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Flashcards in Tissue repair Deck (60)
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1

What does it mean to repair a tissue?

Both restoration of tissue architecture and function after an injury
Complete recovery rarely achieved

2

What are the two mechanisms of tissue repair?

Regeneration of injured tissue
Replacement of lost tissue

3

Which mechanism of tissue repair require cell proliferation of intact or altered cellular matrix?

Both

4

Stem cells produce a baseline cell population which do ____ or ____.

Proliferate, die via apoptosis

5

What are the types of continuously dividing (labile) cells?

Skin basal, hematopoietic, hair follicles and GI cells

6

What does the G0 phase look like for the continuously dividing cells?

Short

7

What are the stable cells and what does it mean to be stable?

Liver, kidney, lung alveoli, bone, breast, endocrine, adipose, vessels
Only need to proliferate when necessary

8

What does the G0 phase look like for stable cells?

Long

9

What are the permanent tissues and what does that mean?

Neurons in CNS, ganglia in PNS, cardiac, skeletal muscle
Cannot divide functionally

10

What are some characteristics of continuously generating cells?

Can easily regenerate after injury with a infinite life span
Dependent on age and health
Contains pools of stem cells
Immune positive for CD34, CD117, Ki67

11

What are the three locations for skin stem cells?

Epidermis, sebaceous gland, hair follicle bulge

12

What are the actions of growth factor?

Stimulate cell division and proliferation
Promote cell differentiation and survival

13

What some examples of growth factors?

Epithelial growth factor (skin, fibroblasts)
Transforming growth factor (hepatocytes, epithelials)
Platelet derived growth factor (s muscle, cytokines)
Erythropoietin
Granulocyte growth factor

14

What does each growth factor have on its target cell?

A specific receptor

15

When cells are injured and proliferate what is released?

Cytokines

16

Where do the cell injury responsive cytokines come from?

Damaged tissue, inflammatory cells, macrophages and vascular endothelial cells and fibroblasts

17

What are the two forms of the extracellular matrix?

Interstital matrix and basement membrane

18

What does the extracellular matrix do?

Sequesters water and mineral from circulation
Stores presynthesized growth factors
Gives cells a scaffolding upon which to adhere and do their assigned tasks

19

What does the ECM regulate overall?

Proliferation, movement, and differentiation of cells living in or on it

20

If the ECM is completely destroyed what happens?

It cannot regenerate and a scar forms

21

When does regeneration occur in labile tissues?

All the time, can make as much as needed

22

When does regeneration occur in stable tissue?

A limited extent, only some can come back or compensate for lost tissue
Only occurs if the residual tissue is healthy and intact

23

When does regeneration occur in permanent tissue?

Pretty much never and will always form scar tissue

24

What are the steps to injury healing?

1. Cut
2. Inflammation
3. Blood clotting
4. Granulation tissue - scab,eschar
5. Wound contraction
6. Wound recovery
7. Scar tissue

25

If an injury is too severe...

regeneration can't happen

26

What are the four components used in regeneration mediated by growth factor?

New vessel formation VEGF
Fibroblast proliferation FGF, TGF
Fibroblast synthesis of immature scar - type 3 collagen
Fibroblast remodeling with mature scar - type 1 collagen

27

What is an eschar?

A scab

28

Granulation tissue does not contain....

Cross linked collagen

29

What are the three examples of wound healing?

First intention - sew shut
Second intention - leave open
Third degree burn

30

What does it mean when a wound is healed by first intention?

Occurs in small wounds that close easily
Suturing or butterfly tape possible to use
Epithelial regeneration predominates over fibrosis
Healing is fast, minimal scarring
well vascularized, no dead tissue