Module 5 - Repair Process Flashcards
Primary Intention
Occurs when the wound margins are neat and approximate
E.g. surgical incisions or paper cuts
Occurs when the wound is clean, free of foreign material, and the edges are held close together
Occurs in 3 phases, initial, granulation, and maturation and scar formation
Initial
Edges of the incision are aligned and sutured or stapled in place
Lasts 3-5 days
The incision area filled with blood, resulting in blood clot formation and platelets releasing growth factor
The area forms a matrix for white blood cell migration resulting in an acute inflammatory reaction
Macrophages and neutrophils ingest and digest cellular debris, fibrin fragments, and red blood cells
As debris is removed the fibrin clot serves as a meshwork for subsequent capillary growth and migration of epithelial cells
Granulation
Granulation tissue includes proliferating fibroblasts, proliferating capillary sprouts (angioblasts), various types of WBC, educate, and ground substance
Lasts 5 days - 4 weeks
Immature connective tissue cells (fibroblasts) migrate to the healing site and secrete collagen, which becomes organized over time and restructured to strengthen the healing site (this stage is referred to as fibrous or scar tissue)
Macrophages produce cytokines which attracts more fibroblasts
Angiogenesis (production of new blood vessels). The wound is pink and vascular due to young budding capillaries
The wound is fireable and at risk for dehiscence
Surface epithelium at the wound edges regenerates and eventually contacts cells spreading from the opposite direction. This eventually thickens and begins to mature, resulting in the wound closely resembling adjacent skin
In a surface wound, re-epithelialization may take 3-5 days
Maturation and scar formation
Overlaps with granulation phase
May start 7 days after surgery or injury and continue for several months or years
Involves further organization of collagen fibers and remodeling process
Wounds becomes stronger and fibroblasts disappears
Myofibroblasts cause contractions of the healing area to aid in closing the defect
Mature scar is formed which is avascular and pale
The scar may be more painful than in the granulation phase
Secondary intention
Occurs when wounds are due to trauma, ulcerations, and infections with excess exudate and wide, irregular wound margins with extensive tissue loss
Wound edges cannot be approximated
May involve debridement of the wound of debris, cell, and exudate
Healing takes place from the edges inward and from the bottom up until the wound is filled
Results in more granulation tissue with a larger scar
Tertiary intention
Also known as delayed primary intention
Occurs due to delayed suturing of a wound where two layers of granulation tissue are sutured together
Occurs when an infected wound is intentionally left open until under control then sutured clase
Occur when a primary wound becomes infected resulting in the opening of the wound to allow granulation and ten re-suturing
Results in a layer and deeper scar than with primary or secondary intention
Complications of Healing-Scar formation - ulceration
blood supply around a scar may be impaired with result in further tissue breakdown and possible ulcerations
Complications of Healing-Scar formation - contracture and obstruction
Scar tissue is nonelastic and shrinks over a period of time which may cause…
Restricted range of motion in joints, causing fixation and deformation of the joint
Shortening or stenosis of a structure such as tubes or ducts, which may lead to an obstruction
Limited mouth and eyelid movement
Complications of Healing-Scar formation - loss of function
results from a loss of normal cells and the loss of specialized structures or normal organization in scar formation
Complications of Healing-Scar formation - hypertrophic scar tissue
an overgrowth of fibrous tissue resulting in excessive collagen deposits leading to hard ridges or scar tissue or keloid formation
Masses can disfigure and may lead to severe contractures
The shortening of scar tissue may pull the skin and underlying tissue out of its normal position
The final phase of the inflammatory response is…
preparing the body for healing
Resolution
Tissues or organ is totally restored to normal structure and function
100% success
Ex. Strep. Pneumonia
Regeneration - simple
Replacement if damaged parenchymal cells by same type of cells
Required cell division to occur
Ex. Liver after degeneration
Repair/organization - simple
Replacement of parenchymal cells by fibrous connective tissue
Outcome is fibrous scar tissue
Ex. Walls of the heart
Regeneration - complex
Replacement of last cells and tissues with cells of the same type by mitosis
Ability to regenerate is dependent on the type of cell
-Skin, lymphoid organs, bone marrow, and mucous membrane divide constantly and rapidly
-Liver, pancreas, Kidney, and bone cells retain their ability to regenerate but do so only if the organ is injured and do so slowly
-Neurons of the central nervous system and skeletal and cardiac muscles do not divide and therefore can lead to permanent injury
Damaged tissue is replaced by identical tissue from the proliferation of nearby cells
Regeneration is limited when the organization of a complex tissue is altered
