Hair Structure

Cuticle – Human Hair

Cuticle – Oragutan hair

Human Orangutan

Slight Lifting Normal cuticle

Cuticle damage by overperming

Asian hair is straight and thick, and resists damage well

Caucasoid hair can be anything from blond to black in color, and may be curly, wavy or straight

African hair is vulnerable to damage, because of its shape and twisted structure

Hair Bulb

Hair follicle

Hair shaft

Brush down Brush up

Hair strength

HAIR FACTS The phases of the hair growth cycleIt is easy to remember the lengths of the different phases ofthe growth cycle. Very roughly speaking: anagen 1000 days (or more) catagen 10 days telogen 100 daysThe hair growth cycle, showing the changes from the growing of a new hair (anagen) to its shedding (telogen): notice how in anagen the hair bulb lies deep inside the scalp and then rises towards the surface before the hair is shed, then moves down again as the new hair growsThe phases of the hair growth cycleIt is easy to remember the lengths of the different phases ofthe growth cycle. Very roughly speaking: anagen 1000 days (or more) catagen 10 days telogen 100 daysThe hair growth cycle, showing the changes from the growing of a new hair (anagen) to its shedding (telogen): notice how in anagen the hair bulb lies deep inside the scalp and then rises towards the surface before the hair is shed, then moves down again as the new hair grows Hair growth Cycle

The phases of the hair growth cycle It is easy to remember the lengths of the different phases of the growth cycle. Very roughly speaking: anagen 1000 days (or more) catagen 10 days telogen 100 days The hair growth cycle, showing the changes from the growing of a new hair (anagen) to its shedding (telogen): notice how in anagen the hair bulb lies deep inside the scalp and then rises towards the surface before the hair is shed, then moves down again as the new hair grows

A method of measuring the rate of hair growth: both cut hairs and newly emerging hairs can be seen

Differences in hair length depend on the length of anagen, which is genetically determined. These two people started off with hair of the same length and went without a haircut for 18 months: the man's hair grows only to his collar before it falls out naturally, but the woman's anagen period is clearly much longer

Electronmicrograph showing new hairs emerging from the hair follicles of the scalp

Zinc deficiency Normal

Hair density patterns

Normal Telogen Phase hair compound e- micrograph

An anagen hair that has been plucked out: notice the soft, sticky tail

A hair, carrying some normal fragments of debris, seen under the electron microscope