Ch.2 Scar formation & tissue repair Flashcards

1
Q

Refers to the restoration of tissue architecture and function after an injury

A

Tissue Repair/healing

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2
Q

Type of tissure repair rxn:

issues are able to replace the damaged components and essentially return to a normal state.

Cell proliferation to survive injury and retain capacity to generate mature cell of damaged tissue.

A

Regeneration

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3
Q

Tissues like the epitheliium that are continuously dividing

A

Labile

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4
Q

injured tissues are incapable of complete restitution, or when the supporting structures of the tissue are damaged, repair occurs by the laying down of connective (fibrous) tissue

A

Scar formation

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5
Q

On what tissues is scar formation common?

A
  1. Stable tissues (not dividing) like solid organs (ex. kidneys)
  2. Permanent tissues (neurons, cardiac muscle)
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6
Q

What cells?

Labile
Cells that are **constantly being lost and must be continually replaced **by new cells that are derived from tissue stem cells and from the remaining mature tissue cells

A
  1. Hematopoetic** Stem cells **in bone marrow
  2. Surface epithelia cells in skin, columnar epithelia in GI tract
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7
Q

What tissue cells?

Cells in the G0 stage of proliferation but are capable of dividing in response to injury

A

parenchyma of most solid organs, such as liver, kidney, and pancreas

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8
Q

What cells?

consist of terminally differentiated nonproliferative cells.

Injury to these tissues is irreversible and usually results in a scar, because the cells cannot regenerate.

A

majority of neurons and cardiac muscle cells

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9
Q

undiferrentiated & can turn into any cell type

discovered in embryos as self-renewing cells that can give rise to all mature cell lineages (totipotential)

A

Embryonic Stem Cells

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10
Q

Moreparitally differentiated, no ability to revert, found in tissues, work to replace and replenish lost cells in area which they reside.

A

Tissue (adult) stem cells

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11
Q

Tissue stem cells live in specialized niches, and injury triggers signals that stimulate their ____and ____ into mature cells that repopulate the injured tissue.

A

Prolieferation & Differentiation

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12
Q
A
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12
Q

Basment membrane of tissue present after injury?
No longer present?

A

Present= mild injury**, regeneration possible **
Gone= severe injury, scar formation

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13
Q

What kind of healing?

Partial surgical resection of the liver, grows back?

A

Regeneration!

Residual tissue was intact

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14
Q

What kind of healing?

Extensive destruction of the liver with collapse of the reticulin framework, as occurs in a liver abscess,

A

Scar fomation

Severe damage by infection/inflamation

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15
Q

2 ways liver regenerates

A
  1. Proliferation of hepatocytes following partial hepatectomy.
  2. Liver regeneration from stem cells.
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16
Q

the replacement of parenchymal cells in any tissue by collagen, as in the heart after myocardial infarction

A

Scar

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17
Q

1st step in scar formation

Neutrophils & monocytes reruited to eleminate offending agents. macrophaes come in an elemintae + activate growth factors that stimulate proliferation of cells in the next stage of repair

6-48hrs

A

Inflammation

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18
Q

2nd step in scar formation

including epithelial cells, endothelial cells, and other vascular cells and fibroblasts, proliferate and migrate to close the now-clean wound

All work to form **granulation tissue **

up to 10 days

A

Cell proliferation

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19
Q

What cell type?

respond to locally produced growth factors and migrate to cover the wound.

A

Epithelial cell

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20
Q

What cell type?

roliferate to form new blood vessels, a process known as angiogenesis,

A

Endothelial and other vascular cells

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21
Q

What cell is this?

proliferate and migrate into the site of injury and **lay down collagen fibers that form the scar.

A

Fibroblasts

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22
Q

The combination of proliferating fibroblasts, ECM, and new blood vessels forms a type of tissue unique to healing wounds

Pink, soft, granular gross appearence

A

Granulation tissue

3-5 days of healing

Left Is granulation tissue. Lots of blood vessels, edema, collagen. Right is mature scare (dense type 1 collagen)
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23
Q

3rd step in scar formation

The connective tissue that has been deposited is reorganized to produce the** stable fibrous scar**

2-3 weeks post injury

A

Remodeling

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24
Q

Healing of skin wounds, epithelial regerneration with minimal scaring

no infection, close physcially via sutures, glue, etc.

