Tissue Repair & Healing Processes

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Granulation tissue is characterized by all of the following EXCEPT:

Actively contracting to reduce wound size.
Having an aggregate of epitheloid histiocytes. (correct)
Being supported by myofibroblasts.
Containing loops of capillaries.

What is the primary process involved in the formation of a fibrous scar during tissue repair?

Granulation tissue formation.
Organisation. (correct)
Resolution.
Acute inflammation.

In cases of pneumonia, organization occurs when:

The lung tissue undergoes liquefactive necrosis.
Myofibroblasts contract excessively within the alveoli.
The inflammatory exudate filling the alveoli becomes organized. (correct)
Granulation tissue forms granulomas within the lung parenchyma.

Wound contraction reduces the tissue defect by approximately what percentage due to myofibroblast contraction?

80% (B) Signup and view all the answers

What is a potential complication of wound contraction following circumferential tissue damage around the lumen of the gut?

Obstruction. (A) Signup and view all the answers

In healing by first intention, what is the immediate response that occludes small blood vessels cut by the incision?

Thrombosis. (B) Signup and view all the answers

What is the role of the coagulated blood on the surface of a wound undergoing healing by first intention?

To keep the wound clean. (A) Signup and view all the answers

In healing by first intention, if the wound edges are closely apposed, what is the effect on collagen and vascular proliferation?

Collagen and vascular proliferation are minimized. (D) Signup and view all the answers

Which of the following characteristics accurately describe permanent cells?

Lose their proliferative ability around the time of birth. (C) Signup and view all the answers

What is the primary distinction between 'healing' and 'repair' in tissue recovery?

Healing results in complete restoration, whereas repair results in replacement by fibrous tissue. (A) Signup and view all the answers

How does regeneration differ from repair in the context of tissue damage?

Regeneration restores function with identical cells, while repair replaces with non-specialized tissue. (C) Signup and view all the answers

Which of the following cellular components directly contribute to the production of growth factors essential for wound healing?

Platelets and macrophages (A) Signup and view all the answers

What cellular process allows for the complete restoration of a minor skin abrasion?

The migration and proliferation of cells from the lesion margins and skin appendages. (C) Signup and view all the answers

A patient with a long-standing history of poorly controlled diabetes mellitus develops a foot ulcer. What is the most likely underlying systemic factor contributing to the impaired wound healing in this patient?

Microangiopathy (B) Signup and view all the answers

Why is contact inhibition important in normal tissue?

It halts cell proliferation once a defect is covered, thus controlling growth and movement. (A) Signup and view all the answers

How does the loss of contact inhibition contribute to neoplasia?

It enables continued proliferation of tumor cells, leading to uncontrolled growth. (A) Signup and view all the answers

An elderly patient undergoing corticosteroid therapy for rheumatoid arthritis sustains a minor skin laceration. Which of the following mechanisms explains how the medication may impair wound healing?

Suppression of the immune response (A) Signup and view all the answers

A patient with advanced metastatic cancer experiences a pathological fracture that fails to heal properly. Which factor is most likely contributing to the impaired bone healing in this scenario?

Malnutrition (A) Signup and view all the answers

A patient sustains a deep cut on their arm that damages both the epidermis and dermis. Which process would be most likely to dominate the initial phase of wound healing?

Repair involving the formation of fibrous scar tissue. (D) Signup and view all the answers

Following a myocardial infarction (heart attack), cardiac muscle cells are permanently damaged. Which of the following outcomes is most likely, considering the nature of cardiac muscle cells?

Repair of the damaged area with fibrous tissue, leading to scar formation. (C) Signup and view all the answers

A 70-year-old patient with peripheral arterial disease develops a non-healing ulcer on their lower leg. What is the primary systemic factor impeding wound healing in this patient?

Inadequate blood supply (C) Signup and view all the answers

Following abdominal surgery, a patient experiences wound dehiscence. Which factor most directly contributes to this complication?

Increased intra-abdominal pressure. (D) Signup and view all the answers

A patient of African-American descent develops a raised scar that extends beyond the original wound boundaries. This scar does not regress over time. Which of the following best describes this type of scar?

