Wound Healing Flashcards Preview

RUSVM Pathology I > Wound Healing > Flashcards

Flashcards in Wound Healing Deck (63):
1

Embryonic Stem Cells

Pluripotent; isolated from blastocysts

2

PDGF, FGF, VEGF-A bind GF-R's on endothelial cells to induce vascular formation by

Endothelial proliferation

Recruitment of pericytes

Deposition of ECM proteins

3

What occurs during the hemostasis phase of wound healing

Vasospasm → relaxation

Platelets aggregate to expose collagen and a network of fibrin forms

4

Repair

Replacement of injured tissue

5

Describe the arrangement of blood vessels in granulation tissue

Arranged perpendicular to fibrosis

6

Growth factors and cytokines involved in angiogenesis

VEGF, angiopoietin, FGF

7

Permanent Cell - Non-Dividing Cell

Have left the cell cycle and cannot undergo mitotic division in postnatal life

_________________________

Neurons, Cardiac and Skeletal Muscle

8

Mechanism of wound healing by primary intention

  • Simple Incision
  • Sutured incision with acute inflammatory response (2-7 days)
    • Redness and swelling
    • Zone of acute inflammation; formulation of granulation tissue
  • Healing Incison
    • Epithelial proliferation and repair
    • Maturing fibrous granulation tissue
  • Linear fibrous scar (6-12 months)

9

Mechanism of wound healing by second intention

  • Ragged, dirty or infected wound (2-3 days)
    • Necrotic slough
    • Acute inflammation
  • Phase of rapid proliferation of vascular granulation tissue (1-2 weeks)
    • Slough and scab
    • Epithelial proliferation
    • Vascular granulation tissue
    • Zone of hyperemia
  • Phase of granulation tissue maturation and wound contraction (3-6 weeks)
    • Fibrous granulation tissue beginning to contract, pull wound edges closer
    • Hyperemia
  • Healed wound
    • Pale depressed scar with puckering

10

The proliferation phase of wound healing occurs when?  And can last for how long?

3-7 days

3-4 weeks

11

Quiescent - Stable Cells

Low level of replication; undergo rapid division in response to stimuli.  Capable of reconstructing the tissue of orgin

_________________________

Smooth muscle, fibrocytes, vascular endothelial cells, chondrocytes, osteocytes

12

Collagen

Triple helices with lots of cross linkage providing tensile strength

13

Characteristics of epithelialization

Proliferate at denuded surfaces

Must disassemble connections to basement membrane and neighboring cells

Must express surface receptors that bind ECM

Regulated by contact inhibition

14

Tissues ability to return to normal depends on 

Retention of ECM structural framework

Regenerative capacity of cells

15

Myofibroblasts

Form within wounds in response to TGF-beta

Increase with time and severity

16

Proud Flesh

Hypertrophic scar - excessive granulation tissue

17

T/F- Capillaries in granulation tissue are sturdy.

False

________________

Capillaries are fragile and bleed easily

18

When does healing begin?

Immediately after a wound develops

19

Process of degradation during inflammation phase of wound healing

Leukocytes clean up cell debris from the injury

20

Wound

Injured tissue

21

Tensile strength is diminished in what type of wound healing?

Secondary intention

22

Growth factors and cytokines involved in collagenase secretion

PDGF

FGF

TNF

TGF-beta inhibits

23

Growth factors are required for cellular

Proliferation

Differentiation

24

Angiogenesis

Formation of new blood vessels from existing ones

25

T/F: Proliferation phase of wound healing increases with age and disease.

