2A - Integumentary & Wound Basics

what are the basic structure & functions of the integument?

Large & Complex

Physical Barrier & Sensory Functions

Temperature Regulation & Sweating

Required for Vitamin D Production

the integument is a barrier to?

harmful chemicals, UV rays, infection

what are the 3 layers of the integument?

1. eipdermis

2. dermis

3. subcutaneous fat

what is the next layer under subcutaneous fat?

fascia

what type of cells is the epidermis mainly made out of?

keratinocytes

where are the thickest portions of the epidermis?

palms and soles

how many layers are in the epidermis and what do they represent?

5 → different stages of cellular differentiation, gradual loss of nuclear material & accumulation of keratin proteins

how does the epidermis receive nutrients? and what is the process?

diffusion through semi-permeable Basement Membrane (BM)

new cells form on the BM and older cells elongate, membrane thickens as they are pushed up

what is the deepest layer of the epidermis?

stratum basale

what is the stratum basale attached to?

dermis by thin BM

what kind of cell activity is confined to the stratum basale?

mitotic activity of keratinocytes

how many rows are on the stratum basale?

single row

how long is epidermal turnover time?

~2-4 weeks

what do keratinocytes produce?

keratin (protective protein)

what are the 5 layers of the epidermis?

1. stratum corneum

2. stratum lucidum

3. stratum granulosum

4. stratum spinososum

5. stratum basale

what are the functions of the ridges in the skin?

allow movement of the epidermis on the dermis and reduces shear forces

do the ridges stay when tissue is injured and it has to repair itself?

no, ridges are lost resulting in weaker tissue and less response to friction

facts about the stratum corneum

• consists of dead keratinocytes

• 20-30 cells thick

• 75% of thickness of the epidermis

• cells are continuously abraded & replaced by cells below

what causes the formation of a callus in the stratum corneum?

friction or pressure

produce keratin (protective protein)

keratinocytes

produce pigment melanin

Protects skin from UV

Gives the skin its color; more = darker, less = lighter

melanocytes

Specialized mechanoreceptors (light touch)

Merkel Cells

what cells are in the deeper layers of epidermis and assist in fighting infection (attack & engulf foreign material)

Langerhan’s Cells

function of hair follicles

Soft keratin → helps regulate body temp by trapping air between hair and skin surface

everywhere except palms and soles

each hair follicle contains what?

sebaceous gland

function of sebaceous glands?

secretes sebum oily substance that lubricates skin & hair → may also slow bacterial growth, reducing colonization

Present everywhere except lips and ears

Secrete sweat into ducts that lead to skin’s surface

Evaporation of sweat helps cool the body

sudoriferous glands

Hard Keratin

Protect terminal digit & assist with function

nails

what are the functions of the epidermis? (5)

• physical & chemical barrier

• regulates fluid

• light touch sensation

• assists with thermoregulation, excretion, vitamin D production

• cosmesis/appearance

how to find newly formed epidermis?

does not depend on the skin color of the person, will have a light pink to white color on the edges of the injury

what are the 2 layers of the dermis?

papillary and reticular dermis

what makes up the dermis?

collagen and elastic fibers contained in an amorphous ground substance, nerve fibers, and nerve-end sensory organs

how thick is the dermis?

2-4mm

Loosely woven fibers embedded in gelatinous matrix (ground substance)

Blisters occur here if friction between epidermis & dermis

papillary dermis (thin superficial)

Dense irregular arranged connective tissue

Provide increased structural support to the skin

reticular dermis

what layer of integument?

shiny or moist due to high H₂O content

dermis

what provides color to the dermis?

capillaries because it is highly vascular

pale pink to rosy red

function of superficial lymphatics in the dermis?

assist in returning H₂O, proteins, and others from tissue to blood stream

main cells found in dermis, produce collagen & elastin fibers, ground substance

Give dermis strength & flexibility

fibroblasts

Help fight infection by engulfing harmful substances & releasing destructive enzymes

Macrophages & Polymorphonuclear Leukocytes (neutrophils)

Specialized secretory cells

Produce chemical mediators of inflammation such as histamine

Attract other cells and cause vasodilation to fight infection or repair injury

mast cells

dermis also contains sensory receptors for…?

