Biological processes and hygiene Human hair close-up Care of the hair and care of the scalp skin may appear separate but are actually intertwined because hair grows from beneath the skin. The living parts of hair ( hair follicle , hair root , root sheath , and sebaceous gland ) are beneath the skin, while the actual hair shaft which emerges (the cuticle which covers the cortex and medulla) has no living processes. Damage or changes made to the visible hair shaft cannot be repaired by a biological process, though much can be done to manage hair and ensure that the cuticle remains intact. Scalp skin, just like any other skin on the body, must be kept healthy to ensure a healthy body and healthy hair production. If the scalp is cleaned regularly by those who have rough hair or have a hair-fall problem, it can result in loss of hair. However, not all scalp disorders are a result of bacterial infections. Some arise inexplicably, and often only the symptoms can be treated for manage