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Integumentary System

Consists of the integument (epidermis & dermis) and its structures (hair, glands & nails)


Two or more types of tissues grouped together and performing specialized functions

The outer layer of skin, called __________ , is composed of stratified squamous epithelium



Cutaneous Membrane

Stratum Basale

Deepest Layer

Stratum Basale

1) is the deepest layer of the epidermis (closest to dermis) 2) Membrane basal cells are stem cells of epidermis. 3)If this layer of skin is destroyed, new skin cannot regenerate. Consists of 1.KERATINOCYTES, 2. MERKEL'S CELLS, and 3. MELANOCYTES

Basal Cell Layer

Stratum Basale

A single row of cuboidal or columnar cells that divide and grow

Stratum Basale


organic process by which keratin is deposited in cells and the cells become horny (as in nails and hair)

Stratum Spinosum

Next to deepest layer Spiny Layer Several layers of cells changing shape (due to keratinization) Some mitosis (only in the deepest portion)

Stratum Granulosum

3 - 4 layers (depending on skin thickness) of cells Continues to flatten as keratinization increases

Stratum Lucidum

Clear Layer (Soles, Palms and Lips) Most structures are not visible (translucent), only in the thick skin

Stratum Corneum

"Horn Like Layer" 25 - 30 + layers of flattened scalelike, keratinized cells that are continously shedding


inner, thick layer composed of connective tissue. contains a matrix of collagen for sterngth and elastin for elasticity. includes blood vessels, hair follicles, nail follicles, sensory receptors, and glands.


Subcutaneous layer, attaches dermis to underlying tissue, adipose, areolar connective tissues (energy reserve and padding), vascular Is involeved in thermoregulation 8% thicker in females site of SQ injections


pigment cells


insoluble pigments that account for the color of e.g. skin and scales and feathers


Provides epidermis with nutrients and aids in thermogegulation

Stratum Reticular

The Reticular Layer Lower 4/5ths of the dermis Primarily dense irregular fibrous connective tissue This layer is between the papillary and subcutaneous layers. It is where most of the structures of the dermis are located, such as hair follicles, sebaceous and sweat glands, nerves, and blood vessels

Stratum Papillarosum

Upper 1/5th of dermis, primarily AREOLAR connective tissue Location of dermal papillae (extensions into epidermis) that form friction ridges

Stratum Papillarosum

This is the upper layer which is in contact with the epidermis. This layer contains dermal papillae and epidermal ridges. The dermal papillae have capillaries that supply cells of the epidermis.

Pili (Hair)

Shaft is dead above skin surface Root is anchored within the skin Bulb is the enlarged base that is the site of Mitosis Color is determined genetically, based on type and amount of pigment produced in the bulb


the fine downy hair covering a human fetus normally shed during the ninth month of gestation


Adult hair, grows continuously, we often cut it to manage it (heads and beards)

Definitive Hair

Adult hair that only grows to a certain length (eyebrows, eyelashes, etc.)

Arrector Pili Muscles

smooth muscles of the skin, attached to hair follicles; when contraction occurs, the hair stands up, resulting in "goose bumps"


Hard, transparent plates of keratinized epidermal cells that grow from root underneath skin fold called the cuticle; nails are smooth and firm and the nail plate shoudl be firmly attached to the nail bed


Half-moon-shaped, whitish area at the base of a nail (area of mitosis)

Exocrine Glands

release their secretions into a duct that carries them to the outside of the body

Sebaceous Glands

Oil glands associated with hair follicles (secrete sebum)


fatty or oily secretion produced by the sebaceous glands

Sudoriferous Glands

Sweat glands

Eccrine Glands

Most numerous sweat glands non oderous involved in thermoregulation

Apocrine Glands

Sweat glands found in axillary and genital region and produces an odor

Mammary Glands

In females, secrete milk under hormonal control

Ceruminous Glands

Modified apocrine glands found in the external ear canal secrete CERUMEN (ear wax)

Functions of Skin

Physical protection, protects against fluid loss, regulates temperature, helps absorb gasses, Synthesis of vitamin D, sensory reception, and communication


Maintenence of body temperature


abnormally high body temperature

Means of Body Heat Loss

Radiation, evaporation, convection, conduction


The transfer of heat through space from warmer surfaces to cooler surrounding


the process of converting a liquid to a gas (ex: sweat of skin)


The transfer of heat by air currents


transfer of heat by direct contact (ex; laying on cool floor)


Dangerously low body temperature caused by prolonged exposure to cold; extreme loss of body heat. "below heat"


reduces blood flow and heat loss by decreasing the diameter of superficial vessels.

