Lymphatic System and Immune System

Flashcards for the Lymphatic and Immune Systems lecture.

What are the three main functions of the lymphatic system?

Return interstitial fluids and proteins to circulation, provide structural basis for immune system, transport dietary lipids.

What are the three main components of the lymphatic system?

Lymphatic fluid, lymph vessels, lymph organs and tissues.

In what tissues of the body are lymphatic capillaries NOT found?

Bone, teeth, bone marrow, and CNS.

What are lacteals?

Specialized lymph capillaries that drain the small intestine of dietary lipids.

What are the two lymphatic ducts formed by the union of collecting ducts?

Thoracic duct and Right lymphatic duct

Where does the thoracic duct empty, and what areas does it drain?

Empties into the left subclavian vein and carries lymph from the lower body, left upper body, and left side of the head and neck.

Where does the right lymphatic duct empty, and what areas does it drain?

Empties into the right subclavian vein and carries lymph from the right side of the head and neck, and right side of the thorax.

What two 'pumps' help transport lymph unidirectionally towards the heart?

Respiratory pump and Skeletal Muscle Pump

What are primary lymphoid organs and what are the 2 locations?

Sites where stem cells become immunocompetent; Red Bone Marrow and Thymus.

What are secondary lymphoid organs/tissues and list them

Sites where most immune responses occur; Lymph Nodes, Spleen, Tonsils.

What is the Thymus's function?

Site of lymphocyte maturation, atrophies in adolescence, not involved in directly fighting antigens.

What type of cells are mostly found in the cortex of the thymus and where do they come from?

Immature T cells migrate here from the red bone marrow

What type of cells are mostly found in the Medulla of the thymus and where do they go?

T cells but more mature. This is where mature lymphocytes enter the bloodstream.

What does the cortex of the lymph node contain?

Germinal centers, B cells and nodular dendritic cells.

What does the medulla of the lymph node contain?

B cells, antibody-producing plasmocytes, and macrophages.

What are the main functions of lymph nodes?

Filter lymph and activate lymphocytes to attack antigens.

What is the route of lymph flow through lymph nodes?

Afferent vessels, subcapsular and medullary sinuses, efferent vessels.

What are some features of the spleen?

Largest lymphoid organ, contains red pulp and white pulp.

What is the function of red pulp in the spleen?

Deals with blood cells (RBC removal, platelet storage, fetal blood formation).

What is the function of white pulp in the spleen?

Lymphoid tissue that deals with lymphocytes and carries out immune function.

What is the function of tonsillar crypts in tonsils?

Trap and destroy bacteria and pathogens.

What are the different types of tonsils?

Palatine, Lingual, Pharyngeal (adenoids).

What is Mucosa-Associated Lymphoid Tissue (MALT)?

Lymphoid tissue in the mucosa lining of respiratory, digestive, and urinary tracts.

What are Peyer's Patches?

Lymphoid follicles lining the small intestine.

What is immunity?

Resistance to disease.

What are the two main divisions of the immune system?

Innate (nonspecific) and Adaptive.

What are the two lines of defense in the Innnate system?

External and Internal.

What are the two branches of the adaptive immune system?

Humoral (B lymphocytes) and Cellular (T lymphocytes).

What are the components of the first line of defense in the innate immune system?

Surface barriers (skin, mucous membranes) and their secretions.

What are the components of the second line of defense in the innate immune system?

Phagocytes, Natural Killer Cells, Chemical Mediators, Inflammation, Fever.

What are the main types of phagocytes?

Macrophages (develop from monocytes) and Neutrophils.

What are the five steps of phagocytosis?

Chemotaxis, Adherence, Ingestion, Digestion, Killing.

How do Natural Killer Cells work?

Target cells lacking 'self' cell-surface receptors and induce apoptosis; enhance the inflammatory response.

What are the key chemical mediators in the innate immune system?

Interferons and Complement.

What is the role of interferons?

Released by virus-infected cells to protect neighboring uninfected cells.

What is the function of the complement system?

Inactive proteins that enhance phagocytosis and kill bacteria by forming a MAC

What are the tasks of inflammation?

Prevent spread of damage, dispose of debris/pathogens, set the stage for repair.

What are the cardinal signs of inflammation?

Pain, Redness, Swelling, Heat (and potentially loss of function).

What are the two major effects of inflammatory chemicals?

Vasodilation and Increased permeability of capillaries.

What is fever?

A systemic response to invading microorganisms caused by pyrogens.

What are the two properties of complete antigens?

Stimulate proliferation of specific lymphocytes/antibodies and react with their products.

What are the two main types of lymphocytes?

B lymphocytes and T lymphocytes.

Where do B and T lymphocytes mature?

B cells mature in red bone marrow (humoral), T cells mature in the thymus (cell-mediated).

What are immunocompetence and self-tolerance?

Ability to recognize and bind to a specific antigen, and unresponsiveness to self-antigens.

What is the humoral immunity response?

Antigen challenge leads to formation of a clone of plasma cells that secrete antibodies, and memory cells.

What is active humoral immunity?

B cells encounter the antigens and produce the antibodies.

What is passive humoral immunity?

Antibodies are produced outside the body.

What are the five classes of antibodies (immunoglobulins)?

IgM, IgA, IgD, IgG, IgE.

What is the function of IgM?

First antibody released, activates complement.

What is the function of IgA?

Secreted into mucus/body fluids, stops pathogens at the first line of defense.

What is the function of IgD?

Antigen receptors on B cells.

What is the function of IgG?

Most abundant, can cross the placenta.

What is the function of IgE?

Allergic reactions and parasitic infections.

What is the purpose of the T-Cells in Cell-Mediated Immunity?

Defend against intracellular antigens.

What are the two major types of T cells?

Helper T cells (CD4) and Cytotoxic T cells (CD8).

What do Class I MHC proteins do?

Inform cytotoxic T cells of microorganisms hiding in cells.

What do Class II MHC proteins do?

Appear on Antigen Presenting Cells and are recognized by Helper T cells.

What is the 2 step process for T Cell activation?

Antigen binding and Co-stimulation.

What are the functions of Helper T cells?

Help activate B and T cells, activate macrophages, and recruit other immune cells.

What do Cytotoxic T cells do?

Directly attack and kill other cells with non-self antigens.

How do Cytotoxic T cells work?

Release perforins and granzymes to induce apoptosis.

What is the role of Regulatory T cells?

Dampen the immune response to prevent autoimmune reactions.

What are the different types of organ transplants?

Autograft, Isograft, Allograft, Xenograft.

Define 'Autograft'.

One body site to another of the same person.

Define 'Isograft'.

Transferred between identical twins.

Define 'Allograft'.

Transferred between people who are not identical twins.

Define 'Xenograft'.

Transferred from another animal species.

What is Acquired Immunodeficiency Syndrome (AIDS)?

Caused by HIV, transmitted by body fluids, cripples the immune system.

What are the four types of hypersensitivities (allergies)?

Anaphylactic, Cytotoxic, Immune Complex, Cell-Mediated.

What happens in Type I hypersensitivity (Anaphylactic Reactions)?

IgE is produced to release histamine.

What happens in Type II hypersensitivity (Cytotoxic)?

Antibodies bind to antigen on specific body cells.

What happens in Type III hypersensitivity (Immune complex hypersensitivity)?

Antigen-antibody complexes form and cannot be cleared, leading to inflammation.

What happens in Type IV hypersensitivity (Delayed hypersensitivity)?

Helper T cells, cytokine-activated macrophages, and cytotoxic T cells cause damage.

What are autoimmune diseases?

Loss of ability to recognize self from non-self; cannot be cured.