Immune System Cells: Mononuclear Phagocytes

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Questions and Answers

What is the primary function of macrophages in the immune system?

Phagocytosis of foreign particles (correct)

Maturation of T cells

Activation of B cells

Production of antibodies

What is the average lifespan of monocytes in the blood?

Several weeks

A few days (correct)

Several months

A few hours

What is the role of macrophages in antigen presentation?

They present antigens to T cells (correct)

They activate B cells

They produce antibodies

They engulf and digest foreign particles

What is the name given to the system comprising mononuclear phagocytes and their tissue distribution?

Reticuloendothelial system (RES) Signup and view all the answers

What is the function of dendritic cells in the immune system?

To induce an adaptive immune response Signup and view all the answers

What is the name given to macrophages found in the liver?

Kupffer cells Signup and view all the answers

What is the name given to macrophages found in the central nervous system?

Microglia Signup and view all the answers

What is the function of macrophages in mediating immune responses?

They mediate both innate and adaptive immune responses Signup and view all the answers

What is the shape of monocyte nuclei?

Oval-kidney bean shaped Signup and view all the answers

What is the primary function of effector mechanisms in the immune system?

To destroy harmful agents Signup and view all the answers

Which immune cell type develops from a common precursor stem cell in the bone marrow, but completes its maturation in the thymus?

T cells Signup and view all the answers

What is a characteristic of innate immune responses?

They do not involve memory cells Signup and view all the answers

Which of the following cells is not a type of polymorphonuclear granulocyte?

Mast cells Signup and view all the answers

What is the primary function of natural killer cells?

To destroy infected cells or tumor cells Signup and view all the answers

Which of the following is a type of humoral effector mechanism?

Complement Signup and view all the answers

What is the function of dendritic cells in the immune response?

To present antigens to T cells Signup and view all the answers

Which immune cells develop from a common precursor stem cell in the bone marrow?

All immune cells except T cells Signup and view all the answers

What is the result of inflammation in the immune response?

The presence of inflammation throughout the immune response Signup and view all the answers

What is the primary function of interdigitating dendritic cells in the immune system?

To pick up antigens and transport them to lymph nodes Signup and view all the answers

Where are follicular dendritic cells primarily found?

Restricted to lymphatic tissue Signup and view all the answers

What is a characteristic of neutrophils?

They have a multi-lobed nucleus Signup and view all the answers

What is the function of eosinophils in the immune response?

They are involved in anti-parasitic responses Signup and view all the answers

What is the lifespan of neutrophils in the blood?

10 hours Signup and view all the answers

Which type of dendritic cell is unrelated to mononuclear phagocytic system?

Follicular dendritic cells Signup and view all the answers

What is the function of interdigitating dendritic cells in the immune response?

To mediate adaptive responses Signup and view all the answers

What is a characteristic of granulocytes?

They contain abundant cytoplasmic granules Signup and view all the answers

Which type of cell is highly phagocytic and key in anti-bacterial responses?

Neutrophils Signup and view all the answers

Study Notes

Mononuclear Phagocytes

Originate in bone marrow (BM) and enter peripheral blood as monocytes
Mature into macrophages (histiocytes) in tissues
0.2 – 0.8 x 10^9/l, 12 – 17 mm diameter, oval – kidney bean shaped nucleus
Monocyte life span in blood = few days, macrophages can live for years in tissues

Functions of Macrophages（mono的長大版）

Phagocytosis of foreign particles吞噬外来颗粒
Production of inflammatory mediators
Antigen presentation to T cells, initiating an adaptive response
Mediate both innate and adaptive responses
in the CNS - microglia
in the liver - Kupffer cells
in the lungs - alveolar macrophages
in the kidney - mesangial cell.

Dendritic Cells

Accessory cells inducing adaptive response
Found in most organs and epidermis of skin

(Interdigitating dendritic cells=Langerhans cells)
Function: pick up antigens, transport to lymph nodes, and present to T cells
Mediate adaptive responses.
Follicular dendritic cells - restricted to lymphatic tissue.
Do not originate in BM.
Unrelated to interdigitating dendritic cells.

Granulocytes

Contain abundant cytoplasmic granules
Include neutrophils, eosinophils, and basophils

Neutrophils (Polymorphonuclear Leukocytes)

Multi-lobed (3 – 5 lobes usually) morphologically diverse nuclei
Most abundant granulocyte (2.5 – 7.5 x 10^9/l)
12 – 15 mm diameter, life span 10 h (blood), days in tissues
Highly phagocytic, key cells in anti-bacterial responses, mediate innate response and support adaptive responses

Eosinophils

Bi-lobed nucleus and acidophilic granules
0.04 – 0.4 x 10^9/l, life span = 2 weeks
Acidic staining granules containing major basic protein
Function primarily in the elimination of infectious agents such as helminth worms.
Mediate hypersensitivity (allergic) reactions – mediate adaptive responses.

Basophils

Basophilic granules.
Dark basic staining granules containing heparin and histamine – stain purple
0.01 – 0.1 x 109/l
Mediate hypersensitivity reactions through release of chemicals such as histamine
Support mast cells in tissues and mediate allergic reactions – mediate adaptive responses

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Description

This quiz covers the characteristics and functions of mononuclear phagocytes, including monocytes and macrophages, which are crucial cells of the immune system. Learn about their origin, development, and lifespan.