Wound healing

Question 1

What 4 factors achieve wound healing? (G-MAC)

Answer 1

Growth factors
Mediators of acute inflammation
Angiogenesis and fibrosis
Cell-ECM interactions

Question 2

What is healing by first intention? How many cells die?

Answer 2

Healing of simple incisions
Wounds have opposed edges
Limited number of epithelial cells and CT die
(e.g. surgical incision)

Question 3

What is healing by secondary intention?

Answer 3

Healing of extensive wounds
Considerable tissue loss
Ragged, dirty, infected wounds
E.g. infarction, ulceration, abscess formation, surface wounds with large defects

Question 4

What is the process of healing by first intention?

Answer 4

Blood clot forms, fibrin neutrophils appear, epidermis thickens
Epithelial cells grow, neutrophils replaced by macrophages
Collagen accumulates, fibroblasts form scar, inflammation disappears
Scar remodels, strengthening repair

Question 5

What is the difference between healing by first and second intention?

Answer 5

Second intention - more intense inflammatory response
Larger granulation tissue forms
Wound contraction

Question 6

What is the process of healing by second intention?

Answer 6

Blood cot forms and neutrophils appear to larger defect in epidermis/ddermis
Granulation tissue fills deficit
Epitheliasation occurs at wound margins
Granulation tissue matures
Wound contracts
Produces irregular scar

Question 7

What features of the epidermis/dermis are lost after healing by second intention?

Answer 7

Adnexa - hair follicles, sebaceous glands, sweat glands

Question 8

What factors influence wound healing?

Answer 8

Systemic factors - nutrition and hormones

Local factors - size/type/location of wound, bacteria

Question 9

What are the 4 stages of wound healing? (overlapping)

Answer 9

Haemostasis - stop bleeding
Inflammation - angiogenesis
Proliferation or granulation - pulls wound closed
Remodelling and maturation