Blood Cells and Their Functions

Containing histamine and heparin, these granules are important for the basophil's role in allergic reactions.

Containing lysosomal enzymes, these smaller granules help the basophil break down cellular debris.

Basophils are responsible for releasing histamine and heparin during allergic reactions, contributing to inflammation and blood vessel dilation.

These are the first responders to infection, engulfing and destroying invading microorganisms.

These cells play a crucial role in fighting parasites and regulating allergic reactions.

Promyelocytes are immature cells that produce azurophilic granules, marking the beginning of granulocyte development.

Myelocytes begin producing specific granules alongside azurophilic granules, defining the type of granulocyte.

Metamyelocytes are characterized by an abundance of specific granules, reflecting the cell's nearly mature form.

Immature neutrophils with a band-shaped nucleus, typically representing 0-3% of blood cells. Their percentage increases during acute infections.

Mature granulocytes have a segmented nucleus, unique to each type of granulocyte.

Monocytes are named for their single, non-segmented nucleus. They make up 3-8% of leukocytes.

Monocytes are the largest leukocytes and have a large, eccentric, kidney-shaped or horseshoe-shaped nucleus. Their cytoplasm is abundant, pale basophilic, and finely granular.

Monocytes have an irregular outline due to extensions called pseudopodia. These extensions aid in their motility and phagocytosis.

Monocytes contain small, dense granules called azurophilic granules, which contain lysosomal hydrolytic enzymes. These enzymes help break down engulfed material.

Monocytes circulate in the blood and then migrate to tissues, differentiating into specific phagocytic cells that form the mononuclear phagocytic system.

Monocytes can process and present antigens to T lymphocytes, making them important for the immune response.

These cells differentiate from the same precursors as T and B cells, but lack their surface markers. They play a crucial role in killing virally infected cells and malignant cells, thus contributing to the body's defense against infections and cancer.

Located in the superior mediastinum, it is a primary lymphoid organ responsible for T cell development and maturation, mainly during childhood. Its activity declines with age, replaced by adipose tissue.

These cells support the developing T lymphocytes within the thymus, forming a network called the cytoreticulum. They provide essential structural support and contribute to T cell maturation.

This region of the thymus is densely packed with developing T lymphocytes, epithelial reticular cells, and macrophages, giving it a dark appearance.

This region of the thymus is lighter in color due to the presence of Hassall's corpuscles, which are clusters of epithelial reticular cells. Mature T cells are found in this area.

These are the sites where lymphocytes undergo development and maturation, preparing them to perform their immune functions.

These are the sites where lymphocytes encounter antigens and mount an immune response.

This structure, found in the abdomen, is a secondary lymphoid organ responsible for filtering blood and removing old or damaged red blood cells. It also houses lymphocytes that mount immune responses against blood-borne antigens.

The region of the spleen where circulating T and B lymphocytes enter to find their specific location.

The first point of contact for blood-borne antigens entering the spleen's tissue.

A region within the white pulp of the spleen containing a central artery surrounded by a sheath of lymphocytes.

A collection of B lymphocytes in the white pulp of the spleen, forming a spherical structure.

The part of the spleen responsible for filtering blood and removing old or damaged red blood cells.

These are the structural components of the red pulp composed of reticular cells and fibers.

These are blood-filled spaces within the red pulp where blood cells flow and are filtered.

They are specialized antigen-presenting cells found in the white pulp of the spleen. They help initiate immune responses by presenting antigens to T lymphocytes.

A ring of lymphoid tissue located at the back of the mouth, within the oropharynx, protecting against inhaled and ingested pathogens.

Found on the back of the tongue, these tonsils also play a role in immune defense.

A single tonsil found in the nasopharynx, the uppermost part of the throat, it protects the respiratory tract from infection.

Located near the opening of the Eustachian tube connects the middle ear to the back of the throat. They help prevent ear infections.

These are invaginations on the surface of the palatine tonsils, allowing for the trapping and presentation of pathogens to immune cells.

Similar to the crypts on the palatine tonsils, these pockets on the lingual tonsils also help trap pathogens.

This type of epithelium lines the pharyngeal tonsil, characterized by its numerous cilia that help move mucus and trapped pathogens.

This type of epithelium lines the palatine tonsils, forming a tough, protective barrier over the tonsil surface.

A ring of lymphatic tissue located in the pharynx, consisting of tonsils that protect against infection.

The two tonsils located on the lateral walls of the oropharynx.

The single tonsil found on the posterior surface of the tongue.

The single tonsil located in the posterosuperior portion of the pharynx (nasopharynx).

Two small tonsils located around the opening of the Eustachian tube in the lateral wall of the nasopharynx.

An abnormal increase in the number of red blood cells (RBCs) in the blood.

A deficiency in the number of red blood cells (RBCs) in the blood.

A condition where red blood cells (RBCs) are abnormally small.