Does that make sense.kl

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<ul><li> 1. Does that Make Sense?</li></ul> <p> 2. Why do we leave cookies out for Santa? The answer is that he feels hungry after traveling the world and through the chimney. He senses this hunger with his sensory receptors. Why are Christmas songs different than Halloween songs? The music sets a tone that affects the way people feel. Without hearing it would be hard to understand the different moods.These are just a few examples of how sensory receptors are usedduring the Christmas holiday. Lets explore what they are and whatelse they do. 3. Sensory receptors- Include our special senses(vision, hearing, balance, taste, and smell) (2).Have receptor potential which is what causes areflex (2). It is like a tea pot that heats and once it hits acertain point causes the whistling sound. Once the potentialis at its climax, it causes the body to react. Allows the brain to interpret sensations with thespecial senses (registering heat, cold) (2). Receptors adapt after a period of time. An examplefrom Anthonys Textbook of Anatomy and Physiology 17thEdition is how when a person first puts on clothes he canfeel the material but after a while does not sense it at all. 4. DistributionReceptors are not distributed equallythroughoutthe body.Receptors in the general source organsproducesomatic senses (2).The two-point discrimination test provesthatthere are more receptors in some areas of the body thanothers (receptors in finger tips &gt; receptors of skin onthe back) (2). 5. Location1.ExteroceptorsSuperficial or near the surface.React to stimuli from outside of the body (2).Examples: receptors that sense the heat from picking upa hot cookie sheet, the cold from licking an ice sickle, apaper cut from opening a holiday card, and the pressurefrom the inside a plane during take-off or landing whilevisiting family. (18 ) 6. 4.Visceroceptors Internal and within body organs (2). Internal stimuli cause a reaction (2).Examples: receptors that sense the craving ofgingerbread men, wanting eggnog, and realizing youcant eat anymore cookies or drink anymore applecider. 3. Proprioceptors Are a type of visceroceptors. Located in skeletal muscle, joint capsules,and tendons (2). Identify body movement.Examples: Help us to realize when we walk, when weraise our hands, sit still, and stand tall. 7. Stimulus Detected1.Mechanoreceptors Activate or start the receptor potential (2). Caused by a change of location of receptor (2).Examples: While exercising our muscles and skin are being stretchedand causes a shift in the receptors positions.2. Chemoreceptors Depends on chemical concentration (2). Examples: The differences between certain smells and tastes. It isa reaction of the different chemical make-up of what is being smeltand tasted (vegetables vs. candy). (19 ). 8. 3. ThermoreceptorsActivated by change in temperature (2).Examples: Why we wear jackets in the winter and shorts in thesummer, and why Santa has long sleeves, long pants, snowboots, and a hat. His cheeks are always rosy because thewinds in the air whip against his cheeks as he flies overneighborhoods.4. NociceptorsSenses pain (2).Examples: What Tim Allen experienced after falling of the rooftrying to tie up Frosty in Christmas with the Kranks.5. PhotoreceptorsFound only in the eye (2).Responds to light (2).Examples: When your eyes adjust on Christmas morning afterbeing in the dark to waking up in the bright early morning. 9. Structure Free nerve ending: Simplest, most common, and mostwidely distributed sensory receptors. Located both on thesurface of the body and in the deep visceral organs. (1) (12 ) Root hair plexuses: Delicate, web-like arrangements offree nerve endings that surround hair follicles and detectvariations of free nerve endings called merkel discs. (1) (13 ) 10. Merkel discs: Responsible for mediating sensations of lightor discriminative touch. Delicate mechanoreceptors thatare more easily deformed than pacinian corpuscles andthus are capable of generating an action potential whenexposed to minimal stimulation. (1) (14 ) Meissner Corpuscle: Numerous in hairless skin areas, suchas nipples, fingertips and lips. These structures are largeand superficially placed ovoid or egg shapedmechanoreceptors. (1) (15 ) 11. Pacinian Corpuscles: Large mechanoreceptorsthat show thick laminated connective tissuecapsules. Found in the deep dermis of theskin, mainly in the hands and feet. Respondquickly to sensations of deep pressure, highfrequency, and stretch. They are sensitive andquick to respond, adapt quickly, and thesensations they evoke seldom last long. (1) (16 ) Muscle Spindles: Consist of a discrete groupingof about 5 to 10 modified muscle fibers calledintrafusal fibers. Found lying between andparallel to the regular muscle fibers. Both endsof spindle are connected or anchored toconnective tissue elements within the musclemass. (1) (17 ) Golgi tendon Organs: Operate to provide thebody with information concerning muscle lengthand the strength of muscle contraction. (1) (18 ) 12. Smell The olfactory receptors are embedded in a specialized (20 ) patchof yellow-tinted mucous membrane in the roof of the nasal cavity. Theolfactory receptor neurons are chemoreceptors. Receptor potentialsare generated in olfactory receptor neurons when gas molecules orchemicals are dissolved in mucus covering the nasal epithelium. The Olfactory Pathways; the Olfactory Bulb, the Olfactory Tract,Olfactory Recess, and the Nasal cavity are a few of the OlfactoryPathways. These pathways basically are the ways that help youbreathe in and out of our nose (2). 