Chapter 18 - Section 18.4 - Study Guide - Assess Your Learning Outcomes - Page 705: 3

Here's a breakdown of each type of white blood cell (WBC), including their appearance, relative size and number, functions, and conditions that lead to their increase in a differential WBC count: **1. Neutrophils:** - **Appearance:** Neutrophils have a multi-lobed nucleus and cytoplasm filled with fine granules that stain faintly. - **Relative Size and Number:** Neutrophils are the most abundant WBCs, comprising about 40-70% of the total WBC count. - **Functions:** Neutrophils are phagocytic cells that quickly respond to bacterial infections and tissue damage. They engulf and destroy bacteria and cellular debris, releasing enzymes and antimicrobial substances. - **Increase:** Neutrophil counts increase in bacterial infections, tissue injuries, and inflammatory conditions. **2. Eosinophils:** - **Appearance:** Eosinophils have a bi-lobed nucleus and large, distinctive granules that stain red. - **Relative Size and Number:** Eosinophils make up around 1-6% of the total WBC count. - **Functions:** Eosinophils are involved in responses against parasitic infections and allergic reactions. They modulate inflammation and release granule contents to combat parasites and dampen allergic responses. - **Increase:** Eosinophil counts increase in allergies, parasitic infections, and certain autoimmune diseases. **3. Basophils:** - **Appearance:** Basophils have a multi-lobed nucleus and large, dark-staining granules. - **Relative Size and Number:** Basophils account for about 0.5-1% of the total WBC count. - **Functions:** Basophils release histamine and other mediators from their granules, contributing to allergic reactions and inflammation. - **Increase:** Basophil counts may increase in allergic reactions and some chronic inflammatory disorders. **4. Lymphocytes:** - **Appearance:** Lymphocytes have a large, round nucleus and a small amount of cytoplasm. - **Relative Size and Number:** Lymphocytes constitute approximately 20-40% of the total WBC count. - **Functions:** Lymphocytes are key players in adaptive immunity. T cells coordinate immune responses and directly attack infected or abnormal cells. B cells produce antibodies, and NK cells target virus-infected cells and tumor cells. - **Increase:** Lymphocyte counts increase in viral infections, chronic infections, and some immune disorders. **5. Monocytes:** - **Appearance:** Monocytes have a kidney-shaped nucleus and abundant cytoplasm. - **Relative Size and Number:** Monocytes comprise around 2-10% of the total WBC count. - **Functions:** Monocytes circulate in the bloodstream and can differentiate into macrophages or dendritic cells. Macrophages engulf and digest pathogens and debris, while dendritic cells present antigens to other immune cells. - **Increase:** Monocyte counts increase in chronic infections, inflammatory conditions, and certain immune disorders. It's important to note that a differential WBC count, also known as a white blood cell differential, is a laboratory test that measures the percentage of each type of WBC in the total WBC count. An increase or decrease in the percentage of certain WBC types can provide valuable information about the underlying health condition, infection, or inflammation a person might be experiencing. However, a high or low count of a specific WBC type does not necessarily pinpoint a single diagnosis and should be interpreted in the context of the patient's overall health and other diagnostic information.

Here's a breakdown of each type of white blood cell (WBC), including their appearance, relative size and number, functions, and conditions that lead to their increase in a differential WBC count: **1. Neutrophils:** - **Appearance:** Neutrophils have a multi-lobed nucleus and cytoplasm filled with fine granules that stain faintly. - **Relative Size and Number:** Neutrophils are the most abundant WBCs, comprising about 40-70% of the total WBC count. - **Functions:** Neutrophils are phagocytic cells that quickly respond to bacterial infections and tissue damage. They engulf and destroy bacteria and cellular debris, releasing enzymes and antimicrobial substances. - **Increase:** Neutrophil counts increase in bacterial infections, tissue injuries, and inflammatory conditions. **2. Eosinophils:** - **Appearance:** Eosinophils have a bi-lobed nucleus and large, distinctive granules that stain red. - **Relative Size and Number:** Eosinophils make up around 1-6% of the total WBC count. - **Functions:** Eosinophils are involved in responses against parasitic infections and allergic reactions. They modulate inflammation and release granule contents to combat parasites and dampen allergic responses. - **Increase:** Eosinophil counts increase in allergies, parasitic infections, and certain autoimmune diseases. **3. Basophils:** - **Appearance:** Basophils have a multi-lobed nucleus and large, dark-staining granules. - **Relative Size and Number:** Basophils account for about 0.5-1% of the total WBC count. - **Functions:** Basophils release histamine and other mediators from their granules, contributing to allergic reactions and inflammation. - **Increase:** Basophil counts may increase in allergic reactions and some chronic inflammatory disorders. **4. Lymphocytes:** - **Appearance:** Lymphocytes have a large, round nucleus and a small amount of cytoplasm. - **Relative Size and Number:** Lymphocytes constitute approximately 20-40% of the total WBC count. - **Functions:** Lymphocytes are key players in adaptive immunity. T cells coordinate immune responses and directly attack infected or abnormal cells. B cells produce antibodies, and NK cells target virus-infected cells and tumor cells. - **Increase:** Lymphocyte counts increase in viral infections, chronic infections, and some immune disorders. **5. Monocytes:** - **Appearance:** Monocytes have a kidney-shaped nucleus and abundant cytoplasm. - **Relative Size and Number:** Monocytes comprise around 2-10% of the total WBC count. - **Functions:** Monocytes circulate in the bloodstream and can differentiate into macrophages or dendritic cells. Macrophages engulf and digest pathogens and debris, while dendritic cells present antigens to other immune cells. - **Increase:** Monocyte counts increase in chronic infections, inflammatory conditions, and certain immune disorders. It's important to note that a differential WBC count, also known as a white blood cell differential, is a laboratory test that measures the percentage of each type of WBC in the total WBC count. An increase or decrease in the percentage of certain WBC types can provide valuable information about the underlying health condition, infection, or inflammation a person might be experiencing. However, a high or low count of a specific WBC type does not necessarily pinpoint a single diagnosis and should be interpreted in the context of the patient's overall health and other diagnostic information.