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Chapter 10: Senses (Study Guide and Practice Questions)Senses are often classified as either GENERAL or SPECIAL sensesCLASSIFICATION OF SENSES GENERAL SENSES Detected by sensory organs that exist as individual cells or receptor unitsWidely distributed throughout the body (skin, muscles, tendons, joints, & other internal organs)Responsible for such sensations as pain, temperature, touch, pressure, & body position SPECIAL SENSESDetected by large & complex organs, or localized grouping of sensory receptorsSenses of smell, taste, vision, hearing, & equilibrium are considered special senses because their receptors are grouped within distinct structures that enhance their functionSENSORY RECEPTOR TYPES1.Classified by presence or absence of covering capsule- encapsulated- unencapsulated (“free” or “naked”) 2. Classified by type of stimuli (mode) required to activate receptors - photoreceptors (light) - chemoreceptors (chemicals) - pain receptors (injury) - thermoreceptors (temperature change) - mechanoreceptors (movement or shape change)SENSORY PATHWAYSAll sense organs have common functional characteristicsAll are able to detect a particular stimulusA stimulus results in generation of a nerve impulseA nerve impulse is processed and perceived as a sensation in the central nervous system Sensory pathway for general senses typically involves conduction of action potentials generated in the receptors through the spinal cord to the thalamus or cerebellum where they synapse, & impulses are then relayed to specific areas of the cerebral cortex for conscious sensory interpretationSensory pathways for the special senses are varied, but also ultimately end in specific sensory areas of the cerebral cortexGENERAL SENSESDistribution is widespread; single-cell receptors are commonMode- the kind of stimulus or change a receptor or sense is able to detect Examples of general sensory receptors and their modesFree nerve ending- pain, discriminative touch, tickle, temperatureBulboid corpuscle (Krause end-bulb)- touch & possibly coldLamellar corpuscle (pacini corpuscle)- pressure & high frequency vibrationTactile corpuscle (Meissner corpuscle)- fine touch & low-frequency vibration Bulbous corpuscle (ruffini corpuscle)- touch & pressureTendon organ (golgi tendon organ)- proprioception (sense of muscle tension)Muscle spindle- proprioception (sense of muscle length)General sense organs are also found in deep organs of the body General sense organs Table 10-1// pg. 210SPECIAL SENSESvisioneyeeyeball is a fluid-filled sphere having a wall of three layers:fibrous layer – tough outer coat- sclera – “white” of eye// *cornea is transparent part of sclera over eye// forms most of fibrous layer//dense bundles of collagen fibers make it white- cornea – transparent part over iris // “window of the eye”// transparent circle on the anterior of the fibrous layer- conjunctiva- mucous membrane that covers front of fibrous layer and extends to inside of eyelids // blood vessels you see on sclera belong to conjunctiva// **inflammation of conjunctiva= “pink eye”- lacrimal gland- secretes tears that moisten conjunctiva2. vascular layer- middle layer// has dense network of blood vessels- choroid- pigmented, melanin-rich layer, prevents scattering of light//most of the vascular layer- iris- the colored part of the eye; the pupil is the hole in the center of the iris; contraction of smooth muscle dilates or contracts pupil- lens- transparent body behind the pupil; focuses or refracts light rays on the retina- ciliary muscle- near front of vascular layer, just outside of the edge of the iris; contraction affects shape of lens just behind the iris, thus altering focus for near objects 3. inner layer- inner most sensory layer(A) retina- contains various kinds of photoreceptors to detect lighti. rods- receptors for night vision and peripheral visionii. cones- receptors for day vision and color visioniii. ganglion cells- receptors for changing light patterns of days, months, seasonseye fluidsaqueous humor- in the anterior chamber in front of the lensvitreous humor- in the posterior chamber behind the lensvisual pathwayvision detects intensity (brightness) and wavelength (color) of light, as well as images and motionlight must be refracted (focused) by the eye to form a detectable imagine innermost layer of retina contains rod and conesimpulse travels from the rods and cones through the bipolar and ganglionic layers of retinanerve impulse leaves the eye through the optic nerve (cranial nerve II); the point of exit is free of receptors and its therefore called a blind spotvisual interpretation occurs in the visual cortex of the occipital lobe of the cerebrum HEARING AND EQUILIBRIUMThe ear functions in hearing and equilibrium (balance) using receptors called *mechanoreceptors*EARExternal ear Auricle (pinna) – appendage on the side of the head surrounding the opening of the external acoustic canalExternal acoustic canal-Curving canal 2.5 cm (1 in) in lengthContains ceruminous glands (produce cerumen= ear wax)Ends at the tympanic membrane (eardrum)Skin of acoustic canal contains many short hairs Middle earHouses ear ossicles (three small bones in ear)MalleusIncusStapesEnds in the oval window (separates the middle ear from the inner ear)The auditory tube (eustachian tube) connects the middle ear to throatInflammation is called otitis media (middle ear