Test 1: lecture 7 tissue repair

Question 1

4 phases of wound repair

Answer 1

hemostasis

acute inflammation

proliferation

remodeling

Question 2

replacement by cells of the same type; requires an intact framework

Answer 2

regeneration

Question 3

2 results of regeneration

Answer 3

renewing tissues such as GI can regrow

Stable tissues such as liver and kidney can undergo compensatory growth

Question 4

What determines whether a tissue will undergo regeneration or healing?

Answer 4

Type of tissue damaged
• Damage to the ECM
• Extent of the wound
• Blood supply, nutrition

Question 5

Although amphibians have the ability to regenerate limbs and some organs, regeneration in mammalian organs is ___

Answer 5

compensatory growth.

functional but not exact replica

Question 6

name two type of cell groups that can undergo regeneration

Answer 6

Continuously dividing (labile) tissues - cells proliferate throughout life, replacing those that are destroyed (e.g. gut epithelium).

Quiescent (stable) tissues- low level of replication; may undergo rapid division in response to stimuli and can restore the tissue of origin. G0 stage but can be stimulated to enter G1 (e.g. parenchymal cells of liver, kidneys, and pancreas).

Question 7

what type of cells can not undergo regeneration

Answer 7

post mitotic (terminally differentiated)

cannot undergo mitotic division

example: neurons, cardiac muscle

Question 8

parenchymal cell death with intact tissue framework results in ___

Answer 8

regeneration of normal structure

liver, skin

Question 9

parenchymal cell death with damaged tissue framework results in

Answer 9

repair by scar formation

heart attack

Question 10

persistant tissue damage results in

Answer 10

fibrosis and tissue scar

cirrhosis, chronic pancreatitis

Question 11

restoration of integrity to injured tissue; typically involves collagen deposition and scar formation.

Answer 11

healing

Question 12

4 stages of wound repair

Answer 12

Hemostasis (vascular phase)

Acute inflammation (cellular phase)

Proliferation (proliferation phase- granulation tissue)

Remodeling (maturation phase, contraction)

Question 13

inflammation phase occurs ___ to ___ hrs after injury

Answer 13

24-96

Question 14

what cells are involved in the inflammation phase

Answer 14

Macrophages remove cell debris (w/neutrophils), degrade ECM, release GF (w/fibroblasts) necessary for the proliferation phase.

Question 15

___ form a loose gel-like matrix to serve as the scaffold for
granulation tissue.

Answer 15

fibrin

Question 16

how long does the proliferation phase last?

Answer 16

3-4 weeks depending on size of wound

Question 17

Granulation tissue proliferation has connective tissue fibers that are ___ to the surface of the wound, fibroblasts, and blood vessels that are ___ to the surface of the wound

Answer 17

parellel

perpendicular

Question 18

epithelial and mesenchymal stem cells are turned on in what stage of wound healing

Answer 18

proliferation (stage 3 → granulation tissue)

Question 19

what starts to form in the wound during the proliferation phase

Answer 19

fibrous connective tissue and blood vessels

Question 20

when does stage 4 of wound healing start

Answer 20

remodeling/maturation phase

3-4 weeks after injury after all other phases are done

Question 21

when does collagen form in wound healing

Answer 21

remodeling/maturation phase

TGFB and ECM will help convert immature connective tissue into collagen

Question 22

contraction in remodeling tissue is by ___

Answer 22

myofibroblasts

Question 23

explain

Answer 23

inflammation phase 24-96 hours

1- neutrophils and macrophages come in and clean up

2. lack of blood causes activation of growth factors which lead to new vessels and recruit fibroblasts, myofibrils and structural cells
3. old ECM is broken down
4. fibrin and serum proteins fill the wound

Question 24

Answer 24

proliferation phase 3-4 weeks → angiogenesis and fibroplasia→ granulation tissue formation

