Consists of the integument (epidermis & dermis) and its structures (hair, glands & nails)
The outer layer of skin, called __________ , is composed of stratified squamous epithelium
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
organic process by which keratin is deposited in cells and the cells become horny (as in nails and hair)
Next to deepest layer Spiny Layer Several layers of cells changing shape (due to keratinization) Some mitosis (only in the deepest portion)
3 - 4 layers (depending on skin thickness) of cells Continues to flatten as keratinization increases
Clear Layer (Soles, Palms and Lips) Most structures are not visible (translucent), only in the thick skin
"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
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
Upper 1/5th of dermis, primarily AREOLAR connective tissue Location of dermal papillae (extensions into epidermis) that form friction ridges
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.
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
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
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
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.
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
to detect heat, cold, touch, pressure, + pain Done in conjunction with the nervous system
Specialized cells known as melanocytes produce ___________, a dark pigment in the deeper layer of the epidermis
redness of the skin; may be caused by capillary congestion, inflammation, heat, sunlight or cold temp or embarrassment
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
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
Stretch Marks Occurs when elastic fibers in the connective tissue are stretched too far
aka bed sores. caused by constant deficiency of blood to the tissues usually over boney projections. occurs in bedridden patients.
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)
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
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
Layers of Dermis from Top to Bottom
PR Stratum Papillarosum (Papillary) upper 1/5 Stratum Reticularosum (Recticular Layer) lower 4/5