Identification

• Hair is a thin string-like matter that grows from the skin of mammals. Hair follicles typically contain an oil gland that lubricates the strands of hair and keeps it soft. Hair grows in cycles, which includes a growth and rest cycle for the hair follicles. During the resting phase, the hair stops growing. During the growing phase old hair is shed, as new hair pushes it from the follicle.
  
  

Features

• Hair consists of a root and shaft. The part of hair that grows under the skin's surface is surrounded by a follicle. The bottom of the shaft of hair is a root. The bulbous end of the root is the hair bulb, and this is where the hair develops from cells. These cells, which come from the bulb, divide quickly. The papilla extends into the hair bulb near the base of the follicle, which contains an artery that provides blood to the root. This blood is needed to feed the cells.
  
  

Time Frame

• Human hair follicles are active for two to six years, and then go into the rest phase for about three months. During the summer months hair tends to grow faster. Children's hair typically grows faster than adults. Diet, health, age and seasons all affect the growth pattern of hair. Baldness is caused when the follicles die and fail to produce new hair. Baldness is more common in men than women, and hereditary characteristics play a significant factor in baldness.
  
  

Types

• Hair comes in various colors and textures. Hair that is straight has a round shape, while curly hair is flat. Those with the flattest shafts of hair have the curliest hair. The color is determined by the pigments. Melanin is a brown-black pigment. Yellow-red pigment is also present, yet it only shows up when there is little melanin in the hair.
  
  

Benefits

• Most mammals have a coat of hair which provides warmth for their bodies. In some animals, hair provides protection or sensory functions. Humans also grow hair all over their bodies. Although humans view hair primarily as cosmetic, the hair that grows around the eyes or in the nose provides protection. This type of hair keeps dust and bugs from vital organs. Eye brows can decrease the amount of light reflected into a human's eyes.