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TISSUE REPAIR BY DR. SADAKAT BASHIR.pptx
- 1. Tissue Repair Dr. SadakatBashir Assistant Professor (BDS, MPH)
- 2. Tissue Repair/Healing • Repair,sometimes called healing refers to the restoration of tissue architecture and function after an injury. • Repair of damaged tissues occurs by two types of reactions: 1. Regeneration. 2. Connective tissue deposition (scar formation).
- 3. Tissue Repair/Healing • Regeneration:is complete restitution of lost tissue components identical to those removed or killed by proliferation of residual (uninjured) cells and maturation of tissue stem cells. • Connective tissue deposition (scar formation): If the injured tissues are incapable of regeneration, or if the the tissue is severely damaged, repair occurs by the deposition of connective tissue.
- 4. Tissue Repair/Healing • Regenerationoccurs for example, in the rapidly dividing epithelia of the skin and intestines, and in some parenchymal organs, notably the liver. • Scar formation takes place in fibrosis of the lungs, liver, kidney and in Myocardial Infarction.
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- 6. Components of woundhealing 1. Inflammation. 2. Proliferation and migration of parenchymal and connective tissue cells. 3. Formation of granulation tissue. 4. Wound contraction. 5. Acquisition of wound strength.
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- 8. Tissue Regeneration • Bothregeneration and scar formation contribute in varying degrees to the ultimate repair. • Both processes involve the proliferation of various cells, and close interactions between cells and the extracellular matrix (ECM).
- 9. Granulation tissue • Granulationtissue is the hallmark of healing. Granulation tissue progressively invades the site of injury. • The term granulation tissue derives from its pink, soft, granular appearance seen an area of going wound healing.
- 10. Granulation tissue • Granulationtissue is: i. the proliferation of fibroblasts ii. new thin-walled, delicate capillaries (angiogenesis), in a loose extracellular matrix. iii. admixed inflammatory cells, mainly macrophages.
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- 12. Healing of skinwound • Healing of skin wound is a process that involves both epithelial regeneration and the formation of connective tissue scar. • Based on the nature and size of the wound, the healing of skin wounds occurs by first or second intention.
- 13. Healing of skinwound Healing by first intension • When the injury involves only the epithelial layer and the principal mechanism of repair is epithelial regeneration it is called primary union or healing by first intention. • It is the process of healing of a clean, uninfected surgical incisions approximated by sutures.
- 14. Healing by secondintension • Healing by second intention is also known as healing by secondary union. • When cell or tissue loss is more extensive like in large wounds, abscesses, ulceration, and ischemic necrosis (infarction) in parenchymal organs. • The repair process in second intension involves a combination of regeneration and scar formation.
- 15. Difference between Primary intension 1.Inflammatory reaction is less marked. 2. No wound contraction. 3. Margins are apposed together. 4. Minimal tissue damage 5. Minimal bleeding 6. Heals quickly 7. Small scar. Secondary intension 1. Intense inflammation. 2. Much granulation tissue formation. 3. Gap persists between margins. 4. Marked damage of tissues. 5. More bleeding. 6. Takes time to heal. 7. Large scar
- 16. Healing by firstVS second intension
- 17. Factors influencing woundhealing Systemic factors: 1.Nutritional status: Protein deficiency and vitamin C deficiency inhibit collagen synthesis and delay wound healing. 2.Metabolic status: DM is associated delay in wound healing. 3.Circulatory status, poor perfusion: Inadequate blood supply impair wound healing. 4.Hormones: Glucocorticoids have anti- inflammatory effects and inhibits collagen synthesis causing delay.
- 18. Factors influencing woundhealing Local factors: 1.Infection (one of the most important cause of delay in healing). 2.Mechanical factors (increased local pressure, high mobility delays healing). 3.Foreign bodies (splinter, steel, glass delays healing). 4.Size and shape of wound (clear cut surgical wound heals quickly). 5.Location of the wound (wound in the face heals quickly)
- 19. Complications of woundhealing Complications of wound healing are grouped into four categories: i. Deficient scar formation. ii. Excessive scar formation. iii. Exuberant granulation tissue formation iv. Formation of contractures.
- 20. Complications of woundhealing Deficient scar formation can lead to two types of complications: 1.Dehiscence or rupture of a wound. 2. Ulceration. Wound dehiscence is common after abdominal surgery and is due to increased abdominal pressure. Wound ulceration is due to inadequate vascularization. Example lower extremity wounds in with atherosclerosis.
