The Skin and Sensation Physiology

The genuflect and brain PhysiologyThe Skin and Sensation PhysiologyIntroductionSkin is the largest reed organ of our personate that protects us from microbes and helps to regulate our body temperature. It contains polar kinds of sensory receptors that respond to variety of stimuli mechanical, thermal and chemical. The familiar receptors of the body react to touch on, pressure, temperature, smart and change of the environment. The encapsulated receptors which include free nerve endings may genius pain and temperature Merkels discs, which aesthesis light pressure and root hairs-breadth plexuses that sense touch by the movement of the hairs. plot of ground the encapsulated receptors atomic number 18 en almostd in a capsule of connective tissue which are the Meisnners, Pacinian and Ruffinis corpuscles. The density of hide receptors is great in areas that are designed to sense our environment. These receptors convey the information to the CNS thus, some(prenominal) stimul us should be of threshold magnitude in order to detect. The sensory system have a limit of its sensitivity therefore, stimulus below minimum magnitude cannot elicit a response. The cutaneous receptors are scattered throughout the skin and the underlying fascia. These receptors are the mechanoreceptors, thermoreceptors, nocireceptors and proprioreceptors that are exquisite to a certain stimuli.Sensation is defined as a state of awareness of the internal and external environment. There are quaternity criteria to be considered in order for a aesthesis to occur. First is the stimulus, the change in the environment in which we should be aware of. Next, there should be a receptor- a cell or organ which is sensitive to the stimulus. There must also have an afferent nerve pathway that will carry the token to the CNS and lastly, there should be sensory cortex where the signals was analyzed and interpreted.Hence, this activity aims to demonstrate the ace sharpness use various models i n haptic localization and adaption, to determine relative sensitivity of selected areas of the skin and to be able to understand the different features of admirer in relation to various stimuli, allowance and after assure phenomenon.MethodologyTactile Distribution Two-point SensibilityBegin the test by asking the report to close his eye. Using a vernier caliper, test the ability of the field of force to differentiate 2 distinct wizards by setting the vernier caliper at the distance with points close together and gradually increasing superstar or two points until the subject has r severallyed the star topology when the skin is touch simultaneously at two points. land the distance in which the subject first felt up the two-point threshold and repeat two trials for each body area listed below.Back of the neck or nape areaFingertipFore build (supine condition)Tip of nose ornamentation of hired handTongueUpper armThigh areaLeg areaTactile mendBegin the test by asking the s ubject to close his eyeball. Using a pencil tip, touch the skin of the test subject until it leaves an indentation. Then ask the subject to locate the exact spot using the pencil tips. Measure the wrongdoing of localization using the vernier caliper and repeat twice for each body location listed below. Observe the localization of improvement.PalmFingertipsForearm (dorsal side)Forearm (ventral side)LipsThigh region point Receptor translationBegin the test by asking the subject to sit and close its eyes. propose a coin on the fortify (antecubital fossa) of the subject. get down the meter of how long it takes until the champ cease. Once the sensation has ceased, add coins of the same size and record the time of pressure sensation. Repeat the same modus operandi on the other fortify and compare the observations.Ask the subject to close his eyes. Using a pencil tip, happen the tip over the strand of hair and slowly pulling it up until the hair spring remote from the tip. Ask the subject in which the sensation is greater when the hair is being bend or when it springs back.webers Law Sensation Intensity DifferenceBegin the test by asking the subject to sit on a bench and place his hand on the arm rest with eyes close. Put the 2-inch square cardboard on the distal phalanges of his index and middle finger. Gradually add 10 gram weight in the cardboard and ask the subject if he felt the weight. After the subjects smell out the weight, remove the cardboard unto the finger and add additional weight from 1 to 5 grams, until he felt the weight increases and compared it with the initial weight. Record the weight increment that produced an added weight sensation.Test other initial weights at 50, 100 and 200 grams and get the Webers dissever.Temperature Adaptation and Negative After-ImagePrepare three megabyte ml beakers with ice piddle, water at room temperature and waterbath at 50oC and assign each container into cold, room temperature and limber up water. A sk the subject to immerse each of his hand on the cold and warm water for two minutes. Record which hands adapts faster in the said temperature. Then rapidly immerse both hands in the waterbath. Describe the sensation on each hand.Referred PainAsk the subject to place his articulatio cubiti in ice water for 2-3 minutes. Are there any changes in sensation localization? Record your observation.ResultsVarious models in tactual localization and adaptation were used on selected areas of the skin for the demonstration of sensation acuity and relative sensitivity of the skin. Also, various stimuli, adaptation and aftersensation phenomenon were also use to understand different features of sensation. The following tables show the results on each exercises performed in this activity.mesa 1. Two-Point Sensibility.The table supra displays the results taken from the tactile distribution procedure for the two point sensitivity of different areas of the skin. Each area was applied with tactile stimuli from the caliper tips and the distance was recorded once the person had made a distinction of