A

Healing by first intention (primary union)

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25
Q

larger wounds that heal by a combination of regeneration and scarring

tissue loss, infection.

A

healing by second intention (secondary union)

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26
Q

process by which new blood vessels form from existing vessels. First process in scar formation

A

Antiogenisis

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27
Q

improve blood flow to a heart ravaged by coronary atherosclerosis

A

Therapies that augment antiogenisis

New blood vessel formation

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28
Q

to frustrate tumor growth or block pathologic vessel growth, as in wet macular degeneration of the eye

A

Therapies that inhibit antiogenisis

Less blood flow

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29
Q

which stimulates both the migration and proliferation of endothelial cells at area of injury.

Secreted by many tumors

A

vascular endothelial growth factor (VEGF)

Antiogenic factor

30
Q

Attract fibroblast, new vessel formationa and depositing of extracellular matrix

A

Fibroblast Growth Factor (FGF)

31
Q

Tumors overlly secrete ____ to direct all mateiral and suppised to the tumor, body thinks this is a normal signal.

A

VEGF

32
Q

Therapy that redcud bodys overall capactiyt to heal but also steers course away from tumor growth

A

Anti- VEGF medication

33
Q

What do these two things result in?

  1. Migration of fibroblasts into the site of injury, where they proliferate
  2. Production and deposition of ECM proteins
A

Laying down of connecitve tissue

34
Q

What is the first thing fibroblast produce at site of scar formation?

A

Type 3 Collagen

Fast acting consists of fibroblasts and an acellular component, the ECM,

35
Q

what tissue is this?

consists of fibroblasts and an acellular component, the ECM, which is composed of collagen and other glycoprotein

A

Connective tissue

36
Q

What are some 3 key functions of the ECM?

A
  1. Mechanical support
  2. Control of cell proliferation
  3. Scaffold for tissue renewal
37
Q

What of the 2 forms of the ECM?

present in the spaces between cells in connective tissue, and between the epithelium and the underlying supportive vascular and smooth muscle structures in parenchymal organs

Afibrillar and nonfibrillar collagens, as well as fibronectin, elastin,

A

Intersitial Matrix

38
Q

What of the 2 forms of the ECM?

highly organized around epithelial cells, endothelial cells, and smooth muscle cells, forming the specialized basement membrane.

Type 4 collagen + laminin

A

basment membrane

39
Q

What component of the ECM?

major ECM component of the interstitial matrix and scar tissue.

A

Collagen

Fibirilla Type 1,2,3,5 scar tissue

40
Q

Needed as a cofactor for synthesis of collagen

A

Vitamin C

41
Q

What disease?

Vitamin C deficeny, results in poor healing of wound and easily bleeding

A

Scurvy

42
Q

The action of ____ is driven by TGF-beta and Platelet Derived Growth Factor (PDGF)

A

Fibroblast

43
Q

Promotes collagen synthesis, innhbits enzyme that break it down.

Inhibit further inflammation, missing= inflammation ensues

A

Transforming growth factor; TGF-Beta

secreted Platelet, T-cells, macrophages, & endothelial cells

44
Q

Stimulates both fibroblas migration & collagen syntheis + smooth musle cells.

Autoimmune or fiborotic diseases have abnormalities in this factor

A

Platlet derived growth factor PDGF

45
Q

In response to cytokines and growth factors____ enter the wound from the edges and migrate toward the center.

A

Fibroblast

46
Q

What tissue is being observed under a microscope?

many fibroblast, new small capillary vessles, much ECM, some macrophages

A

Granulation Tissue

47
Q

Fibroblast may differentiate into ____
contain smooth muscle actin and have increased contractile activity; they help close the wound by pulling its** margins toward the center**

A

Myofibroblasts

5 days after injury, once mature scar= removed via apoptosis

48
Q

most important cytokine for the synthesis and deposition of connective tissue proteins. It is pr**oduced by most of the cells in granulation tissue, **including activated macrophages.

Also antiinflamatory cytokiene and develeopent of fibrosis in lungs, liver, kidneys follwoing chronic inflamation

A

TGF-Beta

49
Q

During final remodeling process of scar formation

Type of collagen deposited shifts from type III collagen early in repair to the more resilient type ____ collagen.

