Wound Healing (1) Flashcards
What occurs in wound healing?
When does primary intention occur?
When does secondary intention occur?
➊ Acute inflammation due to infection/tissue damage. Dead cells are removed, healing begins with organisation (forms granulation tissue), and ends with complete resolution (back to normal) or just repair (scar).
➋ Injury only to epithelial layer, so complete regeneration occurs, e.g. clean wound, small incision
➌ Lots more tissue damage/loss, so is repaired by regeneration and fibrosis e.g. large wounds, abscesses, ulcer, ischaemic necrosis
What are the stages of Primary Healing?
(1) Injury/wound activates coagulation, which leads to the formation of clots
(2) Neutrophils surround the margins of the wound and release proteolytic enzymes to remove the debris/microbes
(3) Epithelial cells migrate and proliferate at the wound’s edges and meet in the midline to close the wound
(4) Macrophages replace the neutrophils, and granulation tissue starts to invade and fill the wound space - Neovessels and oedema forms
(5) Proliferation of fibroblasts produces collagen, which deposits in the wound, and new vessels begin to be removed, and inflammation decreases
How does Secondary Healing differ from Primary Healing?
(1) There’ll be a bigger clot, more oedema, and more intense inflammation
(2) There’s more granulation tissue so a bigger scar will form
(3) Wound contraction occurs here due to the size of the wound
(4) Myofibroblasts are used here, which are modified fibroblasts with smooth muscle features
What are the factors that affect healing?
• Age – Skin gets thinner, and the body shows a decreased inflammatory response so, as you get older, your skin is predisposed to injury and will heal slower
• Nutrition – Proper nutrition is vital to optimal healing, as a wound needs the necessary nutrients for cell repair and growth
• Obesity
• Chronic conditions – CVD, DM and Immunodeficiency can slow down wound repair
• Medication – NSAIDS, Anticoagulants, Immunosuppressants
