Question
A 4-year-old boy falls on a rusty nail and punctures his skin. The wound is cleaned and covered with sterile gauze. Which of the following is the initial event in the healing process?
| A. |
Accumulation of acute inflammatory cells
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| B. |
Deposition of proteoglycans and collagen
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| C. |
Differentiation and migration of myofibroblasts
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| D. |
Differentiation and migration of myofibroblasts
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Show Answer
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Correct Answer � D
Explanation
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Answer : D Differentiation and migration of myofibroblasts
The initial phase of the repair reaction, which typically begins with hemorrhage, involves the formation of a fibrin clot that fills the gap created by the wound.
A thrombus (clot), referred to as a scab after drying out, forms on the wounded skin as a barrier to invading microorganisms.
It also prevents the loss of plasma and tissue fluid. Formed primarily from plasma fibrin, the thrombus is rich in fibronectin.
The thrombus also contains contracting platelets, which are an initial source of growth factors.
Much later, the thrombus undergoes proteolysis, after which it is penetrated by regenerating epithelium.The scab then detaches.
Accumulation of acute inflammatory cells might occur after formation of the initial fibrin clot. Collagen formation and macrophage activity occur much later. Myofibroblasts begin to accumulate in the wound around the 3rd day.
