxycontin), hydrocodone (Vicodin), meperidine (Demerol), hydromorphone (Dilaudid), and fentanyl (Duragesic and others). CNS depressants such as the benzodiazepines Xanax and Valium. CNS stimulants such as Adderall and Ritalin. Abuse of prescription drugs now ranks second to marijuana among illicit drug users, and the number of fatal poisonings from prescription opioid analgesics outnumbers total deaths from heroin and cocaine. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION addict addiction ADD-ikt ah-DIK-shun P/ R/ S/ ad- toward -dict surrender -ion condition, action Person with a psychologic or physical dependence on a substance or practice Habitual psychologic and physiologic dependence on a substance or practice antisocial personality disorder AN-tee-SOH-shal per-son-AL-ih-tee dis-OR-der S/ P/ R/ S/ S/ R/ -al pertaining to anti- against -soci- partner, ally, community -ity condition, state -al- pertaining to person- person Disorder of people who lie, cheat, steal, and have no guilt about their behavior dissociative identity disorder di-SO-see-ah-tiv eye-DEN-tih-tee dis-OR-der S/ P/ R/ -ative quality of dis- apart, away from -soci- partner, ally, community Mental disorder in which part of an individual's personality is separated from the rest, leading to multiple personalities kleptomania klep-toe-MAY-nee-ah S/ R/CF -mania frenzy klept/o- to steal Uncontrollable need to steal narcissism narcissistic (adj) NAR-sih-sizm NAR-sih-SIS-tik S/ S/ R/ Greek mythical character, Narcissus, who was in love with his own reflection in water -ism a process -istic pertaining to narciss- selflove Self-love; person interprets everything purely in relation to himself or herself Relating everything to oneself pathologic gambling path-oh-LOJ-ik GAM-bling S/ R/CF R/ -ic pertaining to path/o- disease -log- study of Morbid, constant, uncontrollable, destructive gambling psychopath SIGH-koh-path S/ R/CF -path disease psych/o- mind Person with antisocial personality disorder pyromania pie-roh-MAY-nee-ah S/ R/CF -mania frenzy pyr/o- fire Morbid impulse to set fires schizoid SKITZ-oyd S/ R/ -oid resemble schiz- split Withdrawn, socially isolated self-mutilation self-myu-tih-LAY-shun S/ R/ R/ -ation process self- own individual -mutil- to maim Injury or disfigurement made to one's own body sociopath SO-see-oh-path S/ R/CF -path disease soci/o- partner, ally, community Person with antisocial personality disorder PSYCHOACTIVE DRUGS (LO 10.6 AND 10.7) Type/Mode of Action Name Common Effects Effects of Abuse Stimulants ("uppers") Speed up activity in the CNS Caffeine Nicotine Amphetamines Cocaine Wakefulness, shorter reaction time, alertness Varies from alertness to calmness, appetite for carbohydrates decreases Wakefulness, alertness, increased metabolism, decreased appetite Euphoria, high energy, illusions of power Restlessness, insomnia, heartbeat irregularities Heart disease; high blood pressure; vasoconstriction; bronchitis; emphysema; lung, throat, mouth cancer Nervousness, high blood pressure, delusions, psychosis, convulsions, death Excitability, paranoia, anxiety, panic, depression, heart failure, death Depressants ("downers") Slow down activity in the CNS Alcohol Barbiturates and tranquilizers 1-2 drinks—reduced inhibitions and anxiety Many drinks—slow reaction time, poor coordination and memory Reduced anxiety and tension, sedation Blackouts, mental and neurologic impairment, psychosis, cirrhosis of liver, death Impaired motor and sensory functions, amnesia, loss of consciousness, death Narcotics Mimic the actions of natural endorphins Codeine, opium, morphine, heroin Euphoria, pleasure, relief of pain High tolerance of pain, nausea, vomiting, constipation, convulsions, coma, death Psychedelics Disrupt normal thought processes Marijuana LSD, mescaline, MDMA (Ecstasy) Relaxation, euphoria, increased appetite, pain relief Exhilaration, euphoria, hallucinations, insightful experiences Sensory distortion, hallucinations, paranoia, throat and lung damage Panic, extreme delusions, bad trips, paranoia, psychosis Antidepressants Affect the neurotransmitters serotonin, norepinephrine, and dopamine Selective serotonin reuptake inhibitors (SSRIs)—Prozac, Paxil, Zoloft Serotonin and norepinphrine reuptake inhibitors (SNRIs)—Effexor XR, Pristiq, Cymbalta Tricyclic antidepressants (TCAs)—amitriptyline, Tofranil Enhanced mental clarity, improved sleep, diminished depression