Integumentary System Flashcards
Integumentary System
Skin and it’s accessory structures (grow from the skin)
Accessory structure: hair, nails, glands
Dermatology
The study and treatment of the integumentary system
Skin
Our largest organ combined of two tissue types; epithelial and connective
Epidermis layer is made of what tissue
Stratified-Squamous Epithelial Tissue (waterproof/ tough)
Dermis layer is made of what tissue
Areolar connective tissue and Dense irregular CT
Hypodermis layer is made of what tissue
Adipose CT (mostly) + areolar CT
Epidermis
4-5 main layers:
Stratum-
• Corneum “Can Lucy give some blood”
• Lucidum
• Granulosum
• Spinosum
• Basal
Epidermis main cell type in all layers
Keratinocytes- cells that move keratin protein (gives skin strength/toughness & waterproofs the skin)
Stratum Basal
Deepest layer: one row of cells
Connected to the basement membrane along “wavy line”
Stratum Basal components
Mostly keratinocytes: undergo mitosis constantly & gets pushed up
Some merkel cells: sensory cells for touch
Some Melanocytes: skin pigment cells
Stratum Spinosum
Thickest layer (many rows)
Mostly Keratinocytes pushed up from the stratum basal.
Begins production of keratin protein
Some Dendritic cells: immune cells that phagocytose bacteria debris and damaged cells
Stratum Granulosum
3-5 rows of cells
Keratinization occur in this layer
⬆️Keratinocytes fill up w/so much keratin protein that they die
Stratum Lucidum
Dead layer
Only in thick skin- thick as paper towel (hand/feet only)
Thin skin- thin as printer paper ⬆️(everywhere else)
Stratum cornuem
Dead scaley layer (many rows thick)
Not cells anymore
Just keratin protein cover in PM
Shed and replace every 4 wks
Melanin
Main skin pigment molecule
Made by melanocyte cells in stratum basal
Protects skin cell DNA from damage
Carotene
Yellow-orange pigment molecule
-comes from diet (egg yolk, carrots, squash)
Hemoglobin
Red-pigmented molecule in blood
-gives skin pinkness.
Dermis layer two layers within?
Papillary layer (~upper 1/4)
-Areolar CT (padding )
Recticular Layer(~lower 3/4)
- Dense irregular CT (stretch)
Dermis layer contains
Blood vessels
Sensory receptors/nerves
Arrector Pili Muscle
Glands
Hair follicles
Dermal blood vessels: Blood Temp. Control
Vasoconstruction- dermal blood vessels constrict
Cause blood to flow deeper w/in the body, warming deeper tissue & organs
Keeps core warm
Skin looks pale
Vasodilation of blood vessels
Dermal blood vessels dilate causes blood to flow more superficially where heat can escape.
Cools you off.
Skin looks flushed
Hypodermis: Subcutaneous Layer
Not part of skin/ integumentary system
Connects skin to muscle beneath
Good site for injections
Hypodermis: Subcutaneous Layer composed of?
Fatty/ padding layer
- Adipose (fat) CT and Areolar CT
Lots of blood vessels
Function: cushioning, insulation, excess calorie storage (“body fat”)
Sebaceous Glands
Secrets sebum(oil)- moisturizers, waterproofs, protect skin and hair – fully activated during puberty
Holocrine type gland
(Whole cells in the gland rupture to release secretion) sebum discharges, through hair follicles.
Apocrine sweat glands
Secretes ”stinky” Sweat
- Rich in protein
- bacteria feeds on this ➡️ produce odor
For thermoregulation
Only in certain areas ( auxiliary, pubic, anal, nipple, beard)
When is Apocrine sweat glands activated?
During puberty
Modified Apocrine Sweat Glands
Ceruminous glands and mammary glands
Ceruminous glands
In ear, canals, secretes cerumen (earwax); traps particles, and prevents infections
Mammary glands
In breast, secretes, milk; nurishes infant
Functions of integumentary system
- Physical protection-from trauma, pathogens, environment
- Body temp regulation
- Secretion- glands
4.Vitamin production- UV light stimulates production of v-D precursor in skin
Activates v-D needed for absorption of Ca+2 & Pi from diet 
