4 - Chronic Inflammation and Tissue Repair (Exam 1) Flashcards

1
Q

What is chronic inflammation?

A

Active inflammation of prolonged duration - weeks, months, years.

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2
Q

What are 3 characteristics of chronic inflammation?

A
  1. Tissue destruction
  2. Infiltration of mononuclear cells (WBCs)
  3. Repair, including angiogenesis and fibrosis
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3
Q

What are 2 ways chronic inflammation can form from acute inflammation?

A
  1. Continued presence of injurious agent

2. Interference to the normal healing process

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4
Q

What are 3 common causes of chronic inflammation?

A
  1. Persistent microbial infection
  2. Autoimmune disease
  3. Prolonged exposure to toxic agents (non-degradable exogenous materials, asbestos, silica)
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5
Q

What are 2 examples of autoimmune disease that cause chronic inflammation?

A
  1. Rheumatoid arthritis

2. Multiple Sclerosis

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6
Q

What are 5 types of chronic inflammatory cells?

A
  1. Macrophages
  2. Lymphocytes
  3. Plasma cells
  4. Eosinophils
  5. Mast cells
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7
Q

What are the primary cells of chronic inflammation?

A

Macrophages - monocytes that have left the circulation

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8
Q

What are 2 examples of mediators that activate macrophages?

A
  1. Cytokines

2. Microbial antigens

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9
Q

What are 5 byproducts produced by macrophages that result in tissue injury?

A
  1. Reactive oxygen species
  2. Eicosanoids
  3. Cytokines
  4. Complement components
  5. Proteases
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10
Q

What is granulomatous inflammation?

A

A form of chronic inflammation, associated with collections of activated macrophages. They assume a flattened shape and can be surrounded by a collar of lymphocytes and plasma cells.

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11
Q

What are 3 characteristics of granulomatous inflammation?

A
  1. Central necrosis due to hypoxia
  2. Granuloma tends to “wall off” the infection
  3. Presents difficulty with antibiotic treatments
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12
Q

What are 2 common categories of cause for granuloma formation?

A
  1. Immune granuloma

2. Microorganisms, parasites, or fungal agents

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13
Q

What types of microorganisms tend to cause granuloma formation?

A

Facultative or obligate intracellular pathogens

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14
Q

What are 4 examples of bacteria that cause granuloma formation?

A
  1. Mycobacterium tuberculosis (Tuberculosis)
  2. Treponem pallidum (Syphalitic Gumma)
  3. Mycobacterium leprae (Leprosy)
  4. Bartonella henselae (Cat scratch disease)
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15
Q

What is 1 example of a parasite that causes granuloma formation?

A

Schistosomiasis

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16
Q

What are 2 examples of fungal causes of granuloma formation?

A
  1. Histoplasmosis

2. Cryptococcus

17
Q

What are the 2 main processes of tissue repair?

A
  1. Cell regeneration

2. Replacement of lost tissue by connective tissue

18
Q

There are 3 types of cells in the body in terms of differentiation, what are they?

A
  1. Labile cells
  2. Stable cells
  3. Permanent cells
19
Q

What are 2 main characteristics of labile cells?

A
  1. Continuously dividing and replacing older cells

2. Proliferation comes from relatively undifferentiated stem cells

20
Q

What are 4 places labile cells are found in the body?

A
  1. Basal cells of integumentary system
  2. Epithelial cells of glands
  3. Hematopoietic cells of bone marrow
  4. Epithelial cells of GI tract
21
Q

What are 2 main characteristics of stable cells?

A
  1. They have a limited ability to replicate
  2. Will undergo rapid mitotic divisions if necessary

Also known as quiscient cells

22
Q

What is 1 place stable cells are found in the body?

A
Parenchymal cells of organs such as:
Kidneys
Liver
Pancreas
Fibroblasts
23
Q

What are 2 main characteristics of permanent cells?

A
  1. Terminally differentiated

2. Non-proliferative in postnatal life

24
Q

What are 2 examples of permanent cells?

A
  1. Neurons

2. Muscle cells

25
Q

What are 7 mediators of cell proliferation?

A
  1. Epidermal growth factor
  2. Platelet derived growth factor
  3. Fibroblast growth factor
  4. Certain kinds of cytokines
  5. Interferon alpha
  6. Prostaglandin E2
  7. Heparin
26
Q

What are 2 characteristics of controlling factors?

A
  1. Play a role in regulation of the extent of cell proliferation
  2. Prevent the overproduction of cells and fibers
27
Q

What are 3 ways controlling factors prevent the overproduction of cells and fibers?

A
  1. Contact inhibition
  2. Suppressor genes
  3. Transforming growth factor beta
28
Q

What is healing by primary intention?

A

The healing of a wound under conditions of minimal tissue loss (surgical incisions)
Often held together by sutures, staples, bandages
Reconstructive phase begins around 3 days, continues as long as 2 weeks

29
Q

What is the sequence of events in the reconstructive phase? (12 steps, ouch)

A
  1. Acute inflammatory phase
  2. Fibrin clot formation
  3. Diapedesis of neutrophils to wound margin within a day
  4. Surface epithelium thickens, mitosis increases in basal cells within 1-2 days
  5. Migration of cells from both sides form monolayer
  6. Fibroblasts and vascular endothelial cells proliferate
  7. Angiogenesis/ neovascularization of wound
  8. Neutrophils replaced/ outnumbered by monocytes and lymphocytes on day 3
  9. Fibroblasts actively proliferating, depositing collagen fibers vertically
  10. Epithelial cells proliferate, form original epithelium
  11. Peak in activity day 5 gives rise to pink “granulation tissue”
  12. Epithelium reaches normal thickness and function

Scar tissue contraction begins later in this process

30
Q

What is healing by secondary intention?

A

The healing of large defects, wounds, or ulcers
Involves more epithelialization, scar formation, and contraction time than primary intention
Follows the same sequence as healing by primary intention, with much longer time needed for steps

31
Q

What is the mature or remodeling phase?

A

Final formation and shaping of scar tissue

32
Q

When does the mature or remodeling phase begin?

A

About 3 weeks after the injury, and continues for 6 months to 2 years depending on if associated with primary or secondary intention healing.

33
Q

What are 4 stages of the mature or remodeling phase?

A
  1. Completion of wound contraction by myofibroblasts
  2. Differentiation of wound tissue
  3. Remodeling of scar tissue
  4. Disappearance of capillaries from scar tissue

Healed wounds will never have the same strength as normal tissue

34
Q

What are complications of wound repair often due to?

A

Overactivity of the inflammatory process

35
Q

What are 2 things that can happen as a result of excessive migration of neutrophils to the wound site?

A
  1. Excessive leakage of serum between endothelial cells

2. Physical disruption of endothelium, epithelium, etc.

36
Q

What is “proud flesh”?

A

Excessive proliferation of granulation tissue that is red and bleeds with touch

37
Q

What is a “keloid”?

A

An excessive scar resulting from the excess formation of collagen