Types of Wounds (Test 1 Lecture 2) Flashcards
What are the 4 phases of normal healing?
Hemostasis (Coagulation)
Inflammation
Proliferation
Remodeling
How far must an injury into the skin go to cause bleeding?
Through the epidermis and BMZ
Which phase initiates the activation of platelets to help stop bleeding?
Hemostasis
What do blood clots consist of?
Fibrin
Aggregated platelets
Blood cells
Whats the purpose of a clot?
Seals disrupted vessels to control blood loss
Provide temporary bacterial barrier
Provide a reservoir of growth factors
Provides an interim matrix that serves as scaffolding for migrating cells
What is the process of breaking down a clot called?
Fibrinolysis
What is the purpose of the inflammatory phase?
To control infection and establish a clean wound bed
- Breaks down devitalized tissue
- White blood cells eliminate excess bacteria
When does vasoconstriction subside and vessels dilate and cell permeability increases?
Inflammatory Phase
How do leukocytes get to the area of the wound?
Chemoattraction by damaged cells and platelets attract the leukocytes
What are the 3 processes of the inflammatory phase?
Vascular Stage
Exudate Stage
Reparative/Proliferative Stage
What happens during the vascular stage of the inflammatory phase?
Cellular filtration pressures and permeability of cells increases leading to: Local Edema Warmth Erythema Discomfort/Pain
What happens during the Exudate stage of the inflammatory phase?
Fluid passes through the walls of vessels into adjacent tissues/spaces to help deposit fibrins and leukocytes
What are the first cells to arrive in a new wound?
Neutrophils
-present within minutes and can dominate area for 2-3 days
What is the primary function of neutrophils?
Remove bacteria and foreign debris via phagocytosis
After neutrophils what is the next type of cells to get to the wound and what is their purpose?
Macrophages
-responsible for finishing bacteria and breaking down damaged tissue
When does true wound healing start?
Reparative stage of the Inflammatory phase
What are the processes that occur during the proliferative phase?
Granulation
Angiogenesis
Wound Contraction
Epithelialization
What happens during granulation and when does it begin?
Fibroblasts and capillary buds develop at edges of the wound and advance to the center.
Starts 3-4 days post injury (as inflammatory phase subsides)
What are some factors that can affect granulation?
Perfusion Status
Oxygen Levels
Nutritional Status
Glucose Level
What is new extra-cellular matrix formed by collagen fiber deposition and new capillary loops known as?
Angiogenesis
What are the 2 mechanisms that angiogenesis can occur?
- Production of new vessels by local endothelia cells
- Recruitment of circulating see progenitor cells
How does the wound contraction part of the proliferative phase work?
Myofibroblasts exert tractional forces on the new ECM. Force pulls edges of wound together so the granulation tissue and new epithelial cells don’t have to travel as far
What happens during epithelialization and when does it occur?
Basal cells from edges of wound migrate inward from the wound edges.
Happens at the same time as contraction (day 21)
What does epithelialization use as a support structure?
Uses ECM and granulation bed
What happens during contact inhibition and when does it occur?
Ceases migration of epithelial cells across a wound bed
-occurs when epithelial cells moving across a wound bed come in contact with other epithelial cells
What type of environment is best for epithelialization?
Moist environment
How can you tell the difference between granulation and epithelialization?
Granulation looks wet and shiny, while epithelialization looks less reflective
How strong is skin when it is first formed?
15% as strong as original tissue
Will become 80% as strong as original
What happens during the remodeling phase?
Completes wound healing
Constant cycle of collagen formation and lysis in the scar
What type of collagen is it converted to during the remodeling phase?
From type 3 to type 1
What are the types of wound closure?
Primary - Surgical (stitches, stables, duck tape, blah blah)
Secondary closure - Normal phases of wound healing
Tertiary - Wound that is healing naturally then needs reopened to clean out infection (kept open until infection is cleared then closed surgically)
What are some characteristics of primary closure?
Heals quickly
Minimal scar tissue
Healing can be slowed by infection, trauma, or secondary breakdown
What are some examples of secondary closure?
Pressure ulcers and dehisced surgical incisions
What can help with secondary closure?
Skin grafts, substitutes, skin flaps, or other surgical interventions
What are the different types of exudate?
Serous - Thin and liquidy (pussy, straw colored)
Purulent - Snot colored, thick mucous, smells (sign of infection)
Fibrinous - Cloudy, filled with fibrin, not adherent (can wipe it off)
Hemorrhagic - Not just blood (thinner then blood, full of serous fluid)
What are the types of exudate that involve a combination?
Sanguineous - Reddish, thin, and watery (occurs with trauma to blood vessels)
Serosanguineous - Clear, pink, think, watery (normal drainage in wound healing
Seropurulent - Yellowish and cloudy (sign of infection
Hemopurulent - Dark red and viscous (contains bacteria, inflammatory cells, tissue that is dead or dying)
What factors may inhibit wound healing?
Level/presence of infection Size of wound Location Type of wound Amount of available blood Co-morbidites Nutrition
How do you define the depth of the wound?
Partial thickness - partial loss of dermal tissue (epidermis and superficial dermis)
Full-Thickness - involves total loss of dermal tissue (can involve deeper tissue, muscle, subQ, Bone)
What causes a chronic wound?
Vascular compromise
Chronic inflammation
Repetitive trauma to injured tissue
