Anatomy - Lymphatic System

What are the three major functions of the lymphatic system?

Fluid balance, fat absorption, and immune defense.

What is a pathogen?

A disease-causing organism or agent.

What is lymph?

Excess tissue fluid that enters lymphatic vessels.

What is interstitial fluid?

Fluid found in the spaces between body cells.

How does interstitial fluid become lymph?

It enters lymphatic capillaries.

What do lymphatic vessels do?

Transport lymph throughout the body.

What do lymph nodes do?

Filter lymph and provide places for immune responses.

What is lymphoid tissue?

Tissue containing large numbers of immune cells.

What are lymphocytes?

White blood cells involved in immune defense.

What does the thymus do?

Provides the location where T cells mature.

Where do T cells originate?

Bone marrow.

Where do T cells mature?

Thymus.

Where do B cells originate and mature?

Bone marrow.

What does the spleen do?

Filters blood and removes pathogens and old blood cells.

What do tonsils do?

Help catch pathogens entering through the mouth and nose.

What does the thoracic duct drain?

Lymph from most of the body.

What does the right lymphatic duct drain?

The upper-right part of the body.

Where does lymph return to the bloodstream?

Near the collarbones.

Where are axillary lymph nodes?

Armpits.

Where are inguinal lymph nodes?

Groin.

What are the two major types of immunity?

Innate and adaptive immunity.

What is innate immunity?

Fast, nonspecific defense present from birth.

What is adaptive immunity?

Specific defense involving B cells and T cells.

What is the first line of immune defense?

Physical barriers like skin, mucus, and tears.

What are phagocytes?

Immune cells that engulf and digest pathogens.

What is phagocytosis?

The process of engulfing and digesting particles.

What are macrophages?

Large phagocytes that engulf pathogens and dead cells.

How do macrophages connect innate and adaptive immunity?

They engulf pathogens and present antigens to T cells.

What are natural killer cells?

Innate immune cells that destroy infected or abnormal cells.

What are interferons?

Proteins that help cells defend against viral infections.

What are cytokines?

Chemical signals that allow immune cells to communicate.

What are pyrogens?

Substances that trigger an increase in body temperature.

What is fever's role in immunity?

Helps create conditions that support immune defense.

What are T cells?

Adaptive immune lymphocytes that coordinate or attack.

What do helper T cells do?

Activate and coordinate other immune cells.

What do cytotoxic T cells do?

Destroy infected or abnormal body cells.

What do regulatory T cells do?

Control immune responses and prevent excessive activity.

What are B cells?

Adaptive immune cells that can become antibody-producing plasma cells.

What are antibodies?

Proteins that bind to specific antigens.

What are plasma cells?

Activated B cells that produce antibodies.

What are memory B cells?

Cells that help create faster responses to future infections.

What is an antigen?

A substance recognized by the immune system that can trigger a response.

What is MHC?

Cell-surface molecules that display antigens to T cells.

Where is Class I MHC found?

Almost all nucleated body cells.

What does Class I MHC display?

Antigens from inside a cell.

Which T cells recognize Class I MHC?

CD8 cytotoxic T cells.

Where is Class II MHC found?

Professional antigen-presenting cells, including macrophages, dendritic cells, and B cells.

What does Class II MHC display?

Antigens from material taken into a cell.

Which T cells recognize Class II MHC?

CD4 helper T cells.

What is CD4 associated with?

Helper T cells and Class II MHC.

What is CD8 associated with?

Cytotoxic T cells and Class I MHC.

What is the variable region of an antibody?

The region that binds a specific antigen.

What is the constant region of an antibody?

The region that helps determine its class and function.

What is an antibody's heavy chain?

One of two longer protein chains.

What is an antibody's light chain?

One of two shorter protein chains.

How many heavy and light chains make up an antibody?

Two heavy chains and two light chains.

What is VDJ recombination?

Gene rearrangement that creates antibody diversity in B cells.

What does VDJ stand for?

Variable, Diversity, and Joining gene segments.

What is agglutination?

Antibodies causing pathogens or particles to clump together.

What is active immunity?

Immunity produced by your own immune system.

What is passive immunity?

Immunity gained by receiving antibodies from another source.

What is natural active immunity?

Developing immunity after an infection.

What is artificial active immunity?

Developing immunity through vaccination.

What is natural passive immunity?

Receiving maternal antibodies through placenta or breast milk.

What is artificial passive immunity?

Receiving antibodies through medical treatment.

Which type of immunity creates memory cells?

Active immunity.

Which type of immunity provides ready-made antibodies?

Passive immunity.

What happens when a B cell is activated?

It multiplies and forms plasma cells and memory B cells.

What is the difference between B cells and T cells?

B cells produce antibodies; T cells coordinate or directly attack.

How do helper T cells activate B cells?

They provide signals that help B cells multiply and differentiate.

What is the connection between macrophages and MHC II?

Macrophages present engulfed antigens using Class II MHC.

What is the connection between infected cells and MHC I?

Infected cells display internal antigens using Class I MHC.

What happens when a pathogen enters the body?

Innate defenses respond first, followed by targeted adaptive immunity.

Why are memory cells important?

They help the immune system respond faster to previously encountered pathogens.