4a integumentary system Flashcards
Major components of integumentary system
Skin
Hair, nails
Glands
Skin
Epidermis avascular
Dermis vascular - fibers extend to hypodermis to anchor it
Hypodermis (subq) connected to fascia (CT around muscle and bones), sub q stores fat and has vessels to supply skin
Lamellated (pacinian) corpuscles in sub q are pressure sensitive nerve endings
Type of cells in epidermis
Keratinized stratified squamous epithelium
Four principal cells of epidermins
Keratinocytes
Melanocytes
Intraepidermal machrophages
Tactile epithelial cells
Keratinocytes
90% of epidermal cells
Arranged in 4-5 layers, produce keratin,
Tough hard outer layer
Releases lamellar granules which release water repellent seal
Melanocytes
8% of epidermis. Produce melanin, which goes into nucleus of keratinocyres and protects nucleus (nucleus doesn’t get damaged but melanin can)
Intraepidermal macrophages
Lagnerhans cells
Produces by red bone marrow, participate in skin immune response and are easily damaged by sun
Tactile epitheleal cells
Merkel cells
Least numerous, deepest layer of epidermis. Contact flattened sensory neuron to detect touch
4 (or 5) layers of epidermis (stratum)
Basal Spinosum Granulosum Corneum Skin where friction is greatest has lucidem superior to corneum
Dermis
Second layer, thicker than epi,
What is the dermis made of
Dense irregular tissue containing collagen and elastic fibers (resists pulling forces, can stretch and recoild easy)
Cells in dermis
Mostly fibroblasts with macrophages and adipocytes near boundry
Whats in the dermis
Blood vessels, nerves, glands, hair follicles.
Melanin
Brown black pigment that increases with exposure to uv light
Carotene
Yellow-orange pigment
Precursor of vitamin a, used to synthesize pigments for vision.
Hemoglobin
Along with carotene and melanin its responsible for skin colour (makes light skinned people appear red)
Where is hair not present
Palms and palmar surfaces of fingers
Soles and plantar surfaces of feet
Benefits of head hair
Stops heat loss, protects against UV damage
*All hair functions as a touch receptor
Anatomy of hair
Shaft and root made of medulla, cortex and cuticle (concentric layers)
Inner medulla of hair
Lacking in thinner
Pigment in dark
Less pigment in grey
No pigment and air bubbles in white hair
Cuticle of hair
Outermost, lots of keratin, arranged like shingles with free end toward the end of the hair
Hair standing up
Arrector pili muscles from autnomic nerve endings contract causing hair to stand upright and goosbumps from skin around shaft forming slight elevations
Hair root plexus
Dendrites of neurons sensitive to touch
Hair growth/loss
Goes through cycles of growth and resting
Grows for 2-6 years rests for 3 months
85% of hair is in growth stage always
Loss is determined by hormones and genetics
Glands of the skin
Sebaceous (oil)
Sudoriferous (sweat)
Ceruminous
Mammary
Sebaceous glands location
Everywhere except pamls and soles
Sebaceous gland secretions
Sebum
Sebaceous glands function
Keeps skin and hair soft
Prevents excess evaporation
Inhibits growth of bacteria
Sudoriferous glands are located
Almost everywhere
Sudoriferous glands secretion
Sweat
Function of sudoriferous glands
Temp reg and waste elimination
Ceruminous glands location and secretion
External ear and wax
Function of ceruminous glands
Sticky barrier that prevents foreign bodies from entering
Mammary glands obvious things
They are modified sweat glands in boobies and secret milk
Mammary glands function
Nourish infant with nutrients AND antibodies
Nails
Plates of tightly packed, hard, dead keratinized epidermal cells
Nail body is the plate
Free edge is the tip
Nail root is buried under a fold
Cuticle is a narrow band of epidermis made of stratum corneum
Lunula is white part
Nail Growth
Affected by age, health, nutrition
Varies by seasons, time of day, environmental factors
Approx 1mm per week, slower in toenails
First of six skin functions
Temp contorl with perspiration and insulation against heat loss
Second of six skin functions
Protection against physical barrier to abrasion, dehydration, invasion and UV rays
Also has WBC for immunity in dermis
Third of six skin functions
Sensation because of many nerve endings to detect various stimuli
Fourth of six skin functions
Excretion. Sweat contains urea and other wastes
Fifth function of skin
Blood reservoir
8-10% blood flow at rest
Increases or decreases depending on need (let off heat or divert blood elsewhere) constriction to divert blood causes pallor
Sixth function of the skin
Endocrine
Synthesizes the D and interacts with precursors in skin to form calcitriol in the liver and kidney
Calciotriol
From Vitamin D, increases serum Ca+ by increasing absorption from gut and reabsorbtion from kidneys
Increases release of calcium from bone
Cyanosis
Blue skin colour from lack of oxygen on hemoglobin (resp or cardiac problems)
Erythema
Reddnes from increased blood supply (exercise, fever, hemorrhage under skin, inflammation)
Pallor
Paleness/blanching from decreased blood supply or anemia
Jaundice
Yellow tones to skin and eyes from bilrubin in blood from
liver disease, obstructed bile duct (bile not being removed from body)
1st, 2nd, 3rd degree burns
Epidermis
Dermis and epidermis
Sub q dermis and epidermis
Types of skin cancer
Basal cell caricnoma
Squamous cell carcinoma
Malignant melanoma (most serious, early metastases is common)
ABCD melanoma
Asymmetry
Border
Colour
Diameter (>6mm)
