Integumentary System Flashcards
What is the largest organ of the body that accounts for 3-5 kg of body weight?
SKIN
The Integumentary System is composed of the following:
- Hair
- Nails
- Oil & Sweat Glands
- Skin
What are the 3 layers of the skin?
- Epidermis
- Dermis
- Hypodermis
Keratinocytes, Melanocytes, Langerhans cells, & Merkel cells are found in what layer of the skin?
EPIDERMIS
Define Keratinocytes.
- building blocks of KERATIN = provide structure, durability, & waterproofing to hair, nails, & outer skin
- constantly dying and being replaced
Define Melanocytes.
- spider-shaped cells
- synthesizes MELANIN = pigment that gives color to skin
> color depends on cellular extensions and NOT to # of cells
These epidermal cells are responsible for ingesting unwanted invaders and originate from bone marrow.
LANGERHANS CELLS
These epidermal cells are also known as tactile cells that combine with nerve endings to create a sensory receptor for TOUCH.
MERKEL CELLS
What is the difference between THICK & THIN Skin?
THICK SKIN
- tougher part found in palms and soles of feet
- has 5 epidermal layers
THIN SKIN
- found everywhere else
- has 4 epidermal layers
How many layers does the skin have and what are they?
5 epidermal layers in THICK skin, but only 4 layers in THIN skin.
These layers are:
1. Stratum Corneum
2. Stratum Lucidum (for thick skin only)
3. Stratum Granulosum
4. Stratum Spinosum
5. Stratum Basale
Define Stratum Corneum.
- outermost layer
- roughest = 20-30 sheets of dead keratinocyte cells
Define Stratum Lucidum.
- a.k.a. “clear layer”
- 2 or 3 of clear, flat dead keratinocytes
- ONLY in THICK skin
Define Stratum Granulosum.
- a.k.a. “granular layer”
- contains LIVING keratin
- grainy appearance due to compressed & flattened keratin
Define Stratum Spinosum.
- a.k.a. “spiny layer”
- contain filaments that helps in holding each other
Define Stratum Basale.
- a.k.a. “basal layer”
- deepest & thinnest
- contains SIMPLE COLUMNAR cells
- connects epidermis to dermis
What are the characteristics of the Dermis?
- has collagen & elastin fibers for strength and elasticity
- has capillaries & blood vessels
- has nerve fibers for temp., pressure, and pain
- has hair follicles, oil & sweat glands that have ducts to the outside of the skin
What are the layers of the Dermis?
- Papillary layer
- Reticular layer
What is the papillary layer of the dermis?
- upper layer of dermis
- composed of thin sheet of areolar connective tissue with little peg-like projections called “dermal papillae”
What are dermal papillae?
Dermal Papillae form friction ridges in thick skin by pressing up the epidermis to help in gripping surfaces
What is the reticular layer of the dermis?
- thicker layer
- 80% of the dermis
- made of dense irregular connective tissue
Where are the nerve fibers and capillaries distributed in the skin?
In the PAPILLARY & RETICULAR Layer of the Dermis
Define the Hypodermis.
- a.k.a. subcutis
- mostly adipose connective tissue
- provides insulation, energy storage, shock absorption, & anchor skin
