AnP Chapter ? (LO6) Flashcards
Skin
Only 1 to 2mm thick in most places, largest organ 17-20sqft
Defines the body’s structure
Self-regenerating tissue
Separates the internal from external environment
Protects the body from invasion by harmful substances
Helps maintain homeostasis
Sensory nerve receptors gather info from outside world
Ability to stretch and flexibility permit freedom of movement
Can signal diseases or disorders in other body systems
EPIDERMIS
Outermost layer
Consists of stratified squamous epithelial tissue
Contains no blood vessels
Obtains oxygen and nutrients by diffusion from dermal layer beneath it
DERMIS
Inner, deeper layer composed of connective tissue
Primarily fibers but also contains elastin fibers and reticular fibers (binds the 2 together)
Contains an abundance of blood vessel, sweat glands, sebaceous glands and nerve endings
Hair follicles
HYPODERMIS
Beneath skin
Subcutaneous tissue
Loose connective tissue and adipose tissue
Subcutaneous fat
hypodermis composed mostly of adipose tissue
Helps insulate the body from outside temp changes
Acts as an energy reservoir
LAYERS OF THE EPIDERMIS
Consists of 4-5 layers and an extra layer in areas with wear and tear
Cells of epidermis outer layer are replaced with new cells
New cells are created in lowest level of the epidermis
The new cells go through changes until they reach skin’s surface
Stratum basale (basal layer) also called stratum germinativum
Innermost layer
Consists of a layer of columnar stem cells
Those stem cells undergo mitosis, producing new skin cells pushing older towards surface
Keratin
tough, fibrous protein
produced when cells are pushed upward and stop dividing
it replaces the cytoplasm and nucleus in each cell
cells flatten and die as they move further away from blood supply
stratum corneum
Outermost layer
Keratin is all that’s left of the dead cells
Consists of up to 30 layers of dead, flat, keratin coated cells
Makes skin surface durable and resistant to abrasions
Effective barrier, preventing h20 from entering body while still allowing evaporation
Keratinocytes
newly arriving flattened cells replace dead cells that flake
Melanocytes
produce melanin, scattered throughout basal layer of epidermis
Melanin
accumulates in cells of epidermis
2 TYPES OF MELANIN
Reddish pheomelanin
Brown-black eumelanin
Skin color is determined b
the amount and type of melanin not melanocytes
how melanin works
Melanocytes release melanin with the help of long projections
Keratinocytes bring the melanin into their cells
Caps of melanin are formed over the top of the cell nucleus to protect from UV rays
Prolonged exposure to sunlight stimulates cells to secrete more melanin
—Protects cell’s nucleus and darkens the skin
Cyanosis
-Blue tint
A deficiency of 02 in circulating blood
jaundice
- yellow discoloration of skin and the whites of the eyes
- Impaired liver function that allows bile to accumulate which stains the skin
Bronzing
A golden brown skin color
A deficiency of hormones from adrenal gland, such as occurs with Addison disease
Albinism
Extremely pale skin, white hair and pink eyes
A genetic lack of melanin
Erythema
Abnormal redness
Increased blood flow in dilated blood vessels close to skin surface
May result from heat, exercise, sunburn or emotions
Pallor
Pale skin
Decreased blood flow occurs from cold temps, fear, emotional stress, low blood pressure or blood lost
Bruise (hematoma
Bluish, black or yellow mark on the skin
The breakdown of clotted blood under skin
HAIR
Everywhere except palms, soles, lips, nipples and some areas of the genitals
Papilla:
cluster of blood vessels and connective tissue that nourishes at the base of the hair
Arrector pili
bundle of smooth muscle attached to each hair follicle
Hair follicle
sheath of epidermis each hair lies within have a rich nerve and blood supply
HAIR TEXTURE AND COLOUR
Colour obtained from melanin
Grey/white: lack of melanin
Red: eumelanin and phenomelanin
2 types of melanin create different shades
Eumelanin: dark
Pheomelanin: blonde
Shape of hair shaft determines whether it’s straight or curly
Round shaft: straight hair
Oval shaft: curly hair
ABNORMAL NAIL CHANGES
Clubbing
- Long term 02 deficiency
- looks like drumstick from above
-nail bed softens causing nail to angle downward
(beaked appearance from side)
ABNORMAL NAIL CHANGES
Flattened/concaved nail beds
may indicate iron deficiency
ABNORMAL NAIL CHANGES
Dark lines beneath nail
- may indicate melanoma in lighter skinned individuals
- such lines may be normal in dark individuals
ABNORMAL NAIL CHANGES
White nails
-may occur in individuals with lung disease such as emphysema
ABNORMAL NAIL CHANGES
Yellowish, thickened, slow growing nails
often occur in individuals with lung disease such as emphysema
Pale nail beds
may be a sign of anemia
SWEAT GLANDS
Most numerous of the skin glands
Adult skin contains 3-4 million sweat glands
Everyday body loses 500ml of insensible perspiration
Endocrine glands
Contain a duct that leads from a secretory portion on to skin surface
Widespread throughout the body, especially abundant on palms, soles, forehead and upper torso
Produce a transparent, watery fluid (sweat)
Sweat contains potassium, ammonium, lactic acid, uric acid and other wastes
Sweat plays a chief role in helping the body maintain a constant core temp and eliminated wastes
Apocrine glands
Contain a duct that leads to a hair follicle
Located mainly in the axillary and anogenital (groin) regions
Scent glands that respond to stress and sexual stimulation
Begin to function at puberty
Sweat produced by these glands don’t have a strong odor unless it accumulates on skin; bacteria degrade substances in sweat = body odor
SEBACEOUS GLANDS
Open into hair follicle
Secretes sebum
Sebum: keeps skin and hair from drying out
- –Mild antibacterial and antifungal effect
- –Excess= pimples and black heads
Sebum production increases during adolescence
CERMINOUS GLANDS
Exist in external ear canal
Cerumen: ear wax
Helps ear from drying out
Excess= diminishing hearing
first degree burn
Partial thickness burn: superficial
Involves only the epidermis
Causes redness, slight
swelling and pain
second degree burn
Partial thickness burn: deep (red, white or tan)
Involves epidermis and part of dermis
Results in blisters, severe pain and swelling
May result in scarring
third degree burn
Partial thickness burn: deep (red, white or tan)
Involves epidermis and part of dermis
Results in blisters, severe pain and swelling
May result in scarring
acne
Inflammation of the sebaceous glands, in which follicle becomes blocked with keratinocytes and sebum creating white and black heads
dermatitis
Inflammation of the sebaceous glands, in which follicle becomes blocked with keratinocytes and sebum creating white and black heads
Eczema
Itchy, red rash caused by an allergy; lesions initially weep or ooze serum and may become crusted, thickened or scaly
Impetigo
Contagious bacterial infection of the skin, producing yellow to red weeping, crusted or pustular lesions around the nose, mouth or cheeks on extremities
Psoriasis
A recurring skin disorder characterized by red papules and scaly silvery plaques with sharply defined borders
Tinea
Any fungal infection of the skin; usually occurs in most areas, such as the groin, axilla and foot (athlete’s foot)
Urticaria
Allergic reaction resulting in multiple red patches (wheals) that are intensely itchy