Touch, Vibration, Temperature, Pressure

what is the function of the dermis? (4)

• support and nourish epidermis

• house epidermal appendages

• assists with infection control and thermoregulation

• provide sensation

May be referred to as hypodermis

Supports the skin

subcutaneous tissue

what are the 2 components of subcutaneous tissue?

adipose tissue and fascia

what does healthy adipose tissue look like?

shiny white to pale yellow (darker if dehydrated)

functions of adipose tissue? (3)

stores fat for energy

insulation

protection (cushion over structures such as bony prominences)

function of fascia? (3)

highly fibrous connective tissue

separates and surrounds structures

facilitates movement between adjacent structures (muscle, tendon, bone)

where are deeper lymphatic vessels located in?

subcutaneous tissues

Regularly arranged fibers surrounded by fascia

Rich vascular supply → red in color, bleeds easily

Non-viable muscle will appear gray or black in color

muscle

Regularly arranged fibers, may be enclosed in fibrous sheath

tendons

ligaments vs. joint capsules based on arrangement of fibers

ligaments = regularly arranged fibers

joint capsule = direction of fibers vary

consist of dense connective tissue

When Healthy, glisteny (silky) white appearance

ligaments and joint capsules

what do non-viable ligaments and joint capsules look like?

dry, leathery, dark, and may be disconnected

Shiny, smooth, milky white appearance, hard when probed

bone

what does unhealthy bone look like?

moth-eaten, irregular surface, dark discoloration

what is slough?

dead fibroblast tissue that is trying to repair itself but it can’t

what are the 3 ways a wound can be characterized as?

superficial, partial-thickness, full thickness

this type of wound only affects the epidermis

superficial → dermis may or may not be expose

ex) abrasion

this type of wound involves the epidermis and part of the dermis

partial-thickness

ex) severe sun burn with blistering and peeling

this type of wound extends through epidermis & dermis to the subcutaneous tissue layer

full-thickness wounds

full-thickness wounds may be further categorized as?

subcutaneous and sub-dermal if tissues such as tendon, muscle, or bone or involved

how do you measure wound size?

like a clock- 12 up at the head, 6 down at the feet

length, width, depth

what is undermining?

tissue under the wound edges becomes eroded, creating a "pocket" or dead space beneath the skin, often extending further than the visible surface

what is tunneling?

narrow channel or tract that extends from the surface of the wound into deeper tissue layers, potentially creating pockets or dead-end passages within the wound

what is a fistula?

a tunnel-like connection between 2 body structures

what should you look for in the periwound area?

• erythema

• heat

• edema

• pain

• loss of function

• sudden response- color and temperature

what is erythema?

change in color

what is turgor?

skin stretched taught, swelling limited by how much the skin can stretch

if the periwound area is > 2 cm, that indicates?

cellulitis → wound is infected

what are cliff edges?

edges of the wound that are circular in shape

what causes rolled edges?

upper epidermal cells roll down over the lower ones instead of migrating across the wound

what is maceration of tissue?

too much fluid in the skin and it puffs out, bad bc dressing is not trying it up and the skin has been sitting in exudate

what are the 3 different types of wound base?

• yellow slough

• red granular

• black eschar

what is black eschar?

dead, dry tissue → needs to be removed before it can heal

Exudate Amount Definition: None

wound tissue dry

Exudate Amount Definition: Scant

wound tissues moist, no measurable exudate

Exudate Amount Definition: Small

wound tissues wet ≤ 25% dressing shows drainage

Exudate Amount Definition: Moderate

wound tissues saturated, 25% - 75% dressing shows drainage

Exudate Amount Definition: Large

wound tissues bathed in fluid; drainage freely expressed, ≥ 75% dressing shows drainage

Exudate Amount Definition: Strike-through

so much that the dressing cannot handle it, fluid comes through dressing

thin, watery clear exudate

serous

thin watery, pale red to pink exudate

serosanguineous

thin, bright red exudate

sanguineous

thin or thick, opaque tan to yellow exudate

purulent

thick, opaque yellow to green with offensive odor

foul purulent

T/F Not all open wounds are contaminated

FALSE → all are contaminated

> ___ colony forming units per gram tissue = infection

10^5

communities of bacteria and microorganism that adhere to solid surfaces → need to be cleared out bc it prevents you from healing

biofilms

___% of chronic wounds have biofilms

60%

• bacteria are present within the wound

• they are not multiplying

• there is a steady state of replicating organisms that maintain a presence in the wound but do not cause delayed healing

contaminated and colonized

• the bacterial burden in the wound bed is increasing

• this burden initiates the body’s immune response locally but not systemically

• the wound is no longer healing at the expected rate

critically colonized

• bacteria are present within the wound and are multiplying

• there is an associated host immune response locally and then systemically

• the wound is painful and may increase in size

infected