Please enable JavaScript.
Coggle requires JavaScript to display documents.
Integumentary System, LAYERS OF SKIN, EPIDERMIS, HYPODERMIS, FUNCTIONS OF…
Integumentary System
disorders
Extreme stretching of skin can cause dermal tears, leaving silvery white scars called
striae
blisters, fluid-filled pockets that separate
epidermal and dermal layers
excessive hairiness, called hirsutism, as well as other signs of
masculinization
Alopecia: hair thinning in both sexes after age 40
Male pattern baldness caused by follicular response to DHT (dihydrotestosterone)
Acne is usually an infectious inflammation of the sebaceous glands, resulting in pimples
(pustules or cysts)
Overactive sebaceous glands in infants can lead to seborrhea, known as “cradle cap”
Cradle Cap (Seborrhea) in a Newborn
.
PROTECTION
Chemical barrier
sweat contains antimicrobial proteins. Sebum and defensin. Acid mantle (retards bacteria multiplication). Melanin protects against UV radiation
physical barrier
keratinized cells block water. limits penetration to some chemicals
Biological Barrier
Phagocytic cells and Macrophages (activate immune response). DNA absorbs UV radiation.
BODY TEMPERATURE REGULATION
If body temperature rises, dilation of dermal vessels can increase sweat gland activity designed to cool body. If body temperature lowers, dermal blood vessels constrict, skin temperature drops to slow passive heat loss
CUTANEOUS SENSATION
respond to temperature, touch and pain stimuli
METABOLIC FUNCTION
Vitamin D is synthesized for calcium absorption in intestine. Keratinozytes activate some hormones. Skin makes collagen to prevent wrinkles.
BLOOD RESERVOIR
skin hols up 5% of total blood.
EXCRETION
skin secrete nitrogenous wastes (ammonia, urea , and uric acid). Sweating can cause salt and water loss
.
LAYERS OF EPIDERMIS
Stratum granulosum:
four to six layers, cells are flattened, keratinization begins, slows water loss, cells above this layer die. (3rd-5)
Stratum Lucidum
found only on thick skin, two or three layers of clear, flat, dead keratinoicytes (2nd-5)
Stratum spinosum:
several layers of cells (4th-5)
Stratum corneum
20–30 rows of flat, anucleated, keratinized dead cells, 3/4 of epidermis. protect deeper cells, prevent water loss, abrasion and penetration, barrier against biological, chemical and physical assaults. (1st-5)
Stratum basale
: deepest layer of epidermis, consist of a layer of cells that mitotic (5th-5)
four cell types found in epidermis
outermost layer of the skin consisting of mostly keratinized Stratified squamous
.
Melanocytes
: produce pigment melanin (protects from UV damage)
Dendritic
: activators of immune system
Keratinozites
: produce keratin
Tactile
: sense touch
SKIN CANCER
Basal Cell Carcinoma
Least malignant and most common
Stratum basale cells proliferate and slowly invade dermis and hypodermis
Cured by surgical excision in 99% of cases
Squamous Cell Carcinoma
Second most common type; can metastasize
Involves keratinocytes of stratum spinosum
Usually is a scaly reddened papule on scalp, ears, lower lip, or hands
Good prognosis if treated by radiation therapy or removed surgically
Melanoma
Cancer of melanocytes; is most dangerous type because it is highly metastatic and
resistant to chemotherapy
Treated by wide surgical excision accompanied by immunotherapy
ABCD Rule
A: asymmetry; the two sides of the pigmented area do not match
B: border irregularity; exhibits indentations
C: color; contains several colors (black, brown, tan, sometimes red or blue)
D: diameter; larger than 6 mm (size of pencil eraser)
BURNS
First Degree Burn
Epidermal damage only
Redness, edema, and pain
Second Degree Burns
Epidermal and upper dermal damage
Blisters appear
First- and second-degree burns are referred to as partial-thickness burns
Third degree burns
Entire thickness of skin involved (referred to as full-thickness burns)
Skin color turns gray-white, cherry red, or blackened
No edema is seen and area is not painful because nerve endings are destroyed
Skin grafting usually necessary
Rule of Nines
Evaluate severity of burns
body is broken into 11 sections, with each section representing 9% of body surface (except genitals, which account for 1%)
– Used to estimate volume of fluid loss
ACCESSORY ORGANS
HAIR
consist of dead keratinized cells, none located on palms, soles, lips, nipples, and portions of genitalia
warm of insects, physical trauma, protection from heat loss, shields skin from sunlight
produced by hair follicles
Structure of hair
Hair bulb consists of: hair matrix (produces hair cells) , hair papilla (supplies nutrients) and melanocytes.
Follicle wall consist of: peripheral (outermost layer of hair follicle), glassy membrane, external and internal root sheath
shaft (area above scalp) consists of: cuticle(outer layer), cortex (several layers of cells between cuticle and medulla) and medulla (central core)
NAILS
modification of epidermis that contains hard keratin
protects distal, dorsal surface of fingers and toes
nail structure
Consist of free edge, nail plate, and root
Nail bed is epidermis underneath keratinized nail plate
Nail matrix: thickened portion of bed responsible for nail growth
Nail folds: skin folds that overlap border of nail
Eponychium (cuticle): nail fold that projects onto surface of nail body
– Lunule (lunula): thickened nail matrix, appears white
GLANDS
sweat glands (sudoriferous)
.
Ecrine glands
have ducts connected to pores, Function in thermoregulation. Secrete 99% water, salts, vitamin C, antibodies, dermcidin, and metabolic waste
apocrine glands
axilary and anogenital areas. Secrete sweat that contains fatty substances and proteins that bacteria break down (leads to odor) ducts into hair follicles. begin to function at puberty. ceruminous and mammary glands
Sebaceous (oil) Glands
most secrete into hair follicles, inactive until puberty. Secrete Sebum
.
.
Strong, flexible connective tissue
fibroblasts, macrophages, and occasionally mast and white blood cells
contains nerves, blood and lymphatic vessels, hair follicles, oil and sweat glands.
LAYERS OF DERMIS
Papillary layer
Superficial layer of areolar connective tissue consisting of loose, interlacing collagen and elastic fibers and blood vessels
Dermal papillae
In thick skin, dermal papillae lie on top of dermal ridges, which give rise to epidermal ridges
superficial region of dermis that sends fingerlike projections up into epidermis
Friction ridges (group of ridges) enhance gripping ability, contribute sense of touch, leave a unique fingerprint
Reticular layer
makes up 80% of dermal thickness
consist of coarse, dense fibrous connective tissue
Bind water, keeping skin hydrated
extracellular matrix contains pockets of adipose cells
DERMIS
.
Deepest layer of the skin, mostly adipose tissue that absorbs shock and insulates. Anchors skin to underlying structures
LAYERS OF SKIN
EPIDERMIS
HYPODERMIS
FUNCTIONS OF SKIN