Chapter 5 Integumentary System Flashcards
Functions of integumentary system
Regulates body temperature Stores blood Protects from external environment Detects cutaneous sensations Excretes and absorbs substances Synthesizes Vit D
Components of integumentary system
Hair Skin Nails Oil and sweat glands Sensory receptors
Subcutaneous layer
Deep to dermis (hypodermis)
Areolar and adipose tissue
Storage depot for fat
Lamellated (pacinian) corpuscle
Nerve ending
Sensitive to pressure
In subcutaneous and sometimes dermis
Epidermis cells and tissue type
Keratinized stratified squamous epithelium
Keratinocytes
Melanocytes
Intrepidermal macrophages
Tactile epithelial cells
Keratinocyte fxns
Produce protein keratin
Produce lamellar granules which release water repellant sealant that decreases water entry and loss and inhibits the entry of foreign materials
Melanocytes
Develop from ectoderm
Produce pigment melanin
Transfer melanin granules to keratinocytes
Susceptible to UV damage
Melanin
Yellow red to brown black
Absorbs UV light
In keratinocytes they cluster to form protective layer on side toward skin surface
Shield nuclear damage
Intraepidermal macrophages
From red bone marrow
(Langerhans cells)
Immune responses against microbes
Help cells recognize invading microbe and destroy it
Tactile epithelial cells
Merkel cells
Least numerous of epidermal cells
Detect touch sensations
Deepest layer of epidermis
4 strata layers of epidermis
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
Stratum basale
Deepest layer of epidermis
Cuboidal or columnar keratinocytes
(Stratum germanitivum)
Some cells are stem cells
Skin graft
Transfer patch of healthy skin to cover a wound
New skin cannot regenerate if injury destroys large area of stratum basale
Stratum spinosum
8-10 layers
Immune responses happen
Superficial to stratum basale
Stratum granulosum
Middle of epidermis
3-5 layers
Keratinocytes undergoing apoptosis
Cells move away from nutrients = degeneration
Stratum lucidum
Only in thick skin
4-6 layers of flattened clear dead keratinocytes
Stratum corneum
25-30 layers of flat dead keratinocytes
Callus
Abnormal thickening of stratum corneum
Caused by constant exposure of skin friction which stimulates increased keratin production from increased cell production
Keratinization
New cells in stratum basale causing them to push towards the surface
Accumulating more and more keratin
How Keratinized cells die off
New keratinocytes are produced
Pushing excess ones away and towards the surface and away from nutrient source causing them to die off.
Increase in rate as more epidermis layers are stripped
(Abrasions and burns)
Psoriasis
Keratinocytes divide and move more quickly than normal from stratum basale to stratum corneum
Shed prematurely in as little as 7-10 days
Treatments: topical ointments
Ultraviolet therapy
Dermis
Second deeper part of skin
Dense irregular connective tissue
Collagen and elastic fibers
Great strength
Papillary region
1/5 of dermal layer Thin collagen and elastic fibers Surface area increased by dermal papillae Contain capillary loops And corpuscles (nerve ending)
Reticular region
Attached to subcutaneous layer Bundles of thick collagen fiber Some adipose Collagen fibers arranged netlike more regular than papillary region Extensibility and elasticity
Striae
Stretch marks
Internal damage to dermis layer
Skin is stretched too much
Small dermal blood vessels ruptured
Epidermal ridges
Ridges and grooves on palms, soles, etc.
Straight lines or whorls
Produced 3rd month fetal dvlpmt
Increase surface area = increase sensitivity
Ducts of sweat glands help to produce fingerprints
Dermatoglyphics
Tension lines
Study of pattern of epidermal ridges
Line of cleavage
Surgical incision parallel to collagen fibers will heal with only a fine scar
Structural basis of skin color
Melanin, hemoglobin, carotene
Albinism
Vitiligo
Inherited inability to produce melanin
loss of melanocytes from patches
Skin color as diagnostic clue
Cyanotic - oxygen from lungs not getting to blood
Jaundice - build up of yellow pigment bilirubin in skin
Erythema - redness of skin, engorgement of capillaries in dermis
Pallor - paleness of skin (shock, anemia)
Hair
Dead Keratinized epidermal cells Shaft - above surface Root - deep in dermis Hair follicle - surrounds root Dermal root sheath - surround follicle Papilla of hair - indent bulb
Arrector pili
Hair root plexus
Smooth muscle, from superficial dermis of skin to dermal root sheath around the side of hair follicle
90* position, stimuli cause goosebumps
Surrounds each hair follicle, generates nerve impulses
Hair growth
Growth stage 2-6 years
Regression stage 2-3 weeks
Resting stage 3 months
Types of hairs
Lanugo - fine no pigmented hairs
Terminal hairs - replace lanugo prior to birth
Vellus hairs - peach fuzz
Sebaceous glands
Oil glands
Connected to hair follicles
Secreting portion lies in dermis usually opens in neck of hair follicle
Secretes sebum
Mix of triglycerides, cholesterol, proteins, inorganic salts
Sweat glands
Sudoriferous glands
Eccrine sweat gland - most common
Apocrine - armpit, groin
Nails
Free edge Nail body Lunula Nail root Hyponychium - secures nail
Vitamin D
UV rays + precursor
Enzymes in liver and kidney modify to calcitriol
Inflammatory phase
Deep wound healing
Blood clot
Eliminate microbes
Vasodilation permeability
Migratory phase
Deep wound healing
Clot becomes scab
Epithelial cells migrate to bridge wound
Fibroblasts synthesize scar tissue
Damaged blood vessels grow
Proliferative phase
Deep wound healing
Epithelial growth continued growth of blood cells
Maturation phase
Deep wound healing
Scab sloughs off
Epidermis restored to thickness
Blood vessels restored
Collagen fibers organized
Scar tissue
Formation : fibrosis
Hypertrophic scar - raised above
Keloid - extends boundaries
Densely arranged collagen fibers
Decreased elasticity
Fewer blood vessels
