Vocabulary & Check Your Knowledge

Lymphatic System and Immune System Vocabulary

Active immunity

Immunity developed from an individual’s own immune system.

Acute inflammation

Inflammation occurring for a limited time period; rapidly developing.

Adaptive immune response

Relatively slow but very specific and effective immune response controlled by lymphocytes.

Afferent lymphatic vessels

Lead into a lymph node.

Allergens

Antigens that evoke type 1 hypersensitivity (allergy) responses.

Anaphylactic Shock

Also called anaphylaxis. An inhaled, ingested or injected (bee sting) allergen causes a significant drop in blood pressure along with contractions of smooth muscles of the airways.

Antibody

Antigen-specific protein secreted by plasma cells, immunoglobulin.

Antigen

Molecule recognized by the receptors of b and t lymphocytes.

Apoptosis

Programmed cell death.

B cells

Lymphocytes that act by differentiating into an antibody-secreting plasma cell.

Barrier defenses

Antipathogen defenses deriving from a barrier that physically prevents pathogens from entering the body to establish an infection.

Bone marrow

Tissue found inside bones, the site of all blood cell differentiation and maturation of b lymphocytes.

Bronchus-associated lymphoid tissue (balt)

Lymphoid nodule associated with the respiratory tract.

CD4 T Cells

CD4 is the receptor that HIV uses to get inside T cells and reproduce. CD4+ helper T cells play an important role in T cell immune responses and antibody responses.

Chemokine

Soluble, long-range, cell-to-cell communication molecule.

Chemotaxis

Movement in response to chemicals; a phenomenon in which injured or infected cells and nearby leukocytes emit the equivalent of a chemical “911” call, attracting more leukocytes to the site.

Chronic inflammation

Inflammation occurring for long periods of time.

Chyle

Lipid-rich lymph inside the lymphatic capillaries of the small intestine.

Cisterna chyli

Bag-like vessel that forms the beginning of the thoracic duct.

Complement

Enzymatic cascade of constitutive blood proteins that have antipathogen effects, including the direct killing of bacteria.

Crypts

Histologically, tonsils do not contain a complete capsule, and the epithelial layer invaginates deeply into the interior of the tonsil to form tonsillar crypts.

Cytokine

Soluble, short-range, cell-to-cell communication molecule.

Deep Lymphatic Vessels

Lymphatic vessels of the organs.

Efferent lymphatic vessels

Lead out of a lymph node.

Erythroblastosis fetalis

Disease of rh factor-positive newborns in rh-negative mothers with multiple rh-positive children; resulting from the action of maternal antibodies against fetal blood.

Genetic mutation that affects both t cell and b cell arms of the immune response.

Genetic Recombination

The combining of gene segments from two different pathogens.

Graft-versus-host disease

In bone marrow transplants, occurs when the transplanted cells mount an immune response against the recipient.

Histamine

Vasoactive mediator in granules of mast cells and is the primary cause of allergies and anaphylactic shock.

HIV

Human Immunodeficiency Virus. An infectious disease usually transmitted via blood or sexual fluids. It attacks the immune system and can lead to AIDS.

Hypersensitivities

Reacting to something that would not normally evoke a reaction.

Immune system

Series of barriers, cells, and soluble mediators that combine to response to infections of the body with pathogenic organisms.

Immunity

After an infection, memory cells remain in the body for a long time and can very quickly mount an immune response against the same pathogen if it tries to re-infect. This protects us from getting diseases from the same pathogen over again.

Immunological memory

Ability of the adaptive immune response to mount a stronger and faster immune response upon re-exposure to a pathogen.

Induration

A firm, raised reddened patch of skin.

Inflammation

Basic innate immune response characterized by heat, redness, pain, and swelling.

Innate immune response

Rapid but relatively nonspecific immune response.

Intercellular

Between cells.

Interferons

Early induced proteins made in virally infected cells that cause nearby cells to make antiviral proteins.

Interstitial Fluid

Fluid that has leaked out of blood capillaries into the tissue spaces.

Interstitial

Between cells of the tissues, often used interchangeably with ‘intercellular’.

Interstitial Space

Spaces between individual cells in the tissues.

Intracellular

Inside the cell membrane or within the cell.

Leukemia

A cancer involving an abundance of leukocytes. It may involve only one specific type of leukocyte from either the myeloid line (myelocytic leukemia) or the lymphoid line (lymphocytic leukemia). In chronic leukemia, mature leukocytes accumulate and fail to die. In acute leukemia, there is an overproduction of young, immature leukocytes. In both conditions the cells do not function properly.

Lymph

Fluid contained within the lymphatic system.

Lymph node

One of the bean-shaped organs found associated with the lymphatic vessels.

Lymphatic capillaries

Smallest of the lymphatic vessels and the origin of lymph flow.

Lymphatic system

Network of lymphatic vessels, lymph nodes, and ducts that carries lymph from the tissues and back to the bloodstream.

