Study Guide for the Immune System

Flashcards cover key concepts from the immune system study guide, emphasizing lymphocytes, immune responses, and pathways.

What is the role of the immune system?

The immune system fights pathogenic organisms, such as bacteria, fungi, and viruses.

What are antigens?

Antigens are molecules that trigger an immune response and to which antibodies and T-cell receptors bind.

What are the three main categories of lymphocytes?

Natural killer cells (NK), T-lymphocytes (T-cells), and B-lymphocytes (B-cells).

What is innate immunity?

Innate immunity is not specific and includes mechanisms such as the skin, mucous membranes, and various defense cells.

What is the first line of defense in the immune system?

The skin and mucous membranes, which present a mechanical barrier to the entry of pathogens.

What role do NK cells play in innate immunity?

NK cells patrol the body for pathogens and diseased cells, attacking a variety of targets without prior sensitization.

What are the four functions of the complement system?

1) Inflammation 2) Immune clearance 3) Phagocytosis 4) Cytolysis.

How do cytokines function in immune response?

Cytokines are proteins that alter the physiology of cells they bind to, often playing roles in communication between cells.

What is the purpose of a fever in the immune response?

Fever is an adaptive response to infection, helping the organism to fight the infection.

What defines adaptive immunity?

Adaptive immunity is highly specific and provides immune memory, allowing a quicker response upon re-exposure to the same pathogen.

What happens to T-cells that recognize 'self' during development?

They are either killed or undergo a state called anergy.

What are cytotoxic T-cells?

TC cells that directly attack and destroy infected or cancerous host cells.

What is the role of helper T-cells?

TH cells assist in activating cytotoxic T-cells and B-cells, increasing the immune response.

What mechanism do B-cells use to produce antibodies?

B-cells bind to foreign antigens via surface antibodies and, with help from helper T-cells, multiply and differentiate into plasma cells.

What is the significance of memory T-cells?

They allow for a rapid response if the same pathogen is encountered again.

What is the difference between cellular and humoral immunity?

Cellular immunity is mediated by T-cells, while humoral immunity is mediated by antibodies produced by B-cells.

What is the role of antigen-presenting cells (APCs)?

APCs present antigens on MHC proteins to T-cells, activating the immune response.

What is the major histocompatibility complex (MHC)?

MHC proteins present antigenic peptides on the surface of cells for recognition by T-cells.

What signifies a professional APC?

These are cells like macrophages that are specialized in presenting antigens via MHC-2.

What occurs when a B-cell binds to its specific antigen?

The B-cell proliferates and differentiates into plasma cells that secrete antibodies.

What is the function of antibodies?

They tag pathogens for destruction but do not directly destroy them.

What are the two categories of adaptive immunity?

Cell-mediated immunity and humoral immunity.

What is a key difference between helper T-cells and cytotoxic T-cells?

Helper T-cells recognize antigens via MHC-2, while cytotoxic T-cells recognize antigens via MHC-1.