False

_____________________

decreases

26

Growth factors and Cytokines involved in fibroblast migration/ replication

PDGF

EGF

FGF

TGF-beta

TNF

IL-1

27

Fibroplasia

Migration and proliferation of fibroblasts

28

Extracellular Matrix consists of

Collagen

Elastin

Fibronectin

Laminin

29

What phase of wound healing is required for return of tensile strength

Maturation

30

TGF-Beta

Produced by platelets and leukocytes

Important for fibroblast migration and proliferation, and collagen/ECM protein synthesis

31

Epithelialization

Regeneration of epithelium

32

Fibrosis

Scar formation by connective tissue remodeling

33

Microscopically, what is found at the center of the wound during degradation

Dead cells

Leukocytes

Cytokines

Serum/clotting proteins

ECM substances

34

Conditions that may cause impaired wound healing

Tension on a tissue

Prolonged inflammation

Disorders in collagen synthesis

Poor blood supply

Impaired ability of cellular regeneration

35

Factors that favor fibrosis

Severe and prolonged tissue injury

Loss of tissue framework

Large amounts of exudate/inflammation

Lack of renewable cell populations

36

Wound contraction is mediated by

Myofibroblasts

37

Fibrous Connective Tissue

Dense accumulation of fibroblasts and collagen

With time, collagen becomes more densely packed

Persists for years

38

What occurs during the proliferation phase of wound healing?

Regeneration of tissue

Granulation tissue formation

Stem cells influced by cytokines/growth factors

Fibroblasts proliferate to fortify the wound → collagen deposition

 

39

Wounds that can be healed by second intention

Gaping wounds

Septic wounds

Foreign bodies

Wound with delayed healing processes

40

Granulation Tissue

Distinctive arrangement of connective tissue fibers, fibroblasts and blood vessels

41

What occurs during the inflammation phase of wound healing?

Cardinal signs seen

ECM components are chemotactic

Degradation

Leukocytes secrete chemotactic and growth factors → proliferation phase

42

Growth factors and cytokines involved in monocyte chemotaxis

Chemokines

TNF

PDGF

FGF

TGF-beta

43

Mechanism of angiogenesis

  1. Proteolysis of ECM
  2. Migration and chemotaxis
  3. Proliferation
  4. Lumen formation, maturation and inhibition of growth
  5. Increased permeability through gaps and transcytosis

44

Phases of cutaneous wound healing

Hemostasis

Inflammation

Proliferation

Maturation

45

Proliferation phase of wound healing is limited by

Proliferative potential of cell types involved

46

Consequences of fibrosis

Loss of functional parenchymal tissue

Alteration of physical properties of tissue

47

What occurs during the maturation phase of wound healing?

Remodeling of granulation tissue, maturation of fibrosis and wound contraction

Re-establishment of cell interactions

Vascular regression

48

Labile - Continuously Dividing Cells

Proliferate throughout life, replacing those cells that are destroyed 

_____________________________

Epithelial cells of liver, kidney, lung, pancreas, skin, mucous membranes

49

T/F: If inflammation is excessive, it can reduce healing.

True

50

Wounds that can be healed by primary intention

Wounds with opposed edges

51

Role of extracellular matrix in regeneration and repair

Liver regeneration with restoration of normal tissue after injury requires intact cellular matrix

If matrix is damaged the injury is repaired by fibrous tissue deposition and scar formation

52

Wound Contraction

Normal part of maturation phase

Can be bad when connective tissue contracts and place tension on surrounding tissues

May immobilize or deform tissue

53

Growth factors  and cytokines involved in  collagen synthesis

TGF-beta

PDGF

54

What induces fibroblasts to synthesize collagen?

Growth factors

55

Important source for epithelial regeneration

Stem Cells

56

The inflammation phase of wound healing occurs in what time frame

24-96 hours

57

Growth factor mechanism

EGF binds receptors on epithelial cells → activates MAPK → induces G0 phase cell cycle

58

Growth factors and cytokines involved in keratinocyte replication

HB-EGF

FGF-7

HGF

59

Maturation phase of wound healing occurs when and can last for how long?

Begins 3-4 weeks after injury

Can last for years

60

Results of the hemostasis phase of wound healing

Reduced blood loss

Binds edges of wound together

Initiate angiogenesis - PDGF, TGF-Beta

61

Describe the arrangement of fibroblasts and connective tissue in granulation tissue

Grow parallel to the wound surface

62

Tissue Stem Cells

Not pluripotent - restricted lineage specific differentiation capacity

Bone marrow - hematopoietic and mesenchymal cells

Skeletal muscle "satellite cells"

63

Matrix Metalloproteinases

Important for degrading the ECM