Pathology

Question 1

What are the steps in healing by first intention (primary union)?

Answer 1

1) Formation of blood clot / scab
2) Acute inflammation (phagocytes phagocytose dead tissue and re-epithelialisation of epidermis begins)
3) Granulation tissue (capillary sprouts begin to proliferate, fibroblasts and myofibroblasts also begin to proliferate and start laying down ECM - which includes collagen)
4) Inflammation subsides (vascularity decreases, collagen increases)
5) Scar matures but still continues to remodel to increase tensile strength

Question 2

What is the fundamental difference between first intention (primary union) healing and second intention (secondary union) healing?

Answer 2

With first intention (primary union) healing, a very minimal amount of granulation tissue is formed whereas with second intention (secondary union) healing, a relatively far greater amount of granulation tissue is formed

Question 3

Which criteria must be met in order for healing to occur by first intention (primary union)?

Answer 3

1) Minimal tissue damage
2) Minimal bacterial contamination
3) Edges of wound promptly apposed