Keloid (C) Signup and view all the answers

A burn patient develops a tightening of the skin around their anterior thorax, restricting movement. What complication of wound healing is most likely occurring?

Contracture (D) Signup and view all the answers

Which of the following growth factors or cytokines is MOST associated with stimulating fibroblast migration during wound healing?

PDGF (D) Signup and view all the answers

Tumor Necrosis Factor (TNF) affects wound healing through which of the following mechanisms?

Activating macrophages and regulating other cytokines (D) Signup and view all the answers

Transforming Growth Factor-beta (TGF-β) is known to be a potent fibrogenic agent. What is its least likely effect on wound healing?

Inhibition of fibroblast proliferation. (D) Signup and view all the answers

Loss of TGF-β receptors is frequently observed in human tumors. How does this loss provide a proliferative advantage to the tumor cells?

By diminishing the inhibitory signals normally mediated by TGF-β. (A) Signup and view all the answers

Considering the roles of various growth factors and cytokines in wound healing, which combination would be MOST effective in promoting angiogenesis and collagen synthesis?

Increased levels of VEGF and TGF-β (A) Signup and view all the answers

In healing by second intention, what is the primary role of granulation tissue?

To fill in tissue defects and repair specialized tissues. (C) Signup and view all the answers

Why does secondary intention healing typically result in more substantial scar formation compared to primary intention healing?

Because larger tissue defects require more granulation tissue and subsequent collagen deposition. (A) Signup and view all the answers

What factor most significantly influences the timescale of healing by second intention?

The volume of the tissue defect. (B) Signup and view all the answers

A patient's surgical wound is healing by primary intention. Approximately when after the surgery is the wound strength expected to be around 10% of that of unwounded skin?

At the end of the first week. (A) Signup and view all the answers

What is the most likely reason for a wound to heal by secondary intention rather than primary intention?

There is significant tissue loss or the wound edges cannot be apposed. (C) Signup and view all the answers

A patient who underwent surgery is concerned about the final strength of their healed wound. What percentage of the original tensile strength is a surgical wound likely to achieve?

70-80% (D) Signup and view all the answers

Which of the following characteristics is most indicative of secondary intention healing compared to primary intention healing?

Significant wound contraction. (D) Signup and view all the answers

What is a key difference in the early stages of wound repair between primary and secondary intention healing that affects the inflammatory response?

Secondary intention generates a larger fibrin clot and more necrotic debris. (B) Signup and view all the answers

Which of the following factors contributes to the formation of a false joint at a fracture site?

Continued movement preventing bone formation, leading to fibrous union. (A) Signup and view all the answers

Why does gross misalignment at a fracture site slow down the healing process and affect functional outcomes?

It disrupts the natural alignment needed for proper bone union and increases the risk of degenerative joint disease. (C) Signup and view all the answers

What is the primary concern regarding infection at a fracture site beyond delayed healing?

Development of chronic osteomyelitis. (B) Signup and view all the answers

Which of the following best describes a pathological fracture?

A fracture that occurs in a bone weakened by pre-existing disease. (C) Signup and view all the answers

How does the interposition of soft tissues between broken bone ends affect fracture healing?

It delays healing until the interposed tissues are removed. (A) Signup and view all the answers

What is the potential long-term consequence of movement of a lesser degree at a fracture site?

Excessive callus formation that may impinge on adjacent structures. (B) Signup and view all the answers

Why might treatment of the underlying cause be necessary in cases of pathological fractures?

To prevent further fractures in weakened bone. (A) Signup and view all the answers

Which of the following describes the regenerative capacity of hepatocytes in the liver following injury?

Hepatocytes have excellent regenerative capacity but may result in cirrhosis if architecture is not properly reconstructed. (B) Signup and view all the answers

Permanent Cells

Cells with no capacity to divide after birth, and cannot be replaced if lost.

Healing

Replacement of damaged tissue with cells from either parenchymal or connective tissue, resulting in minimal defect.

Repair

Stereotyped response to tissue destruction where specialized tissue is replaced by fibrous tissue due to tissue loss.