Sense of TouchSense of Touch

Presented by:Presented by:

Silva, Ma. Edelyn A.Silva, Ma. Edelyn A.

Su, Jennifer Katherine T.Su, Jennifer Katherine T.

ContentsContents

The somatosensory systemThe somatosensory systemThe touch receptorThe touch receptorMechanoreceptorsMechanoreceptorsThermoreceptorsThermoreceptorsPain receptorsPain receptorsProprioreceptorsProprioreceptorsRelation to Dentistry / ApplicationRelation to Dentistry / Application

Somatosensory SystemSomatosensory System

The Ability To Sense The Ability To Sense Touch.Touch.

This system is responThis system is responsible for all the sensatisible for all the sensations we feel - cold, hot, ons we feel - cold, hot, smooth, rough, pressusmooth, rough, pressure, tickle, itch, pain, vire, tickle, itch, pain, vibrations, and more.brations, and more.

A touch receptor is considered A touch receptor is considered rapidly adaptingrapidly adapting if it if it responds to a change in stimulus very quickly. Basically responds to a change in stimulus very quickly. Basically this means that it can sense right away when the skin is this means that it can sense right away when the skin is touching an object and when it stops touching that touching an object and when it stops touching that object. However, rapidly adapting receptors can't sense object. However, rapidly adapting receptors can't sense the continuation and duration of a stimulus touching the the continuation and duration of a stimulus touching the skin (how long the skin is touching an object). These skin (how long the skin is touching an object). These receptors best sense vibrations occurring on or within receptors best sense vibrations occurring on or within the skin.the skin.

A touch receptor is considered A touch receptor is considered slowly adaptingslowly adapting if it does if it does not respond to a change in stimulus very quickly. These not respond to a change in stimulus very quickly. These receptors are very good at sensing the continuous receptors are very good at sensing the continuous pressure of an object touching or indenting the skin but pressure of an object touching or indenting the skin but are not very good at sensing when the stimulus started are not very good at sensing when the stimulus started or ended.or ended.

Touch ReceptorsTouch Receptors

Within the somatosensory system, theWithin the somatosensory system, there are four main types of receptors: mre are four main types of receptors: mechanoreceptors, thermoreceptors, paechanoreceptors, thermoreceptors, pain receptors, and proprioceptors. in receptors, and proprioceptors.

11 . .MechanoreceptorMechanoreceptor

These receptors perceive These receptors perceive sensations such as pressusensations such as pressure, vibrations, and texture. re, vibrations, and texture.

There are four known typeThere are four known types of mechanoreceptors whs of mechanoreceptors whose only function is to percose only function is to perceive indentions and vibratieive indentions and vibrations of the skin: Merkel's dions of the skin: Merkel's disks, Meissner's corpusclesks, Meissner's corpuscles, Ruffini's corpuscles, ans, Ruffini's corpuscles, and Pacinian corpuscles. d Pacinian corpuscles.

Merkel's disks and Meissner's coMerkel's disks and Meissner's corpusclesrpuscles

The most sensitive The most sensitive mechanoreceptors.mechanoreceptors.

Found in the very top Found in the very top layers of the dermis and layers of the dermis and epidermis and are epidermis and are generally found in non-generally found in non-hairy skin such as the hairy skin such as the palms, lips, tongue, soles palms, lips, tongue, soles of feet, fingertips, eyelids, of feet, fingertips, eyelids, and the face. and the face.

Merkel's disks are slowly adapting receptors and Merkel's disks are slowly adapting receptors and Meissner's corpuscles are rapidly adapting receMeissner's corpuscles are rapidly adapting receptors so your skin can perceive both when you aptors so your skin can perceive both when you are touching something and how long the object ire touching something and how long the object is touching the skin. Your brain gets an enormous touching the skin. Your brain gets an enormous amount of information about the texture of objes amount of information about the texture of objects through your fingertips because the ridges thcts through your fingertips because the ridges that make up your fingerprints are full of these senat make up your fingerprints are full of these sensitive mechanoreceptors. sitive mechanoreceptors.

Ruffini's corpuscles and PaciniaRuffini's corpuscles and Pacinian corpusclesn corpuscles

Located deeper in the Located deeper in the dermis and along joints, dermis and along joints, tendons, and muscles.tendons, and muscles.

These These mechanoreceptors can mechanoreceptors can feel sensations such as feel sensations such as vibrations traveling down vibrations traveling down bones and tendons, bones and tendons, rotational movement of rotational movement of limbs, and the stretching limbs, and the stretching of skin. This greatly aids of skin. This greatly aids your ability to do physical your ability to do physical activities such as walking activities such as walking and playing ball. and playing ball.