A

Type 1

50
Q

scar shrinks due to the action of what two things?

A
  1. matrix metalloproteinases (MMPs)
  2. Lysyl Oxidase

Zinc & copper dependent

51
Q

tissues is composed of** inactive, spindle-shaped fibroblasts**, dense bundles of collagen, and other ECM components

A

scar or fibrosis

Right.
52
Q

What does this display?
Application of ____ at the site of extraction cause stimulate the activation of fibroblast to come and start healing process

A

Granulation tissue formation in the oral cavity. Application collagen membranes.

53
Q

Due to the contractile acitvity of _____ wound healing may result in less function because tissue is more tightly pulled together

ex. burn on palm of hand-> scar-> cant fully open hand anymore

A

Myofibroblasts

54
Q

Cooper or zinc defficency?

A

Poor wound healing & maturation becuase MMPs and lysly oxidase not working.

55
Q

What is this process?

  1. inflamation homeostasis
  2. clot formation
  3. neutrophil migration invasion
  4. day 3-7 macrophage replace
  5. angiogenisis (blood vessel formation
  6. Fibroblast driven by GFs
  7. Type 3 collagen formaton
  8. Myofibroblas and traction
  9. Day 7-weeks, type 3 replaced by type 1
  10. more remodeling by lysyl oxidase and MMPs to reduce size of scar.
A

Healing of 1st intention wound

56
Q

Ulcers are an example of what?

leave significan scars

A

2nd intention wounds

57
Q

Are scars vascular? What is the staus of their tensile strength?

A

No, they are avascular & acellular. Tensile strength also never goes back to normal.

58
Q

What disease?

metabolic disease that compromises tissue repair and is an important systemic cause of delayed wound healing.

A

Diabetes

59
Q

What drug?

are antiinflammatory agents that **inhibit production of TGF-β **which means no promotion of collgen depostion= prevent good wound healing

A

Glucocorticoids (steroids)

60
Q

elderly people as a result of chronic venous hypertension, which may be caused by severe varicose veins or congestive heart failure, resulting in poor delivery of oxygen.

A

Venous leg ulcers

60
Q

individuals with atherosclerosis of peripheral arteries, especially associated with diabetes.** Ischemia** resulting from the vascular compromise interferes with repair and may cause necrosis of the skin and underlying tissues, producing painful lesions.

A

Arterial Ulcers

61
Q

affect the lower extremities, particularly the feet. The necrosis and failure to heal are the result of small vessel disease causing ischemia and neuropathy, as well as secondary infections. Extensive granulation tissue in underlying dermins

A

Diabetic Ulcers

left= epidermal ulcer crate, right= extensive granulation
62
Q

areas of skin ulceration and necrosis of underlying tissues caused by prolonged compression of tissues against a bone, e.g.,in bedridden individuals.

A

Pressure Sore

63
Q

contain abundant myofibroblasts and often grow rapidly but tend to then regress over several months.

4 weeks after injury, **within borders **

mostly type 3 collagen, but organized. Normally self regresses and correct

A

Hypertrophic scars

64
Q

Rasised scar tissue that grows beyond the boundaries of the original wound and does not regres.

Excessive healing and scar formation; chaotic fibroblast and collagen (both kinds) overproduction.

Commone in ear lobe, upper back. Rare on palms soles

High reccurance if surgically removed, Cortison injections help

A

Keloid Scars

65
Q

What cause of surgical site infection?

Staph aureus

A

Skin infection

66
Q

What cause of surgical site infection?

streptococci

A

Oral cavity

67
Q

What cause of surgical site infection?

Pseudomonas

A

Burns

68
Q

What cause of surgical site infection?

Penetrating exposed wound, soil ;

A

tetnus

69
Q

Vibrio Vulnifus is in what?

A

Contaminated water supply

70
Q

Bacteria in blood, always travels to heart

A

Bacteremia

71
Q

the abnormal deposition of collagen in internal organs in chronic diseases.

A

Fibrosis

72
Q

Fibrosis is induced by what?

Cause substansial organ dysfunction & faliure.

A

Persistant injury!
Ex. chronic infection & immuological reactions.