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Integumentary System Rita Garcia - Gonzalez Period:3, image, image,…
Integumentary System Rita Garcia - Gonzalez Period:3
Skin Cancer: skin tumor are lumpy (not cancerous) and do not spread (metastasize).
Over expose to UV radiation
Frequent irritation of skin
Squamous Cell Carcinoma: sound most common type; can metastasize
Involve keratinocytes of stratum spinosuim
reddened purple on scalp, ears, lower lip, or hands
Good prognosis of treatment by redacted therapy or removal surgically
Melanoma: Cancer of melancytes and is most dangerous type of cancer because it is highly metastatic.
Treated by surgical erosion accompanied by therapy.
Basal Cell Carcinoma: Least malignant and most common
-Basale cells proliferate and slowly invade dermis and hypodermis
cursed by surgical excision in 99% of cases
Survival is Early detection: ABCD Rule
C: color -> contains several colors. (black, brown, tan, red, or blue)
D: diameter -> large than 6 mm ( size of a pencil eraser)
B: border irregularity exhibits indexation
A: asymmetry -> Two sides of the pigment area do not match.
Burn Degrees: Tissue damage caused by heat, electricity, radiation, or certain chemical.
Second Degree Burn: Epidermal and upper dermal damage --> partial - thickness burn because only the epidermis and upper dermis are included
Third Degree Burn: The entire thickness of the skin included --> Grey-white, cherry red, blackened skin color.
No dermal is seen and area is not painful due to nerve being destroyed
skin grafting usually necessary.
First Degree Burn: Epidermal damage only --> redness, swelling, and pain
The Rules of Nine: its used to evaluate the severity of burns. The body is broken into 11 sections: with each section representing 9% of the body surface. ( except genitals 1%). Used to estimate volume of fluid loss.
Accessory Organs
Nail: scale modification of epidermis that contains hard keratin. Act as protective cover for distal, dorsal surface of finger and toes
Nail bed: Epidermis underneath keratinized nail plate.
Nail Matrix: Thickened portion of bed, responsible for nail growth
Nail fold: Skin that overlap border of nail
Eponychium (cuticle): Nail fold that projects onto surface of nail body.
Lunule (lunula): Thickened nail matrix appear white. * Abnormal color or shape can be a indicator of disease.
Glands: Sweat Glands (sudoriferous glands) ---> all skin surface except nipples and parts of external genitalia contain sweat glands.
Eccrine (merocrine) glands: abundant on palms, soles, and forehead.
Regulated by sympathetic nervous system
Apocrine glands: axillary (armpit) and anogental (genitals) areas.
begins when puberty starts
Milky or yellowish sweat that contains fatty substance and protien
bacterial breaks down sweat, leading to body odor.
Cercuminous glands: lining of external ear can: secrete cerumen ( earwax)
Mammary glands: Secrete milk ( breast milk )
Sebaceous (oil glands): widely distributed; except palms and sole
develop from hair follicles
relatively inactive until puberty
bactericidal (bacteria killing) properties
soften hair and skin
Hair: Consists of dead keratinized cells. None are located on palms, sole, lips, nipples, and portions of external genitalia.
Functions: warns of insects on skin, hair on head guards against physical trauma, protects from heat loss, and shields the skin from sunlight.
Structure of Hair: Hairs (pili)--> flexible strand of dead keratinized cells.
Produced by hair follicles
Contains hard Keratin NOT like soft keratin found in skin
--> Hard keratin is together and more durable, and cells do not flake off.
Region:
shaft: area that extends above scalp, where keratinization is complete
Medulla: central core of large cells and air space
Cortex: several layers of flattened cells surrounding medulla
Cuticle: outer layer consisting of overlapping layers of single cells.