2.2. ThermoreceptorsThermoreceptors These receptors perceive sensations related to the tempThese receptors perceive sensations related to the temp

erature of objects the skin feels.erature of objects the skin feels. They are found in the dermis layer of the skin.They are found in the dermis layer of the skin. There are two basic categories of thermoreceptors: hot aThere are two basic categories of thermoreceptors: hot a

nd cold receptors.nd cold receptors. Thermoreceptors are found all over the body, but cold recThermoreceptors are found all over the body, but cold rec

eptors are found in greater density than heat receptors. Teptors are found in greater density than heat receptors. The highest concentration of thermoreceptors can be founhe highest concentration of thermoreceptors can be found in the face and ears (hence why your nose and ears ald in the face and ears (hence why your nose and ears always get colder faster than the rest of your body on a chilways get colder faster than the rest of your body on a chilly winter day. ly winter day.

Cold receptorsCold receptors Start to perceive cold Start to perceive cold

sensations when the surface sensations when the surface of the skin drops below 95 º of the skin drops below 95 º F. They are most stimulated F. They are most stimulated when the surface of the skin when the surface of the skin is at 77 º F and are no is at 77 º F and are no longer stimulated when the longer stimulated when the surface of the skin drops surface of the skin drops below 41 º F. This is why below 41 º F. This is why your feet or hands start to your feet or hands start to go numb when they are go numb when they are submerged in icy water for a submerged in icy water for a long period of time. long period of time.

Hot receptorsHot receptors Start to perceive hot Start to perceive hot

sensations when the sensations when the surface of the skin surface of the skin rises above 86 º F and rises above 86 º F and are most stimulated at are most stimulated at 113 º F. But beyond 113 º F. But beyond 113 º F, pain 113 º F, pain receptors take over to receptors take over to avoid damage being avoid damage being done to the skin and done to the skin and underlying tissues. underlying tissues.

3.3. Pain receptorsPain receptors There are over three million pain receptors throughout There are over three million pain receptors throughout

the body, found in skin, muscles, bones, blood vessels, the body, found in skin, muscles, bones, blood vessels, and some organs. and some organs.

They can detect pain that is caused by mechanical stimuli They can detect pain that is caused by mechanical stimuli (cut or scrape), thermal stimuli (burn), or chemical stimuli (cut or scrape), thermal stimuli (burn), or chemical stimuli (poison from an insect sting). (poison from an insect sting).

These receptors cause a feeling of sharp pain to These receptors cause a feeling of sharp pain to encourage you to quickly move away from a harmful encourage you to quickly move away from a harmful stimulus such as a broken piece of glass or a hot stove stimulus such as a broken piece of glass or a hot stove stop. stop.

They also have receptors that cause a dull pain in an They also have receptors that cause a dull pain in an area that has been injured to encourage you not to use or area that has been injured to encourage you not to use or touch that limb or body part until the damaged area has touch that limb or body part until the damaged area has healed. While it is never fun to activate these receptors healed. While it is never fun to activate these receptors that cause pain, they play an important part in keeping that cause pain, they play an important part in keeping the body safe from serious injury or damage by sending the body safe from serious injury or damage by sending these early warning signals to the brain.these early warning signals to the brain.

44.. ProprioceptorsProprioceptors Proprioceptors are found in tendons, muscProprioceptors are found in tendons, musc

les, and joint capsules. This location in the les, and joint capsules. This location in the body allows these special cells to detect cbody allows these special cells to detect changes in muscle length and muscle tensihanges in muscle length and muscle tension. Without proprioceptors, we would not bon. Without proprioceptors, we would not be able to do fundamental things such as fee able to do fundamental things such as feeding or clothing ourselves. eding or clothing ourselves.

Touch in DentistryTouch in Dentistry … …

Simple touch reinforces the connection with Simple touch reinforces the connection with patients. patients.

People have different threshold of pain.People have different threshold of pain. Pressure may be perceived by patients as pain Pressure may be perceived by patients as pain

in some dental procedures. in some dental procedures. We use our fingers and We use our fingers and also our tongue and lips also our tongue and lips to explore in order to identify to explore in order to identify structures and forms.structures and forms.

One of the most troublesome biological One of the most troublesome biological factors that dentists must deal with is factors that dentists must deal with is bacterial infection. In addition to the bacterial infection. In addition to the sensitivity caused by infections, the initial sensitivity caused by infections, the initial inability of oral infections in the teeth and inability of oral infections in the teeth and boney structures to drain results in the boney structures to drain results in the build up of pressure. As bacteria quickly build up of pressure. As bacteria quickly multiplies and produces gaseous toxins, multiplies and produces gaseous toxins, pressure increases and pain results. pressure increases and pain results.

Managing the feeling of the Managing the feeling of the patientpatient . .

Operator should know where to rest their Operator should know where to rest their fingers during operation.fingers during operation.

Comfort of the patient.Comfort of the patient.Tell your patient what sensation they could Tell your patient what sensation they could

feel during the procedure. feel during the procedure.

Thank You