Diminished depression, pain relief Effective relief of depression but numerous side effects Anxiety, decreased sex drive, insomnia, restlessness, fatigue, headaches Raised blood pressure, liver and kidney failure, fatal outcome with overdose Decreased sex drive and outcomes, difficulty urinating, sedation, weight gain, dry mouth, fatal outcome with overdose Anxiolytics (anti-anxiety) Affect inhibitory neurotransmitters and their synaptic receptors Benzodiazepines—Librium, Valium, Xanax Selective serotonin reuptake inhibitors (SSRIs) (see above) Azaspirones—BuSpar Beta blockers—Inderal, Tenormin (see Chapter 6) Relief of anxiety and panic disorder in the short term with rapid action Used because they are not addictive Effective in mild to moderate anxiety—takes 2-4 weeks to have effect; not addictive Greatly reduce certain anxiety symptoms, such as shaking, palpitations, and sweating Habit forming, addiction tendencies, drowsiness, dizziness, worsen the effects of alcohol Fatigue, nausea, depression, insomnia Overdose leads to unconsciousness Nausea, diarrhea, bronchospasm, bradycardia, insomnia, erectile dysfunction Antiepileptic drugs (AEDs) (anticonvulsants) Do not cure epilepsy, but suppress seizures while medications are in the body Broad-spectrum AEDs—Depakote, Lamictal, Topamax, Keppra Narrow-spectrum AEDs—phenobarbital, Dilantin, Tegretol, Lyrica Effective for a wide range of all types of seizures Effective for specific types of seizures Weight gain, tremor, hair loss, osteoporosis, low blood count, memory problems GI upset, weight gain, blurred vision, low blood counts, fatigue Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION antiepileptic AN-tih-epi-LEP-tik S/ P/ R/ -ic pertaining to anti- against -epilept- seizure An agent to suppress seizures anxiolytic ANG-zee-oh-LIT-ik S/ R/CF -lytic soluble anxi/o anxiety An agent that reduces the symptoms of anxiety dependence dee-PEN-dense Latin to hang from State of needing someone or something depressant antidepressant dee-PRESS-ant AN-tih-dee-PRESS-ant S/ R/ P/ -ant agent depress- press down anti- against Substance that diminishes activity, sensation, or tone An agent to suppress the symptoms of depression endorphin en-DOR-fin P/ R/ end- within -orphin morphine Natural substance in the brain that has the same effect as opium euphoria yoo-FOR-ee-ah S/ P/ R/ -ia condition eu- normal -phor- bear, carry Exaggerated feeling of well-being narcotic nar-KOT-ik S/ R/CF -tic pertaining to narc/o- sleep, stupor Drug derived from opium or a synthetic drug with similar effects psychedelic sigh-keh-DEL-ik S/ R/ R/ -ic pertaining to psyche- mind, soul -del- manifest, visible Agent that intensifies sensory perception psychoactive sigh-koh-AK-tiv S/ R/CF R/ -ive quality of, nature of psych/o- mind, soul -act- performance Able to alter mood, behavior, and/or cognition stimulant STIM-you-lant S/ R/ -ant agent stimul- excite Agent that excites or strengthens functional activity tolerance TOL-er-ans S/ R/ -ance condition, state of toler- endure The capacity to become accustomed to a stimulus or drug tranquilizer TRANG-kwih-lie-zer S/ R/ -izer affect in a particular way tranquil- calm Agent that calms without sedating or depressing

The Brain and Cranial Nerves

The Brain (LO 10.4) Your adult brain weighs about 3 pounds. Its size and weight are proportional to your body size, not your intelligence. Your brain is divided into three major regions: the cerebrum, the brain stem, and the cerebellum. Cerebrum (LO 10.4) The cerebrum makes up about 80% of your brain. It consists of two cerebral hemispheres, which are mirror images of each other. These hemispheres are separated by a deep longitudinal fissure, and at the bottom of this, they are connected by a bridge of nerve fibers (the corpus callosum). On the surface of the cerebrum, numerous ridges, gyri, are separated by fissures called sulci (Figure 10.5). The cerebral hemispheres are covered by a thin layer of gray matter (nerve cells and dendrites) called the cerebral cortex. It is folded into the gyri, and sulci, and contains 70% of all the neurons in the nervous system. Below the cerebral cortex is a mass of white matter, in which bundles of myelinated nerve fibers connect the neurons of the cortex to the rest of the nervous system. ▼ FIGURE 10.5 Brain. (a) View from the left side. (b) View from above. Functional Cerebral Regions (LO 10.4) Each cerebral