Protective barrier of the epidermis; the corneum and intercellular matrix protect the surface from irritation and dehydration.
barrier function
Lipid substances between corneum cells that protect the cells from water loss and irritation
intercellular matrix
Abbreviated EGF; stimulates cells to reproduce and heal.
epidermal growth factor
Cells that stimulate cells, collagen, and amino acids that form proteins
fibroblasts.
Small, involuntary muscles in the base of the hair follicle that cause goose flesh when the appendage contracts, sometimes called goose bumps and papillae.
arrector pili muscle
Guard cells of the immune system that sense unrecognized foreign invaders, such as bacteria, and then process these antigens for removal through the lymph system.
Langerhans immune cells
Oil that provides protection for the epidermis from external factors and lubricates both the skin and hair.
sebum
Fibrous protein of cells that is also the principal component of skin, hair, and nails; provides resiliency and protection.
keratin
Outermost layer of skin; a thin, protective layer with many cells, mechanisms and nerve endings. It is made up of five layers: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum germinativum.
epidermis
Chronic condition that appears primarily on the cheeks and nose and is characterized by flushing (redness), telangiectasis (distended or dilated surface blood vessels), and, in some cases, the formation of papules and pustules.
rosacea
Capillaries that have been damaged and are now larger, or distended blood vessels; commonly called couperose skin.
telangiectasia
Coiled structures attached to hair follicles found in the underarm and genital areas that secrete sweat.
apocrine glands
Sweat glands found all over the body with openings on the skin’s surface through pores; not attached to hair follicles, secretions do not produce an offensive odor.
eccrine glands
Also called derma, corium, cutis, or true skin; support layer of connective tissue, collagen, and elastin below the epidermis.
dermis layer
Also known as hypodermis; subcutaneous adipose (fat) tissue located beneath the dermis; a protective cushion and energy storage for the body.
subcutaneous layer
Deeper layer of the dermis containing proteins, collagen, and elastin that give the skin its strength and elasticity.
reticular layer
Top layer of the dermis next to the epidermis.
papillary layer
Also known as horny layer; outermost layer of the epidermis, composed of corneocytes
There are 15 to 20 layers in this layer
stratum corneum
Clear, transparent layer of the epidermis under the stratum corneum; thickest on the palms of hands and soles of feet.
stratum lucidum
Also known as granular layer; layer of the epidermis composed of cells filled with keratin that resemble granules; replace cells shed from the stratum corneum.
stratum granulosum
Also known as spiny layer; layer of the epidermis above the stratum germinativum layer containing desmosomes, the intercellular connections made of proteins.
stratum spinosum
Also known as basal cell layer; active layer of the epidermis above the papillary layer of the dermis; cell mitosis takes place here that produces new epidermal skin cells and is responsible for growth.
stratum germinativum
White blood cells that have enzymes to digest and kill bacteria and parasites. These white blood cells also respond to allergies.
leukocytes
Protein fiber found in the dermis; gives skin its elasticity and firmness.
elastin
Glycolipid materials that are a natural part of skin’s intercellular matrix and barrier function.
ceramides
Caused by an elevation in blood sugar, glycation is the binding of a protein molecule to a glucose molecule resulting in the formation of damaged, nonfunctioning structures, known as Advanced Glycation End products( a.k.a. AGES). Glycation alters protein structures and decreases biological activity.
glycation
The protective barrier made up of sebum, lipids, sweat, and water.
Acid mantle
Tube like openings for sweat glands on epidermis
Pores
Fatty tissue found below the dermis that gives smoothness and contour to the body., contains fat for use of energy, and also acts as a protective cushion for the outer skin.
Adipose tissue
Creative oxidants that search the body for other electrons that will allow them to become stable, neutral molecules again.
Free radicals
the study of the structure and
composition of the skin tissue.
Histology
the study of the functions of
living organisms.
Physiology
specialist in the cleansing,
beautification, and preservation of the
health of the skin on the entire body
including the face and neck
Esthetician
technicians,
skin therapists, or specialists.
