Esthetics Chapter #3: Physiology and Histology of the Skin
mast cells
involved in allergic reactions
__________ on epidermis side ensure strength and adhesion to the junction
keratin filaments
cells in epidermis
keratinocytes, melanocytes, immune cells, lamellar granules, and Merkel cells (nerve receptors)
glycosaminoglycans (GAGs)
large protein molecules and water-binding substances found between fibers of the dermis; maintain and support collagen and elastin in cellular spaces
intercellular matrix
lipid substances between corneum cells that protect cells from water loss and irritation
cells in basal layer produce
lipids that form cell membranes and hold cells together
stratum germinativum (basal cell layer)
located above dermis and composed of basal cells laying on a "basement membrane"
sensation
nerve fibers in the skin sense when we are being touched; cause us to feel, react or move
skin types
normal, dry, oily, sensitive, or combination
why is the acid mantle's pH important?
protects body from pathogens and regulates enzymatic function
collagen
protein substance of complex fibers that gives skin its strength and is necessary for wound healing
building blocks of tissues =
proteins
amino acids are building blocks of ________, amino acids form ________, and ________ form proteins
proteins; peptides; peptides
lymph vessels
remove waste products, bacteria and excess water
what is the acid mantle made up of?
sebum, lipids, sweat, and water
what causes damage to the barrier layer?
sensitivities, aging, and dehydration
how does the skin function to protect?
skin is a protective barrier with defense mechanisms to protect the body from injury and invasion; through sebum on epidermis
what works together to protect and regulate the body?
skin layers, nerves, cellular functions, hair follicles, and glands
healthy skin is....
slightly moist, smooth, and somewhat acidic
function of sebum
slows down evaporation of water (transepidermal water loss) and helps maintain water levels in the cells
ingredients with a _____ molecular size can penetrate the skin, ______ products penetrate better
smaller; lipid-soluble
what does the hypodermis contain?
vessels, nerves, fibers, adipose cells, fibroblasts
how do arrector pili in the skin allow for thermoregulation?
warms skin by air pockets create under hairs
skin type is based on
water content (determining its elasticity), oil production (determining its softness), and sensitivity (how it reacts)
transepidermal water loss (TEWL)
water loss caused by evaporation on the skin's surface
follicles
tubelike depressions with oil glands attached to them
pores
tubelike openings on sweat glands of epidermis
reticular layer
denser and deeper layer of the dermis, comprised mainly of collagen and elastin
how physiology and histology of the skin affect estheticians
- new understandings of functions of the skin and how skin interacts with new technology - developing an understanding of client's unique skin characteristics - making personalized treatment recommendations and home care regimens - skin is a very complex body system - learning about aging, UV damage, hormones, and nutrition
layers of the skin
1. hypodermis (subcutaneous tissue) 2. dermis 3. epidermis
6 primary functions of the skin
1. sensation 2. protection 3. heat regulation 4. excretion 5. secretion 6. absorption
5 layers of epidermis
1. stratum corneum 2. stratum lucidum 3. stratum granulosum 4. stratum spinosum 5. stratum germinativum (basal)
melanocytes make up ______% of cells in basal layer
5-10%
acid mantle's pH
5.5
collagen makes up ___% of dermis?
70
normal skin characteristics
few or no pores, radiant look, and little imperfections
what is collagen produced by?
fibroblasts
proteins and peptides trigger....
fibroblasts (cell stimulators) & cells to rejuvenate
elastin
fibrous protein that forms elastic tissue; contributes to stretch and elasticity of skin
keratin
fibrous protein that provides resiliency and protection
lymphocytes
fight infection
subcutis tissue
also known as adipose tissue; fatty tissue found below the dermis that gives smoothness and contour to the body, contains fat for use as energy, and also acts as a protective cushion for the outer skin.
oil skin comes from
androgen
what causes goosebumps?
arrector pili muscle
sebaceous glands
attached to hair follicles and produce oil which protects surface of the skin
penetration routes of skin
follicle walls, oil glands, intercellular, or transcellular
what is located in the dermis?