hemisphere is divided into four lobes: The frontal lobe, located behind the forehead, forms the anterior part of the hemisphere. This lobe is responsible for intellect, planning, problem solving, and the voluntary motor control of muscles. The parietal lobe is posterior to the frontal lobe. This lobe receives and interprets sensory information, like spoken words. The temporal lobe is below the frontal and parietal lobes. This lobe interprets sensory experiences. The occipital lobe forms the posterior part of the hemisphere. This lobe interprets visual images and written words. Deep inside each cerebral hemisphere are spaces called ventricles, which contain watery cerebrospinal fluid (CSF). CSF circulates through the ventricles and around the brain and spinal cord. It helps to protect, cushion, and provide nutrition for the brain and spinal cord. Located beneath the cerebral hemispheres and ventricles are the: Thalamus, which receives all sensory impulses and channels them to the appropriate region of the cortex for interpretation; and Hypothalamus, Figure 10.6 which regulates blood pressure, body temperature, water, and electrolyte balance. ▲ FIGURE 10.6 Hypothalamus, Pituitary Gland, and Pineal Gland. Brainstem and Cerebellum (LO 10.4) The brainstem relays sensory impulses from peripheral nerves to higher brain centers. It also controls vital cardiovascular and respiratory activities. The cerebellum, the most posterior area of the brain, coordinates skeletal muscle activity to maintain the body's posture and balance. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION cerebellum ser-eh-BELL-um S/ R/ -um structure cerebell- little brain The most posterior area of the brain located between the midbrain and the cerebral hemispheres cerebrospinal (adj) cerebrospinal fluid (CSF) SER-ee-broh-SPY-nal S/ R/CF R/ -al pertaining to cerebr/o- brain -spin- spinal cord Pertaining to the brain and spinal cord Fluid formed in the ventricles of the brain; surrounds the brain and spinal cord cerebrum cerebral (adj) SER-ee-brum SER-ee-bral S/ R/ Latin brain -al pertaining to cerebr- cerebrum Cerebral hemispheres Pertaining to the cerebral hemispheres of the brain corpus callosum KOR-pus kah-LOW-sum R/ S/ R/ corpus body -um structure callos- thickening Bridge of nerve fibers connecting the two cerebral hemispheres frontal lobe FRUNT-al LOBE S/ R/ -al pertaining to front- front of Front area of the cerebral hemisphere gyrus gyri (pl) JI-rus JI-ree Greek circle Rounded elevation on the surface of the cerebral hemispheres hypothalamus hypothalamic (adj) high-poh-THAL-ah-muss high-poh-thah-LAM-ik P/ S/ S/ R/ hypo- below -us pertaining to -ic pertaining to -thalam- thalamus An endocrine gland in the floor and wall of the third ventricle of the brain Pertaining to the hypothalamus occipital lobe ock-SIP-it-al LOBE S/ R/ -al pertaining to occipit- back of head Posterior area of the cerebral hemisphere parietal lobe pah-RYE-eh-tal LOBE S/ R/ -al pertaining to pariet- wall Area of the brain under the parietal bone sulcus sulci (pl) SUL-cuss SUL-sigh Latin furrow, ditch Groove on the surface of the cerebral hemispheres that separates gyri temporal lobe TEM-pore-al LOBE S/ R/ -al pertaining to tempor- time, temple Posterior two-thirds of the cerebral hemispheres thalamus THAL-ah-mus Greek inner room Mass of gray matter under the ventricle in each cerebral hemisphere Cranial Nerves, Spinal Cord, and Meninges (LO 10.4) Cranial Nerves (LO 10.4) Your brain communicates with the rest of your body through the cranial nerves and spinal cord. The cranial nerves are part of the peripheral nervous system. They originate on the lower or inferior surface of the brain and are identified by names and numbers, the latter written in Roman numerals (Figure 10.7). ▲ FIGURE 10.7 Cranial Nerves This mnemonic device will help you remember the cranial nerves. Use the sentence in column one (read down) to help you remember the correct order and names of the cranial nerves. The cranial nerves provide sensory and motor functions for your head and neck areas except for the vagus nerve, which supplies your thorax and abdomen. Spinal Cord (LO 10.4) Your spinal cord lies within, and is protected by, the vertebral canal of the spinal column. It has 31 segments, each of which gives rise to a pair of spinal nerves (Figure 10.8). These are the major link between the brain and the peripheral nervous