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Flashcards in Tissue Repair Deck (37)
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1
Q

What is the Parenchyma?

A

Functional parts of an organ

2
Q

What is the Stroma?

A

The structural tissue of organs

Connective tissues

3
Q

What are the causes of Tissue Damage? (6)

A
Trauma
Infection
Physical and Chemical Agents
Tissue Necrosis
Foreign Bodies
Immune Reactions
4
Q

What is Diapedesis?

A

Passage of blood ells through intact walls of the capillaries

Typically accompanies inflammation

5
Q

What events occur in the Haemostasis Phase?

A

Platelet Aggregation
Release of Pro-Inflammatory mediators
Diapedesis

6
Q

What events occur in the proliferation phase?

A

Alterations in cell-cell and cell-matrix interactions
Migration
Cross-talk between MMPs, integrins and cells
Cytokine and growth factor release
ECM production

Re-epithelisation
Angiogenesis
Fibroplasia
ECM deposition

7
Q

What are MMPs?

A

Matrix metalloproteinases

Group of enzymes responsible for the degradation of most extracellular matrix proteins

8
Q

What is ECM?

A

Extracellular Matrix

Collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells
Regulates movement and growth of cells

9
Q

What event occurs during the Remodelling phase?

A

Fibroblast to myofibroblast differentiation

Scar Formation
ECM remodelling and degradation
Contraction

10
Q

What are the phases of tissue repair?

A

Haemostasis
Inflammation
Proliferation
Remodelling

11
Q

What are the fundamentals of inflammation?

A
Rubor - Redness
Calor - Heat
Dolor - Pain
Tumor - Swelling
Functio laesa - Loss of Function
12
Q

What is a fibroblast?

A

Type of cell that synthesises the ECM and collagen, the stroma and plays a critical role in wound healing.

Most common cells of connective tissue

13
Q

What is PDGF?

A

Platelet derived growth factor

14
Q

What is VEGF?

A

Vascular endothelial growth factor

Angiogenesis

15
Q

What is CXCL5?

A

Platelet Factor 4

Binds with high affinity to heparin
Neutralises heparin like molecules on endothelium
Inhibit local antithrombin activity to promote coagulation

Strong chemoattractant for neutrophils and fibroblasts

16
Q

What is CCL5?

A

Chemokine ligand 5

chemotactic for T cells, eosinophils and basophils

17
Q

What is bFGF?

A

Basic Fibroblast Growth Factor

Angiogenesis

18
Q

What is TGFβ?

A

Transforming Growth Factor Beta

Cascade causes differentiation, chemotaxis, proliferation, activation of immune cells

19
Q

What is the function of platelets in tissue repair?

What stage are they involved in?

A

Formation of Platelet Plug

Release pro-inflammatory mediators

Haemostasis Phase

20
Q

What are the stages of Leukocyte Recruitment?

A

Rolling
Integrin Activation by Chemokines
Stable Adhesion
Migration through Endothelium

21
Q

What is the roll of neutrophils in tissue repair?

A

Phagocytosis
Recruited within minutes
Respiratory burst
Anti-microbial

Haemostasis/Inflammation phase

22
Q

What is the respiratory burst?

A

In neutrophils and macrophages

Intracellular bleach (reactive oxygen species) released to kill engulfed bacteria

Green Enzymes - green discharge

23
Q

What is the role of Macrophages in Tissue Repair?

A

Resident macrophages - alveolar macrophages and kupffer cells (liver)

Monocyte derived macrophages
M1 - inflammatory
M2 - removing debris

Phagocytic

Respiratory burst

Produce Nitric Oxide

24
Q

What is Granulation Tissue?

A

New connective tissue and microscopic blood vessels hat form on the surfaces of a wound during the healing process.

Typically grows from the base of the wound and is able to fill wounds of any size

25
Q

What does the outcome of the proliferative phase depend on?

A

Proliferative potential

26
Q

What are Labile cells?

Where are they found?

A

Continually dividing

Reproduce new stem cells to replace functional cells

GI tract
Epidermis
Mucosal epithelia
Bone Marrow

27
Q

What are Quiescent cells?

Where are they found?

A

Stem cells that retain the ability to divide

Enter the cell cycle when activated

Hepatocytes
Renal tubular epithelium
Pancreatic acini

28
Q

What are permanent cells?

Where are they found?

A

Terminally differentiated cells
No proliferative capacity

Damage to these cells leads to scarring

Cardiac myocytes
Brain cells
Neurons
Skeletal muscle
Red blood cells
29
Q

What are the different pathways for angiogenesis? (2)

A

Mobilisation of EPCs (endothelial progenitor cells) from bone marrow

Angiogenesis from pre-existing vessels

Driven by VEGF

30
Q

What substances make up the Extracellular Matrix?

What is the role of each substance?

A

Collagen - tensile strength

Elastin - elastic stretch and recoil

Proteoglycans - regulate structure and permeability, moderate cell growth, bind growth factors

Adhesive glycoproteins - fibronectin and laminin - cell recognition, adhesion, migration and proliferation

Integrins - major cell surface receptors, mediating cell adhesion to ECM

31
Q

What types of cels can become myofibroblasts?

A

Fibrocytes
Resident fibroblasts
Alveolar epithelium

32
Q

What is first intention skin healing?

A

Focal disruption of the basement membrane and limited loss of epithelial cells

surgical incision

33
Q

What is skin healing by second intention?

A

Larger injury than first intension

Edges can’t be Brough together, due to tissue loss

Results in large scar and contraction

34
Q

What are the local factors that delay tissue repair? (7)

A
Poor blood supply (atherosclerosis)
Denervation
Infection (and biofilm formation)
Foreign bodies 
Mechanical stress
Overwhelming necrosis
Size
35
Q

What are the systemic factors that delay tissue repair? (9)

A
Anaemia
Nutritional deficiencies (vitC)
Systemic infection
Smoking
Genetic Disorders (marfans)
Diabetes
Malignancy
Haematological abnormalities
Age
36
Q

How, when and where does fibrosis occur?

A

Excessive deposition of ECM

During abberant wound healing there is too much collagen production

Lung, liver, cardiac, skin, kidney

37
Q

What are complications of skin healing? (3)

A

Deficient scar: dehiscence, ulceration

Excessive scar: hypertrophic, keloid, proud flesh

Contractures: permanent shortening of a muscle or joint