Integumentary System Flashcards
Cutaneous
Related to skin
What are the functions of integumentary system
Protection, sensation, thermal regulation, production of Vit D and excretion
Protection
Skin acts as a physical barrier and protects inner body structures from external chemicals and pathogens and prevents dehydration
Sensation
Skin is innervated- nerve fibers in skin transmit information about temperature, touch, pressure, pain
Thermal regulation
Blood vessels in skin and sweat glands regulated heat loss from the body
Production of vitamin D
UV light activates a precursor compound in skin to make vitamin D
Excretion
Sweat glands secrete water, electrolytes, and small amounts of Urea
Can also help with thermoregulation
What are the three main layers of the skin
Epidermis, dermis, hypodermis
Epidermis sublayers
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosun
Stratum basale
Epidermis features
Stratifed squamous epithelium
Varies in thickness
Avascular
Innervated for tactile sensation
Constantly renewing itself
What cells in sub layer are constantly regenerating and being pushed towards apical layer
Basale
Stratum corneum
Most superficial layer of epidermis that continuously get shed
Desquamation
Constant shedding of flaking apical layers as deeper basale cells regenerate
Made up of dehydrated dead keratinocytes
Keratinocytes
Main skin cells in epidermis
Keratin
Protein produced by keratinocytes
Provide strength and prevent dehydration
Found in human hair and nails
Stratum lucidum
Made up of dead keratinocytes and keratin
Optional layer: found only in thick skin on palms and soles
Stratum granulosum
Made up of dying keratinocytes, keratin and keratohyalin
As keratinocytes migrate away from blood capillaries cells begin to die in this layer
Keratohyalin
Intracellular protein that promotes dehydration of the dying keratinocytes
Gives the cells in stratum granulosum a grainy appearance
Stratum spinosum
Made up of living keratinocytes actively making keratin
Appearance is due to spikey bundle of prekeratin protein
Stratum basale
Made up of single row of mitoticly active stem cells, tactile epithelial cells and melanocytes
Stem cells
Specialize precursor cells that can divide continuously into new cells
Can differentiate into keratinocytes, tactile epithelial cells and melanocytes
Tactile epithelial cells
Merkel cells
Acts as touch receptors
Melanocytes
Produce pigment
Melanin
Black or brown skin pigment
Protect skin against UV radiation which damages DNA
How is skin tone determined
By the amount of melanin produced not the number of melanocytes
Dermis
Layer of skin between epidermis and hypodermis
Connective tissue proper
Contains blood vessels, nerves, hair follicles and glands
Vasoconstriction
When dermis is exposed to cold, blood vessels in skin constrict to conserve blood
Vasodilation
When dermis is exposed to hear, blood vessels dilate to help release heat
Dermis sublayers
Papillary dermis and reticular dermis
Dermal papillary dermis
Finger like projection of dermis into epidermis
Functions of dermal papillae
Increase surface area for diffusion if gases and nutrients from dermis to avascular epidermis
Interlock epidermis to dermis
Papillae form ridges in thick skin
What is responsible for finger prints that increases tactile sensation and grip
Dermal papillae
Where is reticular dermis found and tissue type
Deep to papillary dermis and dense irregular tissue containing thick bundle of collagen and elastic fibers
What tissue type is papillary dermis
Areolar connective tissue
Flexure lines
Decreases from repeated folding
Creases in palm
Striae
Stretch marks
Torn collagen and elastic fibers from extreme skin stretching
Hypodermis
Subcutaneous tissue or superficial fascia
Deepest layer of skin
Contains blood vessels and nerves
Helps insulate and for energy storage
What tissue type is hypodermis
Adipose tissue
What causes Burns
By heat friction radiation electroshock and strong acids or bases
First degree burn
Upper levels of epidermis
Results in redness and pain
Sunburn
Second degree burn
Effect epidermis and dermis
Results in blistering pain and swelling
Scars may form
Third degree burn
Effects epidermis dermis and hypodermis
Results in severe swelling and requires surgical intervention
What is Hair
Tubes of keratin produced by hair follicle
Where is hair found
Everywhere on skin expect palms soles and lips
What is the function of hair
Sensation and some thermoregulation
What are the components of hair
Shaft, root, hair follicle, melanocytes, sebaceous glands, erector pili
Shaft
Hair extends beyond skin
Root
Hair embedded within dermis and epidermis 
Hair follicle
Specialize epithelium that surrounds deepest part of root
Function is hair synthesis
Innervated and can sense movement
Melanocytes
In hair follicles produces melanin for hair color
Different forms in amounts of melanin produce different hair colors
What results in white hairs
Decreasing melanin and presence of air bubbles and shafts
Erector pili
Smooth muscles that attached epidermis to hair follicles in dermis
Contraction of erector pili causes hair to stand perpendicular to skin
Goosebumps
Nails definition and location
Hard plates of keratin on distal tips of digits and dorsal fingers and toes
Function for nails
Protection and manual dexterity ( skill or ability)
Components of a nail
Nail plate, nail bed, nail root, lunule or lunula and eponychicum
Nail plate
Outter portion of nail
Made up of solid plate of keratin
Nail bed
Dermis deep to nail plate
Underlying blood vessels in the dermis gives nails are characteristic pink color
Nail root
Proximal nail plate that provides keratin
Lunule or lunula
white Crescent distal to nail root
Eponychium
Cuticle
Portion of epidermidis that overlaps lunula
Sebaceous glands location
Everywhere on skin except palms and soles
Most prominent on face and scalp
Closely associated with hair follicle
What is the function of sebaceous glands
To produce sebum which is the skin oil and helps moisturize skin and hair
What is acne
Bacterial infection of clogged sebaceous glands
Strongly influenced by sex hormones

What does old age cause sebaceous glands to do
Under produce which causes dry skin and contributes to wrinkles
Who has Sweat glands
Only mammals (sudoriferous glands)
What are the two types of sweat glands
Eccrine and apocrine
Eccrine sweat glands
All over body but most prominent on scalp palms and soles
produces perspiration
Perspiration
Odorless watery fluid produced as a response to stress or increase body temperature
Contains water, electrolytes, and small amounts of urea
What is urea
Nitrogenous waste product
Diaphoresis
Process of sweating
aids to thermal regulation
As sweat evaporates from skin it carries heat to cool off the body
Apocrine Sweat glands
All over body except lips most prominent in axillary and ingunial regions
What are the functions of apocrine sweat glands
Produces oily form of sweat
odor is produced by bacteria and skin that feeds on oils
