Health professionals have identified three main categories of white blood cell: granulocytes, lymphocytes, and monocytes. The sections below discuss these in more detail. Granulocytes are white blood cells that have small granules containing proteins. There are three types of granulocyte cells:. These are present when the body fights off chronic infections.
According to an article in American Family Physician , the normal range per cubic millimeter of white blood cells based on age are:. Doctors may continually monitor white blood cells to determine if the body is mounting an immune response to an infection. During a physical examination, a doctor may perform a white blood cell count WBC using a blood test. They may order a WBC to test for, or rule out, other conditions that may affect white blood cells.
Although a blood sample is the most common approach to testing for white blood cells, a doctor can also test other body fluids, such as cerebrospinal fluid, for the presence of white blood cells.
The following are conditions that may impact how many white blood cells a person has in their body. Leukemia is a type of cancer that affects the blood and bone marrow. Leukemia occurs when white blood cells rapidly produce and are not able to fight infections. Dendritic cells are known as the most efficient antigen-presenting cell type with the ability to interact with T cells and initiate an immune response.
Dendritic cells are receiving increasing scientific and clinical interest due to their key role in the immune response and potential use with tumor vaccines. There are different types of white blood cells that are part of the immune response. Neutrophils or granulocytes are the most common immune cells in the body. With an infection, their number increases rapidly. They are the major components of pus and are found around most common inflammations. Their job is to eat and destroy foreign material.
Basophils and eosinophils are white blood cells that contain large granules inside the cell. In developing embryos, blood formation occurs in aggregates of blood cells in the yolk sac called blood islands.
However, most of blood supply comes from the mother through the placenta. As development progresses, blood formation occurs primarily in the spleen, liver, and lymph nodes. When bone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism. However, maturation, activation, and some proliferation of lymphoid cells occurs in lymphoid organs spleen, thymus, and lymph nodes.
In children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum. In some cases, the liver, thymus, and spleen may resume their haematopoietic function if necessary. This is called extramedullary haematopoiesis. It may cause these organs to hypertrophy and increase in size substantially. During fetal development, the liver functions as the main haematopoetic organ since bones and marrow develop later.
Therefore, the liver is enlarged during development relative to its mature proportions. Privacy Policy. Skip to main content. Cardiovascular System: Blood. Search for:. White Blood Cells. Types of WBCs The different types of white blood cells leukocytes include neutrophils, basophils, eosinophils, lymphocytes, monocytes, and macrophages. Learning Objectives Distinguish between the two major types of leukocytes white blood cells : granulocytes and agranulocytes.
Key Takeaways Key Points The two main types of leukocytes are granulocytes and mononuclear leukocytes agranulocytes. Leukocytes arise from hemopoietic stem cells in the bone marrow.
Leukocytes are involved in pathogen recognition, phagocytosis ingestion of particles , pathogen destruction, inflammation mediation, and antigen presentation. Granulocytes include neutrophils, basophils, eosinophils, and mast cells. This condition causes abnormal production of blood cells.
This includes white blood cells in the bone marrow. Cancer of the blood. Cancers including leukemia and lymphoma can cause uncontrolled growth of an abnormal type of blood cell in the bone marrow. This results in a greatly increased risk for infection or serious bleeding. Myeloproliferative disorder. This disorder refers to various conditions that trigger the excessive production of immature blood cells.
This can result in an unhealthy balance of all types of blood cells in the bone marrow and too many or too few white blood cells in the blood. Some medicines can raise or lower the body's white blood cell count. Conditions such as extreme physical stress caused by an injury or emotional stress can also trigger high white blood cell levels.
So can inflammation, labor or the end of pregnancy, smoking, or even extreme exercise.
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