Ch.2 Scar formation & tissue repair

Question 1

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

Answer 1

Tissue Repair/healing

Question 2

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.

Answer 2

Regeneration

Question 3

Tissues like the epitheliium that are continuously dividing

Answer 3

Labile

Question 4

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

Answer 4

Scar formation

Question 5

On what tissues is scar formation common?

Answer 5

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

Question 6

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

Answer 6

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

Question 7

What tissue cells?

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

Answer 7

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

Question 8

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.

Answer 8

majority of neurons and cardiac muscle cells

Question 9

undiferrentiated & can turn into any cell type

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

Answer 9

Embryonic Stem Cells

Question 10

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

Answer 10

Tissue (adult) stem cells

Question 11

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

Answer 11

Prolieferation & Differentiation

Question 12

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

Answer 12

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

Question 13

What kind of healing?

Partial surgical resection of the liver, grows back?

Answer 13

Regeneration!

Residual tissue was intact

Question 14

What kind of healing?

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

Answer 14

Scar fomation

Severe damage by infection/inflamation

Question 15

2 ways liver regenerates

Answer 15

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

Question 16

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

Answer 16

Scar

Question 17

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

Answer 17

Inflammation

Question 18

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

Answer 18

Cell proliferation

Question 19

What cell type?

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

Answer 19

Epithelial cell

Question 20

What cell type?

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

Answer 20

Endothelial and other vascular cells

Question 21

What cell is this?

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

Answer 21

Fibroblasts

Question 22

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

Pink, soft, granular gross appearence

Answer 22

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)

Question 23

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

Answer 23

Remodeling

Question 24

Healing of skin wounds, epithelial regerneration with **minimal scaring** | no infection, close physcially via sutures, glue, etc.

Answer 24

Healing by first intention (primary union)

Question 25

larger wounds that heal by a combination of regeneration and scarring | tissue loss, infection.

Answer 25

healing by second intention (secondary union)

Question 26

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

Answer 26

Antiogenisis

Question 27

improve blood flow to a heart ravaged by coronary atherosclerosis

Answer 27

Therapies that augment antiogenisis | New blood vessel formation

Question 28

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

Answer 28

Therapies that inhibit antiogenisis | Less blood flow

Question 29

which stimulates both the migration and proliferation of endothelial cells at area of injury. ## Footnote Secreted by many tumors

Answer 29

vascular endothelial growth factor (VEGF) | Antiogenic factor

Question 30

Attract fibroblast, new vessel formationa and depositing of extracellular matrix

Answer 30

Fibroblast Growth Factor (FGF)

Question 31

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

Answer 31

VEGF

Question 32

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

Answer 32

Anti- VEGF medication

Question 33

# 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

Answer 33

Laying down of connecitve tissue

Question 34

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

Answer 34

Type 3 Collagen | Fast acting consists of fibroblasts and an acellular component, the ECM,

Question 35

# what tissue is this? consists of fibroblasts and an acellular component, the ECM, which is composed of collagen and other glycoprotein

Answer 35

Connective tissue

Question 36

What are some 3 key functions of the ECM?

Answer 36

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

Question 37

# 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,

Answer 37

Intersitial Matrix

Question 38

# 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

Answer 38

basment membrane

Question 39

# What component of the ECM? major ECM component of the interstitial matrix and scar tissue.

Answer 39

Collagen | Fibirilla Type 1,2,3,5 **scar tissue**

Question 40

Needed as a cofactor for synthesis of collagen

Answer 40

Vitamin C

Question 41

# What disease? Vitamin C deficeny, results in poor healing of wound and easily bleeding

Answer 41

Scurvy

Question 42

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

Answer 42

Fibroblast

Question 43

Promotes collagen synthesis, innhbits enzyme that break it down. Inhibit further inflammation, missing= inflammation ensues

Answer 43

Transforming growth factor; TGF-Beta | secreted Platelet, T-cells, macrophages, & endothelial cells

Question 44

Stimulates both fibroblas migration & collagen syntheis + smooth musle cells. Autoimmune or fiborotic diseases have abnormalities in this factor

Answer 44

Platlet derived growth factor PDGF

Question 45

In response to **cytokines and growth factors**____ enter the wound from the edges and migrate toward the center.

Answer 45

Fibroblast

Question 46

# What tissue is being observed under a microscope? many fibroblast, new small capillary vessles, much ECM, some macrophages

Answer 46

Granulation Tissue

Question 47

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**

Answer 47

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

Question 48

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

Answer 48

TGF-Beta

Question 49

# 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.

Answer 49

Type 1

Question 50

scar shrinks due to the action of what two things?

Answer 50

1. matrix metalloproteinases (MMPs) 2. Lysyl Oxidase | Zinc & copper dependent

Question 51

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

Answer 51

scar or fibrosis

Question 52

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

Answer 52

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

Question 53

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

Answer 53

Myofibroblasts

Question 54

Cooper or zinc defficency?

Answer 54

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

Question 55

# 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.

Answer 55

Healing of 1st intention wound

Question 56

Ulcers are an example of what? | leave significan scars

Answer 56

2nd intention wounds

Question 57

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

Answer 57

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

Question 58

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

Answer 58

Diabetes

Question 59

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

Answer 59

Glucocorticoids (steroids)

Question 60

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.

Answer 60

Venous leg ulcers

Question 60

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.**

Answer 60

Arterial Ulcers

Question 61

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

Answer 61

Diabetic Ulcers

Question 62

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

Answer 62

Pressure Sore

Question 63

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

Answer 63

Hypertrophic scars

Question 64

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

Answer 64

Keloid Scars

Question 65

# What cause of surgical site infection? Staph aureus

Answer 65

Skin infection

Question 66

# What cause of surgical site infection? streptococci

Answer 66

Oral cavity

Question 67

# What cause of surgical site infection? Pseudomonas

Answer 67

Burns

Question 68

# What cause of surgical site infection? Penetrating exposed wound, soil ;

Answer 68

tetnus

Question 69

Vibrio Vulnifus is in what?

Answer 69

Contaminated water supply

Question 70

Bacteria in blood, always travels to heart

Answer 70

Bacteremia

Question 71

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

Answer 71

Fibrosis

Question 72

Fibrosis is induced by what? | Cause substansial organ dysfunction & faliure.

Answer 72

Persistant injury! Ex. chronic infection & immuological reactions.