Monocytes/Macrophages

Question 1

What do monocytes and granulocytes share?

Answer 1

A common progenitor cell GM-CFU

Question 2

What is the normal % of monocytes in the blood?

Answer 2

Between 2-10%

Question 3

What is the reference value for monocytes?

Answer 3

0.2 - 1.0 x10^9/L

Question 4

What are some of the structural characteristics of the monocyte?

Answer 4

Large
Kidney or horse shoe shaped nucleus.
grey blue cytoplasm
large basophilic granules (few)

Question 5

What are the main roles of the monocytes?

Answer 5

Against bacterial and fungal infections.

Question 6

How long do monocytes circulate in the blood before going into the tissues?

Answer 6

8 hours, then they differentiate into tissue macrophages.

Question 7

What do macrophages secrete alongside phagocytosis in the extracellular space?

Answer 7

Cytokines

Hydrolytic acid

Question 8

What can macrophages act as?

Answer 8

Antigen presenting cells (APC)

Question 9

What is the role of the antigen presenting cell?

Answer 9

To stimulate immature T cells to become either mature ‘cytotoxic CD 8+ cells’ or mature helper (CD 4+ cells)

Question 10

What are the 3 functions of the mature tissue macrophage?

Answer 10

• microbe killing
• removal of debris
• immune response (APC)

Question 11

Where can macrophages be found?

Answer 11

In the peripheral blood
Marrow
Spleen
Liver, Kupffer cells
Brain microglia

Question 12

What are some of the typical causes of monocytosis?

Answer 12

• viral infections
• chronic neutropenia
• some haematological malignancies
• GM-CSF malignancies.