Lymphatic and Immune system

Lymph

Fluid that circulates through lymphatic vessels, containing water, proteins, and immune cells.

Lymphatic Vessels (Lymphatics)

Vessels that carry lymph from tissues to the bloodstream.

Lymph Node

Small bean-shaped structures that filter lymph and house immune cells.

Spleen

An organ that filters blood, removes old red blood cells, and supports the immune system.

Thymus

An organ where T lymphocytes (T cells) mature and become immunocompetent.

Tonsils

Lymphoid tissues in the throat that trap pathogens entering through mouth or nose.

Peyer's Patches

Lymphoid tissues in the small intestine that monitor intestinal bacteria and prevent pathogen growth.

Interstitial Fluid

Fluid that surrounds tissue cells and delivers nutrients and oxygen.

Edema

Swelling caused by excess fluid in tissues.

Pathogen

A microorganism that can cause disease.

First Line of Defense (Skin

Mucous Membranes),Physical and chemical barriers that prevent pathogens from entering the body.

Second Line of Defense

Immune responses such as inflammation, phagocytosis, and fever after pathogens enter the body.

Phagocyte

Cells that engulf and digest pathogens and cell debris.

Phagocytosis

The process by which phagocytes engulf and digest microorganisms or particles.

Macrophage

A large phagocyte that engulfs pathogens, dead cells, and signals the immune system.

Neutrophil

A white blood cell that rapidly responds to infections and performs phagocytosis.

Natural Killer (NK) Cells

Lymphocytes that attack virus-infected and tumor cells without prior exposure.

Inflammation

A localized response to injury or infection causing redness, heat, swelling, and pain.

Fever

An elevated body temperature that enhances immune responses and inhibits pathogen growth.

Antimicrobial Proteins

Proteins that attack pathogens or interfere with their reproduction.

Interferons

Proteins released by virus-infected cells that signal nearby cells to resist viral infection.

Complement Proteins

Proteins in the blood that assist antibodies in destroying pathogens.

Adaptive (Specific) Immunity

Immune response that targets specific pathogens and retains memory for future exposure.

Antigen

A substance that triggers an immune response and is recognized by antibodies or T cells.

Antibody (Immunoglobulin - Ig)

A protein produced by B cells that binds to a specific antigen to neutralize or mark it for destruction.

B Lymphocyte (B Cell)

A white blood cell that produces antibodies as part of humoral immunity.

T Lymphocyte (T Cell)

A white blood cell that performs cellular immune responses including killing infected cells or helping other immune cells.

Plasma Cell

A mature B cell that produces large amounts of antibodies.

Memory B Cell

A B cell that remembers a specific antigen and responds rapidly upon future exposure.

Helper T Cell

A T cell that activates B cells, cytotoxic T cells, and other immune cells.

Cytotoxic T Cell

A T cell that kills virus-infected or cancerous cells.

Memory T Cell

A T cell that remembers antigens and mounts a faster response on re-exposure.

Immunological Memory

The ability of the immune system to respond more rapidly and effectively to a previously encountered antigen.