MLT GlobeBasic Pathology: Tissue repair & healing – page 3
59 Basic Pathology MCQs on Tissue repair & healing with answers and explanations.
In a clean sutured incision, a continuous thin epithelial layer covers the wound within about:
Epidermal cells migrate from both edges and fuse beneath the scab within 24 to 48 hours.
A superficial abrasion damages only the epidermis, leaving the basement membrane intact. It is repaired mainly by:
With intact basement membrane and stem cells, labile epithelium simply regenerates, restoring normal structure without a scar.
Which VEGF family member mainly drives endothelial migration and proliferation to begin capillary sprouting?
VEGF-A acting via VEGFR-2 initiates sprouting angiogenesis. VEGF-C and VEGF-D mainly drive lymphangiogenesis.
In the small intestine, the stem cells that continually replace the shed surface epithelium are located in the:
Labile intestinal epithelium is renewed from crypt stem cells; new cells migrate up to the villi and are shed within days.
After surgical removal of most of the liver (up to about 90%), the organ restores its mass mainly through:
Liver regrowth after partial hepatectomy is driven chiefly by proliferation of surviving hepatocytes; progenitor (oval) cells contribute only when hepatocyte replication is impaired.
The characteristic granulation tissue of wound healing, with new capillaries and fibroblasts, typically becomes evident how long after injury?
Granulation tissue appears about 3-5 days after injury. Within the first day neutrophils dominate; by weeks, collagen accumulates and the tissue matures into scar.
The fibroblasts that populate a healing wound are derived mostly from:
Fibroblasts migrate and proliferate from adjacent connective tissue (with a minor bone-marrow contribution), stimulated by PDGF and TGF-beta.
Which of the following does NOT typically delay wound healing?
Radiation, jaundice, malnutrition, cancer, diabetes and glucocorticoids impair healing. Ordinary UV exposure is not a recognised systemic factor delaying repair.
A patient's excised earlobe keloid returns within months. Which characteristic of keloids explains this?
Keloids are excessive collagen scars that extend beyond the wound edges and commonly recur after excision. They are benign and are more frequent in people of African descent.
A heavily soiled traumatic wound is seen 12 hours after injury. The most appropriate initial approach is:
Late, contaminated wounds carry high infection risk; excising devitalised tissue and delaying closure lets the wound declare itself before closing or leaving it to heal by secondary intention.
Three days after a deep laceration, the granulation tissue first lays down which collagen type, later replaced during remodelling?
Early granulation tissue produces type III collagen; during remodelling it is gradually replaced by the stronger type I collagen of the mature scar.
One week after a sutured caesarean incision, when sutures are removed, the wound typically shows:
At one week, granulation tissue is still present and strength is only about 10% of normal; it rises over months to a maximum of about 70–80%.
Which adhesive glycoprotein, together with fibrin, forms the main scaffold of the provisional matrix in an early wound?
Plasma-derived fibronectin cross-links with fibrin to form the provisional matrix that guides cell migration. Laminin is a basement membrane protein; cadherins and selectins are cell adhesion molecules.
After deep (full-thickness) burns to both hands and forearms, which wound-healing complication is this patient most likely to develop?
Large full-thickness burns heal by secondary intention with abundant myofibroblast activity; excessive contraction produces deforming contractures, especially over joints. Dehiscence and hernia relate to surgical incisions.
Repair by scar formation proceeds in a set order after injury and inflammation. Which step occurs LAST?
New vessels sprout first, then fibroblasts and capillaries form granulation tissue, and finally collagen is reorganised and cross-linked (remodelling), which continues for months.
Which macrophage-derived growth factor recruits fibroblasts and macrophages to a wound and can induce all steps of angiogenesis?
FGF-2 stimulates fibroblast recruitment, re-epithelialization and every step of angiogenesis. Endostatin inhibits angiogenesis.
After massive liver injury, progenitor 'oval cells' near the canals of Hering can differentiate into:
Oval cells are bipotential hepatic progenitors that generate hepatocytes and cholangiocytes when hepatocyte proliferation is impaired.
By convention in pathology texts, the term 'healing' (as opposed to 'repair') is usually applied to:
Repair is conventionally used for parenchymal and connective tissues, and healing for surface epithelia, though the terms are often used interchangeably.
Which vitamin is used to counteract the inhibitory effect of glucocorticoids on wound healing?
Glucocorticoids suppress inflammation and collagen synthesis, delaying healing; vitamin A partially reverses this effect.