Anatomy of the Skin Flashcards
2 primary layers of the skin
epidermis and dermis
primary role of epidermis
protection and moisture retention
what is the epidermis comprised of
mostly dead cells
it is avascular;no blood supply
role of the dermis
Structural integrity of the integument
Provide nutrition/hydration to epidermis
Regulates body temp
what does the dermis contain
blood vessels nerves collagen lymphatics elastin Sebaceous glands sweat glands
what is the rete peg region
area between epidermal and dermal ridges and
valleys
role of the rete peg region
increases the surface area
between these 2 layers
Acts as extra skin to protect against frictional forces
What comprises the subcutaneous layer?
Connective tissue Fat-adipose tissue Blood vessels Lymphatics Nerves
What is the role of the subcutaneous layer?
Blood supply for skin
Provides insulation/cushioning
What is under subcutaneous layer?
Muscles, fascia and bone
What causes the Integument to lose it’s ability to be intact?
Impaired circulation Trauma Burns Pressure Friction Shear Radiation (including sun exposure) Edema Infection Loss of sensation Loss of moisture Skin disease
intrinsic factors that contribute to skin integrity
Age Chronic disease Oxygenation, blood volume Perfusion Immunosuppression from HIV, Chemo Neuropathy, SCI
extrinsic factors that contribute to skin integrity
Medications Nutrition Hydration Radiation and Chemotherapy Stress Infection
what part of the skin does a superficial wound involve?
involves the epidermis
what part of the skin does a partial thickness wound involve?
involves the dermis
what part of the skin does a full thickness wound involve?
Includes all layers of dermis and extends into
underlying tissues
examples of superficial wounds
First degree burns, stage 1 pressure
sores, contusions
examples of partial thickness wounds
Abrasions, skin tears, stage II pressure ulcers,
second degree burns
examples of full thickness wounds
Third degree burns, wounds that extend
through all layers of the skin and/or muscles,
tendons and bones
how can a superficial wound be identified
by redness, swelling, tenderness and warmth
NOT open
how does a superficial would heal
by the inflammatory response
how is a partial thickness wound characterized
by loss of the dermis
OPEN
looks wet
how does a partial thickness wound heal
by inflammation and epitheliazation
how is a full thickness would characterized
by large gaps and wound
edges can’t be approximated
how does a full thickness would heal
by inflammation, epitheliazation, intention and proliferation
what is primary intention healing
the edges are approximated and sutured by
surgery
what is secondary intention healing
contraction and granulation in open full thickness wounds
what is tertiary intention healing
deeper layers are closed but
subcutaneous are left open, contaminated, infected wounds. Wound edges eventually reapproximated
with sutures and then heals by primary closure
what are chronic wounds
Wounds that fail to show a decrease of 50% of their volume in 1 month, so closure could not be achieved in 12 weeks
what are the wound healing time phases
Inflammatory 2-24 hours or up to 2 weeks
Epithelialization -2-4 weeks
Proliferative- 2 weeks to 24 days
Remodeling-end of proliferative phase ->
2yrs
what happens in the inflammatory phase
Body’s immune reaction-hemostasis
Growth factors stimulated
Controlled tissue degradation
Difference between infection and inflammation?
Inflammation- tenderness, changes in skin
color, slight edema, heat
Infection- streaks of redness extending from
wound, intense pain, drainage thick yellow,
brown or green, malodor
what happens during epitheliazation
Body protecting itself from invasion Epithelial cells at wounds edges sebaceous glands & sweat follicles resurface by moving laterally Islands of epidermis may appear on wound surface Migrating tissue connects to adjacent skin & pulls it to cover the wound Occurs from multiple directions New skin- bright pink may not regain normal pigmentation Forms very thin sheet at first
how can epitheliazation be bypassed
if a skin graft is used or the wound is too large
what is epiboly
rolled skin edges that won’t heal any further once it rolls under
how does the dermis assist with temp regulation
blood vessels constrict to keep the heat at the core. They can also dilate to release heat and decrease core temp
how does the dermis provide protection, elimination of waste and homeostatsis
it is a thick layer that contains collagen and elastin for protection
it has sebaceous and sweat glands for removal of wastes and keeps fluids regulated for homeostasis via blood vessels and lymphatics
do all people heal at the same rate?
NO
depends on our age, blood supply, extrinsic factors (medications) nutrition/hydration status., co-morbidities (DM, PVD,PAD)
lifestyle choices, etc.
what factor is most related to loss of skin integrity
decreased profusion (poor circulation)
What is intention healing
relates to wounds beyond the inflammatory phase. They are open
If the wound has been infected, surgically debrided and closed up a week later what type of wound healing is it
TERTIARY because it was infected
what happens in the proliferative phase
Granulation tissue formation-cavity is filling in to create level surface
Shows red or pink granulation buds
(collagen and blood vessels)
Does not replace structures lost
Overlaps with the inflammatory phase
Yellow fibrinous membrane may appear on top of granulation tissue
Less susceptible to infection with this membane
Can be confused with infection
Contraction occurs- wound edges are drawn together
Contraction reduces the areas needing to close by epithelialization
The shape the wound assumes is predictive of the speed of contraction
how fast do linear wounds close
at a quick pace
how fast do circular wounds close
at a slow pace
how fast do square or rectangular wounds close
at a moderate pace
what happens in the remodeling phase
Scar tissue rebuilt to ↑ tensile strength
↑’s to 80% of original pre-injury strength at best
Scar tissue replaced with less vascular tissue
Scar tissue eventually becomes more flexible
what does granulation look like
a beefy red
what type of wound heals primarily by epitheliazation
wounds with a loss of dermis
how does a skin tear heal
by epitheliazation
what phases are needed for epiboly to heal
granulation and contraction
how does an incision heal
by inflammation, granulation, epitheliazation and remodeling
an open blister on the heel involves what tissues
the epidermis and dermis
how would a blister heal
inflammation and epitheliazation
