Tissue Renewal and Repair Flashcards Preview

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Flashcards in Tissue Renewal and Repair Deck (38):
1

What is tissue organization?  What causes it?

Def: response to inflammation that involves replacement of tissue with granulation tissue

2

What are intestinal stem cells called?

Crypt cells

3

What are hepatic stem cells called?  Into what types of cells do they develop? What are the methods of liver regeneration and when are they used?

Oval cells

Hepatocytes or biliary cells

Normal regeneration: hepatocyte proliferation (hyperplasia...)

Serious injury (cancer/hep): oval cells activated

4

Source and function of Epidermal GF (EGF)

Source: Macrophages

Function:  

Stimulates granulation tissue formation

Mitogenic for: 

  1. Fibroblasts
  2. Keratinocytes
  3. Epithelial cells
  4. Hepatocytes

5

Function of TGF-Alpha

Induce production of VEGF

6

Function of Hepatocyte GF (HGF)

Cell migration during embryonic development

Mitogenic for:

  1. Epithelial cells
  2. Endothelial cells
  3. Hepatocytes

7

Stimuli for and Function of VEGF (Vascular endothelial GF)

Stimuli:

  1. Hypoxia
  2. TGF-alpha
  3. TGF-ß
  4. PDGF

Function:  

  1. Angiogenesis (inflammation, ect.) by Capillary Sprouting
    • Increase vasc. permeability
    • stimulate endothelial cell migration/prolif.
  2. Vasculogenesis (embryonic development)

8

Functions of Platelet-Derived GF (PDGF)

Chemotactic for neutrophils and monocytes

Stimulate VEGF production

Migration/Proliferation of:

  1. fibroblasts
  2. smooth m
  3. monocytes

9

Functions of Fibroblast GF (FGF)

Skin reorganization and healing

  • Stimulate angiogenesis
  • Stimulate cell migration in wounds

Hematopoiesis

Chemotactic for:

  1.  Fibroblasts
  2. Keratinocytes

10

Function of FGF-7

Keratinocyte GF (migration and proliferation)

11

Functions of Transforming GF-ß (TGF-ß)

Fibrogenic Agent (Healing by fibrosis)

  • Stimulate collagen, fibronectin, proteoglycans
  • Inhibit collagen degradation

12

Functions of Insulin-like GF-1 (IGF-1)

Healing by fibrosis

  • Stimulate fibroblasts
  • Stimulate ECM proteins (collagen, proteoglycan)

13

Signal transduction mechanism of GF receptors

Tyrosine kinase activity

14

Signal transduction mechanism of cytokine receptors

JAK/STAT

15

Signal transduction mechanism of receptors for histamine, serotonin, NE, epinephrine, chemokines

G-protein

16

What are the stimulating cytokines for liver regeneration?

Priming

Proliferation

Inhibition

17

What are the major proteins of ECM components?

Interstitial matrix

Basement membrane

Interstitial matrix

  • Fibrillar collagen

Basement membrane

  • Type IV collagen
  • Laminin

18

What are the components of granulation tissue?

  1. new vessels (leaky resulting in edema)
  2. fibroblasts
  3. new ECM

19

What are the steps of the healing process?

  1. Inflammatory reaction: contain and eliminate dangerous stimulus
  2. Removal of dead tissue and deposition of ECM
  3. prolif. of connective tissue
  4. Angiogenesis and formation of granulation tissue
  5. remodeling, wound contraction, wound strength

20

Types of angiogenesis, process, and molecules involved

  1. Capillary Sprouting
  • VEGF = increased vasc. permeability and migration/proliferation of endothelial cells
  • Degradation of BM (matrix metalloptroteinases) and disruption of cell-cell contacts for growth
  • Stabilization by periendothelial cells/ECM
    • angioproteins, PDGF, TGFß
    • Recruitment of endothelial precursors

     2. Recruitment of endothelial precursors

  • VEGF mediated
  • bone marrow cells mature into endothelial, pericytes, smooth m.

21

Function of angioprotein 1

capillary maturation and maintenance of endothelial quiescence

22

Function of angioprotein 2

increases responsiveness of endothelial cells to PDGF

23

Function of PDGF in angiogenesis

Recruit smooth m cells

24

Function of TNFß in angiogenesis

Enhances production of ECM proteins

25

Which cytokine is the most important inducer of fibrosis? What is its function?

TGF-ß: increases collagen and fibronectin production and inhibits ECM degradation

26

Differences between Primary and Secondary intention wound healing

1. Amount of damage

2. Amount of cell death

3. Restoration of architecture

4. Other

Primary intention:

  • Small cut, clean edges
  • Limited cell death and ECM damage
  • Restoration of architecture
    • normal epidermal thickness
    • Surface rekeritinizatoin

Secondary intention:

  • Large damage
  • Extensive cell death
  • Abnormal architecture
    • thin epidermis (excess contracture)
  • Fibroblasts become myofibroblasts (contracture of wound)

27

How does protein/vitamin C deficiencies delay healing?

Inhibit collagen synthesis

28

How do glucocorticoids delay healing?

Anti-inflammatory

(-) collagen synthesis

(-) neutrophil infiltration

29

What is dehiscence?

wound ruptures/splits due to mechanical stress on the wound

30

What is the cause of ulcerations in wound healing?

inadequate vascularization

31

Characteristics of:

  1. Hypertrophic scar
  2. Keloid
  3. Desmoid/Aggressive fibromatoses
  4. Exuberent Granulation
  5. Excess contracture

  1. Hypertrophic scar
    • increased fibroblasts and collagen
    • Raised, smooth, firm
  2. Keloid
    • Increased collagen only
    • Grows dignificantly above borders of injury
  3. Desmoid/Aggressive fibromatoses
    • Increased fibroblasts only
  4. Exuberent Granulation
    • protrudes above border
    • Blocks reepithelialization
  5. Excess contracture
    • After serous burns

32

What is pictured?

Keloid scar

33

What category of diseases are associated with Fibrosis?

Chronic inflammation

1. chronic hepatitis (end result of fibrosis is cirrhosis)

2. Silicosis

34

What is pictured?  What are the characteristics of this type of tissue?

Granulation tissue

fibroblasts (yellow arrow), new capillaries (red
arrow), and mononuclear cells (black arrow)

35

What is pictured?

Fibrosis

36

What is pictured?  Characteristics?

Hypertrophic scar

Raised, smooth,firm lesions at site of previous injury

37

What is pictured? Characteristics?

Keloid tissue

Dense bundles of collagen, less cellular, grows beyond original boundaries of injury

38

What is pictured?  (Disease and problem with tissue)

Inflammatory fibrosis associated with Silicosis