system, and are the pathway for sensory and motor impulses. ▲ FIGURE 10.8 Spinal Cord Regions. Your spinal cord is divided into four regions (Figure 10.8): The cervical region is continuous with the brain stem (lower part of the brain). It contains the motor neurons that supply the neck, shoulders, and upper limbs through 8 pairs of cervical spinal nerves (C1-C8); The thoracic region contains the motor neurons that supply the thoracic cage, rib movement, vertebral column movement, and postural back muscles through 12 pairs of thoracic spinal nerves (T1-T12); The lumbar region supplies the hips and the front of the lower limbs through 5 pairs of lumbar nerves (L1-L5); and The sacral region supplies the buttocks, genitalia, and backs of the lower limbs through 5 sacral nerves (S1-S5) and 1 coccygeal nerve, relative to the small bone at the base of the spine. Meninges (LO 10.4) Your brain and spinal cord are protected by the cranium and the vertebrae, cushioned by the CSF, and covered by the meninges (Figure 10.9). The meninges have three layers. ▲ FIGURE 10.9 Meninges of Brain. The dura mater is the outermost layer of tough connective tissue attached to the cranium's inner surface. Within the vertebral canal the dura mater splits into two sheets, separated by the epidural space, into which epidural injections of medication are given to produce analgesia during childbirth or for the treatment of low back pain. The arachnoid mater is a thin web over the brain and spinal cord. The CSF is contained in the subarachnoid space between the arachnoid and pia mater. It is into this space that a needle is introduced to obtain CSF for testing or to place medication in spinal anesthesia. The pia mater is the innermost layer of the meninges, attached to the surface of the brain and spinal cord. It supplies nerves and blood vessels that nourish the outer cells of the brain and spinal cord. Word Analysis and Definition S = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION analgesia an-al-JEE-zee-ah S/ P/ R/ -ia condition an- without -alges- sensation of pain State in which pain is reduced anesthesia an-es-THEE-zee-ah S/ P/ R/CF -ia condition an- without -esthes- feeling Complete loss of sensation arachnoid mater ah-RACK-noyd MAY-ter S/ R/ R/ -oid resembling arachn- cobweb, spider mater mother Weblike middle layer of the three meninges dura mater (Note: Both terms are stand-alone roots.) DYU-rah MAY-ter R/ R/ dura hard mater mother Hard, fibrous outer layer of the meninges epidural epidural space ep-ih-DYU-ral S/ P/ R/ -al pertaining to epi- above -dur- dura Above the dura Space between the dura mater and the wall of the vertebral canal meninges meningitis meh-NIN-jeez men-in-JIE-tis S/ R/ Greek membrane -itis inflammation mening- meninges Three-layered covering of the brain and spinal cord Inflammation of the meninges pia mater (stand-alone roots) PEE-ah MAY-ter R/ R/ pia delicate mater mother Delicate inner layer of the meninges subarachnoid space sub-ah-RACK-noyd SPASE S/ P/ R/ -oid resembling sub- under -arachn -cobweb, spider Space between the pia mater and the arachnoid membrane

The Eyeball and Seeing

The Eyeball (Globe) (LO 11.5) The functions of the eyeball are to continuously: Adjust the amount of light it lets in to reach the retina; Focus on near and distant objects; and Produce images of those objects and instantly transmit them to the brain. As shown earlier in this chapter, the front of the eyeball is covered by the conjunctiva. This thin layer of tissue lines the inside of the eyelids and curves over the eyeball to meet the sclera (Figure 11.9). the tough, white outer layer of the eye. ▲ FIGURE 11.9 Anatomy of the Eyeball. At the center of the front of the eye is the cornea, a transparent, dome-shaped membrane. The cornea has no blood supply and obtains its nutrients from tears and from fluid in the anterior chamber behind it. When light rays strike the eye, they pass through the cornea. Because of its dome curvature, those rays striking the edge of the cornea are bent toward its center. The light rays then go through the pupil, the black opening in the center of the colored area (the iris) in the front of the eye. The iris controls the amount of light entering the eye. For example, when you're in the dark outside at night the iris opens (dilates) to allow more light into the eye. When you're in bright sunlight or in a well-lit room, the