Lymphatic trunks

Large lymphatics that collect lymph from smaller lymphatic vessels and empties into the blood via lymphatic ducts.

Lymphocytes

White blood cells characterized by a large nucleus and small rim of cytoplasm.

Lymphoid nodules

Unencapsulated patches of lymphoid tissue found throughout the body.

Lymphoma

A form of cancer in which masses of malignant T and/or B lymphocytes collect in lymph nodes, the spleen, the liver, and other tissues. These leukocytes do not function properly, and the patient is vulnerable to infection.

Macrophage

Ameboid phagocyte found in several tissues throughout the body.

Mast cell

Cell found in the skin and the lining of body cells that contains cytoplasmic granules with vasoactive mediators such as histamine.

Memory t cells

Long-lived immune cell reserved for future exposure to an pathogen.

MHC

Major Histocompatibility Complex molecules, also called Human Leukocyte Antigen (HLA) are protein structures found on the outside of cells that help the immune system recognize non-self antigens.

Monocyte

Precursor to macrophages and dendritic cells seen in the blood.

Mucosa-associated lymphoid tissue (malt)

Lymphoid nodule associated with the mucosa.

Mucosal

Mucous membranes line body cavities that open to the outside world, including the respiratory tract, gastrointestinal tract, urinary tract and reproductive tracts.

Naïve lymphocyte

Mature b or t cell that has not yet encountered antigen for the first time.

Natural killer cell (nk)

Cytotoxic lymphocyte of innate immune response.

Neutrophil

Phagocytic white blood cell recruited from the bloodstream to the site of infection via the bloodstream.

Opsonization

An antibody or an antimicrobial protein binds to a pathogen, thereby marking it as a target for phagocytes.

Passive immunity

Transfer of immunity to a pathogen to an individual that lacks immunity to this pathogen usually by the injection of antibodies.

Pathogens

Disease causing agents.

Phagocytosis

Movement of material from the outside to the inside of the cells via vesicles made from invaginations of the plasma membrane.

Plasma cell

Differentiated b cell that is actively secreting antibody.

Primary adaptive response

Immune system’s response to the first exposure to a pathogen.

Primary lymphoid organ

Site where lymphocytes mature and proliferate, red bone marrow and thymus gland.

Right lymphatic duct

Drains lymph fluid from the upper right side of body into the right subclavian vein.

S. aureus

Staphylococcus aureus is a bacterium that is commonly found in minor skin infections, as well as in the nose of some healthy people.

Secondary adaptive response

Immune response observed upon re-exposure to a pathogen, which is stronger and faster than a primary response.

Secondary lymphoid organs

Sites where lymphocytes mount adaptive immune responses, examples include lymph nodes and spleen.

Seroconversion

The reciprocal relationship between virus levels in the blood and antibody levels. As the antibody levels rise, the virus levels decline, and this is a sign that the immune response is being at least partially effective (partially, because in many diseases, seroconversion does not necessarily mean a patient is getting well).

Severe combined immunodeficiency disease (scid)

Genetic mutation that affects both t cell and b cell arms of the immune response.

Spleen

Secondary lymphoid organ that filters pathogens from the blood (white pulp) and removes degenerating or damaged blood cells (red pulp).

Superficial Lymphatics

Lymphatic vessels of the subcutaneous tissues of the skin.

Systemic Lupus Erythematosus

SLE is an autoimmune disease in which the immune system recognizes its own cell antigens as being “non-self” and mounts an immune response against them. As a result, many body tissues and vital organs become chronically inflamed and damaged.

T cell

Lymphocyte that acts by secreting molecules that regulate the immune system or by causing the destruction of foreign cells, viruses, and cancer cells.

Thoracic duct

Large duct that drains lymph from the lower limbs, left thorax, left upper limb, and the left side of the head.

Thymocytes

Lymphocytes that develop into T-cells in the thymus gland.

Thymus

Primary lymphoid organ, where t lymphocytes proliferate and mature.

Tonsils

Lymphoid nodules associated with the nasopharynx.

Tissue typing

The determination of MHC molecules in the tissue to be transplanted to better match the donor to the recipient.

Vaccine

A killed or weakened pathogen or its components that, when administered to a healthy individual, leads to the development of immunological memory (a weakened primary immune response) without causing much in the way of symptoms.

Vasodilation

The smooth muscle layer in the wall of the blood vessel relaxes, allowing the vessel to widen. This decreases blood pressure in the vessel.

Wheal and flare response

A soft, pale swelling at the site surrounded by a red zone.

Attribution

Except where otherwise noted, this chapter is adapted from “Lymphatic and Immune Systems” in Building a Medical Terminology Foundation by Kimberlee Carter and Marie Rutherford, licensed under CC BY 4.0. / A derivative of Betts et al., which can be accessed for free from Anatomy and Physiology (OpenStax). Adaptations: dividing Lymphatic and Immune Systems chapter content into sub-chapters.