- 21. Complications of woundhealing Wound dehiscence: a wound which was healing, has reopened or torn apart before it was fully healed. Wounds ulceration: happens when there is not enough blood flow to the area.
- 22. Complications of woundhealing Dehiscence is a wound that reopens along the incision line, while an ulcer is a deeper, more persistent sore that can develop in various areas due to underlying circulatory issues
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- 26. Complications of woundhealing Excessive scar formation can give rise to: (1) hypertrophic scar (2) keloids. • The accumulation of excessive amounts of collagen give rise to a hypertrophic scar. • If the scar tissue grows beyond the boundaries of original wound and does not regress, it is called keloid.
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- 30. Exuberant granulation tissue •Exuberant granulation is the formation of excessive amounts of granulation tissue, which protrudes above the level of the surrounding skin and blocks re-epithelialization (proud flesh). • Excessive granulation must be removed by cautery or surgical excision to allow re-epithelialization.
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- 32. Wound Contracture • Anexaggeration of contraction of wound gives rise to contracture and results in deformities of the wound and the surrounding tissues. • Common areas affected palms, the soles and the anterior aspect of the thorax. • Contractures are commonly seen after serious burns which compromise movement of joints.
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- 34. Remodeling of ConnectiveTissue • The outcome of the repair is influenced by a balance between synthesis and degradation of ECM proteins. • The connective tissue in the scar continues to be modified and remodeled. • Scar is modified and remodeled by an enzyme called matrix metalloproteinases (MMPs) produced by a variety of cell types (fibroblasts, macrophages, neutrophils.
- 35. Remodeling of ConnectiveTissue Matrix metalloproteinases (MMPs) are a group of enzymes that break down the components of the extracellular matrix (ECM). They play a key role in tissue remodeling by degrading collagen, elastin, and other ECM proteins. This helps in processes like wound healing, tissue development, and repair, as well as in the removal of damaged tissue.
- 36. Stem cell • Stemcell is characterized by prolonged self renewal capacity . Embryonic Stem cells: Are pluripotent that means they can generate all tissues of the body. Adult Stem Cells: 1. Bone marrow stem cells 2. Skin hair follicle bulge, inter-follicular area and sebaceous glands
- 37. Stem cell • BoneMarrow Stem Cells are a type of stem cell found in the bone marrow, which is the spongy tissue inside bones. These stem cells are crucial because they can develop into various types of blood cells, including red blood cells, white blood cells, and platelets. • Hematopoietic stem cells (HSCs): These give rise to blood cells and are responsible for replenishing the body’s blood supply. • Mesenchymal stem cells (MSCs): These can develop into bone, cartilage, fat, and other connective tissues. Bone marrow stem cells play a vital role in regenerating tissues and supporting the immune system.
- 38. 1. What isgranulation tissue, and why is it important in the process of wound healing? 2. Define wound healing. What are the complications of wound healing? 3. Explain the difference between primary and secondary intention in wound healing. 4. Discuss the factors that can influence the rate and effectiveness of wound healing. 5. Define homeostasis. Why is it crucial for the human body to maintain homeostasis? 6. Explain the concept of negative feedback mechanism.
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Editor's Notes
- #3 This means that the body can fully repair damaged tissue by using healthy cells around the injury site to grow back the lost parts, or by using stem cells to create new tissue that is just like the original. Stemcell: cells that can develop into many different cell types, including brain cells, muscle cells, and blood cells. They can also repair damaged tissues e.g. mesenchymal stem cell.
- #4 Parenchymal organs are organs in the body that are made up of functional tissue, or parenchyma e.g. lungs, liver, kidneys, pancreas etc Parenchyma is the functional tissue of an organ or structure Pulmonary fibrosis (PF) is a lung disease that causes scarring in the lungs, making it hard to breathe After a heart attack, an inflammatory response begins, clearing away dead tissue and activating fibroblasts which then synthesize and deposit collagen fibers, forming a scar.
