2.5 Wound healing Flashcards Preview

All the things continued > 2.5 Wound healing > Flashcards

Flashcards in 2.5 Wound healing Deck (34):
1

What are the two general mechanisms of healing?

Regeneration or repair

2

What, generally, is regeneration? What is it dependent on?

Replacing damaged tissue with the native tissue

Dependent on the regenerative capacity of the tissue

3

What are labile tissues? Examples?

Tissues that continuously cycle to regenerate tissue

Small/ large bowel
Skin
Bone marrow

4

Where are the stem cells in the small and large bowel?

Crypts

5

Where are the stem cells in the skin?

Stratum basale of epidermis

6

What are the stem cells in the bone marrow?

Hematopoietic stem cells

7

What is the CD marker for hematopoietic stem cells?

CD34

8

What are the stem cells of the lung?

Type II pneumocytes

9

What are stable tissues?

Tissues that are quiescent, but can reenter cell cycle PRN

10

What are some examples of stable tissues?

Hepatocytes--compensatory hyperplasia

11

What are the three permanent tissues in the body?

Myocardium
Skeletal muscle
Neurons

12

When does repair occur, as opposed to regeneration?

If a tissues lacks regenerative capacity, or if the regenerative stem cells are lost

13

What material is initially deposited in tissues that lack regenerative capacity? What are the three major components of this?

Granulation tissue:
-Fibroblasts
-Capillaries
-Myofibroblasts

14

What type of collagen is laid down by fibroblasts with granulation tissue? What is this later replaced with?

Collagen type III initially, followed by type I after collagenases remove type III

15

What is the role of myofibroblasts in wound repair?

Contract wound edges

16

What are the enzymes that remove type III collagen in scar to allow for type I collagen to be depositied? What is the cofactor that is needed for these to work?

Collagenases
Zn is the cofactor

17

What type of signalling is used in regeneration and repair?

Paracrine signalling via growth factors

18

What is the role of TGF-alpha in the tissue repair process? (2)

Epithelial and fibroblast growth factor

19

What is the role of TGF-beta in the tissue repair process? (2)

Fibroblast growth factor and inhibits inflammation

20

What is the role of PDGF in the tissue repair process? (3)

Endothelium repair, smooth muscle repair, and fibroblast growth factor

21

What is the role of FGF in the tissue repair process? (2)

Angiogenesis and skeletal development

22

What is the role of VEGF in the tissue repair process?

Angiogenesis

23

What is primary intention wound healing?

Wound edges are brought together with minimal scar formation

24

What is healing by secondary intention?

Edges are not approximated--granulation tissue fills the defect

25

What causes wound to reduce in size?

Myofibroblasts

26

What is the most common cause of delayed wound healing?

Infection

27

What vitamin deficiency can cause delayed wound healing? Minerals?

-Vit C
-Cu
-Zn

28

What is procollagen?

Alpha chains of Gly-X-Y wrapped around each other, prior to crosslinking

29

What is the usual primary structure of collagen?

{Gly-X-Y | X=proline, Y=lysine}

30

What is the role of vitamin C in the formation of collagen?

Hydroxylation of proline / K

31

What is the role of Cu in collagen formation?

Lysl oxidase, an enzyme responsible for cross linking collagen chain, requires Cu as a cofactor

32

What, generally, is dehiscence?

Rupture of wound, commonly seen after abdominal surgery

33

What is a hypertrophic scar? What type of collagen is this made of?

Excess production of scar tissue that is localized to the wound

Type I collagen

34

What is a Keloid? What type of collagen is this comprised of?

Excess production of scar tissue that is out of proportion to the wound

Excessive type III collagen