Ch. 10: Physiology & History of the Skin Flashcards
What is the largest organ in the body?
Skin / Integumentary System
What is the basic material and foundation (building blocks) of our cells and skin?
Proteins
Where is skin thickest?
Palms of the hands and soles of the feet (approximately 4mm)
Where is skin thinnest?
Eyelids (1.5mm)
How much does the skin of an average adult weigh?
7 lbs.
What are the 6 primary functions of the skin?
Sensation Heat Absorption Protection Excretion Secretion
What is the acid mantle?
The protective barrier made up of Sebum, Lipids, Sweat, and Water.
Define: Hydrolipidic
Hydrolypidic film is an oil-water balance that protects the skins surface.
What is the average pH of the skin?
5.5
Define: Barrier Functions
Protective barrier of the epidermis; the corneum and intercellular matrix protect the surface from irritation and dehydration.
What is Transepidermal Water Loss (TEWL) ?
Water loss caused by evaporation on the skin’s surface.
What is the Intercellular Matrix?
Lipid substances between corneum cells that protect the cells from water loss and irritation.
What is the skin’s most amazing feature?
To heal itself.
What is the Epidermal Growth Factor (EGF) ?
Stimulates cells to reproduce and heal.
Fibroblasts are triggered by _____ and _____.
Proteins and Peptides
What are Fibroblasts?
Cells that stimulate cells, collagen, and amino acids that form proteins.
Describe the skin function; Sensation.
Sensory nerve endings in the dermis respond to touch, pain, cold, heat, and pressure.
Describe the skin function; Heat Regulation
- The body’s average internal thermostat is 98.6℉ (37℃)
- The body maintains thermoregulation through evaporation, perspiration, radiation, and insulation.
- Millions os sweat glands release heat from the body through perspiration to keep from overheating.
- Blood flow and vessel dilation assist in cooling the body.
- Fat layers help to insulate and warm the body.
What is an Esthetician’s primary focus?
Preserving, Protecting, and Nourishing the Skin.
What is the Arrector Pili Muscles?
Small, involuntary muscles in the base of the hair follicle that causes “gooses bumps” when the appendage contracts.
Describe the skin function; Excretion
Sweat Glands (sudoriferous glands) excrete perspiration and detoxify the body by excreting excess water, salt, and unwanted chemicals through the pores.
What are Sudoriferous Glands?
- Also known as Sweat Glands.
- Excrete perspiration, regulate body temperature, and detoxify the body by excreting excess salt & unwanted chemicals.
Define: Pores
Tube-like openings for sweat glands on the epidermis.
Describe the skin function; Secretion
- Oil Glands (sebaceous glands) which produce sebum, help keep the skin softand protected from outside elements.
- Sebum coating the surface of the skin slows down the evaporation of water & helps maintain water levels in the cells.
Define: Follicles
Hair follicles and sebaceous follicles are tube-like openings in the epidermis.
Describe the skin function; Absorption
- Absorption of ingredients, water, and oxygen is necessary for our skins health.
- The skin selectively absorbs topical products, & creams through the cells, hair follicles, and sebaceous glands.
- Vitamin D is synthesized and produced in the skin upon exposure to the sun.
What 2 Layers is the skin comprised of?
The Epidermis and Dermis
What is the Epidermis?
The outermost layer of skin; a thin, protective layer with many cells, mechanisms, and nerve endings. It is made up of 5 layers.
What are the 5 Layers of the Epidermis?
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Germinativum
What are Keratinocytes?
Epidermal cells composed of keratin, lipids, and other proteins.
What is Keratin?
Fiberous protein of cells that is also the principal component of skin, hair, and nails; provides resiliency and protection.
Name the Epidermal Layer:
Function: Is the top, outermost layer of the epidermis; consisting of hardened corneocytes. Is very thin, yet it is waterproof, permeable, regenerates itself, detoxifies the body, and responds to stimuli.
Stratum Corneum
horny layer
What are Corneocytes?
- Another name for stratum corneum cells.
* Hardened, waterproof, protective keratinocytes; these dead protein cells are dried out and lack nuclei.
Define: Desquamation
The process of keratinocytes continually being shed from the skin.
Name the Epidermal Layer:
Function: A thin, translucent layer of dead skin cells beneath he outermost layer of the epidermis. The cells here release lipids forming bilayers of oil and water. Forms our fingerprints and footprints.
