Exam 3: Chronic Inflammation and Repair

Question 1

What are the characteristics of chronic inflammation?

Answer 1

Predominance of mononuclear cells –> mainly macrophages, lymphocytes, and plasma cells
Vascular changes are minimal
Increased connective tissue (fibrosis)
Alteration in tissue architecture

Question 2

Why does chronic inflammation occur?

Answer 2

Neutrophils are short lived
Neutrophils signal macrophages
Macrophages are longer lived –> can proliferate in tissues
Persistence of antigen
Some stimuli signal chronic inflammatory cells directly

Question 3

When does an abscess develop?

Answer 3

When acute inflammation fails to eliminate stimulus

Question 4

What is an abscess?

Answer 4

Liquefaction due to neutrophil enzymes

Question 5

What does the color of exudate in an abscess depend on?

Answer 5

Pigment produced by inciting stimulus

Question 6

What happens around exudate to form an abscess?

Answer 6

Fibroblasts produce collagen and form a thin connective tissue, which can mature into a fibrous capsule which eventually walls off

Question 7

What is the inner wall of an abscess?

Answer 7

Granulation tissue: “pyogenic membrane”

Full of vessels that allow continual recruitment of neutrophils

Question 8

Describe NAG

Answer 8

Grossly abscess and granulomas can be very similar in appearance. Sometimes abscesses can have thicker capsules but it depends on duration
Neoplasms can also be similar grossly
Differentials are Neoplasia, Abscess, and Granuloma (NAG)

Question 9

Describe macrophages

Answer 9

Have abundant cytoplasm, can be foamy

Large, round nucleus that is sometimes indented

Question 10

What does granulomatous mean?

Answer 10

Macrophages

Question 11

What is granulomatous inflammation dependent upon?

Answer 11

Presence of indigestible organisms/particles

Presence of cell mediated immunity to inciting agent

Question 12

What is seen grossly with granulomatous inflammation?

Answer 12

DIffuse: tissue appears thickened
Nodules: firm nodules of various sizes

Question 13

What is seen microscopically with granulomatous inflammation?

Answer 13

Numerous macrophages present

Often accompanied by variable numbers of lymphocytes and plasma cells and connective tissue

Question 14

What is the effect of granulomatous inflammation?

Answer 14

Chronic infection which the body cannot eliminate

Interfere with organ function

Question 15

What are causes of granulomatous inflammation?

Answer 15

Bacteria
Fungi
Parasitic disease
Foreign bodes

Question 16

What are bacteria and fungi resistant to that allows them to cause granulomatous inflammation?

Answer 16

Phagocytosis

Question 17

What does the look of macrophages depend on?

Answer 17

Differentiation status

Question 18

What are epithelioid macrophages?

Answer 18

Abundant eosinophilic cytoplasm and large pale nuclei

More secretory and less phagocytic than typical macrophages

Question 19

What are giant cells?

Answer 19

Large, multinucleated cells that arise from the fusion of macrophages

Question 20

What is a granuloma?

Answer 20

Macrophages that are in aggregates

Question 21

Describe classic granulomas

Answer 21

Central core of caseous necrosis
Zone of epithelioid macrophages and giant cells
Zone of lymphocytes
An outer zone of fibroblasts and fibrosis

Question 22

How can you differentiate between diffuse and nodular granulomatous inflammation?

Answer 22

Morphologic forms based on immunologic response
Th2–> diffuse granulomatous inflammation
Th1–> nodular granulomas

Question 23

What is a stage 1 granuloma?

Answer 23

Days after infection

The lesion site is infiltrated by neutrophils, monocytes, macrophages, and lymphocytes. Epithelioid macrophages form

Question 24

What is a stage 2 granuloma?

Answer 24

From roughly 48 hours to multiple days and weeks
Lesions contain macrophages, epithelioid macrophages, thin rims of fibrous connective tissue, variable numbers of lymphocytes, MGCs can also form

Question 25

What is a stage 3 granuloma?

Answer 25

From weeks to 1 month The central area can caseate or become dense with macrophages and mineralize Lymphocytes, plasma cells, a zone of fibroblasts, and a fibrous connective tissue capsule surround this core

Question 26

What is a stage 4 granuloma?

Answer 26

From several weeks to months The lesion can be walled off by a dense capsule Regions within the lesion can become mineralized and overtake the surrounding tissue

Question 27

What is a good example of diffuse granulomatous inflammation?