infection) Inner ear Bony labyrinth filled with perilymph (watery fluid) Subdivided into the vestibule, semicircular canals, cochleaMembranous labyrinth filled with a thicker fluid called endolymph HEARINGHearing detects changes in intensity (loudness) & frequency (tone) of sound waves (pressure waves in air)Sound waves are funneled by auricle into external acoustic canal and vibrate the tympanic membraneVibrations of tympanic membrane are amplified by auditory ossicles and transmitted to the oval windowVibrations of the oval window trigger vibrations of perilymph, which in turn vibrates endolymphSensory hair cells on the spiral organ (organ of Corti) respond when bent by the movement of surrounding endolymph set in motion by sound waves; can become damaged by chronic exposure to loud noiseEQUILIBRIUMTwo types of balance: static and dynamic STATIC EQUILIBRIUM (sense of gravity)Detected by ciliated hair cells (mechanoreceptors) of the two maculae in the vestibuleWhen the head tilts, gravity pulls the heavy gel of each macula, bending the sensory cilia and producing a nerve signal DYNAMIC EQUILIBRIUM (sense of speed and direction of movement)Detected by ciliated hair cells (mechanoreceptors) of the crista ampullaries (with flaplike cupula) in the ampulla of each semicircular canalWhen speed or direction of movement of head changes, the flow of endolymph in semicircular canals is altered, which causes change in bending of sensory cilia (producing a nerve signal)Vestibular nerve carries nerve impulses from the equilibrium receptors of the vestibule; joins with cochlear nerve to form vestibulocochlear nerve (cranial nerve VIII)TASTE (gustation)Receptors are chemoreceptors called gustatory cells, located in taste budsCranial nerves VII & IX carry gustatory impulses Primary taste modesSweet- detects sugarSours- detects acidBitter- detects alkaline solutionsSalty- detects sodium ionsMetallic- detects metal ionsUmami (savory)- detects glutamate (an amino acid)SMELL (olfactory)Olfactory receptors in olfactory mucosa of nasal cavity are extremely sensitive but easily adapt (become fatigued)Odor- causing chemicals initiate a nerve impulse that is carried on cranial nerve I and interpreted as a specific odor by the brainOlfaction has a strong relationship with emotions and memory through the limbic systemINTEGRATION OF SENSESAll senses are processed and finally perceived in the brain (NOT RECEPTORS)Sensory information is combined to form an overall sensory perception of our worldFlavor Combination of gustatory and olfactory senses; can be affected by other senses, such as touch, pain, or temperature Nasal congestion interferes with stimulation of olfactory receptors and thereby dulls flavor sensationsPosture & Balance – both senses of equilibrium with vision and proprioception- combine to help us maintain a safe body positionSome sensory information is processed subconsciouslyOur senses may decline as we ageChapter 10: Senses (Study Questions)The receptors in the eye can be classified as photoreceptors. Taste and smell receptors can be classified as ________________________ and tendon organs (golgi tendon organs) and muscle spindles can be classified as _________________________.The specific mechanoreceptor for hearing is the ________________________________The specific mechanoreceptor for balance is the ________________________________The gustatory cells are involved with the sense of _____________________________________Six “primary” kinds of taste sensations that result from the stimulation of the taste buds are ________________________,________________________,________________________, ________________________,________________________, and ________________________,Taste buds can be found on much larger structures on the tongue called _____________________The chemoreceptors responsible for the sense of smell are the _____________________________Tears are formed in this glandHole in the iris that lets light inReceptors for night or dim light visionThick jelly like fluid or humor of the eyeTough, white outer layer of the eyeReceptors for red, blue, and green color visionCiliary muscles pull on this to help the eye focusDark pigmented middle layer of the eye that prevents the scattering of incoming lightTransparent part of the outer eye later, the window of the eyeColored front part of the middle eye layerThin, watery humor of the eye___ sclera___ cornea___ iris___ pupil___ lacrimal___ lens___ rods___ cones___ choroid___ vitreous___ aqueousTube connecting the middle ear and the throatWatery fluid that fills the bony labyrinthSnail-shaped structure of the inner earThe organ of hearingThick fluid in the membranous labyrinthAnother term for eardrumCollective name for malleus, incus, & stapes___ tympanic membrane___ ossicles___ auditory tube___ perilymph___ endolymph___ cochlea___ spiral organ (organ of Corti)MatchOlfactory cellsMeissner’s corpusclesChemoreceptorEyeTouch ___ special sense organ___ general sense organ___ nose___ krause’s end bulbs___ taste budsMatch Detect changes in pH and CO2 levels in the bloodFine touchEncapsulated nerve endingGeneral sensory receptors found deep within skeletal muscle tissueStimulation of receptors in deep structures that may affect sensation far removed from site of injury or disease___ proprioceptors___ golgi tendon organ___ referred pain___ chemoreceptors___ Meissner’s corpuscle The “white” of the eye is more commonly called:Choroid