ch 14 Lymphatic and Immune Systems

Comprehensive vocabulary flashcards covering the anatomy, physiology, immune mechanisms, opportunistic infections, diagnostic tests, and pathologies of the lymphatic and immune systems.

Lymph

Clear watery fluid that surrounds body cells (interstitial fluid) and flows in a system of lymph vessels throughout the body; originates in the blood, is rich in lymphocytes and monocytes, and absorbs lipids in the intestines.

Lymph Capillaries

Thin-walled tubes that begin in spaces around cells throughout the body and carry lymph from tissue spaces to larger lymph vessels.

Lymph Vessels

Tubes with thicker walls than lymph capillaries that contain valves to ensure lymph travels in one direction toward the thoracic cavity.

Lymph Nodes

Masses of lymph cells and vessels surrounded by a fibrous connective tissue capsule located along lymph vessels; they house macrophages, B lymphocytes, and T lymphocytes.

Spleen

Lymphatic organ that destroys old RBCs, filters microorganisms and foreign material out of the blood, activates B and T cells during filtration, and stores blood, especially erythrocytes and platelets.

Thymus Gland

Specialized primary lymphoid organ located in the anterior superior mediastinum (in front of the heart and behind the sternum) where T cells mature, providing immunity in fetal life and early growth.

Natural Immunity

Genetic predisposition present in the body at birth that is not dependent on prior exposure to an antigen; relies on phagocytosis, macrophages, and natural killer cells.

Adaptive Immunity

Acquired immune defense that can be active (obtained by contracting a disease, vaccination, or stem cell transplant) or passive (obtained via antitoxins, immunoglobulins, or maternal antibodies).

Humoral Immunity

Branch of adaptive immunity involving B lymphocytes that originate in bone marrow, mature into plasma cells, and produce immunoglobulins (antibodies) to block antigens on mucosal surfaces and in the blood.

Cell-Mediated Immunity

Branch of adaptive immunity that does not involve antibodies, but instead employs cytotoxic T cells, helper T cells, suppressor T cells, and cytokine secretion.

Cytotoxic T Cells (CD8+ T cells)

T lymphocytes that attach directly to foreign antigens and kill them.

Helper T Cells (CD4+ T cells)

T lymphocytes that promote antibody synthesis by B cells and stimulate the actions of other T cells.

Suppressor T Cells (Tregs)

Regulatory T cells that inhibit B and T cells, preventing them from attacking the body's own healthy cells.

Dendritic Cells

Monocyte-derived macrophage-like cells found under epithelial tissue and in most organs that recognize and digest foreign antigens to initiate adaptive immune responses.

IgG

The most prevalent immunoglobulin in blood plasma, produced in primary and secondary immune responses to neutralize toxins, bacteria, and viruses; capable of crossing the placenta from mother to fetus.

IgM

The immunoglobulin that protects newborns and is usually the first antibody to increase during an immune response.

IgA

Immunoglobulin found in mucosal secretions and colostrum (early breast milk) that provides localized protection at mucosal surfaces.

IgE

Immunoglobulin secreted by sensitized plasma cells that increases in concentration during allergic reactions.

IgD

Immunoglobulin attached to the surface of B lymphocytes whose specific function remains undetermined.

Monoclonal Antibodies (MoAb)

Multiple identical copies of cells or genes engineered to kill tumor cells as a form of passive immunotherapy.

Acquired Immunodeficiency Syndrome (AIDS)

Advanced stage of HIV infection characterized by the severe loss of cellular immunity due to destruction of CD4+ helper T cells, predisposing patients to opportunistic infections and malignancies.

Wasting Syndrome

Profound involuntary loss of weight accompanied by muscle atrophy, fatigue, weakness, and significant appetite loss in patients who are not actively attempting to lose weight.

Kaposi Sarcoma

An opportunistic vascular cancer in immunocompromised patients that causes red or purple patches of abnormal tissue under the skin, in mucosal linings (mouth, nose, throat), lymph nodes, or internal organs.

Candidiasis

Opportunistic yeast-like fungal infection seen in AIDS that causes thrush in the oral cavity and throat.

Cryptococcus (Crypto)

Yeast-like fungal infection capable of infecting the lungs, brain, and bloodstream in immunocompromised patients.

Cryptosporidiosis

Parasitic opportunistic infection that affects the gastrointestinal tract, brain, and bloodstream.

Cytomegalovirus (CMV)

Opportunistic viral infection seen in AIDS patients that leads to enteritis and retinitis.

Histoplasmosis (Histo)

Fungal infection acquired from inhaling bird and bat droppings that causes opportunistic lung infection in immunocompromised hosts.

Mycobacterium avium-intracellulare (MAI)

Opportunistic bacterial pathogen that causes systemic lung and bloodstream infections in AIDS patients.

Pneumocystis pneumonia (PCP)

Opportunistic lung infection in immunocompromised individuals caused by an organism found in soil and carried by animals.

Toxoplasmosis (Toxo)

Parasitic opportunistic infection transmitted by eating uncooked pork that targets the central nervous system (CNS).

Reverse Transcriptase Inhibitors (RTI)

Class of antiretroviral drugs that inhibit the viral enzyme reverse transcriptase, which HIV uses to replicate its genome.

Protease Inhibitors

Class of antiretroviral drugs that inhibit the viral proteolytic enzyme required by HIV to process viral proteins necessary for structure and reproduction.

HAART

Highly active antiretroviral therapy; a treatment regimen combining reverse transcriptase inhibitors with protease inhibitors to suppress and destroy HIV.

Urticaria (Hives)

An acute hypersensitivity reaction marked by itchy, red, elevated cutaneous welts or wheals.

Atopic Dermatitis

Allergic skin inflammation producing an erythematous, pruritic rash triggered by exposure to soaps, cosmetics, or chemicals.

Hodgkin Disease

Malignant tumor of lymphoid tissue in the spleen and lymph nodes pathologically characterized by the presence of Reed-Sternberg cells.

Non-Hodgkin Lymphoma

Malignancies of lymphoid tissue lacking Reed-Sternberg cells, including follicular lymphoma and large cell lymphoma.

Multiple Myeloma

Malignancy originating in bone marrow cells.

Thymoma

Malignant tumor of the thymus gland, frequently associated with myasthenia gravis, anemia, lupus, or rheumatoid arthritis.

CD4+ Cell Count

Laboratory blood test measuring helper T cell numbers; normal reference range is $500\text{–}1500\text{ cells/mm}^3$, while AIDS diagnosis corresponds to counts below $250\text{ cells/mm}^3$.

ELISA Test

Diagnostic screening test that detects anti-HIV antibodies in the bloodstream, followed up with a more specific Western blot test.

Immunoelectrophoresis

Laboratory test that separates immunoglobulins ($\text{IgG}$, $\text{IgM}$, $\text{IgE}$, $\text{IgA}$, $\text{IgD}$) to detect abnormal antibody spikes characteristic of multiple myeloma.

Viral Load Test

Laboratory test measuring the quantitative amount of human immunodeficiency virus (HIV) present in a patient's bloodstream.

Computed Tomography (CT) Scan

Radiologic cross-sectional imaging in the transverse plane used to identify abnormalities in lymphoid organs, including lymph nodes, spleen, and thymus gland.