(thÃ»r'mÄ«'Én) An electrically charged particle or ion that is emitted by a heated conducting material. The electrons emitted from the cathodes of electron tubes (such as cathode ray tubes) are thermions.
A low white blood cell count (leukopenia) is a decrease in disease-fighting cells (leukocytes) in your blood. Leukopenia is almost always related to a decrease in a certain type of white blood cell (neutrophil). The definition of low white blood cell count varies from one medical practice to another. In general, for adults a count lower than 4,000 white blood cells per microliter of blood is considered a low white blood cell count. For children, that threshold varies with age.
White blood cells are crucial when it comes to your dogâs health. After all, they are the defense team that protects against common illnesses and serious infections. Unfortunately, their numbers arenât always high. A low white blood cell count in dogs, known as neutropenia, can leave your dog susceptible. This article will discuss what causes a low white blood cell count and what you can do about it. First, it helps to understand the makeup of white blood cells and their functions. There are five different types of white blood cells -- neutrophils, eosinophils, basophils, lymphocytes, and monocytes. 1  Neutrophils and eosinophils are released into the bloodstream to destroy bacteria. 2  Researchers arenât entirely clear as to the main purpose of basophils. 3  Lymphocytes are produced in the lymph nodes and spleen.