Ch_22_Lecture_Objectives

Lymph

A clear fluid that circulates in the lymphatic system, containing white blood cells and other substances.

Lymph vessels

Vessels that transport lymph throughout the body, connecting lymphatic capillaries to lymph nodes and eventually to the bloodstream.

Lymphoid tissues/organs

Structures of the immune system, including primary (thymus, bone marrow) and secondary (spleen, lymph nodes) where lymphocytes are produced and activated.

Lymphatic capillaries vs. blood capillaries

Lymphatic capillaries are more permeable and have blind ends, allowing for better absorption of interstitial fluid.

Superficial lymphatics

Lymphatic vessels that collect lymph from the skin and subcutaneous tissues.

Deep lymphatics

Lymphatic vessels that collect lymph from muscles and deeper structures.

Thoracic duct

The lymphatic vessel that collects lymph from the left side of the body above the diaphragm and everything below the diaphragm.

Right lymphatic duct

The lymphatic vessel that collects lymph from the right side of the body above the diaphragm.

Cisterna chyli

The structure that receives lymph from inferior parts of the abdomen, pelvis, and lower limbs.

Germinal center

The area within lymphoid tissues where B cells proliferate and differentiate.

MALT

Mucosa-associated lymphoid tissue; a type of lymphoid tissue found in mucosal linings.

Lymph nodes

Small structures that filter lymph and house lymphocytes, with afferent vessels bringing lymph in and efferent vessels carrying lymph away.

Thymus

A primary lymphoid organ where T cells mature and is known for the blood-thymus barrier.

Spleen

A secondary lymphoid organ that filters blood and has red pulp (for blood filtration) and white pulp (for immune response).

Innate immunity

The body's initial, non-specific defense mechanisms against pathogens, including physical barriers and certain immune cells.

Adaptive immunity

The immune response that is specific and acquired over time, involving lymphocytes and memory for future responses.

Lymphocytopoiesis

The process of lymphocyte development, starting from stem cells in bone marrow.

Phagocytes

Cells that engulf and digest pathogens; includes microphages and macrophages.

Interferons

Proteins released by cells in response to viral infections that help inhibit viral replication.

Immune surveillance

The monitoring function of the immune system, primarily performed by cytotoxic T cells.

Cytotoxic T cells

T cells that kill cancerous or infected cells.

Clonal selection

The process by which specific B and T cells are selected for proliferation in response to an antigen.

Antibody titer

The concentration of antibodies in the blood, indicating the level of immune response to a pathogen.

Primary immune response

The initial response by the immune system upon first exposure to an antigen.

Secondary immune response

The faster and stronger response by the immune system upon subsequent exposures to the same antigen.

Naturally acquired active immunity

Immunity gained through exposure to a pathogen and the subsequent production of antibodies.

Artificially acquired active immunity

Immunity gained through vaccination.

Naturally acquired passive immunity

Immunity obtained from maternal antibodies.

Artificially acquired passive immunity

Immunity obtained by the injection of antibodies.

Antibody classes (IgA, IgD, IgE, IgG, IgM)

Different types of antibodies that perform various functions in immune responses.

Constant segment of antibody

The part of the antibody that remains the same regardless of the antigen.

Variable segment of antibody

The part of the antibody that contains the antigen-binding site and varies between antibodies to bind different antigens.

Actions of antibodies

Neutralization, opsonization, agglutination, precipitation, complement activation, and enhancement of phagocytosis.

Autoimmune disorders

Conditions in which the immune system mistakenly attacks the body's own tissues.

SCID

Severe Combined Immunodeficiency; a genetic disorder affecting T and B lymphocyte functions.

AIDS

Acquired Immunodeficiency Syndrome; a condition caused by HIV, affecting helper T cells.

Lymphedema

Swelling due to excess lymph fluid in the body tissues, often from blockage of lymphatic vessels.

Tonsillitis

Inflammation of the tonsils, often due to infection.

Lymphadenitis

Inflammation of the lymph nodes, commonly due to infection.

Hypersensitivities

Exaggerated immune responses that can lead to allergies or anaphylaxis.