A: Touch is to use your skin to have physical contact with another object.  Touch receptors are located in clusters around your skin.  They look like onions or jelly material.  When the are squeezed, the layers rub against each other causing an electrical nerve impulse.  The most sensitive touch receptors are located at your face, back of your neck, chest, arm (upper), fingers, soles of your feet, and between your legs. 

A: This is a chart showing all of the sensory receptors in skin; the name, function, and location.

A: Skin works with the hypothalamus.   Regions of the hypothalamus contain heat and cold sensitive cells.  The hypothalamus responds by increasing the number of nerve impulses transmitted by the brain.   That lets the skin adjust. 

When you get hot, it is called hyperthemia.   Your skin tries to prevent it from going over 37 degrees Celsius (99 degrees Fahrenheit).  Sweat glands in your skin are activated which cools the skin and body (after the sweat evaporates).  The arteriovenous anastomis also opens which causes the flow of blood the increase.  It's basically used as a cooling system.  The good thing about blood is that it also adjusts according to the skin temperature.   If it is too hot, blood can be used for cooling.  If it is too cold, blood is used for warming up.  Another thing that also changes is that the arrector pilli relaxes, letting hair stick holding the water down onto the skin, which allows the water to cool.  Finally, your blood vessels open so that more blood can enter.

There is also a name for when you are too cold, hypothermia.  "Too Cold" for your body is when your temperature is under 36.5 degrees Celsius (under 97 degrees Fahrenheit).  The arteriovenus anastomosis closes (so that blood knows to warm instead of cool), letting blood flow increase.   Also, the arrector pilli tightens, not allowing hair to stick and not keeping water cool you so you will not be colder.  Goose pimples/goose bumps will also form; they have no use to humans but it makes other mammals warmer.  Goose pimples are formed when the muscles in your hair follicles contract.  Shivering also helps you warm up.   It increases the muscle activity in your body and produces heat.  Lastly, the blood vessels close so there is less heat loss.

But how?  Well, basically, your brain knows when, and therefore sends messages to the hypothalamus which makes the skin adjust accordingly.

A: Your skin lets out human waste by sweating.   Sweating consists of salt and water.  It lets out this waste only when you are hot.  Sweat comes from the pores of your skin and is a system of cooling.  When you are hotter, during a hot season, you let out more waste in the form of sweat.   The sweat glands in your skin trigger sweat and are connected to pores.  The hypothalmus tells the brain when to trigger sweat and your brain controls the skin to do so.

A: Hair is used for warmth and also help you cool down.  Hair grows from the follicles in the Epidermis.  Cells at the root will divide and push upward, causing hair to grow up.  At a certain height, the hair dies and kertin hardens it.  Melanin controls the hair color that you have.

Fingerprints are "replacing" hair.   Wherever there is no hair, there are fingerprints.  Fingerprints are tiny ridges on your fingers and toes which enable those parts to be more sensitive to touch.   No two people's fingerprints are the same.  Fingerprints are formed naturally, many months before you are born.

A: Acne usually occurs during puberty when there is a change in your hormone levels.  That causes extra keratin to produce, which leads to blackheads, and finally acne.

Cuts and bruises are formed when your skin is punctured.  These are caused when blood vessels bleed into the surrounding tissue.   After you bleed, platelets and other substances allow scabs to grow.  The scab helps protect the injured area until new skin growns and the scab falls off.

A: Three basic disorders occur in your skin (there are too many to mention all).  They are acne, skin cancer, and dermatitis. 

Acne usually occurs in teenagers.  It is when extra keratin is made, leading to blackheads then acne. 

Skin cancer can come to people of all ages.   It is when your skin is exposed to too many ultraviolet rays.

Dermatitis (including eczema) occurs in children aged 5 and up.   A rash forms, usually on the chest, elbow, and/or knees.  Skin looses water and becomes dry which causes itchyness.  This skin disorder is very hard to cure and is may be caused by the body's immune response attacking itself.

A: There are three main disorders/diseases that are most common.  Here is a quick review telling about all of them:

Attention Defict Disorder, otherwise known as ADD occurs in people of all ages.  It can be associated with making your sense of touch much more sensitive than other people.  It is caused when things aren't being filtered through your brain properly.

Another disorder is Tactile defensiveness, which also can be a problem for people of all pages.  People with this disorder have a tendency to react negatively to the sensation of touch and possibly trigger anxiety or panic.

Sensory Intergrative Dysfunction is another disorder.  It usually occurs in kids.  It makes people uneasy, have poor balance, and have under or over sensitivity to touch.  The main cause is that there is a dysfunction in the central nervous system.

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