blood and lymph vessels, capillaries, follicles, sebaceous glands, sweat glands, sensory nerves, additional receptors, arrector pili muscles
our skin has miles of ____________, millions of ___________ and _________ within a network of fibers
blood vessels; sweat glands; nerves
stratum spinosum
cells continue to divide and change shape and enzymes are creating lipids and proteins
Lamellar granules
cells that contain lipids to maintain barrier function
melanocytes
cells that product pigment melanin and protect body from UV rays
__________ from epidermis are embedded into layers to provide strength and adhesion
collagen fibrils
stratum granulosum
composed of cells that resemble granules and are filled with keratin
extracellular matrix (ECM)
composed of collagen, other proteins, and glycosaminoglycans
keratinocytes
composed of keratin, lipids, and other proteins; comprise 95% of epidermis
function of extracellular matrix
comprise fluid with other components to maintain balance, provide dermal support, and assist cell metabolism, growth, and migration
hair papillae
cone-shaped elevations at base of the follicle that fit into hair bulb
dermis consists of
connective tissues made of collagen protein and elastin fibers
dermal/epidermal junction (DEJ)
connects dermis to epidermis; consists of layers of connective collagen tissue with many small pockets and holes
how does the body protect us from the cold?
constriction of blood vessels, decreased blood flow, and fat layers
blood vessel dilation _____ the body
cools
stretch marks are caused by
damaged elastin fibers
terminal differentiation
daughter cells that are not able to divide anymore are now programmed to end up as one specific type of cell
do the same or different nerve sensors detect different sensations such as heat, cold, touch, pain, and pressure?
different
characteristics of sensitive skin
dry, flushed, unable to protect nerve endings
keratinocytes and melanocytes form
even placement of pigment granules
what helps collagen and elastin retain moisture?
glycosaminoglycans
Langerhans cells
guard cells; work to absorb, process and carry antigens to the nearest lymph node
hard keratin is found in
hair and nails
appendages of the skin include
hair, nails, sweat glands, oil glands
keratinocytes become _______ in stratum corneum
hardened corneocytes
what controls skin's functions?
hormones, growth factors, and other biochemicals
evaporation
how skin cools itself on the surface; sweat
dry skin does well with products containing
humectants (attract water)
hyaluronic acid
hydrating fluids found in the skin; hydrophilic agent with water-binding properties
example of sensation
massage sends messages to the brain via nerve stimulation which lowers stress and promotes circulation
pigment granules are called _______ which produce ______
melanosomes; melanin
dermal papillae
membranes of ridges and grooves that are attached to the epidermis
tactile corpuscles
nerve endings that are sensitive to touch and pressure
androgen stimulates
oil production which in large quantities, enlarges pores, thickens their lining which then causes pimples
hydrolipidic film
oil-water balance that protects the skin's surface
sebum
oily substance that protects surface of the skin and lubricates skin and hair
layers of the dermis
papillary layer and reticular layer
Langerhans immune cells
protect body from infection by identifying antigens
acid mantle
protective barrier made up of sebum, lipids, sweat, and water
barrier function
protective barrier of the epidermis; the corneum and intercellular matrix protect the surface from irritation and dehydration
fibroblasts
produce proteins and aid in collagen and elastin production
what does epidermal growth factor and fibroblast growth factor do?
stimulate fibroblasts, cells, proteins, and DNA synthesis
epidermal growth factor
stimulates cells to reproduce and heal
which layer does cells undergo continuous mitosis in the skin?
stratum germinativum
what is the largest layer of the epidermis?
stratum spinosum
vitamin D is produced in skin upon...
sun exposure
perspiration
sweat glands release heat from body to keep us from overheating
desmosomes
the structures that assist in holding cells together; intercellular connections made of proteins; keratin filaments
how does the skin regulate body temperature?
through evaporation, perspiration, radiation, and insulation
how does the skin function in excretion?
through sweat glands
how does the skin absorb topical products?
through the cells, hair follicles, and oil glands
blood clotting allows skin
to heal itself to its normal thickness
Merkel cells (sensory cells)
touch receptors located in the basal layer
leukocytes
white blood cells, fight infection; have enzymes to digest and kill bacteria, parasites, and allergies