Block III: video 4

Question 1

What are the histological characteristic of mast cell?

Answer 1

1. A large cell with round nucleus
2. Contains large granules in the cytoplasm – which stain with eosin in H&E of plastic embedded tissue
3. Shows metachromatic staining of the granules with toludine blue
4. Contains large dense staining granules in EM

Question 2

identify

Answer 2

Mast cells stained with H&E in plastic embedded sections

Question 3

identify

Answer 3

Mast cells stained with H&E in plastic embedded sections

Question 4

identify

Answer 4

Light micrograph of mast cell
stained with toluidine blue

Question 5

identify

Answer 5

EM of mast cell

Question 6

Where is mast cell prominent?

Answer 6

immune system

Question 7

What are the types of immunological reactions of mast cells?

Answer 7

1. Hypersensitivity reactions in which the immune system activation over-reacts often resulting in immune system action which may be
   detrimental to the body (This can be either humoral immediate hypersensitivity reactions within minutes or delayed cytotoxic reactions)
2. Adaptive immune system: this normally requires a longer time for
   response and requires the synthesis of immunoglobulin antibodies or the production of cytotoxic t-lymphocytes

Question 8

What is Type I hypersensitivity?

Answer 8

Mast cells may be involved in Type I hypersensitivity reactions which
depend upon the binding of immunoglobulin E (IgE) to the plasma
membrane of the cell prior to the hypersensitivity reaction

Question 9

What are some functions of the mast cell?

Answer 9

1. function involves pharmacological actions of the substances released from its granules, cytoplasm, and membranes.
2. involved in immediate hypersensitivity Type I immune reactions

Question 10

What does the granules in mast cells contain?

Answer 10

1. histamine
2. eosinophile chemotactic factor
3. neutrophil chemotactic factor
4. neutral proteases
5. heparin

Question 11

What does histamine do?

Answer 11

potent vasodialator and causes
contraction of smooth muscle in airways (edema)

Question 12

What does eosinophile chemotactic factor do?

Answer 12

attracts eosinophils into area as part of the inflammatory process

Question 13

What does neutrophil chemotactic factor do?

Answer 13

attracts neutrophils into area

Question 14

What does neutral proteases do?

Answer 14

(serine proteases) = generate
angiotensin II in response to vascular tissue injury and may induce apoptosis in damaged vascular
smooth muscle cells (tryptase and Chymase)

Question 15

what does heparin do?

Answer 15

may act to condense the contents; interacts with platelets (highly negative)

Question 16

By what does the degranulation of the mast cell happen?

Answer 16

is brought about typically by binding of antigen to IgE molecules which are bound to the surface of the mast cell. Can also involve complement related binding

Question 17

WHat happens in response to 1st contact with allergen?

Answer 17

the immune system will produce large amounts of IgE which will become bound to the surface of
the mast cell (and basophil)

Question 18

WHat happens in response to 2nd exposure to the allergen?

Answer 18

crosslinking of as few as 2 of the IgE molecules on the surface can lead to degranulation of the cell and release of the contents of the granules

Question 19

identify

Answer 19

EM of mast cell undergoing degranulation

Question 20

WHat other stuff does the mast cell release?

Answer 20

additional secondary mediators including prostaglandin D2, bradykinins, thromboxin A2 and leukotrienes from membrane lipid as
important mediators of vasodialation, vasoconstriction, and bronchiospams

Question 21

What are leukotrienes?

Answer 21

(similar action to histamine, but slower action) are also released from
the plasma membrane upon degranulation causing bronchospasms.

Leukotrienes are resistant to antihistamines and thus anti-histamine therapy will not entirely
relieve allergenic responses

Question 22

What are some CC involving mast cell degranulation?

Answer 22

1. hay fever
2. asthma
3. anaphylactic shock

Question 23

What is hay fever?

Answer 23

edema of nasal mucosa due to release of histamine

Question 24

What is asthma?

Answer 24

bronchiospasms due to leukotriene and histamine effects on smooth muscle in lungs

Question 25

What is anaphylactic shock?

Answer 25

results from a large loss of fluids from vascular system due to effects of histamine and leukotrienes leading to vascular collapse. Effects occur in 1 -3 minutes after contact with allergen. Immediate treatment with vasoconstrictors like epinephrine is required or death can occur

Question 26

What are some histological characteristics of macrophage?

