Lymphatic System Flashcards
Functions of the Lymphatic System
- Fluid Balance: Returns excess tissue fluids from tissues to the circulatory/cardiovascular systems.
- Absorption of fats: Transports newly digested fats from the intestines into circulation. Lacteals in the digestive system absorb fats.
- Protection: Houses and transports leukocytes. Fight infections and help prevent cancer.
Primary & Accessory structures of the Lymphatic System
- Tonsils: Palatine; Pharyngeal/Adenoids; Lingual
- Thymus Gland: Site of T-Lymphocyte maturation. Shrinks after puberty.
- Spleen: Cleanses blood; Destroys old RBCs; Stores blood.
Albumin
Fluid retention in the blood vessels so that it doesn’t leak out.
What are the main components of the lymphatic system?
• Lymph: The fluid that circulates within the lymphatic system, containing white blood cells, especially lymphocytes.
• Lymphatic vessels: Network of vessels that carry lymph throughout the body.
• Lymph nodes: Small, bean-shaped structures that filter lymph and house lymphocytes.
• Thymus: An organ where T lymphocytes mature.
• Spleen: Filters blood, recycles old red blood cells, and stores white blood cells.
• Tonsils: Lymphoid tissues that protect against pathogens entering through the mouth and throat.
• Bone marrow: Produces blood cells, including lymphocytes.
What is the primary function of the lymphatic system?
• Fluid balance: Returns interstitial fluid to the bloodstream.
• Fat absorption: Absorbs fats and fat-soluble vitamins from the digestive system into the bloodstream.
• Immune response: Provides a platform for the production and circulation of immune cells to protect against pathogens.
What are the two main types of immunity?
Innate immunity: The body’s first line of defense, which includes physical barriers (skin, mucous membranes), and immune cells like macrophages and neutrophils that respond quickly to pathogens.
• Adaptive immunity: A specific response to pathogens involving lymphocytes (B cells and T cells) and the production of antibodies.
What is the role of B cells in the immune system?
• B cells are a type of lymphocyte that produces antibodies.
• They recognize specific antigens and can differentiate into plasma cells that secrete large volumes of antibodies, or memory B cells that respond more rapidly to future exposures to the same antigen.
What is the function of T cells in the immune system?
• T cells are a type of lymphocyte involved in the adaptive immune response.
• Helper T cells: Activate B cells, other T cells, and macrophages.
• Cytotoxic T cells: Destroy infected or cancerous cells.
• Regulatory T cells: Help regulate or suppress other immune cells to prevent overactivity and autoimmunity.
What is the role of the thymus in immunity?
• The thymus is where T cells mature and become capable of recognizing and attacking pathogens. It is particularly active during childhood and shrinks after puberty.
What are the main functions of the spleen in the immune system?
• Filtration of blood: Removes old or damaged red blood cells and platelets.
• Immune surveillance: Contains white blood cells that monitor and respond to pathogens in the blood.
• Storage: Acts as a reservoir for blood, especially white blood cells and platelets.
What are antigens and antibodies?
• Antigens: Substances (usually proteins) on the surface of pathogens that are recognized by the immune system as foreign, triggering an immune response.
• Antibodies: Proteins produced by B cells that specifically bind to antigens to neutralize or mark them for destruction by other immune cells.
What is lymph, and how is it formed?
• Lymph is a clear fluid that originates from interstitial fluid (fluid between cells). It is collected by lymphatic capillaries from tissues and transported through lymphatic vessels back into the bloodstream.
What are the roles of macrophages and dendritic cells in the immune system?
• Macrophages: Engulf and digest pathogens, dead cells, and cellular debris; they also present antigens to T cells, initiating an adaptive immune response.
• Dendritic cells: Act as antigen-presenting cells, capturing antigens from pathogens and presenting them to T cells to trigger an adaptive immune response.
What are natural killer (NK) cells, and what is their function?
• NK cells are a type of lymphocyte that provides rapid responses to virus-infected cells and tumor cells. They can recognize and destroy cells that lack “self” markers without prior sensitization.
What is the difference between active and passive immunity?
• Active immunity: Immunity developed through direct exposure to a pathogen, either through infection or vaccination, leading to the production of memory cells and antibodies.
• Passive immunity: Temporary immunity gained by receiving antibodies from another source, such as maternal antibodies through breast milk or antibody-containing blood products.
