Unit 1.1 Integumentary System

What are the three layers of the integumentary system?

Epidermis, dermis, and subcutaneous

What are the functions of the epidermis?

- Provides a physical and chemical barrier

- Regulates fluid

- Provides light touch sensation

- Assists with excretion

- Critical to endogenous vitamin D production

- Contributes to cosmesis/appearance

What are the layers of the epidermis?

Stratum corneum

Stratum lucidum

Stratum granulosum

Stratum spinosum

Stratum Basale

What are the characteristics of the stratum corneum layer?

- Contains multiple layers of flattened, dead, interlocking keratinocytes

- typically dry

- water resistant

- permits slow water loss by insensible perspiration

What are the characteristics of the stratum lucidum layer?

appears as a glassy layer in thick skin only

What are the characteristics of the stratum granulosum layer?

- keratinocytes produce keratohyalin and keratin

- keratin fibers develop as cells become thinner and flatter

- Gradually, the cell membranes thicken, the organelles disintegrate, and the cells die

What are the characteristics of the stratum spinosum layer?

- Keratinocytes are bound together by maculae adherens attached to tonofibrils of the cytoskeleton

- Some keratinocytes divide in this layer

- Langerhans cells and melanocytes are often present

What are the characteristics of the stratum basale layer?

- Is the deepest, basal layer

- Attachment to basal lamina

- Contains epidermal basal (stem) cells, melanocytes, and Merkel cells

What is the function of the keratinocyte cell?

These are continuously dividing cells that produce keratin

What keratins function?

a protective protein that creates a tough, water-resistant physical barrier to protect the body from trauma and infection

What is the function of melanocyte cells?

They produce the pigment melanin

What is the function of melanin?

which gives skin its color and provides protection against the harmful effects of ultraviolet (UV) radiation

What is the function of Langerhans cells?

They help fight infection by attacking and engulfing (phagocytizing) foreign material that enters the skin

What is the function of Merkel cells?

These are specialized mechanoreceptors that provide information regarding light touch sensation

What are the functions of the dermis?

- Supports and nourishes the epidermis

- Houses epidermal appendages

- Assists with infection control

- Assists with thermoregulation

- Provides sensation

What are the two layers of the dermis?

papillary layer and reticular layer

What structures are in the papillary layer?

Dermal papillae, pain receptors, capillary loops, and extensions of skin appendages

What structures are in the reticular layer?

Blood vessels, appendages: sebaceous and sweat glands, hair follicles, and nerve receptors: pressure

What do fibroblast cells do?

They are the primary cells of the dermis and are responsible for producing collagen and elastin fibers, which give the skin its structural strength and flexibility

Where are the Meissner's Corpuscles located in the dermis?

papillary layer

What's the function of the Meissner's corpuscle?

Specifically known for detecting sensitive light touch

Where are the Pacinian Corpuscles located in the dermis?

reticular layer

What's the function of the Pacinian corpuscle?

Specifically known for detecting deep pressure and rapid vibrations

Where does erosion take place?

Epidermis

What are the clinical signs of erosion (superficial partial thickness)?

Characterized primarily by erythema (redness) . Because the epidermis is avascular, there is minimal to no bleeding

What's the appearance of erosion (superficial partial thickness)?

These wounds look like a reddened area or a scrape where the very top layer of skin has been removed, but the integrity of the deeper, blood-vessel-containing dermis remains intact.

What's an example of erosion (superficial partial thickness)?

A superficial (first-degree) burn or a simple abrasion

Where does partial-thickness skin loss occur?

Dermis

What are the clinical signs of partial-thickness skin loss?

Unlike superficial wounds, partial-thickness wounds involve the highly vascular dermis, leading to bleeding.

What's the appearance of partial-thickness skin loss?

They often appear as a blister or a raw, moist wound bed. Because they do not penetrate the entire dermis, they do not typically show subcutaneous fat or deeper structures.

What's an example of partial-thickness skin loss?

Skin tears, Stage 2 pressure injuries, and superficial or deep second-degree burns

Where does full-thickness skin loss occur?

epidermis, dermis, and subcutaneous

What are the clinical signs of full-thickness skin loss?

These wounds may exhibit the exposure of bone, tendon, ligament, or muscle .

What's the appearance of full-thickness skin loss?

often looks like a crater or "pothole". You can differentiate the depth by the color of the exposed tissue:

o   Subcutaneous (Adipose) Tissue: Glistening white to pale yellow

o   Muscle: Bright/dark red and bleeds readily.

o   Tendon/Ligament: Glistening white and fibrous.

o   Bone: Shiny, smooth, and milky white.

What's an example of a full-thickness skin loss?

Surgical incisions, "third-degree" burns, and Stage 3 or 4 pressure injuries