- #6 2. main functional cells (like those in the liver or heart) and the supporting cells (like those in muscles or skin) grow and move to repair damaged tissue. 3.Granulation tissue is a new connective tissue that grows in the body to help heal wounds. It's made up of cells and capillaries that form a granular appearance. Granulation tissue is a normal part of the healing process and is usually pink or red in color. 5. process of a wound becoming stronger and more stable as it heals
- #10 Angiogenesis is the process of forming new blood vessels from existing blood vessels Admixed inflammatory cells are a combination of inflammatory cells, such as lymphocytes, plasma cells, and histiocytes, that are found together in a tissue
- #13 It’s the healing process of a clean surgical cut that is closed with stitches.
- #14 Ischemia is a condition where blood flow to an organ or tissue is reduced, while infarction is when blood flow is completely cut off, causing tissue death. Necrosis is the term for tissue death.
- #15 3. It means the edges of the wound are brought together or joined. 3. It means there is still a space or opening between the edges of the wound.
- #16 Inflammation is stronger because there is more dead tissue, fluid, and fibrin that need to be cleaned up.
- #17 Glucocorticoids are a group of hormones or drugs that are part of the steroid family Poor perfusion is a condition where blood flow to the body's tissues and organs is inadequate. Circulatory status refers to the condition of the body's circulatory system, produced by fibroblasts. Collagen is involved in all phases of wound healing, including the formation of new tissue, blood vessels, and granulation tissue.
- #18 Infection delays wound healing because the body has to focus on fighting the infection first. Mechanical factors like pressure, movement, or tension on the wound can slow healing because they disrupt the formation of new tissue. For example, increased pressure can reduce blood flow to the area, while constant movement can pull the wound apart, preventing it from closing properly. This makes it harder for the body to repair the damage. Foreign body can cause continued irritation or infection. some areas of the body have better blood supply, which helps deliver nutrients and oxygen needed for repair. For example, wounds on the face tend to heal faster due to rich blood flow, while wounds on areas like the legs or feet may take longer to heal because they have less blood circulation. Additionally, wounds in areas that move a lot (like joints) can face more stress and tension, which may slow healing.
- #19 3. Granulation tissue is the new tissue that forms when a wound is healing, but in this case, it’s forming in excess, which might be more than needed. 4. as a wound heals, the skin or tissue tightens and shrinks more than usual. This can cause the area to become stiff or restricted, sometimes leading to a reduced range of motion or deformity
- #20 rupture of a wound" means that a wound, which was healing, has reopened or torn apart before it was fully healed. happens when there isn't enough blood flow to the area. For example, people with atherosclerosis (narrowed blood vessels) can get wounds on their legs that don't heal properly because the blood can't reach the area well enough
- #21 rupture of a wound" means that a wound, which was healing, has reopened or torn apart before it was fully healed. happens when there isn't enough blood flow to the area. For example, people with atherosclerosis (narrowed blood vessels) can get wounds on their legs that don't heal properly because the blood can't reach the area well enough
- #26 Regress: to go back to a former condition "When too much collagen builds up in a wound, it leads to a hypertrophic scar, which is a raised, thick scar."
- #30 Blocks re-epithelialization" means it prevents the skin from growing back over the wound. Removing the excess tissue either by burning it off with heat (cautery) or cutting it away with a surgical instrument
- #32 When the wound heals too tightly, it can cause contracture, which leads to deformities in the wound and the surrounding skin or tissue. A contracture is a permanent or temporary shortening of muscles, tendons, ligaments, or skin that limits movement in a joint or body part. The anterior aspect of the thorax is the front of the chest wall, also known as the pectus. It includes the sternum, clavicles, ribs, and intercostal spaces
- #34 Remodeling is the final stage of wound healing, where the new tissue gradually matures and strengthens. Collagen fibers are rearranged and aligned to improve the strength and function of the healed tissue. The outcome of tissue repair depends on the balance between the creation and breakdown of extracellular matrix (ECM) proteins. If too much is produced or broken down, it can affect the healing process and lead to issues like scarring or weak tissue.
- #35 Matrix metalloproteinases (MMPs) are a group of enzymes that help wounds heal by breaking down and remodeling damaged tissue
- #36 Hair follicle bulge:region around the hair follicle that contains stem cells responsible for hair growth and repair.Inter-follicular area:area between hair follicles in the skin, containing keratinocytes and other cells important for the skin’s barrier function.Sebaceous glands: These are glands that secrete sebum (oil) to lubricate the skin and hair, helping to prevent dryness.
- #37 Replenishing the body’s blood supply means producing new blood cells to replace those that are used or worn out.