CorneaScleraRetina None of the aboveThe “colored” part of the eye is known as:RetinaCorneaPupilScleraIrisThe transparent portion of the sclera, referred to as the window of the eye, is the:Retina CorneaPupil Iris The mucous membrane that covers the front of the eye is called the:CorneaChoroidConjunctivaCiliary bodyNone of the aboveThe structure that can contract or dilate to allow more or less light to enter the eye is the:LensChoroidRetinaCorneaIrisWhen the eye is looking a objects far in the distance, the lens is _____________ and the ciliary muscle is _____________Rounded; contractedRounded; relaxedSlightly rounded; contractedSlightly curved; relaxed None of the aboveThe lens of the eye is held in place by the:Ciliary muscleAqueous humorVitreous humorCorneaWhen the lens loses its elasticity and can no longer bring near objects into focus, the condition is known as:GlaucomaPresbyopiaAstigmatismStrabismusThe fluid in front of the lens that is constantly being formed, drained, and replaced in the anterior chamber is the:Vitreous humorProtoplasm Aqueous humorConjunctivaIf drainage of the aqueous humor is blocked, the internal pressure within the eye will increase, and a condition known as ____________________ could occurpresbyopiaglaucomacolor blindnesscataractsthe rods and cones are the photoreceptor cells and are located on the:scleracorneachoroidretinathe area that contains the greatest concentration of cones on the retina is the:fovea centralisretinal arteryciliary bodyoptic discIf our eyes are abnormally elongated, the image focuses in front of the retina, and a condition known as ______________ occursHyperopiaCataractsNight blindnessMyopiaMatch External earMiddle earInner ear___ malleus___ perilymph___ incus___ ceruminous glands___ cochlea___ acoustic canal___ semicircular canals___ stapes___ eustachian tube___ organ of Corti The external ear has two parts the ____________________________ and the ___________________ _____________________ ___________________Another name for the tympanic membrane is the ______________________________________The bones of the middle ear are collectively referred to as _____________________________The stapes presses against a membrane that covers a small opening called the ___________________________________________________A middle ear infection is called _____________________ __________________________The _________________________ is located adjacent to the oval window between the semicircular canals and the cochleaLocated within the semicircular canals and the vestibule are ____________________________ for balance and equilibriumThe sensory cells in the ____________________________ ____________________________ are stimulated when movement of the head causes the endolymph to moveStructures known as (papillae or olfactory cells) are found on the tongueNerve impulses generated by stimulation of taste buds travel primarily through two (cranial or spinal) nervesTo be detected by olfactory receptors, chemicals must be dissolved in the watery (mucus or plasma) that lines the nasal cavityThe pathways taken by olfactory nerve impulses and the areas where these impulses are interpreted are closely associated with areas of the brain important in (hearing or memory)(chemoreceptor or mechanoreceptor) is the term used to describe the types of receptors that generate nervous impulses resulting in the sense of taste or smell(gustation or olfaction) allows us to chemically analyze food before we swallowA savory, meaty taste is described as (salty or umami)The decrease in olfactory receptor sensitivity over a short time is known as (adaptation or deprivation)Most of the taste buds are located on the circumvallate papillae at the (front or back) of the tongueThe golgi tendon receptors and muscle spindles are important:ProprioceptorsPhotoreceptorsChemoreceptorsNone of the aboveAnother name for farsightedness is:MyopiaHyperopiaAstigmatismNone of the aboveIn addition to its role in hearing, the ear also functions as:The sense organ of equilibrium and balanceA sense organ for chemoreceptorsThe sense organ for gustatory cellsNone of the aboveThe occipital lobe is responsible for:Interpretation of mechanoreceptorsInterpretation of chemoreceptorsVisual interpretationNone of the aboveAnother name for the tympanic membrane is the:OssicleEardrumExternal auditory canalOval window The inner ear consists of three spaces in the temporal bone, assembled in a complex maze called the:Crista ampullarisBony labyrinthOrgan of cortiOssiclesThree layers of tissue form the eyeball. They are the:Iris, conjunctiva, and corneaChoroid, iris, and pupilRetina, rods, and conesFibrous, vascular, and inner layerThe jellylike fluid behind the lens in the posterior chamber is the:Aqueous humorVitreous humorEndolymphPerilymphThe eustachian tube connects the throat with the:Tympanic membraneExternal earInner earMiddle earThe receptors for night vision are the:RodsConesFovea centralisChemoreceptors-49593524384000 INCLUDEPICTURE "C:\\var\\folders\\12\\dvgqclnx2d1fv_0w08wghtcc0000gn\\T\\com.microsoft.Word\\WebArchiveCopyPasteTempFiles\\xEye-Anatomy-2.jpg.pagespeed.ic.-cihYpHQNi.jpg" \* MERGEFORMAT INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "C:\\var\\folders\\12\\dvgqclnx2d1fv_0w08wghtcc0000gn\\T\\com.microsoft.Word\\WebArchiveCopyPasteTempFiles\\i3qjL-hNimHv1cDJaSwn6Q.jpg" \* MERGEFORMAT ................
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