Tissue Repair

Question 1

What is the onset and duration of acute inflammation compared to chronic inflammation?

Answer 1

acute- onsets in seconds to minutes and lasts days while chronic onsets in days and can last months.

Question 2

What is regeneration?

What is repair

Answer 2

regen- replacing wounded tissues with same type of tissue (native tissue)
repair- replace with scar

Question 3

Tissues are divided into ___ types based on their regenerative capabilities. What are they?

Answer 3

3

1. labile tisses
2. Stable tissues
3. permanent tissues

Question 4

what are labile tissues?

Answer 4

continuously cycle to regenerate tissue (such as skin; have stem cells which can regenerate)

Question 5

Where are stem cells in the small and large bowel? skin? bone marrow? lung?

Answer 5

crypts
basal layer
hematopoietic stem cells (marker is CD34 important to know)
type 2 pneumocyte

Question 6

What are stable tissues? whats an example?

Answer 6

sit outside of regenerative cycle (are quiescent) but reenter cell cycle.
The liver can regenerate by compensatory hyperplasia after partial resection. Hepatocytes produce additional cells and then re-enter quiescence.

Question 7

What are permanent tissues?

what are some examples?

Answer 7

lack significant regenerative potential.

myocardium, skeletal muscle, neurons

Question 8

how do permanent tissues heal if damaged?

Answer 8

through repair- i.e. a scar because they can’t regenerate.

Question 9

transudate is usually associated with ____. Describe transudate.

Answer 9

hydrostatic pressure. Low number of proteins compared to fluid. Fluid leaks out of vessel. Protein stays in vessel. Low protein can cause these leaky vessels.

Question 10

exudate is usually associated with ______. Describe exudate.

Answer 10

Inflammation. there is space between the cells and fluid and proteins will leak out.

Question 11

Acute inflammation is associated with what vascular response?

Answer 11

vasodilation (increased flow)
vascular permeability (transudate/exudate)

Question 12

What cell is responsible for Growth Factor Secretion?

Answer 12

Macrophage.

Question 13

What cell is responsible for Neovascularization?

Answer 13

Endothelial Cell

Question 14

What cell is responsible for Collagen deposition?

Answer 14

fibroblast/myofibroblast

Question 15

What cell is responsible for collagen remodeling/retraction?

Answer 15

fibroblast

Question 16

What cell is responsible for re-epithelialization/regeneration?

Answer 16

epithelial cell/ hepatocytes

Question 17

What is granulation tissue?

Answer 17

new vascular tissue on the healing surface of a wound.

Question 18

What in granulation tissue composed of?

Answer 18

fibroblasts
new capillaries
loose ECM
inflammatory cells (mostly macrophages)

Question 19

what is reepithelialization?

Answer 19

repair of the epithelium.

Question 20

what is repair of the liver called?

Answer 20

regeneration.

Question 21

How is epithelium repaired?

Answer 21

Reepitheliazation. cells are rapidly replaced by proliferation of residual cells. The basement membrane must be intact in order for this to work.

Question 22

How are organ systems such as the liver repaired?

Answer 22

Through regeneration. Loss of liver mass or inflammation triggers cytokines and growth factors to regenerate. Can occur by proliferation of surviving hepatocytes or repopulation of progenitor cells.

Question 23

What is the process of forming a normal scar?

Answer 23

angiogenesis–>granulation tissue–>maturation and reorganization of fibrous tissue (remodeling)–>stable fibrous scar

Question 24

The intial scar is made of what?

Answer 24

collagen type III

Question 25

scar remodeling occurs with what type of collagen?

Answer 25

type I

Question 26

What is the distinguishes a pathologic scar from a normal scar?

Answer 26

accumulation of excessive amounts of collagen

Question 27

What are two types of pathologic scars?

Answer 27

hypertrophic and Keloid

Question 28

Whats the difference between a hypertrophic and keloid type of pathologic scar?

Answer 28

both grow outside the bondaries of the injury. A hypertrophic scar regresses however. A keloid persists.

Question 29

What are local factors that can adversely influence repair?

Answer 29

infection persistence of insult trauma (either by early movement prior to full repair or by foreign material)

Question 30

what are nutritional systemic factors that can adversely influence repair?

Answer 30

This impairs collagen synthesis. Can occur via protein deficiency or vitamin C deficiency

Question 31

what are metabolic systemic factors that can adversely influence repair?

Answer 31

This delays repair. It occurs in diabetes and with glucocorticoids (this inhibit collagen synthesis)

Question 32

What are the systemic factors (general) that can adversely influence repair?

Answer 32

nutritional metabolic venous drainage impairment

Question 33

how do varicose veins adversely influence repair

Answer 33

impairs venous drainage (a systemic impairment)