PATH: Regeneration, Repair, and Healing

Question 1

What are the three phase of cutaneous wound healing?

Answer 1

1) Inflammation 2) Proliferation 3) Maturation

Question 2

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

Answer 2

Healing by first intention occurs on clean cuts or slices and will result in no scar formation, but bigger defects will undergo healing by second intention and can result in a substantial scar and contraction

Question 3

What is granulation tissue characterized by?

Answer 3

Acute inflammation, Neovascularization, edma due to leaky vessels, fibroblasts, collagen; gorssly-looks pink with tiny granules

Question 4

What is the major cellular contributor to the formation of granulation tissue?

Answer 4

Macrophages

Question 5

What, generally, is involved in scar formation?

Answer 5

ECM remodeling, tissue remodeling (into granulation tissue), increased collagen deposition and regression of vasculature (blanching), and formation

Question 6

What cells moderate wound contraction?

Answer 6

Myofibroblasts

Question 7

How do myofibroblasts develop?

Answer 7

Occurs do to signalling via PDGF, TGF-B, and FGF-2 (secreted from macrophages), fibrocytes, and epithelial cells

Question 8

What is connective tissue remodeling?

Answer 8

The balance between ECM synthesis and degradation

Question 9

True or False: Scar tissue has a greater tensile strength than naive tissue.

Answer 9

False- scar (granulation) tissue will never have the same tensile strength naive tissue does

Question 10

What systemic factors can lead to decreased wound healing?

Answer 10

Nutrition status, Metabolic status, Circulatory status, and hormones

Question 11

What local factors lead to decreased wound healing? Which is the most common?

Answer 11

Infection (most common/important), mechanical factors, foreign bodies, and size, location, and type of wound

Question 12

What are keloids?

Answer 12

Hypertrophic scars that occur due to too much wound healing and formation of thick collagen bands

Question 13

What is wound dehiscence?

Answer 13

Ulceration

Question 14

What is contracture?

Answer 14

Tissue repair gone wrong in which pts. develop severe, deforming/disfiguring contractions and can cause immobility or loss of function

Question 15

What is fibrosis?

Answer 15

Excessive deposition of ollagen in tissue often triggered by chronic inflammation

Question 16

What proteins stimulate fibrosis?

Answer 16

PDGF, FGF, TGF-B, TNF, IL-1, IL-4, IL-13

Question 17

What is tissue regeneration?

Answer 17

Proliferation of cells and tissues to replace lost structure with complete restitution of the lost or damaged tissue

Question 18

What is tissue repair?

Answer 18

A combination of tissue regeneration and scar formation by collagen deposition which may restore some original structures, but can cause structural derangements

Question 19

If ECM damage has occurred, what type of tissue healing response will happen?

Answer 19

Repair

Question 20

What is the cell population?

Answer 20

The number of cells in a tissue or organ

Question 21

What are the three groups of tissue based on proliferative activity?

Answer 21

Labile tissue (continuously dividing), Quiescent tissue (stable), and permanent tissue (non-dividing)

Question 22

What cells produce epidermal growth factor in wound healing?

Answer 22

Macrophages, keratinocytes, and inflammatory cells

Question 23

What is the effect of platelet derived growth factor?

Answer 23

Migration and proliferation of fibroblasts, smooth muscle cells, and monocytes to areas of wound healing

Question 24

What are the tissue distributions of collagen Types 1-4?

Answer 24

1- dermis, bone, and tends (ubiquitous in hard and soft tissues, 2- cartilage, IV disks, vitreous humor, 3- smooth muscle, endometrium, arteries, uterus, liver, spleen, and lung (hollow organs, soft tissue) 4- basement membrane