December 3, 2015 - Wound Healing Flashcards Preview

COURSE 2 > December 3, 2015 - Wound Healing > Flashcards

Flashcards in December 3, 2015 - Wound Healing Deck (12):
1

Wound Healing:

The restoration of surface integrity and continuity of the skin after wounding, with a tissue strength approaching normal.

2

Phases of Wound Healing

Hemostasis

Inflammatory

Proliferative

Remodeling

3

Hemostasis Phase

Begins at the time of the wounding

Lasts 24-48 hours

Transient vasoconstriction caused by platelets via TXA-2 (Thromboxane A2). This slows blood flow to aid in hemostasis.

Platelets form thrombus.

Clotting factors are activated.

4

Inflammatory Phase

Vasodilation that is prostaglandin and histamine mediated

Increased blood flow supplies cells and substrates for wound healing

Macrophages and neutrophils remove necrotic tissue, debris, and bacteria

Macrophages secrete TGF-B which attracts fibroblasts

5

Proliferative Phase

Lasts 2-4 weeks

Fibroblasts, attracted by TGF-B, move into the wound

Fibroblasts produce collagen and extracellular matrix to replace the platelet/fibrin plug

Angiogenesis occurs

6

Remodeling Phase

During the proliferative phase, the collagen is randomly laid down. This changes in the remodeling phase.

Macrophages and fibroblasts replace the random collagen with more orderly and extensively cross-linked collagen (mostly Type I) as in normal skin.

The scar will achieve 80% of the strength of regular skin.

7

Local Factors that Impede Wound Healing

Infection

Foreign body

Ischemia

Radiation

Trauma

Cancer

Toxins

Vascular insufficiency

Tissue edema

8

Systemic Factors that Impede Wound Healing

Inherited disorders

Nutritional deficiency

Aging

Diabetes

Liver disease

Alcoholism

Uremia

Medications

Smoking

Psychiatric

9

Smoking and Delayed Healing

Smoking causes vasoconstriction by nicotime, which reduces blood to the area.

Additionally, it causes atherosclerosis.

Additionally, the carbon monoxide shifts oxyhemoglobin curve to the left, impairing oxygen delivery to the tissues.

10

Hypertrophic Scars

Histologically, increased amounts of collagen and ECM, but not organized.

 

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11

Keloid Scars

Histologically, whorls of fibroblasts arranged around vessels. May get worse with surgery. 

Heavy genetic influence.

Often affects darker-skinned patients.

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12

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