iris closes (constricts) to allow less light into the eye. After traveling through the pupil, the light rays pass through the transparent lens. This lens can become thicker and thinner, enabling it to bend light rays and focus them on the retina at the back of the eye. Accommodation is the process of changing focus, and refraction is the process of bending light rays. The lens does not contain blood vessels (avascular) or nerves, and with increasing age, it loses its elasticity. Because of this reduced elasticity, when you reach your forties, your eyes may have difficulty focusing on near objects, a condition called presbyopia. Keynotes The cornea protects the eye and, by changing shape, provides about 60% of the eye's focusing power. The iris controls the amount of light entering the eye. The lens changes its shape to focus rays of light on the retina. Medical shorthand for a quick, normal eye examination can be PERRLA: Pupils Equal, Round, Reactive to Light and Accommodation. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION avascular a-VAS-cue-lar S/ P/ R/ -ar pertaining to a- without -vascul- blood vessel Without a blood supply constrict (verb) constriction (noun) kon-STRIKT kon-STRIK-shun P/ R/ S/ con- with, together -strict narrow -ion action, condition Become or make narrow A narrowed portion of a structure dilate (verb) dilation (noun) DIE-late die-LAY-shun S/ R/ Latin dilate -ion action, condition dilat- dilate To perform or undergo dilation Stretching or enlarging an opening or a structure iris EYE-ris Greek diaphragm of the eye Colored portion of the eye with the pupil in its center lens LENZ Latin lentil shape Transparent refractive structure behind the iris presbyopia prez-bee-OH-pee-ah S/ R/ -opia sight presby- old man Difficulty in nearsighted vision occurring in middle and old age pupil pupillary (adj) (Note: Change to II.) PYU-pill PYU-pill-ah-ree S/ R/ Latin pupil -ary pertaining to pupill- pupil The opening in the center of the iris that allows light to reach the lens Pertaining to the pupil refract (verb) refraction (noun) ree-FRAKT ree-FRAKT-shun S/ R/ Latin break up -ion condition refract- bend Bend or change direction of a ray of light The bending of light retina retinal (adj) RET-ih-nah RET-ih-nal S/ R/ Latin net -al pertaining to retin- retina Light-sensitive innermost layer of the eyeball Pertaining to the retina sclera scleral (adj) scleritis SKLAIR-ah SKLAIR-al sklair-RI-tis S/ R/ S/ Greek hard -al pertaining to scler- hardness, white of eye -itis inflammation Fibrous outer covering of the eyeball and the white of the eye Pertaining to the sclera Inflammation of the sclera The retina is the size of a postage stamp and has ten layers of cells. Located at the back of the eye (Figure 11.10a), it's the final destination for light rays. The retina has 130 million rods (Figure 11.10b), which perceive only light, not color, and function mostly in dim lighting. The retina has 6.5 million light- and color-activated cones (Figure 11.10b), which have precise visual acuity (sharpness). Different cones respond to red, blue, and green light. The perception of color is based on the intensity of various color mixtures from the three cone types. ▲ FIGURE 11.10 Structure of the Retina. (a) Retina. (b) Rods and cones. Some people have a hereditary lack of response by one or more of the three cone types and show color blindness. The most common form of this is red-green color blindness. Here, red-green colors and related shades cannot be distinguished from each other. The rods and cones convert the light rays' energy into electrical impulses. The optic nerve—a bundle of more than a million nerve fibers—transmits these impulses to the visual cortex at the back of the brain. The area where the optic nerve leaves the retina is called the optic disc. Because it has no rods and cones, the optic disc cannot form images; as a result, it's called the "blind spot." Just lateral to the optic disc at the back of the retina is a circular, yellowish region called the macula lutea (Figure 11.10a). In the center of the macula is a small pit called the fovea centralis, which has 4,000 tiny cones but no rods. Each cone has its own nerve fiber, and this gives the fovea area the sharpest vision. As you read this text, the words are precisely focused on your fovea centralis. Behind the light-sensitive photoreceptor layer of the retina is a vascular layer called the choroid. This layer, together with the iris and its muscle, is called the uvea. Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION choroid KOR-oid Greek membrane Region of the retina and uvea fovea centralis FOH-vee-ah sen-TRAH-lis S/ R/ fovea Latin a pit -is pertaining to central- center Small pit in the center of the macula that has the highest visual acuity macula lutea MACK-you-lah LOO-tee-ah macula Latin small spot lutea Latin yellow Yellowish spot on the back of the retina; contains the fovea optic optical (adj) OP-tik OP-tih-kal S/ R/ Greek eye -al pertaining to optic- eye Pertaining to the eye or vision Pertaining to the eye or vision photoreceptor foh-toe-ree-SEP-tor S/ R/CF R/ -or that which does something phot/o- light -recept- receive A photoreceptor cell receives light and converts it into electrical impulses uvea uveitis YOU-vee-ah you-vee-EYE-tis S/ R/ Latin vascular layer -itis inflammation uve- uvea Middle coat of the eyeball; includes the iris, ciliary body, and choroid Inflammation of the uvea visual acuity VIH-zhoo-wal ah-KYU-ih-tee acuity Latin sharpen Sharpness and clearness of vision Refraction (LO 11.5) The optic nerves leave each orbit through the optic foramen. Light travels at 186,000 miles per second, and even when it hits the eye, this speed remains the same. Light rays that hit the center of the cornea pass straight through the eye, while rays that hit away from the center then bend toward the center. These light rays then hit the lens and bend again, and in normal vision, the image is focused sharply on the retina (Figure 11.11). ▲ FIGURE 11.11 Normal Vision. Farsighted people are said to have hyperopia (Figure 11.12). Because the eyeball is shortened, objects close to the eye are focused behind the retina and vision is blurred. Convex lenses help to correct the problem. ▲ FIGURE 11.12 Hyperopia (Farsightedness). Nearsighted people are said to have myopia (Figure 11.13). Because the eyeball is elongated, far-away objects are focused in front of the retina. Vision is blurred. Concave lenses help to correct the problem. ▲ FIGURE 11.13 Myopia (Nearsightedness). In presbyopia, a condition mentioned earlier in this chapter, the lens loses its flexibility, making it difficult to focus for near vision. This usually occurs when you reach your forties. Convex bifocal or transitional lenses help to correct this problem. In astigmatism, unequal curvatures of the cornea cause unequal focusing and blurred images. This problem can be corrected with cylindrical lenses, which refract light more in one plane than in another. A surgical procedure, radial keratotomy, is used to treat myopia. Radial cuts, like the spokes of a wheel, flatten the cornea so it can refract the light rays to focus on the retina. Laser surgery can also change the shape of the cornea. It can flatten it to correct myopia, or it can alter the cornea's outer edges to correct hyperopia. Laser-assisted in situ keratomileusis (LASIK) is used to treat myopia, hyperopia, and astigmatism. LASIK involves a computer-controlled laser that uses a cold beam of ultraviolet light, which alters the shape of the cornea by vaporizing the tissue. Abbreviation LASIK laser-assisted in situ keratomileusis Word Analysis and DefinitionS = Suffix P = Prefix R = Root R/CF = Combining Form WORD PRONUNCIATION ELEMENTS DEFINITION astigmatism ah-STIG-maht-izm S/ P/ R/ -ism process a- without -stigmat- focus Inability to focus light rays that enter the eye in different planes concave convex kon-KAVE kon-VEKS Latin concavus arched Latin convexus vaulted Having a hollowed surface A surface that is evenly curved outward foramen foramina (pl) fo-RAY-men fo-RAM-ih-nah Latin hole An opening through a structure hyperopia high-per-OH-pee-ah P/ S/ hyper- beyond -opia sight Able to see distant objects but unable to see close objects in situ IN SIGH-tyu Latin in its original place In the correct place keratomileusis ker-ah-TOE-mill-oo-sis R/CF R/ kerat/o- cornea -mileusis lathe Cuts and shapes the cornea keratotomy ker-ah-TOT-oh-mee S/ R/CF -tomy surgical incision kerat/o- cornea Incision in the cornea myopia (Note: One "op" is removed to allow the term to flow.) my-OH-pee-ah R/ S/ myop- to blink -opia sight Able to see close objects but unable to see distant objects radial (adj) RAY-dee-al S/ R/ -al pertaining to radi- radius Diverging in all directions from any given center