integumentarylab-dawsondavis | Somatosensory System

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Unit 4 Integumentary System Lab BACKGROUND A sensation is defined as a state of awareness, of the internal or external environment. For a sensation to occur, four criteria must be met. First, there must be a stimulus. This is a change in the environment to which we will become aware. Next, there must be a receptor. A receptor is a cell, or an organ, which is sensitive to the stimulus. There also must be a afferent (sensory) nerve
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  Unit 4 Integumentary System Lab BACKGROUND A sensation  is defined as a state of awareness, of the internal or external environment. For a sensation to occur, four criteria must be met. First, there must be a stimulus. This is a change in the environment to which we will become aware. Next, there must be a receptor. A receptor is a cell, or an organ, which is sensitive to the stimulus. There also must be a afferent (sensory) nerve pathway, to carry signals to the central nervous system. Finally, there must be sensory cortex, where the signals will be analyed and interpreted. Structure of Touc Rece!tors #eissner$s cor!usc%es  are receptors for light touch. These are located in the upper dermis, usuallywithin dermal papillae. This location places them as close to the body surface as possible, thus enabling them to respond to light agitation of the s!in. ithin the corpuscle, the sensory nerve ending is coiled, parallel to the plane of the s!in surface. #ompression of the s!in (by touching) deforms the receptor, causing depolariation. &acinian cor!usc%es  are receptors for deep pressure. These are typically located in the lower dermis or underlying fascia. Their deep location ma!es them sensitive only to more profound deformation of the s!in. Notice the concentric layering of connective tissue surrounding the nerve ending. $eformation of this tissue results in depolariation of the neuron.%oth light touch and deep pressure are fast&adapting senses. The bulb of connective tissue is involved with adaption. hen deformation of these receptors first occurs, there is a burst of electrical activity. 'f the stimulus is sustained, the bulb then mechanically adusts to it, and allowsthe sensory nerve to repolarie. The effect is loss of sensation. As soon as the pattern of deformation changes, the neuron immediately depolaries again. ensation detecting nerves found in this system are called sensory ner'es and are activated by different sensations, be it temperature, pain, or tactile sense (touch). *n the end of each sensory nerve there are many different receptors which detect different feelings. For example, termorece!tors  specifically detect temperature. ome thermoreceptors detect cold conditions whilst other thermoreceptors are activated by warmth. &ART I TOUC( R)C)&TOR D)NSIT*  Location + Density of Cutaneous Rece!tors The density of touch receptors varies with location on the body. The fingertips, toes, and lips have the greatest density. These areas of the body have the highest tactile resolution+ the ability to discriminate between one and two points of stimulation.ou will use a two&point discrimination test to compare tactile resolution (and receptor density) between various parts of your body. An estheiometer is used for this test normally, we are going to try to use calipers. The minimum distance between point, which can be determined as two points of contact, is calledthe two&point threshold.%egin the test by closing the calipers (a single point of contact) and gently touch the s!in of the test subect. The subect should have his-her eyes closed. *pen the calipers slightly and repeat the process. eep repeating the process, opening the calipers a little more each time, until the subect reports two points of contact. /ecord the distance between points, in millimeters. Area being teste, T-o.!oint treso%, /mm0  #hee! (of the face+)000000100000000000000%ac! of hand0000002.34000000000000005alm of hand000006.7000000000000000Fingertip000000.61000000000000008ip00000.2000000000000000%ac! of nec!00003.90000000000000000ole of foot002.:1000000000000000000%ac! of calf002.23000000000000000000 &ART II TACTIL) LOCALI1ATION This tests the ability to determine where tactile stimulation has occurred. ;sing a felt&tip mar!er, touch thes!in of the test subect. <is-her eyes should be closed. The subect then will try to touch the exact spot with a mar!er (of a different color)= measure the distance between the two mar!s. Area Teste, Distance /mm0 5alm of hand6.1000000000000%ac! of hand00000.60000000Forearm (anterior)00000:.70000000Forearm (posterior)00004.900000000ole of foot00004.:00000000%ac! of calf00006.>00000000 C%ass Data Touc Rece!tor Density  Area Teste,Team 2Team 3Team Team 4 #hee! (of the face+)%ac! of hand5alm of handFingertip8ip%ac! of nec!ole of foot%ac! of calf  Tacti%e Location Area Teste,Team 2Team 3Team Team 4 5alm of hand%ac! of handForearm anteriorForearm posteriorole of foot%ac! of calf  &ART III ADA&TATION O5 T)#&)RATUR) R)C)&TORS 'f you have 6 containers= one with cold water, one with room temp water and one with hot water and you simultaneously put a hand in the hot and cold temp containers for a 4 minutes...what will happen when you plunge them into the room temp water? rite a hypothesis+ (guess what is going to happen)  The warmer water will ma!e the hands warm and when we put our hands in the cooler water, hands will feel weird because of the water being colder than before. 5erform the experiment. hat did you feel when you put both hands in the room temp water? *bservation+ The hands that are cold will sut get warmer and didn@t have much change. %ut the water the waswarmer then the medium so when my hands got really hot, then my hands had to change from hot bac! to the normal. 
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