Integumentary System Flashcards
What are the 2 components of the cutaneous layer?
- Epidermis 2. Dermis
True or false the hypodermis is part of the cutaneous layer.
False
What are the 6 functions of the skin?
1. Thermoregulation
- sweat and increased capillary blood flow for cooling,
- hair for retaining heat
2. Protection from external enviroment
3. Cutaneous sensation
-pain, touch, pressure, temp
4. Excretion
5. Vit D synthesis
6. Absorbing certain substances
What are the 4 major types of cells found in the epidermis, and what are thier characteristics/fxns?
1. Keratinocytes- most numerous formed when new cells become filled with keratin
2. Melanocytes- cells contain a melansome, that produces
3. Langerhans cells- Dendritic cells of skin
4. Merkel Cells- responsible for sensation of touch, Found in the basal layer of the epidermis, where they are in contact w/ Merkel discs (type of sensory neuron)
How is melanine produced?
From Tyrosine in the prescence of tyrosinase.
What are the 5 layers of the epidermis, and breifly describe them.
Come, Lets Get Some Beer (superficial to deep)
1. Stratum Corneum = most superficial layer, dead keratinocytes, continously sloughed off.
2. Startium Lucidum= only found on palms, fingertips, and soles. composed of dead keratinocytes
3. Stratium Granulosum = Transition between deeper living cells and dead superficial cells. Filled with granules of keratin. Lamellar granules release waterproofing lipids.
4. Startium Spinosum= layer just superficial to basale layer. Cells are still alive, some dividing but some starting to flatten out
5. Stratim Basale= deepest layer, living keratin cells undergoing continous mitosis.
How is keratin produced?
produced from tonofilaments (type of intermediate filaments) which contain a protein precusr to keratin.
What types of connective tissues make up the dermis?
Dense irregular tissue, collagen tissue, and elastic connective tissues.
What are the 2 components of the dermis
1. Papillary region
2. Reticular region
Describe the papillary region of the dermis?
More superiorficial. Contain dermal papilllae for better adhesions and diffision to apidermis. Contains: meissner corpuscles (touch/light touch) and free nreve endings for warmth, pain, tickle, itch
Describe the reticular region of the dermis?
Deeper of the 2 regions. Spaces betwen fibers filled with adipose tissues, hair follicles nerves, sebaceous and sudoriferous glands.
What are epidermal ridges?
Finger tips, formed by the dermal papillary. Important for increasing grip by increasing friction.
What type of tissues mainly compose the subcutaneous/hypodermis
- Areolar and adipose tissues, containing larger bloos vessels.
- Contains Pacinain corpuscles (sense pressure)
What 3 pigments affect skin color
- melanin= dark brown, genetically determined how much you usually produce (all races have ! the same # of melanoctyes)
- carotene= yellow-orange pigment that is a precusor to Vit A. Genetically determined
- hemoglobin =pinkness of skin
What is hair composed of?
Dead keratinized cells bonded by proteins
Where is the root of the hair located?
The dermis
Where does the germinal layer of cells in the hair bulb arises from?
The startum basale of the epidermis, so cells from epidermis physically located in the dermis d/t external root sheath.
What are the 3 layers of the of the hair shaft and root?
- Medulla
- Cortex
- Cuticle
Describe hair growth
The division of cells at the base of the hair follicles whereby new cells produced in the matrix push the growing hair through the pilary canal.
What structures are associated w/ hair?
- Sebaceous glands
- Arrector pili muscle (goos bumps)
- Hair root plexus= dendrites and nerve endigs around hair follicle that generate nerve pulses when hairs are moved
What are the 3 componets of a nail
- nail body = portion of the nail visible
- a free edge= the portion you cut
- nail root= where the nail emerges
What is the lunula of the nail?
The whitish cresent shaped area of the proximal nail end.
What are sebaceous glands and what are there fxns?
Oil glands
- keeps hair from drying out
- prevents excessive evaporation of water from the skin
- inhibits some bacterial growth.
What are sudoriferous glands and there 2 types?
Sweat glands
- Eccocrine sweat glands =most common
- Apocrine sweat glands = found in association w/ hair that develops at puberty
What is psorasis?
A condition in which keratinocytes divide quiker than normal causing immature keratinocytes to make abnormal keratin causing a scaly apperance usually seen on knees, elbows and scalp.
What are the 3 common types of skin cancer?
- Basal cell carcinoma (most common)
- Squamous cell carcinoma
- Malignant melonoma (least common but most dangerous)
Describe albinism.
The inhertited inability to produce melanin.
-in most cases they lack the ability to synthesize tyrosinase
What is Vitiligo?
Partial or complete loss of melanocytes from patches of skin, possibly auto immune
What is erythema?
Redness of the skin, caused by the engorgement of capillaries in the dermis.
What are striae?
Streaks in the skin caused by tearing of the skin during periods of rapid growth.
-intially purple/reddish then color fades
Define Alopecia.
Partial or complete lack of hair that can be permanent or temporary.
Define Contact dermatitis.
Inflammation of skin characterized by redness itching and swelling and caused by exposure of the skin to chemicals that cause an allergic rxn.
What are the 2 types of wound healing?
- Epidermal wound healing -function returns
- Deep wound healing -loss of function d/t scar tissue
When does epiderma healing occur and describe the process.
Occurs when wounds that only affect the epidermis (superficial wounds)
-Basal cells at the margins of the wound break contact with the basement membrane and migrate until they make contact with each other (contact inhibition). Mitosis is stimulated and keratinocytes move up to form superficial layers.
What are the 4 stages of Deep wound healing
- Inflammatory phase=blood clot forms and blood flow/permability increases to the wound.
- Migratory phase= epithelial cells migrate beneath the scaband bridge the wound and fibroblast migrate and begin to produce collagen
- Proliferative phase= growth of epithelial cells beneath scab, collagen increases, blood vessels regenerated.
- Maturation phase= scab is lost, collagen fibers become more organized. This phase can last a long time.
Describe a first degree burn.
- Only volves the epidermis
- skin fxn remains
- heals 3-6 days
Describe second degree burns.
- Destroys epidermis and possibly parts of the dermis. Associated structures remain intact
- some fxn loss, with some scarring
- 3-4 wk healing time
Describe third degree burns.
- Destorys the epidermis as well as the dermis and associated structure
- varying apperance =white to charred
- marked edema
- numbness from destrustion of nerve endings
- slow growth
What is the rule of 9’s for adult burns
Provides quick means for esitmating the surface area affected by a burn.
head=9%
upper extremities=9% a piece
lower extremities=18% a piece
chest+abd=18%
back=18%
What is the rule of 9’s for adult children
Provides quick means for esitmating the surface area affected by a burn.
head=18%
upper extremities=9% a piece
lower extremities=14% a piece
chest+abd=18%
back=18%
Define an abrasion?
an area where the skin has been scraped away
Define athletes foot
A superficial fungal infection of the skin of the foot
Define a blister
a collection of serous fluid with the epidermis or between the epidermis and dermis, d/t severe short term friction
Define a callus
an area of hardened and thickened skin d/t persistant pressure and friction
Define eczema
an inflammation of the skin characterized by patches of red, blistering dry extremely itchy skin
Wart
mass produced by uncontrolled growth of epithelial skin cells vasued by HPV
Hirsutism
condition of excessive body hair
Lanugo
fine, non-pigmented hairs that cover the body of the fetus
Terminal hairs
Coarse heavily pigmented hair ()hair of head eyebrows..)
Vellus hairs
short fine pale hairs that develop on most of the body during childhood.
