Integument Flashcards
Characteristics of the Epidermis
- Tough, leathery outer surface of skin
- .05-.15 mm in thickness (up to 1.4 in thick skin)
- 5 layers
- Fairly avascular
how often does the epidermis regenerate?
every 14-21 days
Cell components of the epidermis
Keratinocytes, Eosinophils, Melanocytes, Lymphocytes, Langerhans cells, Merkel and Basal Cells
Layers of the epidermis
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
Stratum Basale
- Single row of keratinocytes (produce keratin)
- Deepest layer
- Attached to dermis via basement membrane (extra-cellular) and basal cells
- Diffusion through the basement membrane is how the epidermis receives its nutrition
- Concentration of Merkel cells
Stratum Spinosum
- Several rows of mature, slightly flattened keratinocytes called tonofibrils
- Melanocytes appear between stratum basale and stratum spinosum
- Appear “spiny” due to kearatin filaments
- Where most Langerhans cells are found
Stratum Granulosum
- 3-5 rows of flattened cells
- increased keratin concentration
Stratum Lucidum
- Few layers of flattened cells, densely packed
- Mostly flattened eosinophils
- Dead keratinocytes
Stratum Corneum
- Outermost layer
- 15-20 cells thick (dead keratinized cells)
- 3/4 of the thickness of epidermis
Melanocytes
produce the pigment melanin
Merkle Cells
specialized mechanoreceptors for light touch
Langerhan’s Cells
- found in deeper layers
- help to fight infection
What do keratinocyte (living and dead) provide?
mechanical strength
Non-cellular components of the epidermis
a. Basement membrane – binds dermis to epidermis
b. Desmosomes – between epithelial cells; bond them together
c. Hemidesmosomes – bind basal cells to basement membrane
d. Tonofibrils – protects skin from friction and pressure
e. Hair follicles
f. Sudoriferous Glands
What are Sudoriferous Glands
- Present everywhere except the lips and ears
- Secrete sweat in to ducts
- Helps to decrease the growth of bacteria
Characteristics of the Dermis
2-4 mm thick
layers are less defined than in epidermis
Papillary Dermis
- Superficial layer
- Contain FIBROBLASTS, mast cells and macrophages
- Loosely woven fibers with ground substance
- Ridges and valleys conform to the contours of the
__________________ layer of the epidermis and
creates an anchor - Where blisters occur
Reticular Dermis
- Dense, irregular CT
- Primarily type I collagen
- Has elastin fibers
- Location of nerve endings, glands and hair follicle plexus
- Deepest layer
- Gives structural support
Cell Types in the Dermis
Fibroblasts
Macrophages
Mast Cells
Fibroblasts in Dermis
Produce blank and blank fibers
Macrophages in the Dermis
Fight infection by releasing destructive enzymes
Mast Cells in the Dermis
- Secretory cells
- Produce ____________ which is important in initiating an inflammatory response
Non-Cellular Components in the Dermis
- Root hair plexus
- Each hair has a sebaceous gland that secretes sebum
- Ruffini Corpuscles
- Meissner and Pacinian Corpuscles
Root Hair Plexus
- Soft keratin
- Found everywhere except ___________ &
____________ - Help regulate body temperature by trapping air between
hair and skin surface
Ruffini Corpuscles
detect deep touch/pressure and vibration
Meissner and Pacinian Corpuscles
More tactile corpuscles
2 Components of Subcutaneous Tissue/Hypodermis
Adipose tissue
Fascia
Adipose Tissue
- Highly vascular loose connective tissue
- Stores fat to provide energy, cushion bones and provide insulation
Fascia
- Highly fibrous connective tissue
- Lymph vessels located at this level
Vascular Supply
- Arterioles and venules are in the reticular layer and terminate into
the papillary layer as capillary loops. - Lymphatic terminal vessels are interspaced between the capillary
loops
What occurs when nerves cross the dermal/epidermal junction?
They lose Schwann cells and become free nerve endings
Integument Functions
- Provide protection from the environment
- Provide sensation (free nerve ending, Merkel cells, Meissner corpuscle, Pacinian corpuscle, Krause bulb, Ruffini corpuscle, root hair plexus
- Prevent fluid loss – hygroscopy
- Contribute to immunity (Langerhans cells)
- Thermoregulation
- Protection from UV rays
- Synthesis and storage of vitamin D
Erosion/ Superficial Lesion
- Abrasion
- wound only involves the epidermis
Partial Thickness Skin Involvement
- Wound involves the entire epidermis and part of the dermal layer
- Will bleed d/t microvascular compromise
- Stage II pressure ulcer; skin tears; deeper abrasions, superficial and
partial thickness burns - Forms scar to heal
Full Thickness Skin Involvement
- Wound through epidermis and entire dermis; may also include fascia
or other deep tissues (tendon, bone etc.) - Stage III & IV pressure ulcers, full thickness burns, traumatic wounds, surgical wounds
- Repair occurs primarily through secondary intention (see below)
Suspected Deep Tissue Injury
- Purple or maroon areas of intact skin or blood-filled blisters caused by damage to the underlying soft tissues.
- Represent a serious form of pressure wound
- Deep tissue injuries are also known to deteriorate quickly even under optimal care
Types of Wound Healing/ Healing Response
Category 1/ Primary Intention
Category 2/ Delayed Primary Intention
Category 3/ Secondary Intention
Category 4
Inflammation/Inflammatory Stage =
Hemostasis
Inflammation
Proliferation =
- Angiogenesis
- Fibroplasia
- Matrix Deposition
- Re-epithelialization
Maturation =
Maturation
Remodeling
Hemostasis (clot formation)
Inflammation
Angiogenesis
Fibroplasia
Matrix Deposit
Re-Epithelialization
Maturation Phase
