Blood, Lymphatic & Immune System – Lecture Review

Vocabulary flashcards covering major terms from lectures on the lymphatic, immune and blood systems.

Lymphatic System

Network of vessels, tissues and organs that drains interstitial fluid, transports dietary fats and initiates immune responses

Immunology

Study of the body’s defenses against disease-causing agents

Innate Immunity

Non-specific defence mechanisms that protects against a broad range of pathogens, first line immune defence

Adaptive Immunity

Specific, acquired defense involving lymphocyte activation and immunological memory

B Cell

Lymphocyte that matures in bone marrow and differentiates into plasma cells that produce antibodies

T Cell

Lymphocyte that matures in the thymus; includes helper and cytotoxic subsets

Natural Killer (NK) Cell

Innate lymphocyte that destroys virus-infected or tumor cells without prior sensitization

Antigen-Presenting Cell (APC)

Cell (e.g., macrophage, dendritic cell) that processes antigens and displays them with MHC molecules to T cells

Interstitial Fluid

Fluid that surrounds body cells and is derived from blood plasma

Lymph

Clear fluid formed from interstitial fluid that flows through lymphatic vessels

Lymphatic Capillary

Blind-ended microscopic vessel that begins the lymph drainage pathway

Lymphatic Vessel

Valve-bearing tube that carries lymph from capillaries toward lymph nodes

Lymph Node

Bean-shaped organ that filters lymph and houses immune cells

Afferent Lymphatic Vessel

Vessel that brings lymph into a lymph node

Efferent Lymphatic Vessel

Vessel that carries filtered lymph away from a lymph node

Lymph Trunk

Large vessel (e.g., lumbar, intestinal) formed by the convergence of lymphatic vessels

Thoracic Duct

Main lymphatic duct that drains most of the body into the left subclavian vein

Right Lymphatic Duct

Duct that drains the right upper quadrant of the body into the right subclavian vein

Primary Lymphatic Organs

Sites where lymphocytes become immunocompetent: bone marrow and thymus

Secondary Lymphatic Organs

Sites where immune responses occur: lymph nodes, spleen, tonsils, lymphatic nodules

Thymus

Bilobed organ in the mediastinum where T cells mature

Spleen

Largest lymphatic organ; filters blood, recycles RBCs, stores platelets

White Pulp

Splenic tissue rich in lymphocytes for immune defense

Red Pulp

Splenic tissue involved in RBC breakdown and blood storage

Lymphoid Tissue

Diffuse lymphatic tissue lacking a capsule; found in mucous membranes

Inflammation

Non-specific tissue response characterized by redness, heat, swelling and pain

Vasodilation

Widening of blood vessels during inflammation, increasing blood flow and permeability

Humoral Immunity

Adaptive response mediated by antibodies in body fluids

Cell-Mediated Immunity

Adaptive response in which T cells directly attack infected or abnormal cells

Antigen

Substance that provokes an adaptive immune response

Epitope

Specific antigenic determinant recognized by lymphocyte receptors

Immunogenicity

Ability of an antigen to initiate an immune response

Reactivity

Ability of an antigen to react with specific antibodies or cells

Plasma Cell

Effector B cell that secretes large quantities of antibody

Cytokine

Small protein mediator that regulates immune cell behavior

Interferon

Cytokine that inhibits viral replication in host cells

Immunoglobulin G (IgG)

Most abundant antibody; provides long-term immunity and crosses placenta

Immunoglobulin A (IgA)

Antibody that protects mucosal surfaces and is present in secretions

Immunoglobulin M (IgM)

First antibody produced during an initial infection

Immunoglobulin E (IgE)

Antibody involved in allergic reactions and parasite defense

Immunoglobulin D (IgD)

Antibody that functions as a B-cell receptor during early immune response

AIDS (Acquired Immunodeficiency Syndrome)

Condition of severe immune deficiency caused by HIV destruction of CD4 T cells

Hypersensitivity

Exaggerated immune reaction causing tissue damage; classified as Types I-IV

Autoimmune Disease

Disorder in which the immune system attacks self-tissues

Vaccine

Preparation of antigenic material that induces protective adaptive immunity

Haematopoiesis

Formation of blood cells from pluripotent stem cells in bone marrow

Erythrocyte (RBC)

Anucleate, biconcave cell that transports oxygen via hemoglobin

Hemoglobin

Iron-containing protein in RBCs that binds reversibly to oxygen and CO₂

Carbonic Anhydrase

RBC enzyme that catalyzes CO₂ + H₂O ⇌ H₂CO₃, aiding CO₂ transport

Leukocyte (WBC)

Nucleated blood cell involved in body defense

Neutrophil

Granulocyte that performs phagocytosis; predominant in bacterial infections

Eosinophil

Granulocyte active against parasites and in allergic responses

Basophil

Granulocyte that releases histamine and other mediators of inflammation

Lymphocyte

Agranular WBC including B cells, T cells and NK cells; central to immunity

Monocyte

Agranular WBC that differentiates into tissue macrophages

Platelet

Cell fragment essential for blood clotting

Thrombopoietin

Hormone that stimulates platelet production

Plasma

Liquid component of blood composed of water, proteins and solutes

Albumin

Most abundant plasma protein; maintains osmotic pressure and transports molecules

Globulins

Plasma proteins; α and β forms transport; γ form constitutes antibodies

Fibrinogen

Plasma protein converted to fibrin during clot formation

Hematocrit (Packed Cell Volume)

Percentage of blood volume occupied by red blood cells