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Human Skin: Functions and Structure

Skin is the largest organ in the human body, It covers a total area of about 1.8 square meters. The skin is tasked with protecting our body from the external elements as well as microbes. The skin is also responsible for maintaining our body temperature. Once the skin was removed from the victim, hypothermia would set in within hours, causing the victim to freeze to death. Undoubtedly, it was also one of the most painful ways to die as there are millions of nerve endings and touch receptors in the skin.

Functions of the Skin

  • It primarily provides protection in these ways – prevents mechanical shocks, excess water loss, entry of disease-causing germs, and protection against excess UV
  • Serves as a sense organ for sensations such as pain, touch, pressure, etc
  • It is responsible to regulate temperature
  • Stores food in the form of a layer of fat contained in special cells
  • It synthesizes vitamin D when it is exposed to sunshine.

skin-layers

Structure Of Skin

It provides a protective covering throughout our body and acts as the body’s initial barrier against external harmful substances or foreign particles.  The hair is made up of a protein called keratin, and the same protein is found in hooves, horns, claws, and nails of other animals too.
The structure of the skin is made up of three layers,They are:

Epidermis

It is the outermost layer of the skin. The cells in this layer are called keratinocytes. The keratinocytes are composed of a protein called keratin. Keratin strengthens the skin and makes it waterproof. Melanocytes that produce melanin are also present in this layer. In addition, Merkel cells essential for light-touch sensation, and Langerhans cells, part of the immune system are also present on the skin.
The epidermis is subdivided into the following layers:

  • Stratum corneum
  • Granular cell layer
  • Spinous cell layer
  • Basal cell layer

Dermis

It consists of papillae which form finger-like projections. This layer constitutes of fat, fibres and collagen which makes the skin flexible and strong. Dermis synthesizes Vitamin D to absorb calcium on exposure to sunlight. It consists of blood vessels which supply blood for the formation of new cells. They are also vital in regulating body temperature. Nerves in the dermis are sensitive to environmental factors such as pressure and temperature. Also, it contains the hair follicles and sebaceous oil gland which produces sebum.
It acts as a lubricant and protects the skin by acting against the microbes. Sweat glands are produced all over the skin and release sweat through specialized ducts. They help the body to eliminate salts and minerals such as urea. An arrector pili muscle is attached to each hair follicle. This helps in the erection of hair when we experience cold or strong emotions.

Hypodermis

This subcutaneous layer is made up of fat and forms the innermost layer. Its thickness is dependant on the region where they appear and vary. For Ex: the area around the eye is comparatively thinner for the easy movement of the eye. Fat stored provides energy and is crucial in reacting to ambient temperature. It insulates the body from heat and cold. It cushions the internal organs, muscles and bones, and protects them from any injuries.