Organization of Immune System Flashcards

Study Notes

Three Lines of Defense

First line: Barriers at body surfaces, such as skin layers and chemicals in saliva and tears.
Second line: Innate immunity, which is nonspecific and activated when the first line fails, involving inflammation and immune organs.
Third line: Adaptive immunity, characterized by a specific response and the ability to remember past infections.

1st Line of Defense

Comprises physical barriers like skin and chemical barriers in bodily fluids.
Harbors beneficial bacteria that help exclude harmful pathogens.

2nd Line of Defense

Employs nonspecific mechanisms like inflammation and swelling.
Involves components such as complement proteins and lymphatic organs, including lymph nodes, spleen, and tonsils.

Inflammation Mechanism

Body's response to infection increases blood flow to the affected area.
White blood cells are recruited to localize and eliminate pathogens, often accompanied by fever.

Fever Response

Represents systemic inflammation, beneficial for a short duration.
High temperatures hinder bacterial survival and growth, giving the immune system time to react.
Prolonged fever can damage healthy cells and impair enzyme function.

Complement Proteins

Attack bacterial cells by piercing their membranes, leading to cell death.
They remain inactive in circulation until they encounter a pathogen.

Lymphatic System

Comprises lymph nodes and vessels that filter and return tissue fluid to the bloodstream.
Functions in fat transport and immune defense, evident when lymph nodes swell in response to infection.

Areas for Blood Cells

Blood cells reside primarily in lymph nodes, spleen, and tonsils before being activated in response to infection.

3rd Line of Defense

Involves a highly specific adaptive immune response, functioning with memory and rapid response capabilities.
Engages effector T and B cells for effective immune action.

Effector T Cells

Stimulate the proliferation of white blood cells.
Release signaling chemicals to enhance the immune response in the lymph nodes.

Effector B Cells

Produce antibodies tailored to specific pathogens such as bacteria and fungi.
The antibody response takes time as the immune system must identify the correct type.

Memory T and B Cells

Store information about specific antibodies needed for previously encountered pathogens.
Remain inactive until re-exposure, leading to a quicker response and preventing future illness.
Memory duration varies, affecting immunity against specific diseases.

Reasons for Recurring Illness

Pathogen evasion occurs through mutations that alter receptor types and markers on cells.
Previous antibodies may be ineffective against new strains, necessitating the generation of new antibodies.

Description

This quiz covers the key concepts of the immune system, focusing on its three lines of defense. It includes definitions and explanations of the first, second, and third lines of defense, detailing how they work together to protect the body. Ideal for students studying immunology or related biological sciences.