Estheticians are referred to as
• Covers 22 square feet.
• Weighs about 7 pounds.
• Protects muscles, bones, and nerves.
• Serves as a barrier against environment.
• Eyelids have thinnest skin.
• Palms and soles have thickest skin.
• Contains about one-half to two-thirds of
the blood in the body.
• Contains one-half of the primary immune
cells.
Skin Facts
- Slightly moist.
- Soft and flexible.
- Smooth and fine-grained.
- Possesses slightly acid reaction.
Healthy Skin Characteristics
- Millions of cells
- 8 feet of blood vessels
- 32 feet of nerves
- 650 sweat glands
- 100 oil glands
- 65 hairs
- 1,300 nerve endings
- 155 pressure receptors
- 12 cold and heat receptors
Contents of One
Square Inch of Skin
– Sensation – Heat Regulation – Absorption – Protection – Excretion – Secretion
Skin Functions
• Protects body from injury and bacterial
invasion.
• Acid mantle is a protective barrier made
up of sebum, lipids, sweat, and water.
• The hydrophilic component protects skin
from drying out and exposure.
• Skin repairs itself when injured.
Protection
(pigment protects skin from the sun)
Melanin
• Skin responds to: • Heat, cold, touch, pressure, pain • Millions of nerve-end fibers on the skin’s surface detect stimuli. • Sensations send messages to the brain.
Sensation
• Protects body from environment.
• Average body temperature is 98.6 degrees.
• Maintains thermoregulation through:
• Evaporation, perspiration, radiation, and
insulation
• Protects from cold and heat.
Heat Regulation
• Sudoriferous glands: sweat glands
excrete perspiration and detoxify the body
by excreting excess water, salt, and
unwanted chemicals.
• Pores: openings for the sweat glands; the
vehicle through which waste is excreted.
Excretion
• Sebum lubricates the skin and hair.
• Skin is about 50 to 70 % water.
• Sebum slows evaporation of water
(transepidermal water loss – TEWL).
• Emotional stress and hormone imbalances
can stimulate oil glands to increase sebum
flow, which can lead to skin problems.
Secretion
The skin is composed of two main layers, the epidermis and the
dermis.
Layers of the Skin
the mother cells that divide in the
basal layer forming new daughter cells.
Stem cells
move up through layers before
becoming hardened corneocytes
of the stratum corneum.
Daughter cells
• Stratum corneum – the “horny” cells. • Stratum lucidum – the “clear” cells. • Stratum granulosum – the “grainy” cells. • Stratum spinosum – the “spiny” cells. • Stratum germinativum – the “growth” layer.
Epidermis Layers
• Pheomelanin: Red to yellow in color. Fair skin has about 20 melanosomes per keratinocyte. • Eumelanin: Dark brown to black. Dark skin contains about 200 melanosomes per keratinocyte.
Two Types of Melanin
• Motor nerve fibers: distributed to arrector
pili muscles attached to hair follicles;
cause goose flesh; include secretory
nerves.
• Sensory nerve fibers: react to heat, cold,
touch, pressure, and pain; send messages
to the brain.
Nerves
• Hair is an appendage of the skin. • Hair is a slender, threadlike outgrowth of the skin and scalp. • Hair contains 90 percent hard keratin, which forms long, continuous sheets (fingernails) or long, endless fibers (hair).
Hair and the Skin
- The nail is an appendage of the skin.
- A hard, translucent plate that protects the fingers and toes.
- Composed of keratin.
- Onyx is the technical term for nail.
- Nail contains no blood vessels and grows about 1/10th of an inch per month.
Nails and the Skin
Blood and lymph nourish the skin.
Skin Nourishment
• Also known as aging rays. • Contribute up to 95% of sun’s UVR reaching the Earth’s surface. • UVA weakens the skin’s collagen and elastin fibers causing wrinkling and sagging in the tissues. • Can penetrate glass and clouds.
UVA Rays
• Also known as burning rays.
• Cause burning, tanning, aging, and skin
cancer.
• Skin should be checked regularly for signs
of potential skin cancer.
UVB Rays