15. Lymphatic and Immune System

What is the primary function of the lymphatic system?

To return excess fluid from tissues back to the bloodstream.

What does the lymphatic system help filter out?

Pathogens, debris, and abnormal cells.

What are the three main jobs of the lymphatic system?

Fluid balance, filtration & protection, and fat absorption.

What is interstitial fluid?

Fluid that surrounds and bathes the body’s cells.

How is lymph formed?

Excess interstitial fluid is collected by lymphatic capillaries.

What does lymph primarily contain?

Water, proteins, white blood cells, and cell debris.

What prevents backflow in lymphatic vessels?

One-way valves.

What is the difference between lymphatic circulation and blood circulation?

Lymphatic circulation is a one-way system; blood circulation is a closed loop.

What are lymph nodes responsible for?

Filtering out bacteria, viruses, and debris.

Where do T cells mature?

In the thymus.

What is lymphadenopathy?

Swollen lymph nodes due to infections or other causes.

Describe lymphangitis.

Inflammation of lymphatic vessels, often caused by bacterial infections.

What is lymphoma?

Cancer of the lymphocytes, a type of white blood cell.

What viral infection is often referred to as the 'kissing disease'?

Mononucleosis.

What is tonsillitis?

Inflammation or infection of the tonsils.

What is the main goal of the immune system?

To recognize and remove anything that does not belong in the body.

Define 'self' in the context of immunity.

'Self' refers to the body’s own cells marked with unique ID tags.

Define 'non-self'.

'Non-self' refers to anything foreign to the body recognized by the immune system as a threat.

What are the two main branches of the immune system?

Innate (nonspecific) immunity and adaptive (specific) immunity.

What is innate immunity?

Your first line of defense, fast and non-specific.

What are the external barriers in innate immunity?

Skin, mucous membranes, saliva, tears, and stomach acid.

What role do neutrophils play in the immune response?

They are the first to arrive during infection and help eat and destroy germs.

What is the purpose of inflammation?

To bring more blood and immune cells to the area of injury or infection.

What is adaptive immunity?

The part of the immune system that learns and remembers specific invaders.

What do B cells do?

They produce antibodies as part of humoral immunity.

What is an antibody?

A protein made by B cells that binds to a specific antigen.

What is an antigen?

A foreign substance that triggers an immune response.

What are the five classes of antibodies?

IgG, IgM, IgA, IgE, IgD.

What makes IgG special?

It is the most common antibody and provides long-term protection.

What is the function of IgM?

It is the first antibody made during a new infection.

Where is IgA found?

In saliva, tears, and mucous.

What is the role of IgE?

It is involved in allergic reactions.

What is the structure of an antibody?

A Y-shaped structure with heavy and light chains.

What is opsonization?

The process of tagging pathogens to make them easier for phagocytes to destroy.

What happens during agglutination?

Antibodies clump antigens together.

What can occur as a result of an antigen-antibody reaction?

Agglutination, neutralization, precipitation, or complement activation.

Differences between IgG and IgM?

IgG provides long-term protection; IgM is the first responder in infections.

What is secretory IgA?

IgA that protects mucosal surfaces from pathogens.

What role does IgD play in the immune response?

It helps activate B cells.

What are monoclonal antibodies?

Identical antibodies made by one type of B cell.

What are polyclonal antibodies?

A mixture of antibodies made by several B cells.

What is cell-mediated immunity?

A type of immunity that protects the body from threats inside cells.

What type of cells are responsible for cell-mediated immunity?

T cells.

What are helper T cells?

They activate B cells and cytotoxic T cells and release cytokines.

What is the primary function of cytotoxic T cells?

To kill virus-infected or cancerous cells.

What is an autoimmune disorder?

When the immune system mistakenly attacks the body’s own cells.

What characterizes immunodeficiency disorders?

The immune system is weakened or not functioning properly.

How does a hypersensitivity reaction occur?

An overreaction of the immune system to a harmless substance.

What are common symptoms of an allergic reaction?

Sneezing, itching, runny nose, and swelling.

What is the Complete Blood Count (CBC) used for?

To check white blood cell counts for infections or immunodeficiency.

What does ESR / CRP measure?

Inflammation markers in the blood.

What is the purpose of serology tests?

To detect antibodies or antigens related to infections or autoimmune diseases.

What does flow cytometry help classify?

Lymphomas and leukemias based on T or B cell populations.

What function does lymphadenopathy indicate?

Swollen lymph nodes, often due to infection.

Why is the thymus important for the immune system?

It is where T cells mature and learn to differentiate self from non-self.