1. fibrin acts as framework for granulation tissue with connective tissue parallel and vessels perpendicular
2. basement membrane reforms and re-epithelization occurs to close area
3. stem cells found in hair follicles activate

Question 25

Answer 25

remodeling phase - 3-4 weeks after injury → collagen formation and wound closure platelets and macrophages release **TFG B** that stimulate the **formation of collagen** and **myofibroblast activation**

Question 26

what are the white spaces

Answer 26

edema picture of acute wound with fibrin and neutrophils

Question 27

Answer 27

7 day wound see scab and re-epithelization cell in proliferation phase → depositing granulation tissue

Question 28

Answer 28

7 day wound see scab and re-epithelization- cells are stretched to cover injury less edema- area now filled with fibrous connective tissue and congested red blood cells **cell in proliferation phase → depositing granulation tissue, vessels and fibroblast**

Question 29

Answer 29

cirrhosis heals by fibrosis- bands of fibrosis will contract to form nodules

Question 30

what are some things that disrupt repair

Answer 30

**Bacterial infection** **Poor Nutrition:** protein deficiency; Vitamin C deficiency **Glucocorticoid therapy:** anti-inflammatory; impairs collagen synthesis **Mechanical factors:** local pressure, torsion, movement **Dehiscence** **Poor perfusion** **Amount of tissue injured** **Tissue type:** those that cannot regenerate (e.g. myocardium) lead to scarring Aberrations of cell growth and ECM production (**proud flesh)**

Question 31

granulation tissue granuloma

Answer 31

**granulation tissue**-proliferative phase of tissue healing → fibroplasia and neovascularization **granuloma-** chronic inflammation→ epithelioid macrophage and multinucleated giant cells

Question 32

fibrin vs fibrous

Answer 32

fibrin part of acute/vascular phase of wound healing. leaks from endothelium that has been injured. part of the clotting cascade. acts as framework for fibroblasts to come in and deposit fibrous connective tissue/collagen

Question 33

\_\_\_ is when organ becomes functional due to cell hyperplasia and hypertrophy (not a replica)

Answer 33

compensatory growth branch of regeneration

Question 34

1st phase of wound repair

Answer 34

hemostasis (vascular phase)

Question 35

what happens during the hemostasis phase of wound healin

Answer 35

first phase stops blood flow and then starts rebuilding injury causes vasospasm→ platelets clot and release TGF that causes vasoconstriction and thrombogenesis and angiogenesis

Question 36

explain how oxygen effects wound healing

Answer 36

oxygen tension- lack of O2 to an area causes the production of growth factors that will activate macrophages, fibroblasts and endothelial cells

Question 37

Macrophages clean up cell debris, degrade ECM and release growth factors (along with fibroblasts) to enhance proliferation of endothelial cells, fibroblasts for new ECM, ___ for contraction, and ___ cells for return to normal structure and function.

Answer 37

myofibroblasts parenchymal

Question 38

Degradation of the ECM occurs through physical separation or tearing, ___ from plasma proteins, infiltration by inflammatory cells, and degradation by ___ produced by macrophages, fibroblasts, mast cells, and most leukocytes.

Answer 38

dilution MMPs

Question 39

what three processes occur during proliferation

Answer 39

granulation tissue phase ## Footnote angiogenesis, epithelialization, and fibroplasia.

Question 40

Excessive/exuberant granulation can lead to a type of hypertrophic scar called \_\_\_\_

Answer 40

proud flesh.

Question 41

Contraction of healing tissue is mediated by \_\_\_\_

Answer 41

**myofibroblasts** (specialized fibroblasts with contractile activity). ## Footnote Secretion of **TGF-β** by platelets and macrophages Function is to contract the wound and thus bring together injured tissue separated by edema and inflammation.

Question 42

Scirrhous Reaction

Answer 42

when too much connective tissue/collagen is put down causes damage to original tissue cirrhosis (bands of fibrous tissue that contract to form nodules)