Means of Maintaining Heat

Vasoconstriction, sweat cessation, goose-bumps

Cutaneous Absorption

The absorption of drugs, allergens, and other substances through unbroken skin

Synthesis of Vitamin D

precursors for vitamin D are found in the skin. When the skin is exposed to ultraviolet light, these precursors are converted into active vitamin

Sensory Reception

to detect heat, cold, touch, pressure, + pain Done in conjunction with the nervous system

Causes of Skin Color

Melanin, carotene, hemoglobin

Specialized cells known as melanocytes produce ___________, a dark pigment in the deeper layer of the epidermis



orange-yellow skin pigment from diet


Red pigment in blood cells


Absence of pigment in the skin, hair, and eyes due to lack of melanin secretion


redness of the skin; may be caused by capillary congestion, inflammation, heat, sunlight or cold temp or embarrassment


bluish discoloration of the skin, associated with poor circulation, lack of oxygen


deficient amount of oxygen in tissue cells


yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood Ex. can be a symptom of gallstones or liver infection or anemia

Cutaneous Carcinoma

(basal cell and squamous cell) are the most common type of skin cancer

Cutaneous Melanoma

Melanomas develop from melanocytes and range in color from brown to black and gray to blue. The outline of a malignant melanoma is irregular, rather than smooth, and is often bumpy. Unlike cutaneous carcinomas, melanoma is generally not associated with continued sun exposure. A cutaneous melanoma may arise from normal-appearing skin or from a mole. The lesion grows horizontally but may thicken and grow vertically into the skin, invading deeper tissues. If the melanoma is removed before it invades the deeper tissues, its growth may be arrested. Once it spreads vertically into deeper tissue layers, it is difficult to treat and the survival rate is very low


Degradation of the connective tissue fibers in the skin due to age and other contributing factors such as sun exposure, and smoking

Linea Albicans

Stretch Marks Occurs when elastic fibers in the connective tissue are stretched too far


Due to the the underlying dermal papillae used for grip friction

Decubitus Ulcers

aka bed sores. caused by constant deficiency of blood to the tissues usually over boney projections. occurs in bedridden patients.


Inflammation of the skin due to hypersensitivity or infection

Acne Vulgaris

Hyperactivity of the sebaceous glands, most common skin disorder


Hyperthermal damage to the skin

Rules of 9

An aid for estimating the extent of damage burns cause, the body is subdivided into regions, each representing 9% (or some multiple of 9%) of the total skin surface

1st Degree Burns

Superficial, redness, swollen, surface layers only, symptoms local only, minor discomfort, no blister or scar (mild sunburn)

2nd Degree Burns

Deep epidermis and upper dermis are damaged, skin is red with blisters

3rd Degree Burns

damages the entire thickness of the skin; skin appears to be charred; nerve endings destroyed, requires skin grafing


the actual freezing of tiissue fluids accompanied by damage to the skin and underlying tissues

1st Degree Frostbite

Cyanosis and swelling

2nd Degree Frostbite

Blisters and hyperemic skin

3rd Degree Frostbite

Sever edema, bleeding, pain or numbness, necrosis


Death of tissue


baldness; hair loss


Itching of the skin.

Wound Healing

1)Wound occurs, vessels are broken, bleeding occurs 2) Blood clot forms (activation of platelets and fibroinogen) 3) Scab forms, inflammation occurs to isolate and destroy dead cells and invading bacteria, growth factors are released from injury cells 4) Formation of granulation tissue, if damage is not severe, it acts as a framework for new epethelial tissue, if severe...scar tissue is formed 5) Scab is sloughed

Layers of Epidermis from Top to Bottom

Come, Look, Grandmother, Spit, Balls Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale

Function of Melanin other than color

Melanin aside from giving color to skin, absorbs ultraviolet radiation in sunlight which would cause mutations in the DNA of the skin cells

7 Functions of Integumentary System

PSSHTCC Physical Protection; barrier to pathogens and UV light Synthesizes Vitamin D; compounds in the skin combine with UV rays from the sun to make vitamin D Sensory Reception; detects hot/cold, pain, pressure Hydroregulation; protects body from desiccation or water absorption keratin Thermoregulation; regulates temperature against hyperthermia and hypothermia by sweating, vasoconstriction, vasodilation Cutaneous Absorption; gasses, small amounts of UV light, certain toxins Communication; non-verbal, chemical, and visual

Skin Glands


Layers of Dermis from Top to Bottom

PR Stratum Papillarosum (Papillary) upper 1/5 Stratum Reticularosum (Recticular Layer) lower 4/5

Sweat Glands

Eccrine Apocrine (stinks)

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