A guide to your sense of touch

The skin has several structures which are involved in relaying touch messages. They are:

Receptor endings

The sensory receptors receive their signals from the receptor endings. There are several different types, each one responds to a different type of touch.

Sensory receptors

The skin has sensory receptors which receive information from the external environment. These receptors can discern between the following inputs:

• Pain

• Heat

• Cold

• Touch

• Pressure

The amount of receptors will vary from one part of the body to another. For example, there are more pain receptors than cold receptors throughout the body. Furthermore, some body parts will feel higher levels of one type of touch than another. The fingertips, for example, have the highest amount of touch receptors in the body.

Nerve fibres

They relay the messages from the sensory receptors to the nerves, and from there on the brain. There are different types of nerve fibres present. Some only react to sudden changes in condition such as sharp pain, for example, whereas others are continually providing some kind of feedback.

Once the touch system picks up signals and relays them into the nerves, they are then forwarded onto the post central gyros. This is an area in the front, middle part of the brain. This area is also referred to as the somatosensory cortex, and it is the main sensory reception and coordinating area, within the brain.

It is the somatosensory system which discerns what to do with different touch signals. Some of this process is hard-wired into the body. For example, the pain reflex is governed by the autonomic nervous system. This is an ancient nerve complex in the body, which dates back to the earliest stages of human development. Its function is to maintain life. So, in the case of a person who places their hand on a hot surface without looking, he does not have to think about what to do. Rather, pain is felt and the body immediately recoils.

However, many aspects of human touch control are learned rather than
hard-wired responses. For example, a child might enjoy playing in water, and then associates this with the pleasurable feeling of running water. Later in life, this person may well immediately feel pleasure whenever he/she is in running water.