Cells and the Immune System - The Immune System Flashcards
What Trigger an Immune Response?
Antigens.
Where are Antigens found?
Antigens are found on the surface of cells.
What are Antigens used to Identify by the Immune System?
Pathogens, abnormal body cells, toxins and cells from other individuals of the same species.
How many (Main) Stages are apart of the Immune Response?
Four main stages.
What is the First Main Stage of the Immune Response?
Phagocytes engulf pathogens.
What are Phagocytes?
A phagocyte, for example a macrophage, is a variant of white blood cell that carries out phagocytosis.
What are Lysosomes?
Lysosomes are organelles that contain lysozymes, a type of enzyme.
What is the Second Main Stage of the Immune Response?
Phagocytes activate T-cells (T-lymphocytes), which are another type of white blood cell.
What are T-cells (T-lymphocytes)?
A type of white blood cell that has receptor proteins on its surface that bind to complementary antigens on a specific pathogen.
What are Two Examples of T-cells?
Helper T-cells, and Cytotoxic T-cells.
How do Helper T-cells respond to Pathogens?
Helper T-cells release chemical signals that activate and stimulate phagocytes and cytotoxic T-cells.
How do Cytotoxic T-cells Respond to Foreign Cells?
They kill abnormal and foreign cells by inducing apoptosis.
What are B-cells (B-lymphocytes)?
B-cells (which are activated by helper T-cells) secrete antibodies and divide into plasma cells.
What are found on the Surface of B-cells?
Antibodies.
What do Antibodies do?
Antibodies are proteins that bind to antigens to form an antigen-antibody complex.
What happens when the Antibody on the Surface of a B-cell meets a Complementary Antigen?
It binds to it, and this combined with substances released from helper T-cells activates the B-cell. This is called clonal selection, and the activated B-cell divides into plasma cells.
What are Plasma Cells?
Plasma cells are identical to B-cells. They secrete many antibodies for a specific antigen.
What are the Antibodies Produced by Plasma Cells known as?
Monoclonal antibodies.
What is Agglutination?
Antibodies have two binding sites, so it can bind to two pathogens at the same time. This results in pathogens clumping together.
Why is Agglutination Important?
Since many pathogens end up clumped together, it’ll be easier for macrophages to phagocytose many pathogens at once, resulting in the destruction of this specific pathogen.
What are Antibodies?
Antibodies consist of amino acid chains. The specificity of it depends on variable regions, which form the antigen binding sites.
What is the Variable Region on an Antibody?
Each antibody has a variable region, with a unique tertiary structure that is complementary to one specific antigen.
What is the Same for all Antibodies?
The constant region is the same for all antibodies.
What are the Two Types of Immune Response?
Cellular and humoral.
