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