27 Questions
What is the primary function of macrophages in the immune system?
Phagocytosis of foreign particles
What is the average lifespan of monocytes in the blood?
A few days
What is the role of macrophages in antigen presentation?
They present antigens to T cells
What is the name given to the system comprising mononuclear phagocytes and their tissue distribution?
Reticuloendothelial system (RES)
What is the function of dendritic cells in the immune system?
To induce an adaptive immune response
What is the name given to macrophages found in the liver?
Kupffer cells
What is the name given to macrophages found in the central nervous system?
Microglia
What is the function of macrophages in mediating immune responses?
They mediate both innate and adaptive immune responses
What is the shape of monocyte nuclei?
Oval-kidney bean shaped
What is the primary function of effector mechanisms in the immune system?
To destroy harmful agents
Which immune cell type develops from a common precursor stem cell in the bone marrow, but completes its maturation in the thymus?
T cells
What is a characteristic of innate immune responses?
They do not involve memory cells
Which of the following cells is not a type of polymorphonuclear granulocyte?
Mast cells
What is the primary function of natural killer cells?
To destroy infected cells or tumor cells
Which of the following is a type of humoral effector mechanism?
Complement
What is the function of dendritic cells in the immune response?
To present antigens to T cells
Which immune cells develop from a common precursor stem cell in the bone marrow?
All immune cells except T cells
What is the result of inflammation in the immune response?
The presence of inflammation throughout the immune response
What is the primary function of interdigitating dendritic cells in the immune system?
To pick up antigens and transport them to lymph nodes
Where are follicular dendritic cells primarily found?
Restricted to lymphatic tissue
What is a characteristic of neutrophils?
They have a multi-lobed nucleus
What is the function of eosinophils in the immune response?
They are involved in anti-parasitic responses
What is the lifespan of neutrophils in the blood?
10 hours
Which type of dendritic cell is unrelated to mononuclear phagocytic system?
Follicular dendritic cells
What is the function of interdigitating dendritic cells in the immune response?
To mediate adaptive responses
What is a characteristic of granulocytes?
They contain abundant cytoplasmic granules
Which type of cell is highly phagocytic and key in anti-bacterial responses?
Neutrophils
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
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.
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