Answer 26

1. large cell with lightly basophilic cytoplasm 2. plasma membrane highly folded with numerous projections 3. nucleus often indented or kidney shaped 4. numerous lysosomes

Question 27

When is the macrophage most easily recognized?

Answer 27

when has phagocytosed debris

Question 28

Where is macrophage derived from?

Answer 28

derived from monocytes in blood that enter CT

Question 29

WHat is the macrophage member or?

Answer 29

mononuclear phagocyte system

Question 30

identify

Answer 30

EM of macrophage

Question 31

identify

Answer 31

lung, alveolar macrophage

Question 32

identify

Answer 32

Macrophages (black) filled with phagocytosed dye

Question 33

What are some functions of the macrophage?

Answer 33

1. phagocytosis of microbes, particulate material, and antigen-antibody complexes. 2. secretion of a variety of immunologically important molecules including interleukin I (lymphocyte mitogenic factor) and interferon (antiviral)

Question 34

What do macrophages have on their plasma membrane?

Answer 34

major histocompatibility complex II.

Question 35

What is major histocompatibility complex II?

Answer 35

Antigenic fragments from the phagocytosed structures such as bacteria broken down by the macrophage become bound to the major histocompatibility complex II which is transported to the plasma membrane where the antigenic fragments can be presented to lymphocytes to trigger immune reactions

Question 36

What are the two types of macrophages and their fucntions?

Answer 36

1. Classically activated macrophages (M1 macrophages), occur early in the inflammatory process and have the capacity, through the production of nitric oxide (NO) and other intermediates, to destroy microorganisms at the site of inflammation. 2. Alternatively activated macrophages (M2 macrophages)- Occur later in areas of inflammation and in general are anti-inflammatory and work toward resolution of inflammation and promote rebuilding of extra-cellular matrix, cell proliferation, and angiogenesis. (repair)

Question 37

What are foreign body giant cells?

Answer 37

When stimulated macrophages may fuse to give giant multinucleated cells known as foreign body giant cells in order to either surround and wall-off large foreign objects or to phagocytose large particles. These foreign body giant cells allow macrophages to wall-off from the body clusters of bacteria or parasites that can not be handled by a single macrophage. In this process the macrophages can form large masses of cells known as granulomas In addition, these foreign body giant cells can be clinically important at the surface of biopolymer implants , stents, pins and other surgical implants where they may attempt to destroy the implants

Question 38

What is Matrix metalloproteinases?

Answer 38

family of proteins known as the matrix metalloproteinases (MMPs) which are zinc-associated proteinases.They are particularly prominent in their ability to degrade collagen. play an important role of remodeling of connective tissue both under normal and pathological conditions. In addition, expression of the metalloproteinases has been linked to the ability of cancer cells such as endometrial cancer cells to metastasize.

Question 39

What are plasma cells derived from?

Answer 39

antigenically stimulated B-lymphocytes

Question 40

How is the pattern of plasma cells called?

Answer 40

round nucleus with clockface chromatin pattern; due to heterochromatin

Question 41

What organelle is visible adjacent in plasma cells?

Answer 41

juxta-nuclear Golgi - negative staining in LM

Question 42

how is the staining in plasma cells?

Answer 42

basophilic translucent (nongranular) cytoplasm

Question 43

WHat is the function of plasma cells?

Answer 43

Is the synthesis of antibodies (immunoglobulins)

Question 44

identify

Answer 44

Plasma cells (arrows) in lamina propria of intestine; negative golgi can be seen

Question 45

identify

Answer 45

EM of plasma cell

Question 46

What is reticular CT?

Answer 46

specialized connective tissue of lymphoid and blood-forming (hemopoietic) organs such as bone marrow, spleen, tonsils, lymph nodes

Question 47

by what are reticular fibers formed?

Answer 47

in reticular CT made by a specialized cell called a reticular cell

Question 48

How is the gorund substance in reticular CT?

Answer 48

ground substance = blood plasma or lymph. NO GAGS

Question 49

What is the function of reticular CT?

Answer 49

Provides a CT supporting stroma that allows easy movement of fluid and cells through organ

Question 50

How deos cell in reticular CT aid?

Answer 50

cell wraps around fibers and maintains them; similar to fibroblast