Page 79 - Concise Pathology for Exam Preparation ( PDFDrive )

64 SECTION I General Pathology

Q. Write briefly on healing by secondary intention.

Ans. Secondary union (Fig. 3.4B) is seen in open wounds with separated edges, extensive
loss of cells and large defects.

Characteristic Features of Healing by Secondary Intention

• Associated with large defects filled with blood clots, necrotic debris and exudate.
• Inflammatory reaction is more intense.
• Large amounts of granulation tissue are deposited.
• There is formation of epithelial spurs from margins of the wound.
• Typically demonstrates ‘wound contraction’ which is mediated by myofibroblasts and
aids in decreasing the gap between the dermal edges of the large wound.
• Substantial scar formation and thinning of the epidermis is seen.

Regaining Wound Strength
• After 7–10 days, 10% of the original tensile strength is regained.
• After 3 months, 80% of the original tensile strength is regained.

Q. Differentiate between healing by primary and secondary intention.

Ans. Differences between healing by primary and secondary intention are enlisted in Table 3.2.

TABLE 3.2. Differences between healing by primary and secondary intention

Features Healing by primary intention Healing by secondary intention
Nature of wound Seen in incised wounds with well op- Seen in large, open, infected wounds
posed edges (clean and uninfected with separated edges; associated
wound) with extensive loss of cells
Amount of fibrin and blood Filled with moderate amount of fibrin Filled with a large blood clot and
and blood necrotic debris and exudate
Inflammatory reaction Less intense More intense
Amount of granulation tissue Less granulation tissue Extensive granulation tissue
Wound contraction Wound contraction is not seen Wound contraction is seen
Complications Less common More common

Q. Write in detail on healing in specialized tissues.
Ans. Healing in Specialized Tissues
1. Fracture healing
Fractures can be:
(a) Traumatic or pathological (due to a pre-existing disease)
(b) Complete or incomplete
(c) Simple (overlying tissue is intact), comminuted (bone is splintered or displaced) or
compound (fracture site communicates with the skin surface)
(d) Stress fracture (slowly developed fracture, which develops over a period of in-
creased physical activity)
There are three main steps in callus formation (Flowchart 3.6):
• Procallus formation
• Osseous callus formation
• Remodelling

mebooksfree.com