Monocytes

Information about Monocytes

Monocyte

A monocyte is a leukocyte, part of the human body's immune system that protects against blood-borne pathogens and moves quickly (aprox. 8-12 hours) to sites of infection in the tissues. Monocytes are usually identified in stained smears by their large bilobate nucleus.

Physiology

Monocyte

Monocytes are produced by the bone marrow from haematopoietic stem cell precursors called monoblasts. Monocytes circulate in the bloodstream for about one to three days and then typically move into tissues throughout the body. They constitute between three to eight percent of the leukocytes in the blood. In the tissues monocytes mature into different types of macrophages at different anatomical locations.

Monocytes are responsible for phagocytosis (ingestion) of foreign substances in the body. Monocytes can perform phagocytosis using intermediary (opsonising) proteins such as antibodies or complement that coat the pathogen, as well as by binding to the microbe directly via pattern-recognition receptors that recognize pathogens. Monocytes are also capable of killing infected host cells via antibody, termed antibody-mediated cellular cytotoxicity. Vacuolization may be present in a cell that has recently phagocytized foreign matter.

Monocytes which migrate from the bloodstream to other tissues are called macrophages. Macrophages are responsible for protecting tissues from foreign substances but are also suspected to be the predominant cells involved in triggering atherosclerosis. They are cells that possess a large smooth nucleus, a large area of cytoplasm and many internal vesicles for processing foreign material.

Diagnostic use

A scanning electron microscope (SEM) image of normal circulating human blood. One can see red blood cells, several knobby white blood cells including lymphocytes, a monocyte, a neutrophil, and many small disc-shaped platelets.

A monocyte count is part of a complete blood count and is expressed either as a ratio of monocytes to the total number of white blood cells counted, or by absolute numbers. Both may be useful in determining or refuting a possible diagnosis. Monocytosis is the state of excess monocytes in the peripheral blood. It may be indicative of various disease states. Examples of processes that can increase a monocyte count include:
- chronic inflammation
- stress response
- hyperadrenocorticism
- immune-mediated disease
- pyogranulomatous disease
- necrosis
- red cell regeneration

Dendritic cells

Monocytes can be used to generate dendritic cells in vitro.

External links

• • [ e] Blood
General	Plasma - Hematopoietic stem cells
Lymphoid - WBC	T cells: Cytotoxic CD8⁺, Helper CD4⁺/Regulatory, γδ, Natural Killer T cell B cells: Plasma, Memory Natural killer cells (Lymphokine-activated killer cell)
Myeloid - WBC	Granulocytes (Neutrophil, Eosinophil, Basophil) - Mast cell precursors Dendritic cells (Langerhans cells, Follicular dendritic cells) Monocytes/Macrophages (Histiocytes, Kupffer cells, Langhans giant cells, Microglia, Osteoclasts) Megakaryoblast - Megakaryocyte - Platelets
Myeloid - RBC	Reticulocyte - Normoblast

• • [ e] Immune system / Immunology
Systems	Adaptive immune system vs. Innate immune system • Humoral immune system vs. Cellular immune system • Complement system (Anaphylatoxins)
Antibodies and antigens	Antibody (Monoclonal antibodies, Polyclonal antibodies, Autoantibody) • Allotype • Isotype • Idiotype • Antigen (Superantigen)
Immune cells	White blood cells (T cell, B cell, NK cell, Mast cell, Basophil, Eosinophil) • Phagocyte (Neutrophil, Macrophage, Dendritic cell) • Antigen-presenting cell • Reticuloendothelial system
Immunity vs. tolerance	Immunity • Autoimmunity • Allergy • Tolerance (Central) • Immunodeficiency
Immunogenetics	Somatic hypermutation • V(D)J recombination • Immunoglobulin class switching • MHC / HLA
Other	Cytokines • Inflammation • Opsonin

White blood cells or leukocytes are cells of the immune system which defend the body against both infectious disease and foreign materials. Several different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone
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The human body is the entire physical structure of a human organism. The human body consists of a head, neck, torso, two arms and two legs. The average height of an adult human is about 1.6 m (5 to 6 feet) tall. This size is largely determined by genes.
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immune system is a collection of mechanisms within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own healthy
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A pathogen or infectious agent is a biological agent that causes disease or illness to its host.^[1] The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant.
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Bone marrow (or medulla ossea) is the soft tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells.

