From Canvas (Lymph Anatomy Vocabulary) - Unit 7: Blood and the Lymphatic System

Immunology

The medical specialty that studies the anatomy and physiology of the lymphatic system, utilizing diagnostic tests, medical and surgical procedures, and drugs to treat lymphatic and immune response diseases.

Lymph

A clear, colorless, alkaline fluid that is composed of about 95% water along with proteins, salts, and organic substances. It originates from blood and tissue fluid and moves through the lymphatic vessels to maintain fluid balance and transport immune cells.

Lymphatic System

A vital subsystem of the immune response that produces antibodies and lymphocytes, maintains internal fluid balance, and comprises the bone marrow, thymus, lymphoid tissues, lymph nodes, spleen, and lymphatic vessels.

Lymph Capillaries

The smallest lymphatic vessels that originate in tissue spaces as blind-ended sacs to retrieve accumulated interstitial fluid filtered from capillary blood, preventing tissue swelling or edema.

Lymph Vessels

Vessels originating in intercellular spaces that transport lymph in only one direction (away from tissues toward the thoracic cavity). They feature internal valves to prevent backflow and continuously merge into larger vessels until they reach the lymphatic ducts.

Lymphatic Ducts

The only points of entry where lymph re-enters the body's blood vessels, consisting of the right lymphatic duct (drains the right side of the head, neck, chest, and right upper extremity into the right subclavian vein) and the thoracic duct (drains the remaining regions of the body into the left subclavian vein).

Lymph Nodes

Collections of lymphatic tissue located at intervals along lymphatic vessels (500 to 600 in total) that house B cells, T cells, and macrophages. They filter out dead cells or bacteria, perform phagocytosis, produce antibodies, and are heavily utilized in cancer staging and prognosis.

Thymus

A lymphatic gland located in the mediastinum beneath the sternum that secretes the hormone thymosin, which directs red bone marrow to produce T cells. It serves as the maturation site for aggressive T lymphocytes, performing its primary work during childhood and shrinking as the body ages.

Spleen

The largest lymphatic organ, located in the Left Upper Quadrant (LUQ) of the abdomen below the diaphragm and behind the stomach. It filters blood via macrophage phagocytosis to remove pathogens and old red blood cells (converting them to bile), and stores whole blood in its venous sinuses for release during hemorrhagic emergencies.

Splenectomy

The surgical removal of the spleen, an operation after which an individual can survive because other lymphoid tissues and the liver assume its filtration duties.

Tonsils

Masses of lymphatic tissue divided into the adenoids, palatine tonsils, and lingual tonsils that form a protective ring under the mucous membrane of the mouth and throat to serve as a first line of defense against inhaled or ingested pathogens.

Bone Marrow

The soft, blood-forming tissue filling bone cavities that contains fat alongside mature and immature cells; its red bone marrow produces stem cells (hemocytoblasts) that differentiate into red blood cells, platelets, or five distinct types of white blood cells.

Immune System

The collective framework of natural body defenses—including intact skin, cleansing secretions, white blood cells, body chemicals, and antibodies—and organs (bone marrow, thymus, lymphoid tissues, lymph nodes, spleen, and lymphatic vessels) that fight off disease and cancer.

Immunity

The body's developed or inherited capability to defend itself against specific foreign agents, pathogens, or diseases.

Natural Immunity

The innate, genetic form of immunity with which an individual is born, providing immediate baseline protection.

Acquired Immunity

The defense capability a body develops against a specific agent, which can occur naturally from contracting and surviving a disease, or artificially through clinical interventions.

Passive Acquired Immunity

A short-lived form of immunity lasting only a few weeks, achieved artificially by injecting pre-formed antibodies (such as gamma globulin given after exposure to measles or hepatitis) directly into a person's body.

Active Acquired Immunity

A long-lasting form of protection acquired either naturally by surviving an active infection or artificially through being inoculated with a vaccine, antigen, or toxoid.

Immunization

The clinical process of creating artificial active immunity within an individual against a specific disease.

Immune Reaction

The collective defense mechanism of the body that triggers an immune response, producing targeted antibodies to destroy invading foreign antigens and malignant cells.

Humoral Immune Response

An immune reaction that takes place when B lymphocytes interact with specific invading antigens and respond by producing specialized protective antibodies known as immunoglobulins.

Cell-Mediated Immune Response

An immune reaction that occurs when T lymphocytes encounter specific invading antigens, multiplying rapidly to directly engulf and digest the invader while producing long-lasting memory cells for future resistance.