Download Integument System

Chapter 5
Integument Functions
 Protection
 Barrier to microorganisms, abrasions, and water loss
 Thermoregulation
 Vasoconstriction or –dilation of blood vessels,
 Goose bumps or sweat
 Fat and hair
 Sensation
 Nerve endings to detect external stimuli throughout
 Meissner’s corpuscles, Merkel discs, Pacinian corpuscles, hair
follicle receptors, and free nerve endings
 Metabolic roles
 Vitamin D from cholesterol
 Proteins to deter wrinkles
 Excretion
 Removes wastes from body (sweat)
Functional Organization of Integument
Integument
System
Cutaneous
Membrane
Epidermis
Accesory
Structures
Hair
Follicles
Dermis
Papillary
Layer
Reticular
Layer
Exocrine
Glands
Nails
The Skin as an Organ
 Largest of the body
 All 4 epithelial tissue types represented
 Ranges in thickness
 Thick (palms, fingertips, soles of feet)
 Thin (rest of body)
 2 layers
 Epidermis is stratified squamous

4/5 layers and 4 cell types
 Dermis is dense irregular CT
 Multiple cell types and accessory structures; 2 layers
 Hypodermis not true integument
 Connective tissue and fat cells
Epidermal Cells
 Keratinocytes
 Produce keratin
 Joined by desmosomes
 Formed deep
 Dead at surface


Accelerated on feet/hands
Calluses from constant friction
 Melanocyte
 Produce melanin
 Formed deep
 Keratinocytes take up


Skin color due to activity not
number
Tans signal DNA damage, fades as
keratinocytes destroy
Epidermal Cells (cont.)
 Merkel cells
 Touch sensitive cells
 Epidermal/dermal border
 Langerhans cells
 Phagocytic cells
 Assist immune system response
 Formed in bone marrow
Epidermal Layers
 Stratum basale
 Single row, many nuclei
 Attached to basal lamina
 Some melanocytes and langerhans cells
 Stratum spinosum
 Thick layers of ‘spiny’ keratinocytes
 Langerhans cells most abundant
 Stratum granulosum
 Thin, 3-5 layers
 Keraticoytes fill w/ keratin
 Cell ‘toughen’ and die
 Stratum lucidum
 Thin, translucent layer
 Only in thick skin
 Few, dead, densely packed keratinocytes
 Stratum corneum
 20-30 cells thick
 14 days for cells to reach and remain 14 more
Dermis
 Flexible and strong CT
 Elastic, reticular, and collagen fibers
 Fibroblasts, macrophages (WBC), and mast cells
(histamine)
 Tearing causes stretch marks (striae)
 Blisters when epi- and dermis separate by fluid-filled
pocket
 2 layers
 Papillary layer
 Reticular layer
Dermal Layers
Papillary layer (20%)
Reticular layer (80%)
 Areolar CT
 Dense irregular CT
 Ridged surface projections =
 Accessory structures
dermal papilla
 Epidermal ridges feet/palms
 Increase friction, enhance grip,
and fingerprints (sweat gland)
 Contain pain and touch
receptors (Meissner’s
corpuscle)
 Collagen fibers and adipose
 Holds water = hydration
 Cleavage lines
 Orientation related to skin
stresses
 Parallel cuts remain closed =
faster healing
 Right angles pulled open with
recoil
Skin Coloration
 Melanin is black, yellow-brown, or brown
 Made by skin and stimulated by sun
 Freckles and moles are accumulations
 Carotene is yellow to orange pigments
 Accumulates in st. corneum and fatty tissue in skin
 Most obvious where st. corneum thickest
 Hemoglobin is crimson colored respiratory pigment
 Reduced blood supply turns skin white
 Poorly oxygenated blood appears blue = cyanosis

Response to extreme cold or from respiratory disorders
Skin Color Disruptions
 Leathery skin – clumping of elastin fibers from excessive
sun (cancer too)
 Redness – embarrassment, fever, inflammation or allergy
 Pallor/blanching – emotional distress, anemia, low BP
 Jaundice – liver disease, bile pigment deposition
 Bronzing – hypofunctioning of adrenal cortex, Addison’s
 Black and blue – escaped blood clots in tissue,
hematomas
Sudoriferous (Sweat) Glands
 Almost everywhere
 Innervation contracts  secretion
 Eccrine sweat glands
 Palms, soles, forehead
 Hypotonic blood filtrate released by exocytosis


Body cooling
Emotional
 Gland in dermis, duct into surface pore
 Apocrine sweat glands*
 Axillary and anogenital regions
 Secretions into hair follicle ducts
 Similar to sweat

Starts at puberty = body odor
 Ceruminous
 Cerumen (earwax)
 Mammary glands
Sebaceous (Oil) Gland
 Almost everywhere, but palms and soles
 Holocrine: collect and then burst, releasing sebum
 Secreted onto hair follicle or into a pore
 Softens hair and prevents water loss = brittle

Sodium laureth sulfate
 Lubricates skin
 Antibacterial function
 Disorders
 Whitehead, blackhead, acne
 ‘Cradle cap’
 Dandruff , seborrheic dermatitis
http://z.about.com/d/dermatology/1/0/p/6/Comedone_papule.jpg
Hair
 Other mammals = warmth
 Humans = protection, sensation, filters
 Few areas lack (palms, soles, lips)
 ‘Hair’ (shaft and root) are dead, keratinized cells
 Ribbonlike = kinky, oval = wavy, round = course
 Matrix with 3 layers: medulla, cortex, cuticle
 Follicle into dermis  expands to bulb
 Receptors surround
 Papilla w/ capillaries = nutrients
 Arrector pili muscle
 Hair pigment from melanocytes
Nails
 Modified hard keratinized epidermis
 Protect, grasp, and itch
 Richly vascularized
 Free edge, nail body (st. corneum), nail
bed (st. spinosum), and root (lunula)
 Nail folds (lateral and proximal) extend =
eponychium (cuticle)
 Hyponychium (quick)
Burns
 Loss of fluids  renal shut down, denatured proteins
 IV of fluids immediately
 Extra caloric intake
 Sepis
 Protective role decreased after 24 hours
 Immune system done 1 -2 days after
 Rule of nines
 11 areas at 9% body (genitals 1%)
 Estimate
 Classifying
 1st degree: epidermal damage; redness and swelling (sunburn)
 2nd degree: epidermis and upper dermis; blisters form (cooking)
 3rd degree: epidermis and dermis; gray-white/blackened, nerve
destruction

Skin grafting