CH. 3 Physiology & Histology Flashcards
The study of the structure & composition of skin tissue.
Skin Histology.
The study of living organisms.
Physiology.
Largest & one of the most important organs of the body.
Integumentary system (skin).
Where is the thinnest skin on the body?
Eyelids.
Where is the thickest skin on the body?
Palms & Soles of feet.
Appendages of the skin include…
Hair, nails, sweat, & oil glands.
Acid mantle is made up of…
sebum, lipids, sweat, & water.
Acid mantle has an average pH of…
5.5
Skin’s mechanism that protects from irritation & intercellular trans-epidermal water loss.
Barrier function.
Caused by evaporation on the skin surface.
TEWL
Substances that contribute to the barrier function of the epidermis.
Lipids.
The intercellular cement between epidermal cells is made up of…
Lipids.
The pigment in the eyes, hair, & skin that gives us some protection from UV rays emitted by the sun.
Melanin.
Most abundant in the fingertips, thus are designed to be one of the most sensitive parts of the body.
Sensory nerve fibers.
Average body temp is…
98.6
Accomplished by constriction of blood vessels & decreased blood flow. When the arrector pili muscles contract and cause “goose bumps”
Protection from cold.
Fat layers help insulate & warm the body.
Protection from heat.
Millions of sweat glands release heat from the body through…
Perspiration.
Excrete perspiration & detoxify the body by excreting excess water, salt, & unwanted chemicals through the pores.
Sudoriferous Glands. (aka sweat glands)
Sweat like sebum is part of the…
Acid Mantle.
Opening for the sweat glands…
Pores.
An oily substance that protects the surface of the skin & lubricates the skin & hair.
Sebum.
Soften the skin, & protect skin from outside elements
Sebaceous Glands.
Slows evaporation.
Sebum.
Penetration is determined by…
The size of the molecule.
Means “between” the cells.
Intercellular.
Means “across” or through the cells.
Transcellular.
What are the layers of the skin?
Epidermis & Dermis.
Outermost & thinnest layer of the skin.
Contains no blood vessels.
Has many nerve endingd & is composed of 5 layers.
Epidermis.
Composed of keratin, comprise 95% of the epidermis.
Contain both protein & lipids.
Keratinocyte.
The mother cells that divide in the basal layer forming new daughter cells.
Stem cells.
Composed of 5 layers called strata.
Epidermis layer.
Top outermost layer of the epidermis.
Thin yet waterproof, permeable regenerates itself, detoxifies the body, & responds to stimuli.
AKA the horny layer.
Stratum Corneum.
The shedding of keratinocytes between skin cells.
Desquamation.
Flat, scaly keratinized cells also called keratinocytes.
Squamous cells.
The average cell turnover rate for the skin cells of the epidermis is…
28 days.
The clear, transparent layer just under the skin surface.
It consists of small cells through which light can pass.
Also forms our unique fingerprints & footprints.
Stratum Lucidum.
Consists of cells that look like distinct granules & they are filled w/ keratin.
The production of keratin & intercellular lipids also take place here.
Stratum Granulosum.
Above the Stratum germinativum.
AKA the spiny layer.
Stratum Spinosum.
The protein bonds that create the junctions between the cells.
Desmosomes.
Protect the body from infections by identifying foreign material (antigens).
Langerhans cells.
Largest layer of the epidermis.
Stratum Spinosum.
Deepest layer in the epidermis.
In this layer, stem cells undergo continuous cell division.
Also contains melanocytes.
AKA basal cell layer.
Stratum Germinativum.
Cells that produce pigment granules.
Melanocytes.
Produce a complex protein (melanin) which determines skin, eye, & hair color.
Melanosomes.
Stimulated by exposure to sunlight & protects the cells below by absorbing & blocking UV radiation.
Melanin production.
Children
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Stratum Corneum.
Stratum Lucidum,
Stratum Granulosum.
Stratum Spinosum.
Stratum Germinativum (basale)
The enzyme that stimulates melanocites & thus produces melanin.
Tyrosinase.
What are the 2 types of melanin?
Pheomelanin.
Eumelanin.
Red to yellow in color. (melanin)
Pheomelanin.
Dark brown to black. (melanin)
Eumelanin.
About 25x thicker than the epidermis.
It is highly sensitive & contains blood vessels, lymph vessels, nerves, sweat & oil glands, hair follicle, arrector, arrector pili muscles, & papillae.
AKA Derma, corium, cutis, or true skin.
Dermis.
Connects the dermis to the epidermis.
Dermal epidermal junction.
What are the two layers of the epidermis?
Papillary.
Reticular.
Superficial layer of the dermis.
Papillary.
Deeper layer of the dermis.
Reticular.
Produce proteins & aid in the production of collagen & elastin.
Fibroblast cells.
A protein substance of complex fibers that gives skin its strength & is necessary for wound healing.
Collagen.
Makes up 70% of the dermis.
Collagen.
Gives support & function to the skin.
Collagen.
The fibrous protein that forms elastic tissue & gives skin its elasticity.
Elastin.
The primary cause of wrinkles is the damage &…
Loss of elastin.
