Your skin is the largest organ in your body. It makes up about
16% of your body weight and covers about 1.73 square meters.
The skin is composed of
several layers. The very top layer is the epidermis and is the
layer of skin you can see. The epidermis is waterproof and
serves as a protective wrap for the underlying skin layers and
the rest of the body. It contains melanin, which protects
against the sun’s harmful rays and also gives skin its color.
The epidermis also contains very sensitive cells called touch
receptors that give the brain a variety of information about the
environment the body is in. It is the layer upon the dermis, the
second layer of skin.
The dermis contains
hair follicles, sweat glands, oil glands, blood vessels, nerve
endings, and a variety of touch receptors. Its primary function
is to sustain and support the epidermis by diffusing nutrients
to it and replacing the skin cells that are shed off the upper
layer.
The bottom layer is the
subcutaneous tissue which is composed of fat and connective
tissue. The layer of fat acts as an insulator and helps regulate
body temperature. It also acts as a cushion to protect
underlying tissue from damage when you bump into things. The
connective tissue keeps the skin attached to the muscles and
tendons underneath.
Our sense of touch is
controlled by a huge network of nerve endings and touch
receptors in the skin known as the somatosensory system. This
system is responsible for all the sensations we feel – cold,
hot, smooth, rough, pressure, tickle, itch, pain, vibrations,
and more. Within the somatosensory system, there are four main
types of receptors: mechanoreceptors, thermoreceptors, pain
receptors, and proprioceptors.
Mechanoreceptors
perceive sensations such as pressure, vibrations, and texture.
Thermoreceptors
perceive sensations related to the temperature of objects the
skin feels.
Pain receptors detect
pain or stimuli that can or does cause damage to the skin and
other tissues of the body.
Proprioceptors sense
the position of the different parts of the body in relation to
each other and the surrounding environment.
Your skin regenerates itself about every 28 days and you have an
entirely new layer of skin. It naturally sheds dead skin cells
every day.
There are millions of bacteria on your skin. These bacteria are
harmless, and your skin microbiota can even help your immune
cells to fight microbes that can cause diseases.