Unit 12 Lymphatic System Vocab

B lymphocytes (B cells)

lymphocytes that mature in the bone marrow before moving out to the blood and the rest of the body; also called B cells

interstitial fluid

fluid in the spaces between cells

lymph

clear, transparent, sometimes faintly yellow fluid that is collected from tissues throughout the body and flows in the lymphatic vessels

lymph nodes

small, bean-shaped structures found along the lymphatic vessels throughout the body

macrophages

cells that phagocytize (surround and destroy) foreign cells, such as bacteria and viruses

mucosa-associated lymphatic tissue (MALT)

lymphatic tissue found in mucous membranes that line passageways open to the outside world; these include the respiratory, gastrointestinal, urinary, and reproductive tracts

natural killer (NK) cells

lymphocytes that play an important role in the nonspecific defense system of the body by killing virus-infected cells and cancer cells

pathogens

disease-causing agents

spleen

the largest lymphatic organ in the body, located in the abdomen below the diaphragm; filters blood and activates an immune response if necessary

T lymphocytes (T cells)

lymphocytes that complete their maturation in the thymus before they move out to the blood and the rest of the body; also called T cells

complement proteins

proteins in the blood that work with immune system cells and antibodies to defend the body against infection

interferons

proteins released by cells that have been infected with viruses; interfere with virus reproduction

phagocytosis

the process by which a cell engulfs and destroys foreign matter and cellular debris

pyrogens

chemicals that tend to cause fever by raising the set-point temperature of the neurons in the hypothalamus

active immunity

immunity in which the blood plasma cells in the body make antibodies as a result of previous exposure to a disease or a vaccine

antigen-presenting cells (APCs)

cells that process protein antigens and present them on their surface in a form that can be recognized by lymphocytes (white blood cells)

apoptosis

a programmed process of cellular self-destruction (cell suicide)

cellular immunity

immunity that arises from the activation of T lymphocytes (T cells) by antigen-presenting cells; cell-mediated immunity

clonal selection

repeated division of a lymphocyte that produces many exact genetic copies of itself

humoral immunity

immunity associated with free antibodies that circulate in the blood: antibody-mediated immunity

immunoglobulins

antibodies; proteins that recognize particular antigens with great specificity

interleukins

chemicals released by helper T cells and other cells that stimulate an immune response

major histocompatibility complex glycoproteins (MHCs)

family of proteins found on the surfaces of lymphocytes and other cells; help the immune system recognize foreign antigens and ignore “self” tissues

passive immunity

immunity that comes from antibodies received from an outside source, such as breast milk

anaphylaxis

a severe and potentially life-threatening allergic reaction that may include airway obstruction and very low blood pressure

autoimmune disorder

a condition in which the immune system attacks the body’s own tissue