Sense of Touch (grades 5-8)

A virtual science-themed library created by neuroscientists at UNE for kids in grade k-8!

UNE's Brain Fair e-Library 

Why can't you tickle yourself?

Some scientists believe the&nbsp;cerebellum prevents us from tickling ourselves because it can distinguish expected sensations from unexpected sensations.

Your skin is covered with sensors that help you tell the difference between hot and cold!

These are called thermoreceptors and they help you avoid burning your hand on a stove, or freezing your hand on cold medal in the middle of winter!

The amount of pain a person feels can depend on many factors, including how much pain is expected, where on/ in the body pain is occurring, and environment a person is in when they are experiencing pain. 

Operation Ouch - Pain Receptors | Biology for Kids

Interestingly, the brain can modify the pain signals. Check out this video for a tip in dealing with pain.

Crazy, but true! People with red hair are more sensitive to pain. People with red hair have less of melanocortin-1 receptor, a gene which produces skin and hair pigment. Scientists have also determined this same gene helps the body regulate pain.

FMI click <a href="https://www.pbs.org/newshour/science/fact-or-fiction-do-redheads-feel-more-pain">here</a>!

This is a cross-section of your skin. You can see all the different sensors.

Image credit: https://biologyboom.com/write-a-note-on-mechanoreceptors-tactile-receptors-in-the-skin/

There are many different types of sensors that detect different feelings. All of these sensors connect to special cells in your body called “neurons”, and these neurons help communicate this information to your brain!

Neurons are some of the cells that make up your nerves, and your nerves connect your brain to your entire body.

All over your body you have specialized sensors that help detect harmful and painful things, like a paper-cut or a bee sting. These receptors are called nociceptors.

You also have tiny little discs deep in your skin called Pacinian Corpuscles that help feel pressure, like when you wear a heavy backpack to school!&nbsp;

The star-nosed mole&nbsp;is a small&nbsp;mole found in northern parts of North America. It is a unique animal that has a touch organ on it's face that has more than 25,000 sensory receptors. These receptors are known as&nbsp;Eismer's organs and they can detect&nbsp;seismic wave&nbsp;vibrations. It is through these vibrations it is able to sense or detect prey.

Center for Excellence in the Neurosciences

The narwhal is a type of whale that lives in arctic waters. Although few people have ever seen a narwhal, they are widely recognized for their unique tusk which lends itself to the most magical of nicknames: “unicorn of the sea.”

The narwhal’s tusk is actually an&nbsp;overgrown tooth, one of only two teeth they have. It was assumed that this tusk was used for breaking ice, but actually it is a giant sensory organ. 

The narwhal tusk is&nbsp;incredibly sensitive&nbsp;on the outside, with up to ten million nerve endings on each one!

You also have specialized sensors that help you tell when you’ve touched something, like picking up a baseball or grabbing onto a door handle. These specialized sensors are called Meissner’s Corpuscles!

All of the skin on your body is full of tiny microscopic sensors that help you interact and feel the world around! They help you tell whether something is hot, like a cup of hot cocoa, or heavy like a weight at the gym, or even scratchy like a wool sweater or sandpaper!

Lets take a closer look at what’s under your skin!

What did you observe while testing how well you could tell two toothpicks apart from one?

On the right here is a representative image of the shortest distance some of your body parts can tell the difference between one and two toothpicks!

Did you know that the cornea, the surface of your eye, has the greatest density of nerves in your body? Can you guess why? Please don’t poke your eye to find out!

(So-matt-Oh-sense-A-shin)

Somatic sensations are: touch, movement, body position, temperature and pain

This information is transmitted from the body to the brain through two separate pathways depending on the type of information they carry.

Pathway for: touch, movement, body position

Although your entire body is covered in these sensors, your body isn’t EVENLY covered in these sensors. Have you ever wondered why you feel things with your fingertips instead of your forearm? This is connected to how dense the sensors in your skin are.

The density of receptors in your skin can be measured by determining the shortest distance between 2 points that can be accurately distinguished as 2 points. The shorter the distance, the higher the density of receptors, and the greater the area of the cerebral cortex that is needed to represent that area.

At-Home Science: Two-Point Discrimination Test

Lets find out how well different parts of your body can tell the difference between one and two separate stimuli!

What you will need: •Construction paper, a ruler, toothpicks, and some tape…and a paper to record your observations •Your tool will look similar to the image below.

Did you know that there are special sensors in your fingers, toes, eyes and nose that help you feel the things around you? These are responsible for your sense of touch.

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