Hair is a very important part of the human body. It is one of the defining characteristics of mammals and a very important part of the body as it serves several purposes. Some of which include: warmth, protection and beauty.
The growth of the hair begins inside the hair follicle (a dynamic organ found in the mammalian skin) which follows a specific growth cycle having specific characteristics that determine the length of the hair. The hair follicle is fed by nutrient-rich blood supply and as such, poor diet disrupts the nutrient supply to the follicle thereby affecting the growth of the hair. An overall balanced diet is essential for a shiny, lustrous and strong hair.
Research shows that there are about 100,000 to 350,000 hair follicles on the human scalp, with each growing an average of 1000 days and rests for a period of around 100 days before being shed and new hair begins to grow. This varies from person to person and can be influenced by age, diet, weather and state of health. If kept in a good and perfect condition, your hair would grow an average of half an inch every month.
While human beings have devised several means of staying warm during outdoor activities by making use of different head wears and jackets, the hairs found on the human body primarily serves as a source of heat insulation as it helps to keep the internal body temperature regulated while protecting the body from ultra-violet radiation exposure. In many mammals such as hedgehogs and porcupines, hair can be very dense and then is referred to as fur. These have been transformed into hard spines or quills and these are covered with thick layers of keratin which serves as a form of protection against their predator. In humans, body hair is mostly reduced as it doesn’t play a major role in temperature regulation as it does in other animals.
The hair on the human scalp provides both protective and adornment functions as it protects the head from various elements by serving as a thermal insulator. It also protects the scalp from sunburn and other effects of light radiation. Hair on other parts of the human body also provide related protective and adornment functions. The eyelash which grows at the edges of the eyelids protects the eyes from dirt. They are used to sense when sweat, dust, dirt and any other potential substance that is harmful to the eyes are very close to the eyes, that is why the eyes reflexively close as a result of the sensation and also, it helps to reduce the amount of light that enters the eyes. Eyebrows, which are the hairs found around the eye area also serves as a shield to the eyes as it prevents dirt, sweat and water from making its way into the eyes. They also play an important role in non-verbal communication as they are able to display several emotions like excitement, sadness, surprise and even anger. In animals, the hairs (fur) on their body are connected to the nerves and also serve as a transmitter for sensory input.
Apart from giving warmth to the body and serving as a protection to the body, hair also serves as a great social significance for human beings as it is mainly cosmetic and contributes greatly to the way a person looks. Hair grows all over the body. The only places it does not grow are the lips, the soles of our feet, the palms and the fingers.