Stratum Lucidum
clear layer
Name the Epidermal Layer:
Function: Composed of cells that resemble granules and are filled with keratin. In this layer, enzymes dissolve the structures (desmosomes) that hold cells together. Fatty acids and other intracellular lipids are made here.
Stratum Granulosum
granular layer
What is the average cell turnover rate in adults?
28 days
Name the Epidermal Layer:
Function: Is the largest layer in the epidermis. Cell appendages, which resemble prickly spines, become Desmosomes and Langerhans are also found in this layer. Forms the even placement of pigment granules.
Stratum Spinosum
spiny layer
Name the Epidermal Layer:
Function: Is located above the dermis. Stem cells undergo continuous cell division (mitosis) to replenish the regular loss of skin cells shed from the surface. Merkel cells are located in this layer.
Stratum Germinativum
basal cell layer
What is Terminal Differentiation?
Daughter cells that are unable to divide anymore are now programmed to end up as one specific kind of cell.
What are Merkel Cells?
Touch receptors or sensory cells located in the basal layer.
Define: Melanocytes
Cells that produce skin pigment granules in the basal layer.
Define: Melanosomes
Pigment carrying granules that produce melanin.
Define: Melanin
A complex protein that determines hair, eye, and skin color, and a defense mechanism to protect skin from the sun.
What are Dendrites?
The arms, or cellular projections, that branch out to interact with other cells in the extracellular matrix between cells.
What is the enzyme that stimulates melanocytes and thus produces melanin?
Tyrosinase
What 2 types of melanin does the body produce? How are they different?
Pheomelanin: red to yellow in color.
Eumelanin: dark brown to black.
What are products used to suppress melanin production by interrupting biochemical processes referred to as?
Brightening Agents or Tyrosinase Inhibitors
What is the Dermis?
- also called the Derma, Corium, Cutis, or true skin.
- Is the support layer of connective tissue, collagen, and elastin below the epidermis.
- Supplies the skin with oxygen and nutrients
Define: Collagen
A protein substance of complex fibers that gives skin its strength and is necessary for wound healing.
Define: Elastin
The fibrous protein that forms elastic tissue that gives skin its elasticity.
What is the function of Lymph Vessels?
To remove waste products, bacteria, and excess water.
What is Ground Substances?
Also referred to as the Extracellular Matrix (EMC). Is a fluid matrix composed of collagen, other proteins, and GAGs (glycosaminoglycan’s).
What are Glycosaminoglycans?
Found between the fibers of the dermis; A water-binding substance that maintains water balance, providing dermal support and assist cell metabolism, growth, and migration.
What is Hyaluronic acid?
- Hydrating fluids found in the skin; hydrophilic agent with water-binding properties.
- Is a Glycosaminoglycan
The Dermis consist of what 2 layers?
Papillary and Reticular
Name the Dermal Layer:
Function: Connects the dermis to the epidermis, forming the dermal/epidermal junction. Consists of capillaries (nourish skin), or corpuscles (nerve endings), and the small cone-shaped structures at the bottom of hair follicles.
Papillary Layer
Name the Dermal Layer:
Function: Denser layer of the dermis, is comprised mostly of collagen and elastin. Can be broken down by UV damage and other factors.
Reticular Layer
How long does hair on the scalp grown on average per day?
.35mm / per day
Hair contains what percentage of Keratin?
90%
What is the technical term for a nail?
Onyx
The dermis of the skin contains what two types of duct glands and what do they produce?
Sebaceous glands: excrete oils
Sudoriferous glands: excrete sweat
Describe Sebaceous Glands
- Are connected to the hair follicle and produce oil, which protects the surface of the skin.
- Oily secretions lubricate both the skin and the scalp.
- If the ducts become clogged, comedones (blackheads) are formed.
Describe Sudoriferous Glands
- Help regulate body temperature and eliminate waste products by excreting sweat. The excretion of sweat is controlled by the nervous system.
- Contains two types of sweat glands. Apocrine and Eccrine.
- Have a coiled base and duct openings at the surface.
What are Apocrine Glands?
- Coiled structures attached to the hair follicles found under the arms and in the genital area.
- Secretions are released through the oil glands and
more active during emotional changes. - Odors associated with these glands are due to the interaction of secretions and bacteria on the surface of the skin.
What are Eccrine Glands?
- Found all over the body; primarily the forehead, palms, and soles.
- These glands are not connected to the hair follicle and do not typically produce an odor.
- More active when the body is subjected to physical activity and high temperatures.