Ch 35: The Immune System Flashcards
(31 cards)
Which secretion is not a barrier that prevents pathogens from entering the body?
Lysozyme
Ear wax
Antigens
Mucus
antigens
True or false? The leukocytes of the innate immune system are B cells, macrophages, and neutrophils.
False. The leukocytes of the innate immune system are mast cells, macrophages, and neutrophils.
How do cells involved in the innate immune response detect the presence of pathogens?
Leukocytes recognize unique molecules on pathogens.
_________ are leukocytes that can engulf and digest a pathogen.
Macrophages
Which of the following statements best describes the role of mast cells in the inflammatory response?
a. ) They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream.
b. ) They release chemicals that constrict blood vessels at some distance from the wound site.
c. ) They secrete substances that degrade bacterial cell walls and engulf and digest the invaders.
d. ) They release cytokines to stimulate the release of additional neutrophils and macrophages.
a.) They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream.
Which of the following events occurs first when a wound that breaks the skin has occurred?
a. ) Mast cells secrete chemical messengers to regulate blood flow to the wound.
b. ) Neutrophils secrete substances that degrade bacterial cell walls.
c. ) Macrophages present bacterial proteins as antigens on their plasma membrane.
d. ) Platelets release proteins that form clots and decrease bleeding.
d.) Platelets release proteins that form clots and decrease bleeding.
What cellular structure would you predict to be in abundance in plasma cell that function to sythesize large quantities of secreted proteins (antibodies)?
rough endoplasmic reticulum
What cellular structure would you predict to be in abundance in macrophages that function in antigen destruction?
lysosomes
Which cell type provides long term immunity after a vaccination?
memory cells
Sort the items into the appropriate bins depending on whether they are involved in the humoral response, the cell-mediated response, or both the humoral and the cell-mediated responses.
antibodies antigen-presenting cells B cells cytotoxic T-cells helper T-cells and cytokines memory cells plasma cells
Humoral response:
- B cells
- Antibodies
- Plasma cells
Cell-Mediated Response:
- Cytotoxic T cells
Both:
- Helper T cells and cytokines
- Memory cells
- Antigen-presenting cells
Cytotoxic T cells are the effector cells in the cell-mediated immune response. The diagram below summarizes the interaction of a cytotoxic T cell and its target cell.
see image
B cells are involved in the humoral immune response. The flowchart below summarizes the steps involved in B cell activation.
see image
All animals have innate immunity. Only _________ have adaptive immunity.
In jawed vertebrates, innate immune defenses coexist with the more recently evolved system of adaptive immunity. Because most of the recent discoveries regarding vertebrate innate immunity have come from studies of mice and humans, we’ll focus here on mammals. In this section we’ll consider the innate defenses that are similar to those found among invertebrates—barrier defenses, phagocytosis, and antimicrobial peptides—as well as some that are unique to vertebrates, such as natural killer cells, interferons, and the inflammatory response.
vertebrates
What are the two elements of adaptive immunity?
humoral response: antibodies defend against infection in body fluids/ extracellular spaces
cell-mediated response: cytotoxic cells defend against infection in body cells
The adaptive response relies on T cells and B cells, which are types of white blood cells called lymphocytes. Like all blood cells, lymphocytes originate from ____ _____ in the bone marrow. Some migrate from the bone marrow to the thymus, an organ in the thoracic cavity above the heart. These lymphocytes mature into T cells. Lymphocytes that remain and mature in the bone marrow develop as B cells.
stem cells
An antigen is any substance that….
…elicits a B or T cell response.
Each antigen receptor binds to just ___ part of one molecule from a particular ________, such as a species of bacteria or strain of virus.
one
pathogen
The cells of the immune system produce millions of different antigen receptors. A given lymphocyte, however, produces just one variety; all of the antigen receptors made by a single B or T cell are _________.
identical
Although drawings of B and T cells typically include just a few antigen receptors, a single B or T cell actually has about _____ antigen receptors on its surface.
100,000
The small, accessible portion of an antigen that binds to an antigen receptor is called an _______. An example is a group of amino acids in a particular protein. A single antigen usually has several ________, each binding a receptor with a different specificity.
epitope
epitopes
Each B cell antigen receptor is a Y-shaped protein consisting of four __________ chains: two identical heavy chains and two identical light chains. Disulfide bridges link the chains together.
polypeptide
Binding of a B cell antigen receptor to an antigen is an early step in B cell activation, leading eventually to formation of cells that secrete a soluble form of the receptor. This secreted protein is called an antibody, also known as an __________. Antibodies have the same Y-shaped structure as B cell antigen receptors, but lack a membrane anchor. As you’ll see later, antibodies provide a direct defense against pathogens in body fluids.
immunoglobulin
The antigen-binding site of a membrane-bound receptor or antibody has a unique shape that provides a lock-and-key fit for a particular _______. This stable interaction involves many noncovalent bonds between an epitope and the surface of the binding site. Differences in the amino acid sequences of variable regions provide the variation in binding surfaces that enables binding to be highly specific.
B cell antigen receptors and antibodies bind to epitopes of intact antigens in the blood and lymph. They can bind to antigens on the surface of pathogens or ____ in body fluids.
epitope
free
For a T cell, the antigen receptor consists of two different polypeptide chains, an α chain and a β chain, linked by a disulfide bridge. Near the base of the T cell antigen receptor (often called simply a T cell receptor) is a transmembrane region that anchors the molecule in the cell’s plasma membrane. At the outer tip of the molecule, the variable (V) regions of the α and β chains together form a single antigen-binding site. The remainder of the molecule is made up of the ________ (C) regions.
constant
