Lecture 24 - Cutaneous Wound Healing Flashcards
what are the layers of skin? breifly describe each
*the skin is the first 2 layers (1.5-4 mm thick)
1) Epidermis
- principle protective structure of skin (from infection and protection from other elements - ie waterproofing)
- avascular
- renews itself every 28 days
- composed of epithelial cells
2) Dermis
- composed of loose connective tissue allowing blood vessels and sensory nerve endings to pass through.
- supports and nourishes the epidermis
- nerves, hair follicles, sebaceous glands and sweat glands
3) Subcutaneous Layer
- Constist of an energy reserve (subcutaneous fat)
- Role: thermal protection; shock absorption – protection
- Contains: Pacini corpuscles and other mechanoreceptors
what is Hyperkeratosis?
abnormal thickening (hyperplasia) of the «stratum corneum» found on the epidermis of a person with diabetes
what is Granulation tissue?
tissue formation, red, raspberry-like in appearance, includes small blood vessels and collagen fibers. Granulation tissue acts as a support that allows migration of the epithelial cells in the epidermis and covering of the wound.
what is Maceration?
overabundance of humidity in the tissues (whitened skin)
what is Fibrin?
thin yellowish layer, deposit found on the surface of the wound during the inflammatory phase (globulin, filament-like insoluble, white and elastic, contains deposits as a result of spontaneous blood coagulation, lymph and certain exudates. The filaments form a network that includes knots containing platelet aggregates.)
what is Necrotic tissue/slough/cangrenous?
dead tissue that are yellow, grey, blackish or greenish in appearance.
what is Eschar?
black, hard crust (scar) resulting from necrosis of a cutaneous or mucous covering
what is Erythema?
redness found on skin covering (integument) more or less intense disappearing with pressure.
what is Undermining?
area where the skin thickness is detached from the tissues below.
what is sinus tract?
deep, formed anatomical tunnel
describe partial thickness wounds
Note: there are remaining sebatious glands bc its a partial thickness wound and therefore these islands come and it heals faster - this cannot occur in a full-thickness wound and therefore it takes longer to heal
describe full thickness wound healing
describe the 4 stages of wound healing
Phase I: Hemostasis
- Stopping of bleeding / coagulation
- Accumulation of platelets & fibrin: «fibrin clot»
Phase II: Inflammatory
- Inflammatory response: redness, edema, warmth, pain, ↓ range of motion
- ↑ blood vessel permeability→ plasma leaks into the interstitial space → oedema
• Autogenic debridement: process through which the body uses its own mechanisms to remove dead tissue.
N.B. A humid environnement is required
• Infection control through white blood cells (leukocytes): neutrophil, macrophages, lymphocytes
Phase III : Proliferation (fibroblastic)
• Repair (healing) through enhanced cellular activity.
• Forming of granulation tissue:
– Angiogenesis:newbloodvesselsforemdviaendothelialcells. – Collagen/extra-cellularmatrix:viathefibroblasts
• Closing of the wound by granular tissue contraction (myofibroblasts) and by epithelialisation (mitosis of the epithelial cells)
Phase IV : Remodeling (maturation)
• Collagen fibers organize themselves, increase their elasticity and resistance to traction in order to regain the consistency/ configuration of healthy tissue.
the 4 stages of acute wound healing and cells involved timeline
what classifies a chronic wound?
Chronic wound:
- One that deviates from the expected sequence of repair in terms of time, appearance and response to aggressive and appropriate treatment.
- 4to12weeksand+
what are the 4 types of chronic wounds?
! Pressure ulcers ! Venous ulcers ! Arterial ulcers ! Neuropathic ulcers
descibe the pathophysiology of pressure ulcers
Localized areas of tissue necrosis that tend to develop when soft tissue is compressed between a bony prominence and an external surface for a prolonged pediod of time
describe a stage 1 pressure ulcer
describe a stage 2 pressure ulcer
describe a stage 3 pressure ulcer
describe a stage 4 pressure ulcer
describe pressure sore classification/characteristics
Stage – Unspecified
- Complete tissue loss whereby the bed of the wound is covered by humid, necrotic tissue or eschar.
- Unable to determine the stage of the pressure sore until the necrotic tissue or the eschar is debrided to see the bed of the wound.
what is the pathophysiology of venous ulcers?
- Muscle contraction (calf muscle) pumps blood and enhances venous return.
- Unidirectional valves prevent blood from flowing back.
- Venous hypertension can occur when there is insufficiency of the valves.
cause of venous hypertension