two-points. For the head fraction or medial part of the body, the nape area or the back of the neck, the tip of the nose and the spit got a threshold of 10mm, 8mm and 4mm, respectively. For the upper extremities, the fingertip, the palm of hand, the forearm in supine position and the upper arm got a threshold of 2mm, 8mm, 31mm, and 34mm, respectively. Lastly, for the lower extremities, the thigh area and the fork area got a threshold of 32mm and 36mm, respectively. expose of the nine different areas of the body where the stimuli was applied, the fingertip is noted to be having the most sensitive area darn the leg area is the least among them all.Table 2. Tactile Localization.The table above displays the results taken from the tactile localization procedure of different areas of the skin. Two trials were performed and their difference measures the phantasm of localization on eac h area. The fingertips and the lips received no error of localization since the subject had pointed the exact location of the indentation twice. This amount of error was followed by the palm having an error of localization of 1mm since the subject had pointed the indentation from a distance of 6mm on the 1st trial and 5mm on the second trial. This was then followed by the thigh area, the dorsal part of the forearm and finally the ventral part of the forearm having an error of localization of 5mm, 6mm and 16mm, respectively. Noticeably, the fingertips and the lips had the least error since it received no error at all as compared to the ventral portion of the forearm that had the most error of them all.Table 3.a. Adaptation of Touch Receptors.The table above displays the results taken from the touch receptors adaptation procedure applied on the right and left forearm. The subject had a coin placed on its forearm with the time recorded once it cant encounter the weight of the coin any more. The right forearms distinction is 5.1 seconds for one coin and 9.3 seconds for doubled while the left forearms distinction is 4.5 seconds for one coin and 8.8 seconds for doubled. This shows that the subjects left forearm adapts faster than its right forearm. The difference of time in distinction was measured through subtracting the seconds felt by the right forearm to the left forearm. Having doubled coin received a less difference of time in distinction than having a single coin since the recorded seconds are 0.5 seconds and 0.6, respectively. It is also noticeable that the sense of pressure is shorter when there is only one coin then, returned but got longer after the addition of coins.Table 3.b. Adaptation of Touch Receptors.(++) = felt most (+) = slightly felt (-) = not feltAnother adaptation procedure was performed using the subjects hair and the results are being shown on the table above. Its hair strand was bent and sprung back using a pencil tip. The subject responded that the sensation felt greater when the hair was sprang back and least when it was bent.Table 4. Sensation Intensity Difference.The table above displays the results taken from the sensation intensity difference procedure of the fingers using Webers Law. Different initial weights were given to the subjects two fingers which response was recorded after adding additional weights for the intensity difference. The Webers fraction came from the quotient of the two weights as how the formula displays on the table above. It is noticeable that the 10g weight got the most Webers fraction of 0.3 as compare to the other three weights 50g, 100g and 200g that got the same 0.1 Webers fraction.Table 5. Temperature Adaptation and Negative After-Image.(+) = adapts faster (-) = adapts slowly/not adaptingThe table above displays the results taken from the temperature adaptation and negative afterimage procedure of the two hands exposed on different temperatures. With hands in each beaker, the hand that is placed on warm water adapts faster than the ones in the cold water. When both hands were transferred onto the 3rd beaker containing room temperature water, the ones exposed on cold water earlier adapts too slow like it had foregone numb as compare to the ones exposed on warm water earlier.Table 6. Referred Pain.(+) = present sensation felt (-) = no sensation feltThe table above displays the results taken from the referred pain procedure applied at the elbow and had affected the sensation of the arm. After the elbow was dipped on an ice water for 2 minutes, the subject responded that the sensation had a change in location. It was then recorded that the location of the sensation is now felt on the upper arm.DiscussionConclusionThe skin, the largest organ of the body and its somatosensory system or touch system, allows the human body to perceive the physical sensations of pressure, temperature, pain, experience texture and temperature and perceive the position and movement of the bodys muscles and joints. Using various models and procedures, several accounts were recorded including the lips and fingertips as the most sensitive and the more wild weights and temperature as the slowest to be adapted. These are all due to the receptor cells found in the skin that can be broken down into three functional categories mechanoreceptors that sense different ranges of pressure and texture, thermoreceptors that sense and detect changes in temperature, and nociceptors that sense pain ranging from acute and easy to tolerate to chronic and intolerable.Literature CitedBoundless. Skin and Body Senses Pressure, Temperature, and Pain. Boundless Psychology. Boundless, 06 Oct. 2014. Retrieved 16 Jan. 2015 from https//www.boundless.com/psychology/textbooks/boundless-psychology-textbook/sensation-and-perception-5/sensory-processes-38/skin-and-body-senses-pressure-temperature-and-pain-165-12700/Experiencing Sensation and Perception. Chapter 12 Skin Senses. Retrieved from Ja nuary 17, 2015. Available at http//psych.hanover.edu/classes/sensation/chapters/Chapter 12.pdf.Touch. Retrieved from January 17, 2015. Available at http//psychology.jrank.org/pages/634/Touch.html