Skin, Hair & Nails Flashcards
basal cell layer
forms new skin cells. Their major ingredient is the tough, fibrous protein keratin. The melanocytes interspersed along this layer produce the pigment melanin, which gives brown tones to the skin and hair
Melanocytes
produce the pigment melanin, which gives brown tones to the skin and hair. All people have the same number of melanocytes; however, the amount of melanin they produce varies with genetic, hormonal, and environmental influences.
horny cell layer.
This layer consists of dead keratinized cells that are interwoven and closely packed.
The epidermis is completely replaced every _____ weeks. In fact, each person sheds about _______pound of skin each year.
The epidermis is uniformly thin except on the surfaces that are exposed to friction, such as the palms and the soles.
4, 1
The epidermis is avascular; it is nourished by blood vessels in the _________ below.
dermis
Skin color is derived from three sources:
(1) mainly from the brown pigment melanin
(2) also from the yellow-orange tones of the pigment carotene
(3) from the red-purple tones in the underlying vascular bed.
The dermis is the inner supportive layer consisting mostly of connective tissue, or __________.
collagen
The nerves, sensory receptors, blood vessels, and lymphatics lie in the __________.
dermis
The subcutaneous layer is _________ tissue, which is made up of lobules of fat cells.
What is its purpose?
adipose
The subcutaneous tissue stores fat for energy, provides insulation for temperature control, and aids in protection by its soft cushioning effect. Also, the loose subcutaneous layer gives skin its increased mobility over structures underneath.
vestigial
not needed
People have two types of hair:
Fine, faint vellus hair covers most of the body (except the palms and soles, the dorsa of the distal parts of the fingers, the umbilicus, the glans penis, and inside the labia).
terminal hair, the darker, thicker hair that grows on the scalp and eyebrows and, after puberty, on the axillae, the pubic area, and the face and chest in the male.
Dry skin results from loss of ______, not directly from loss of oil.
water
Function of the Skin
“Triple P TIC WAP”
Protection Prevents penetration Perception Temperature regulation Identification Communication Wound repair Absorption & Excretion Production of Vitamin D
Function of the Skin: Production of vitamin D
The skin is the surface on which ultraviolet light converts cholesterol into vitamin D.
Function of the Skin: Absorption and excretion
Skin allows limited excretion of some metabolic wastes, byproducts of cellular decomposition such as minerals, sugars, amino acids, cholesterol, uric acid, and urea.
Function of the Skin: Wound Repair
Skin allows cell replacement of surface wounds.
Function of the Skin: Communication
Emotions are expressed in the sign language of the face and in the body posture. Vascular mechanisms such as blushing or blanching also signal emotional states.
Function of the Skin: Identification
People identify one another by unique combinations of facial characteristics, hair, skin color, and even fingerprints. Self-image is often enhanced or deterred by the way society’s standards of beauty measure up to each person’s perceived characteristics.
