Bio Ch 33 Flashcards
Immune System
protects us from all sorts of harmful invaders, including bacterial and viral pathogens, various toxins, and perhaps even cancerous cells that occasionally arise
PAMPs
pathogenic-associated molecular patterns; when receptors bind to these, they trigger an immune reaction, increasing the odds that the pathogen can be eliminated
Innate Immunity
type of host defense; can recognized common microbial invaders very quickly but show no sign of an increased response upon repeated exposure to the same invader
Adaptive immunity
most vertebrate animals exhibit this, characterized by the production of a very large number of diverse receptors that are found on the surface of specialized white blood cells (such as B and T lymphocytes in humans)
Antigens
foreign substance, usually a protein or a polysaccharide, that stimulates the immune system to react, such as to produce antibodies
Lymphatic system
closely associated with the cardiovascular and immune systems; includes the lymphatic vessels and the lymphoid organs; 3 main functions that contribute to homeostasis - (1) capillaries that absorb excess tissue fluid and return it to the bloodstream, (2) lacteals absorb fats in the form of lipoproteins and transport them in the bloodstream, & (3) organs & vessels are sites of production and distribution of lymphocytes, which help defend the body against pathogens
Lymphatic vessels
form a one-way system that begins with ____ capillaries
Lymphatic capillaries
tiny, closed-ended vessels that take up excess tissue fluid
Lymph
fluid inside lymphatic capillaries
Lymphoid (lymphatic) organs
organ other than a lymphatic vessel that is part of the lymphatic system; lymph nodes, tonsils, spleen, thymus gland, and bone marrow
Primary lymphoid organs
bone marrow, thymus
Secondary lymphoid organs
sites where some lymphocytes are activated by antigens
Red bone marrow
major primary lymphoid organ; spongy, semisolid red tissue where hematopoietic stem cells divide and produce all the types of blood cells, including lymphocytes
B cells
type of lymphocyte that begins development in the red bone marrow and remains there until they are mature
T cells
type of lymphocyte; immature, migrate from the bone marrow via the bloodstream to the thymus, where they mature
Thymus
soft, bilobed; primary lymphoid organ located in the thoracic cavity between the trachea and the sternum ventral to the heart
Lymph nodes
small ovoid structures occurring along lymphatic vessels; major type of secondary lymphoid organ
Spleen
oval secondary lymphoid organ with a dull purplish color; located in the upper left side of the abdominal cavity posterior to the stomach; most of this contains red pulp that filters and cleanses the blood
Immunity
capability of removing or killing foreign substances, pathogens, and cancer cells from the body
Inflammatory response
when tissues are damaged by a variety of causes, including pathogens, a series of events known as this occurs
Histamine
substances, produced by basophils in blood and mast cells in connective tissue, that causes capillaries to dilate
Mast cells
connective tissue that releases histamine in allergic reactions
Neutrophils
able to leave the bloodstream and phagocytize bacteria in tissues
Eosinophils
can be phagocytic but they are better known for mounting an attack against animal parasites such as tapeworms that are too large to be phagocytized
Macrophages
1 of 2 longer-living types of phagocytic white blood cells; found in all sorts of tissues
Dendritic cells
1 of 2 longer-living types of phagocytic white blood cells; especially prevalent in the skin
Natural killer (NK) cells
large, granular lymphocytes that kill virus-infected cells and cancer cells by cell-to-cell contact; do their work while adaptive defenses are still mobilizing; produce cytokines that promote adaptive immunity
Complement
composed of a number of blood plasma proteins, produced mainly by the liver, they _____ certain immune responses
Interferons
antiviral agent produced by an infected cell that blocks the infection of another cell
Cytokines
soluble proteins that affect the behavior of other cells
Antigen receptors
both B cells and T cells are capable of binding to and “recognizing” specific antigens because they have these on their plasma membrane
B-cell receptor
receptor for antigen on the surface of a B cell
Clonal selection theory
states that the antigen receptor of each B cell or T cell binds to only a single type of antigen
Plasma cells
mature B cell that mass-produces antibodies
Memory B cells
cells that always remember a particular antigen and make us immune to a particular illness (but not to any other illness)
Antibody-mediated immunity
defense of the body by B cells; AKA humoral immunity
Immuniglobulins (Ig)
antibodies; classes of these determined by structure of the constant region
Monoclonal antibodies
one of many antibodies produced by a clone of hybridoma cells that all bind to the same antigen
T-cell receptor (TCR)
molecule on the surface of a T cell that can bind to a specific antigen fragment in combination with an MHC molecule
MHC (major histocompatibility complex) protein
protein marker that is a part of cell-surface markers anchored in the plasma membrane, which the immune system uses to identify “self”
Helper T cells
regulate adaptive immunity
Cytotoxic T cells
attack and kill virus-infected cells and cancer cells
Antigen-presenting cells (APCs)
cell that displays an antigen to certain cells of the immune system so they can defend the body against that particular antigen
Memory T cells
T cell that differentiated during an initial infection and responds rapidly during subsequent exposure to the same antigen
Cell-mediated immunity
destruction or elimination of pathogens and other threats by T cells, macrophages, natural killer cells, or other cells
HIV (human immunodeficiency virus)
virus responsible for AIDS
Active immunity
occurs when an individual produces their own immune response against an antigen
Immunization
involves the use of vaccines, substances that contain an antigen to which the immune system responds
Passive immunity
occurs when an individual receives another person’s antibodies or immune cells
Severe combined immunodeficiency (SCID)
both T cells and B cells are either lacking completely or not functioning well enough to protect the body from a variety of infections that aren’t a problem for most people
Allergies
hypersensitivities to substances such as pollen, food, or animal hair, that ordinarily would do no harm to the body
Immediate allergic response
can occur within seconds of contact with an allergen
Asthma
airways leading to the lungs constrict, resulting in difficulty breathing accompanied by wheezing
Anaphylactic shock
immediate allergic response that occurs after an allergen has entered the bloodstream
Delayed allergic response
initiated by memory T cells at the site of allergen contact in the body; regulated by the cytokines secreted by these sensitized T cells at the site
Autoimmune disease
immune system mistakenly attacks their body’s own cells or molecules