Hair contains 90%…
Hard keratin.
Ingrown hair or _____ is a bacterial infection.
Folliculitis.
Hair on the scalp grows an average of… per day.
.35 millimeters
(1/60 inch) per day
Connects the dermis to the epidermis, forming the epidermal/dermal junction.
Comprises 10-20% of the dermis.
Papillary layer.
Denser & deeper layer of the dermis.
Comprised mainly of collagen & elastin.
Damage to these elastin fibers is the primary cause of sagging, wrinkles, & aging.
Makes up 80% of the dermis.
The Reticular layer.
Sits below the reticular layer.
Composed of loose connective tissue or subcutis tissue, aka adipose tissue.
This layer is 80% fat.
This tissue creates a protective cushion that gives contour & shape to the body, as well as providing a source of energy.
This layer decreases & thins w/ age.
Subcutaneous tissue.
Cordlike bundles of fibers made up of neurons.
Form a network of pathways for conducting information throughout the body.
Nerves.
What are the two types of nerves?
Motor (efferent)
Sensory (afferent)
Stimulate muscles, such as the arrector pili muscles, attached to the hair follicles.
Motor nerves.
Secrete oil.
Sebaceous glands.
Secrete sweat.
Sudoriferous glands.
Connected to the hair follicle & produce oil, which protects the surface of the skin.
If the ducts become clogged, comedones or blackheads form.
Larger on the face & scalp.
Sebaceous glands.
Fluids that nourish the skin.
Blood & lymph.
Supplies oxygen & nutrients to the skin.
Blood.
Nutrients are molecules from food such as…
Proteins, carbohydrates, & fats.
Help regulate body temp & eliminate waste products by excreting sweat.
They have a coiled base & duct opening at the surface known as pores.
Sudoriferous glands.
What are the two types of sweat glands?
Apocrine.
Eccrine.
Coiled structures found under arms & in the genital area.
More active during emotional changes.
Apocrine glands.
Found all over the body but primarily on the forehead, palm, & soles.
Eccrine glands.
A complex defense mechanism that protects the body from foreign substances.
Immune system.
Molecules formed to fight & neutralize bacteria, viruses, & antigens.
Antibodies.
Identify molecules that have foreign peptides.
T-cells.
White blood cells that have enzymes to digest & kill bacteria & parasites.
Leukocytes.
…. surround cells & provide protection, hydration, & nourishment to the cells.
Intercellular lipids & proteins.
A group of waxy lipid molecules important to barrier function & water holding capacity as glycolipids.
Ceramides.
Reduced if the skin is dry, damages, or matures.
Lipids.
Organs such as the skin, heart, liver, & kidneys have their cells replaced every…
6 to 9 months.
Cells of the bones are replaced every…
7 years.
…are not easily replaced after being damaged by UV radiation.
Elastin & collagen.
The sun and its… have the greatest impact on how skin ages.
Ultraviolet (UV) electromagnetic radiation.
Ultraviolet Radiation (UVR) is a proven…
Carcinogen.
UV exposure alters DNA & can cause…
Skin cancer.
Approximately how much of aging is caused by sun exposure?
80-85%
UVA is also known as…
Aging rays.
Contribute up to 95% of the sun’s ultraviolet radiation reaching the earth’s surface.
Penetrate into the skin & cause genetic damage to the cell & death.
Wakens the skins collagen & elastin fibers causing skin sagging & wrinkles.
Present all year and more prevalent than UVB.
UVA radiation.
UVB is also known as…
Burning rays.
Causes burning of the skin as well as tanning, aging, & cancer.
Contributes to the body’s synthesis of Vitamin D & other important minerals.
UVB radiation.
Molecules w/ an unbalanced electrical charge.
Take electrons from compounds in the body such as proteins, lipids, or DNA.
The destabilize & oxidize the once healthy molecules & create more free radicals, starting a chain reaction of cellular destruction.
Free radicals.
Pollutants can also change the health of the _____ thereby speeding up the aging process.
Underlying cells & tissues.
Caused by an elevation of blood sugar.
Contributes to aging, wrinkles & age spots as well as many other age related diseases such as arterial stiffening, cataracts, & neurological impairment.
Glycation.
Chronic vascular disorder characterized by couperose veins & congestion of the skin.
Rosacea.
Often suggested to balance estrogen for women experiencing menopause.
May be linked to breast cancer.
Hormone replacement therapy (HRT)
Applying moisturizing lotions, sunscreen, & even foundation helps protect skin from….
Airborne pollutants & the environment.
Consuming alcohol also has a damaging affect on the skin by…
Dilating the blood vessels & capillaries, causing them to burst over time.
Anything tht causes a rise in our blood sugar results in…
Inflammation on a cellular level.
Estrogen is a crucial hormone for..
Good health & the appearance of the skin.
_____ is an anti inflammatory & antioxidant & is a key factor in tissue repair.
Estrogen.
Changes begin in pre-menopause because of a decrease in…
Estrogen.
Hormone Replacement Therapies (HRT) may be derived from…
Animal source estrogen or plant source estrogen.
