Hair Structure, Growth, and Function

102.14 Hair Theory Term Trichology main purposes of hair the shape of the follicle will determine the two primary parts of the hair hair root hair fiber papilla germinal matrix cells hair pulled out from the roots will grow again unless 3 major layers of hair cuticle cortex merdulla sebaceous oil glands sebum oil acid mantle arrector pili muscle keratinization hair is primarily made up of amino acids coil around each other to become protein chains that form the twisting gives hair ability to 3 stages of hair growth anagen catagen telogen hair growth can be affected by 3 factors affecting the behavior of hair hereditary enviornment products or appliances cuticle cortex higher cuticle/cortex ratio lower cuticle/cortex ratio melanocytes produce melanosomes which contain the pigment two types of melanin eumelanin pheomelanin melanins influence the resulting hair colors by albinism gray hair Definition technical name for the study of hair protection from heat, cold, and injury shape of the hair shaft hair root and hair fiber portion of hair inside the hair follicle under the skin's surface portion of hair that extends above skin's surface filled with capillaries that supply nourishment to cells around it undergo cell division produce cells that ultimately keratinize and form the three layers of hair the papilla is destroyed 1. cuticle 2. cortex 3. merdulla outer covering of the hair shaft second layer with unique protein structures central core of the hair shaft produce sebum to prevent hair and skin from becoming too dry mixes with perspiration to form the acid mantle protects the cuticle of hair fiber and maintains the natural pH of the hair and skin causes hair to stand on end when a person is scared or cold process of cells changing shape, drying out, and forming keratin protein protein cortex stretch 1. anagen 2. catagen 3. telogen active growing attached root sheath brief transitional cell division stops resting no attached root sheath illness lack of vitamins and minerals disease medication Hereditary environment products or appliances determines hair structure, color, shape, and diameter affects absorption of moisture from the air affect structural organization of hair hair, reistant, coar soft, elastic, fine more resistant easily molded melanin eumelanin and pheomelanin brown/black red/yellow the amount, size, and distribution total lack of pigmentation in the hair and skin reduced melanin in cortex referred to as mottled hair grows from papilla with gray color results usually from natural aging can be caused by serious illnesses, emotional conditions, and heredity melanin in the skin when looking through a microscope, which portion of the hair would display living cells? hair grows from a tube-like "pocket" called a root sheath or the follicle in straight hair is typically the hair follicle that produces tightly curled hair is typically located on the bottom of the follicle and supplying nourishment to the germinal matrix is the the outer covering of the hair shaft made up of overlapping layers of transparent scales is called the the layer of hair consisting of unique protein structures that give the hair most of its pigment and strength is called the hair that has been pulled out from the roots will grow back under which of the following circumstances what helps prevent the hair and skin from becoming too dry what is formed when sebum produced by the oil glands mixes with the body's perspiration the muscle that causes the hair to stand on end when a person is scared or cold is known as the which of the following terms is known as the active growing stage of hair catagen, a brief transitional stage, lasts for what amount of time the resting stage of hair growth when the hair bulb has no attached root sheath Is referred to as the the lips, soles of the feet, palms of the hands, and eyelids do not have hair that is 90% cortex and 10% cuticle when compared to hair that is 40% cuticle would be considered to be what is the total lack of pigmentation in the hair and skin called gray hair is caused by a eumelanin is the type of melanin that produces people with lighter colored hair have melanin in the protects both skin and hair from sun's damaging rays sent to surface to protect the skin's sensitive cells, resulting in a "suntan" hair bulb follicle round elliptical papilla cuticle cortex the papilla has not been destroyed sebum acid mantle arrector pili anagen stage only a few weeks telogen stage hair more elastic albinism reduced color pigment, melanin, in the cortex layer of the hair brown/black hair color cortex only