Root: area within the scalp, where keratinzation is still going on
Function of The Skin: Skin in first and foremost a barrier
Body Temperature Regulation
Under normal, resting body temperature, sweat glands produce about 500 ml/day of unnoticeable sweat
• If body temperature rises, dilation of dermal vessels can increase sweat gland activity to produce 12 L (3 gallons) of noticeable sweat – designed to cool body
• Cold external environment – Dermal blood vessels constrict – Skin temperature drops to slow passive heat loss
Cutaneous Sensations
• Cutaneous sensory receptors are part of the nervous system
Exteroreceptors respond to stimuli outside body, such as temperature and touch
Free nerve endings sense painful stimuli
Protections:
Chemical barrier – Skin secretes many chemicals, such as: ▪ Sweat, which contains antimicrobial proteins
▪ Sebum and defensins, which kill bacteria
▪ Cells also secrete antimicrobial defensin
Acid mantle: low pH of skin retards bacterial multiplication
Melanin provides a chemical barrier against UV radiation damage
Physical barrier – Flat, dead, keratinized cells of stratum corneum, surrounded by glycolipids, block most water and water-soluble substances
Some chemicals have limited penetration of skin
▪ Lipid-soluble substances
▪ Plant oleoresins (e.g., poison ivy)
▪ Organic solvents (acetone, paint thinner)
▪ Salts of heavy metals (lead, mercury)
▪ Some drugs (nitroglycerin)
▪ Drug agents (enhancers that help carry other drugs across skin)
Biological barriers – Epidermis contains phagocytic cells
▪ Dendritic cells of epidermis engulf foreign antigens (invaders) and present to white blood cells, activating the immune response – Dermis contains macrophages
▪ Macrophages also activate immune system by presenting foreign antigens to white blood cells – DNA can absorb harmful UV radiation, converting it to harmless heat
Metabolic Functions
• Skin can synthesize vitamin D needed for calcium absorption in intestine
• Chemicals from keratinocytes can disarm some carcinogens
• Keratinocytes can activate some hormones
– Example: convert cortisone into hydrocortisone
• Skin makes collagenase, which aids in natural turnover of collagen to prevent wrinkles
Blood Reservoir
• Skin can hold up to 5% of the body’s total blood volume
• Skin vessels can be constricted to shunt blood to other organs, such as an exercising muscle
Excretion
• Skin can secrete limited amounts of nitrogenous wastes, such as ammonia, urea, and uric acid
• Sweating can cause salt and water loss
Layers of the Skin
Dermis: Underlies Epidermis and is mostly fibrous connective tissue and vascular ( blood vessel going through it)
< Strong, Flexible connective tissue > Fibroblast, Macrophages, occasionally most cells and white blood cells.
Fibers in the matrix body together: make up the "hide" that is used to make leather. It contains nerves, blood vessels, and lymphatic vessels.
Contains epidermal hair follicles, oil glands, and sweat glands
Papillary: Layer of areolar connective tissue which consists of loose, interacting collagen and elastic fibers and blood vessels.
Dermal papilae --> Superficial region of dermis that sends finge like projections up into epidermis
In the thick skin --> dermal papillae lie on top of dermal ridges, which gives rise to epidermal ridges.
enhances grip
contributes to dense of touch
seat in ridges leaves unique fingerprint patterns
Reticular Layer: Make up 80% of dermal thickness
Many elastic fibers provide stretch-recoil properties
Collagen fibers provide strength and resiliency
*Bind water, keeping skin hydrated
Epidermis: The superficial region that consist the epithelial tissue and is a vascular.
Consists mostly of keratinized stratified squamous epithelium.
< Layers of Epidermis >: Made up of four or five distinct layer
Stratum Granulosum (Granular Layer): Four to six cells thick, but cells are flattened, so layers are thin.
*Cell appearance changes: Keratinization begins and slows water loss
*Cells above this layer die --> Too far from dermal capillaries to survive
Stratum Lucidum: Only in the thick layer of skin. Consists thin, translucent band of two to three rows of clear, flat, dead keratinocytes.
Stratum Spinosum ( Prickly Layer ): Keratinocytes in this layer appear spiky so they are called Pickle cells.
*several cell layers thick
Stratum Corneum (horny Layer): Lies superficial to the Stratum Granulosum.
*20-30 rows of flat and dead keratinized dead cells
*Protects depper cells from the environment
*prevenst water loss
*Protections from abrasion and penetration
*acts as a barrier against biological, chemical, and physical assaults
Stratum Basale ( Basal Layer ): The deepest of all epidermal layers.
*Firmly attached to dermis
*Consists of a single row of cells that divide activity (Mitotic)
Hypodermis ( Subcutaneous ): Its the deep layer of the skin and is not part of the skin but shares some functions. Mostly adipose tissue that absorbs shock and insulates.
Other disorders associated with the Integument System
Staph Infection: Bacterial skin infection caused by staphylocuccus
Chickenpox: viral ifection that causes blistering
Psoriasis: skin inflammation caused by autoimine disease
Fungal Infection: Collection of diseases caused by fungi
Acne: Clogged pores by dirt or over-porduction of skin oil
