Cell Types in Repair and Inflammation - Nichols

Question 1

What is the main fiber of the extracellular matrix?

Answer 1

collagen (makes up about 25% of all protein in body)

Question 2

What are fibroblasts?

Answer 2

long-lived cells that produce the interstitial ground substance (extracellular matrix) of supporting tissue throughout the body. They are key cellular players in the process of tissue repair. Can differentiate into specialized connective tissue cells (osteocytes, chondrocytes, adipocytes).

Question 3

What do myofibroblasts do?

Answer 3

They are the effector cells of wound contraction.

Question 4

How are scars different from the tissues they replace?

Answer 4

Scars lack the specialized function of tissues they replace and are smaller (resulting in contraction of wound)

Question 5

What are neutrophils?

Answer 5

AKA polymorphonuclear leukocytes (polys, PMNs, segs). They are first responder phagocytes. They are the predominant type of white blood cell type in acute inflammation. They respond to infection and necrosis.

Question 6

What effect will steroids have on neutrophil count in blood?

Answer 6

Neutrophils tend to be marginated in blood vessels, crawling along the lining, not in the central stream. Corticosteroids will cause demargination and the blood count can double.

Question 7

What is a neutrophilia?

Answer 7

Increased number of segmented neutrophils in the blood

Question 8

What color do neutrophils stain?

Answer 8

neutral color. (most other granulocytes are red or blue)

Question 9

Describe the nucleus of a neutrophil.

Answer 9

Generally segmented into 2-5 lobes connected by thin filaments.

Question 10

Neutrophils with more than 6 lobed nuclei are considered hypersegmented. What are they associated with?

Answer 10

Hypersegmented neutorphils are associated with megaloblastic anemia due to vitamin B12 or folate deficiency

Question 11

What are bands?

Answer 11

Immature neutrophils. They are much more common in the bone marrow where blood is manufactured. Not fully matured but capable of phagocytosis. Bands are included in total neutrophil count.

Question 12

What is bandemia? Can corticosteroids cause this?

Answer 12

during severe infection, bone marrow will release large quantities of bands into the blood to fight the infection. The release of many immature neutrophils is called a “left shift”.
Corticosteroids can not cause bandemia or left shift

Question 13

What are macrophages?

Answer 13

phagocytes derived from blood monocytes. They arrive at sites of inflammation later than neutrophils, but are the dominant cellular players in chronic inflammation. They phagocytose invading antigens and secrete IL-1, Il12, IL-23 and chemokines once they have ingested them. They can also stimulate growth, tissue repair, and fibrosis. They are large cells with oval nuclei that are never segmented.

Question 14

What do M1 macrophages do?

Answer 14

Phagocytose bacteria and antigens and then release IL-1, IL-12, IL-23 and chemokines to summon and direct other inflammatory cells. They are pro-inflammatory.

Question 15

What are M2 macrophages?

Answer 15

These secrete transforming fowth factor-beta and other growth factors that stimulate tissue repair and fibrosis. They are anti-inflammatory

Question 16

What color would you expect the cytoplasm of macrophages to stain?

Answer 16

Depends on what they have ingested recently. Those that have been at a hemmorrhage have brown cytoplasm from hemosiderin. Macrophages in a pneumonia and in arterial atheromas have bubbly cytoplasm cleared of lipid debris (foam cells).

Question 17

What are lymphocytes?

Answer 17

fundamentl cellular players in the adaptive immune system. Produce B and T cels.

Question 18

Which type of T cell are cytotoxic cells?

Answer 18

CD8

Question 19

Which type of T cells are helper cells?

Answer 19

CD4

Question 20

What are plasma cells? What are they derived from?

Answer 20

Plasma cells are cells that produce large amounts of single-specificity antibody in adaptive humoral immune responses. They are derived from activated B cells. They have nuclear chromatin clumped around the periphery in a clockface configuration and have prominent Golgi apparatus

Question 21

What are eosinophils?

Answer 21

granulocytic leukocytes found in the inflammation around parasitic infestations and in allergic reactions, especially asthma. They participate most in immune reactions mediated by IgE immunoglobulin. contain major basic protein, which is toxic to both parasites and host cells. They avidly take up eosin (red) dye. Usually have two-lobed nuclei.

Question 22

What should you look for in a patient with peripheral blood eosinophilia?

Answer 22

allergen or parasites

Question 23

What are mast cells?

Answer 23

sparsely distributed bone-marrow-derived sentinel cells around blood vessels, nerves and skin that participate in both acute and chronic inflammation. They have prominent cytoplasmic granules loaded with histamine and other chemotactic factors. They avidly take up blue dye (hematoxylin and basophilic). Have surface receptors for IgE that when activated cause degranulation.

Question 24

What is a basophil?

Answer 24

circulating counterpart of the mast cells.

Question 25

What are multinucleated giant cells?

Answer 25

generally they are a fused group of macrophages.They come in two types: Langhans type and foreign body type.

Question 26

What are Langhans type ginat cells associated with?

Answer 26

Langhans are associated with immune granulomas.

Question 27

What is a granuloma?

Answer 27

an aggregate of activated macrophages working together.