Question

Help us to stay healthy and protect us from diseases​

Answer 1

Answer:

WHITE BLOOD CELL (WBC)

Explanation:

Answer 2

White blood cells

White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system.[1]

White blood cell

SEM blood cells.jpg

A scanning electron microscope image of normal circulating human blood. In addition to the irregularly shaped leukocytes, both red blood cells and many small disc-shaped platelets are visible.

Details

System

Immune system

Identifiers

Acronym(s)

WBC

MeSH

D007962

TH

H2.00.04.1.02001

FMA

62852

Anatomical terms of microanatomy

[edit on Wikidata]

All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets. The different white blood cell types are classified in standard ways; two pairs of broadest categories classify them either by structure (granulocytes or agranulocytes) or by cell lineage (myeloid cells or lymphoid cells). These broadest categories can be further divided into the five main types: neutrophils, eosinophils (acidophiles), basophils, lymphocytes, and monocytes.[2] These types are distinguished by their physical and functional characteristics. Monocytes and neutrophils are phagocytic. Further subtypes can be classified; for example, among lymphocytes, there are B cells (named from bursa or bone marrow cells), T cells (named from thymus cells), and natural killer cells.

The number of leukocytes in the blood is often an indicator of disease, and thus the white blood cell count is an important subset of the complete blood count. The normal white cell count is usually between 4 × 109/L and 1.1 × 1010/L. In the US, this is usually expressed as 4,000 to 11,000 white blood cells per microliter of blood.[3] White blood cells make up approximately 1% of the total blood volume in a healthy adult,[4] making them substantially less numerous than the red blood cells at 40% to 45%. However, this 1% of the blood makes a large difference to health, because immunity depends on it. An increase in the number of leukocytes over the upper limits is called leukocytosis. It is normal when it is part of healthy immune responses, which happen frequently. It is occasionally abnormal, when it is neoplastic or autoimmune in origin. A decrease below the lower limit is called leukopenia. This indicates a weakened immune system.