Marrow types

There are two types of bone marrow: red marrow (also known as myeloid tissue) and
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Hematopoietic stem cells (HSC) are stem cells which give rise to all the blood cell types including myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells) and lymphoid lineages (T-cells, B-cells, NK-cells).
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Monoblasts are normally found in bone marrow and do not appear in the normal peripheral blood. They mature into monocytes which in turn develop into macrophages.

Structure

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Macrophages (Greek: "big eaters", from makros "large" + phagein "eat") are cells within the tissues that originate from specific white blood cells called monocytes.
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Phagocytosis is the cellular process of engulfing solid particles by the cell membrane to form an internal phagosome, or "food vacuole." The phagosome is usually delivered to the lysosome, an organelle involved in the breakdown of cellular components, which fuses with the
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An opsonin is any molecule that acts as a binding enhancer for the process of phagocytosis, for example, by coating the negatively-charged molecules on the membrane.

Mechanism

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Antibodies (also known as immunoglobulins) are proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses.
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complement system is a biochemical cascade which helps clear pathogens from an organism. It is one part of the larger immune system.

The complement system consists of a number of small proteins found in the blood, normally circulating as inactive zymogens.
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vacuole (11) cytoplasm (12) lysosome (13) centrioles]] Vacuoles are found in the cytoplasm of most plant cells. Vacuoles are membrane-bound compartments within some eukaryotic cells that can serve a variety of secretory, excretory, and storage functions.
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Atherosclerosis
Classification & external resources

Changes in endothelial dysfunction in atherosclerosis (note text comments about geometry error)
ICD-10 I 70.
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Vesicle may refer to

Vesicle (biology), a relatively small and enclosed compartment within a cell
Vesicular texture, a small enclosed cavity found in some volcanic rock, such as basalt

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complete blood count (CBC), also known as full blood count (FBC) or full blood exam (FBE) or blood panel, is a test requested by a doctor or other medical professional that gives information about the cells in a patient's blood.
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Monocytosis is an increase in the number of circulating monocytes. In humans, 950/μL is regarded as at the upper limit of normal; monocyte counts above this level are regarded as monocytosis.

Monocytosis often occurs during chronic inflammation.
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Chronic inflammation (also known as chronic systemic inflammation) is an inflammatory immune response of prolonged duration that eventually leads to tissue damage. Chronic inflammation is differentiated from acute inflammation by extended duration, lasting anywhere from a
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Please help recruit one or [ improve this article] yourself. See the talk page for details.
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Cushing's syndrome
Classification & external resources

Cortisol
ICD-10 E 24.
ICD-9 255.0

DiseasesDB 3242
MedlinePlus 000410
eMedicine med/485
MeSH D003480

Cushing's syndrome (also called hypercortisolism
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Immune-mediated diseases are conditions which result from abnormal activity of the body's immune system. The immune system may over-react (for example, immune-mediated contact dermatitis) or start attacking the body (for example, autoimmune hemolytic anemia).
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Necrosis (in Greek Νεκρός = Dead) is the name given to accidental death of cells and living tissue. Necrosis is less orderly than apoptosis, which is part of programmed cell death.
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Red blood cells are the most common type of blood cell and the vertebrate body's principal means of delivering oxygen from the lungs or gills to body tissues via the blood.
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Dendritic cells (DCs) are immune cells and form part of the mammalian immune system. Their main function is to process antigen material and present it on the surface to other cells of the immune system, thus functioning as antigen-presenting cells.
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Agranulocytes are a category of white blood cells characterised by the absence of granules in their cytoplasm.

There are two types of agranulocytes:

Lymphocytes
Monocytes.

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Haematopoiesis (from Ancient Greek: haima blood; poiesis to make) (or hematopoiesis in the United States; sometimes also haemopoiesis or hemopoiesis) is the formation of blood cellular components.
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Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of white blood cells and form an integral part of the immune system. Their name arrives from staining characteristics on hematoxylin and eosin (H&E) histological preparations.
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A phagocyte is a cell that ingests and destroys foreign matter such as microorganisms or debris by a process known as phagocytosis.

Types of Phagocytes

There are three main categories of phagocytes: ^[1]

macrophages (and monocytes)

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Monocytes

Information about Monocytes

Physiology

Diagnostic use

Dendritic cells

See also

External links

Marrow types

Structure

Mechanism

Types of Phagocytes