Call your doctor if your baby: 1  Is under 3 months old and has a temperature over 100.4 F. 2  Is over 3 months old and has a fever over 102 F. 3  Has a fever that lasts longer than 24 hours.  Has diarrhea, vomiting, or a rash with the 1  fever. Is very sleepy or looks sick.  Can't be soothed.
There is two main pigments found in human hair: Eumelanin has an oval or elliptical shape, which gives color to brown or black hair and is dark pigment. The higher the concentration of Eumelanin the darker the hair. Pheomelanin is what produces the color in blonde or red hair.
1 Melanocyte stem cells are responsible for regeneration of melanocytes, a type of pigment cell. 2  Melanocytes produce the pigment melanin, and therefore play an important role in skin and hair follicle pigmentation. 3  It is not yet certain where these stem cells are found in humans. These stem cells are found in the basal layer of the epidermis. 2  Hair follicle stem cells ensure constant renewal of the hair follicles. 3  They can also regenerate the epidermis and sebaceous glands if these tissues are damaged. 4  Hair follicle stem cells are found throughout the hair follicles.