13. Taste Taste Buds are the sense organs that respond togustatory, or taste, stimuli. They are located in the liningof the mouth and on the soft palate, most are on thesmall elevated projections of the tongue called papillae.As chemoreceptors, the taste buds, like olfactoryreceptors, tend to be quite sensitive but fatigue easily. Neural Pathway connects one part of the nervous systemwith another and usually consists of bundles ofelongated, myelin-insulated neurons. Neural pathwaysserve to connect relatively distant areas of the brain ornervous system. Nervous impulses generated in theanterior two thirds of the tongue travel over the facialnerve (2). 14. Hearing The Pressure Wave: The sound waves we hear travel through air just like the wavestravel through the slinky. The above illustration shows the relativeconformations of air molecules as they transmit a sound wavedownward. Soud travels through the air and along the outer andmiddle ear as a series of compressions (crests) and rarefractions(troughs) of air molecules. These patterns of molecules stimulateparts of the ear as described below to create the perception ofsound. How the Ear Perceives Sound: The audirory canal (a.k.a. the outer auditory meatus) brings whatyou hear from the outside of the ear to the middle ear. At the endof the auditory canal, there is a thin layer of skin called thetympanic membrane (more commonly called the ear drum). Thewaves of sound hit the ear drum, and get further transferred ontothe three small bones in the middle ear collectively known as theauditory ossicles: incus (anvil), stapes (stirrup), and malleus(hammer). 15. These structures act as a chain, which lead through anopening in the bone between the middle and the inner ears.The middle ear is filled with air, and the inner ear is filledwith fluid, so this opening is covered by a thin membrane tokeep them separate. This membrane allows the sound wavesto be transmitted into the inner ear, and finally to a bundle of30,000 nerve fibers each representing a different frequency.Noise is filtered out of this signal and the brain interprets thesignal. The brains interpretation of sound gives it an addedproperty: pitch. This is basically how the brain interprets thefrequency. The higher the frequency, the higer the pitch.Since frequency is the inverse of the period, the longer thewavelength, the lower the pitch. The amplitude of the wavetranslates into how loud the brain takes the sound to be. Wave addition contributes to the rich complex sounds the wehear each day. A voice is just the addition of many simplerwaves to give a unique sound. If two waves are addedtogether, and they happen to have the same amplitude, thecompressions of one are in the same position as therarefractions of the other (and vice versa) the end result isno sound. This is how your noise cancelling headphoneswork. They take in sounds from the outside, and emit a wavethat has just the right properties to cancel them out. 16. Inner Ear(20 ) Middle Ear (20 )(20 ) 17. (21 )Balance: Proprioception from Latin proprius, meaning "onesown," and perception is one of the human senses.There are between nine and 21 in all, depending onwhich sense researcher you ask. Rather than sensingexternal reality, proprioception is the sense of theorientation of ones limbs in space. This is distinctfrom the sense of balance, which derives from thefluids in the inner ear, and is called equilibrioception.Proprioception is what police officers test when theypull someone over and suspect drunkenness. Withoutproprioception, wed need to consciously watch ourfeet to make sure that we stay upright while walking.(21) 18. Proprioception doesnt come from any specific organ, butfrom the nervous system as a whole. Its input comesfrom sensory receptors distinct from tactile receptors nerves from inside the body rather than on the surface.Proprioceptive ability can be trained, as can any motoractivity. (21) Without proprioception, drivers would be unable to keeptheir eyes on the road while driving, as they would needto pay attention to the position of their arms and legswhile working the pedals and steering wheel. And Iwould not be able to type this article without staring atthe keys. If you happen to be snacking while readingthis article, you would be unable to put food into yourmouth without taking breaks to judge the position andorientation of your hands. (21) 19. VISION: THE EYE The eye is the bodys sensory organ for vision. Thisorgan converts the energy of light into electrical nerveimpulses that are interpreted by the brain.Approximately five sixths of the eyeball is hidden in thesocket. There are three layers of tissue in the eye. Thethree layers of tissue are the sclera, the choroid, and theretina (2). The anterior layer of the sclera is called the cornea andlies over the iris, the colored part of the eye. Themiddle or choroid part of the eye contains many bloodvessels and large amounts of pigment. The iris or thecolored part of the eye, consists of circular and radialsmooth muscle fibers arranged to form a doughnutshaped structure. The hole in the middle is called thepupil. The iris attaches to the ciliary body (2). 20. The retina is the innermost coat of the eyeball. Three layers of neurons make up the major portion of the retina; the photoreceptor, bipolar neurons, and ganglion neurons. Rods and cones are our visual receptors (2).(16 ) 21. Process of seeingFormation of retinal Image Refraction of light rays Accommodation of lens Constriction of pupil Convergence of eyes 22. Role of Photopigments Rods- photopigment in rods is rhodopsin; highly lightsensitive; breaks down into opsin and retinal; separationof opsin and retinal in the presence of light causes anaction potential in rod cells; energy is needed to reformrhodopsin retina Cones- three types of cones are present in the retina,with each having a different photopigment; conepigments are less light sensitive than rhodophsin andneed brighter light to breakdown 23. Questions Deer cant see color so wearing bright orange vests dontscare them off. It keeps other hunters from shootingpeople with those vests instead of mistaking theirmovements as an animal. Nearsighted means you cant see very good far andfarsighted means you cant see very well near.</p>