Answer 27

Johne's in cattle

Question 28

How can you identify that there is diffuse granulomatous inflammation?

Answer 28

There are no well defined modules | There is a diffuse accumulation of epithelioid macrophages

Question 29

What is lymphocytic inflammation?

Answer 29

Accumulation of lymphocytes

Question 30

What is seen grossly with lymphocytic inflammation?

Answer 30

Difficult to determine grossly | If infiltrates are extensive, the tissue may have a tan/white color

Question 31

What is seen microscopically with lymphocytic inflammation?

Answer 31

Lymphocytes present | Can be mixed with plasma cells

Question 32

What are causes of lymphocytic inflammation?

Answer 32

Certain viral infections (rabies, WNV, EEE Certain bacterial infections (listeria) Some parasitic infections (Toxoplasma gondii)

Question 33

What are effects of lymphocytic inflammation?

Answer 33

Indicates the immune response is occurring against an agent | Many cases involving the nervous system are fatal

Question 34

Describe lymphocytes

Answer 34

Small cells, with very little cytoplasm Lymphocytes entered unresolved areas of acute inflammation within 24-48 hours In some organs (brain), will have a perivascular pattern

Question 35

What are B cells?

Answer 35

1. Lymphocytes take up and present antigen | 2. Differentiate into plasma cells- secrete immunoglobulins

Question 36

When do plasma cells predominate?

Answer 36

Certain chronic inflammatory conditions

Question 37

Describe eosinophilic granulomas

Answer 37

Recruited into and stimulated to proliferate- IL-5 and eotaxin Dense infiltrate of eosinophils with macrophages, varying numbers of lymphocytes and plasma cells

Question 38

What does fibrosis stimulate?

Answer 38

Fibroblasts

Question 39

What do fibroblasts contribute to?

Answer 39

Structural integrity of tissue

Question 40

What are fibroblasts responsible for?

Answer 40

Synthesis of collagen and extracellular matrix proteins | Produce cytokines and chemokines that regulate the extracellular environment

Question 41

What do fibroblastic growth factors signal?

Answer 41

Proliferation

Question 42

What is fibrous connective tissue?

Answer 42

Dense accumulation of fibroblasts and collagen | With time, connective tissue becomes more dense and fewer inflammatory cells

Question 43

What are the 4 phases of wound healing?

Answer 43

Hemostasis Inflammation Proliferation Remodeling

Question 44

What is the hemostasis phase of wound healing?

Answer 44

Platelet plug, angiogenesis

Question 45

What is the inflammation phase of wound healing?

Answer 45

Cardinal signs of inflammation | Clean up cell debris from tissue injury

Question 46

How does excessive inflammation effect wound healing?

Answer 46

It inhibits it

Question 47

What is the proliferation phase of wound healing?

Answer 47

New endothelium, epithelium, and connective tissue to restore normal function

Question 48

What is the remodeling phase of wound healing?

Answer 48

Remodeling of granulation tissue and conversion to mature connective tissue

Question 49

What does wound repair require?

Answer 49

Extracellular matrix and it must be resynthesized

Question 50

What is granulation tissue?

Answer 50

Fibroblasts and endothelial cells proliferate to fill in tissue defects

Question 51

How do fibroblasts grow?

Answer 51

Parallel to the wound surface and perpendicular to the proliferating capillaries

Question 52

What can excessive granulation tissue lead to?

Answer 52

A hypertrophic scar

Question 53

How is healing affected if the basement membranes are damaged?

Answer 53

Healing will take longer

Question 54

What happens if healing is delayed?

Answer 54

Altered healing can occur leading to extensive fibrosis

Question 55

What is 1st intention healing?

Answer 55

Primary intention healing When edges are directly apposed Heals rapidly with little trace of wound

Question 56

What is 2nd intention healing?

Answer 56

Gaping wound or infected wound | Connective tissue disorganized

Question 57

What is epithelialization?

Answer 57

Epithelial cells at periphery proliferate | Very rapid in 1st intention healing

Question 58

What must epithelialization move along?

Answer 58

A basement membrane

Question 59

Describe bone healing

Answer 59

Hematoma Fibroblast proliferation and mesenchymal proliferation Callus formed (primary) Secondary callus formed

Question 60

What inhibits fracture repair?

Answer 60

``` Malnutrition Infection Instability Necrotic bone fragments Movement at site Inadequate blood supply ```