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46 Cards in this Set
- Front
- Back
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immune system
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body's defense against invading microbes and foreign cells, as well as against the body's own cells that have gone bad. The immune system consists of cells and some molecules. This system has no organs; instead, it uses the pathways of the lymphatic and circulatory systems to transport immune system cells
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nonspecific defenses
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-The skin provides a barrier to keep out invaders, and oil-secreting glands in the skin increase the effectiveness of this barrier.
-Mucous membranes trap microbes. Such membranes line the respiratory and digestive system organs. -Cilia move trapped dirt and microbes. Cilia are tiny, hair-like structures found in the respiratory and digestive tracts. Dirt and microbes are moved into the throat, swallowed, and removed through digestion and excretion. -Hydrochloric acid destroys most bacteria ingested. This acid is found in the stomach and provides a battlefield where "good" bacteria (normal flora) fight "bad" bacteria. |
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Which of the following is one nonspecific defense against invaders to the body?
A White blood cells B Vaccine C Antibodies D Mucous membranes |
D is the correct answer. Choices A and C are specific defenses. Choice B is active immunity.
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lymphatic system
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works in conjunction with the immune system. The main function of the lymphatic system is to keep the body healthy. The tubes that carry lymph fluid throughout the body are the lymphatic vessels. These vessels are structured similarly to the circulatory system's veins. Lymphatic vessels originate as capillaries in spaces between cells. They are found throughout the body, except in avascular tissue, the spleen, bone marrow, or the central nervous system.
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lymph
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Extra tissue fluid surrounds every cell of the body. Excess tissue fluid is call lymph when it is absorbed by the lymphatic vessels. Lymph moves through the lymphatic system, carrying lymphocytes (white blood cells) and a few red blood cells and fat particles. Lymph fluid is prevented from flowing backward by valves; therefore, the system is a one-way track. The lymph is moved by the squeezing action from the movement of arms, legs, and other skeletal muscles. Lymph passes through lymph nodes where it is filtered to remove microbes and impurities.
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lymph nodes
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oval-shaped organs that are located in various places along the lymphatic vessels. These nodes are composed of masses of reticular connective tissue and white blood cells. The nodes act as sort of a net to trap bacteria or other harmful substances. As lymph passes through the nodes, it gets strained and cleaned before being returned to the blood stream. When the nodes get full they enlarge, which is a sign that they are doing their job of cleansing the blood. The lymph nodes are the only organs that filter lymph. Purified lymph returns to the bloodstream via the circulatory system's veins.
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spleen
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ductless, vertebrate gland located on the left side of the abdomen, right underneath the diaphragm. It is divided into lobules containing red pulp and white pulp. Red pulp contains red blood cells and white blood cells, including lymphocytes and macrophages. White pulp contains only lymphocytes and macrophages and no red blood cells.
The spleen serves to filter blood, with the lymphocytes and macrophages filtering out microbes and other foreign material. Excess blood is also stored in the spleen. When the body needs an increase in blood flow, the spleen releases blood. |
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thymus gland
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located just behind the sternum, overlaying the heart and straddling the trachea. The thymus is large in youth and diminishes in size with age. This gland produces the hormone thymosin, which stimulates the differentiation and maturation of T cells.
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tonsils
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lymphatic tissue arranged in a ring at the back of the throat. This tissue protects against invasion of inhaled or ingested foreigners. Tonsils "invite infection," which allows for the production of memory cells for later exposure.
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Which of the following produces thymosin?
A Thymus B Spleen C Lymph D Tonsil |
A is the correct answer. The spleen is a gland. Lymph is a fluid. Tonsils are lymphatic tissue.
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nonspecific response
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of the human body is a general response, no matter the invader. The body's inflammatory reaction is a nonspecific response.
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inflammatory response
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ocalizes the damage, removes damaged cells, and prepares for tissue restoration.
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capillary injury
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When capillaries are injured, the capillary releases the chemical histamine. This chemical dilates the capillary, allowing a larger volume of blood to flow through. This makes the injured area look red. Increased blood flow also delivers more immune system cells to fight any microbes present. With the release of histamine also comes the chemical bradykinin. This chemical is responsible for the brain interpretation of pain and the swelling associated with an injury. Bradykinin also increases extra tissue fluid moving through the injury and increases the permeability of the surrounding capillaries, thereby delivering neutrophils and monocytes as the first line of defense against invaders. Neutrophils consume bacteria through a process call phagocytosis. Phago- means "eating" and cyt- means "cell." Neutrophils surround bacteria and split the bacteria apart with enzymes. Monocytes grow into macrophages, which hunt and consume microbes. Macrophages also initiate the production of more white blood cells.
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complement system
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complex and works like a chain reaction. The activation of one complement protein activates another one, and another one, and so on. When microbes are detected, the complement system chain of events occurs. The complementary system is driven by several complement proteins working together. Some are activated and produce additional proteins that degrade microbes. Others instigate chemical release that serves as signals for inflammation and phagocytosis. Still another group of complement proteins mark microbes for death, which attracts phagocytes.
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immune system cells
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The immune system has a connection with both the skeletal and circulatory systems. White blood cells are created in the red marrow located at the end of long bones, and in the ribs, skull, pelvis, spinal column, clavicles, and sternum. Once created, white blood cells travel throughout the circulatory system.
Specialized cells, called multipotent stem cells, within red bone marrow can potentially differentiate into specific types of blood cells, including white blood cells. And, there are five types of white blood cells that mount attacks on invaders. |
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granular leukocytes
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When these cells are stained, the tiny granules in their cytoplasm can be seen easily.
Basophils release histamines. These cells comprise approximately one percent of all white blood cells in the body. Eosinophils phagocytize antigens and antibodies before splitting them apart. These cells comprise approximately one to four percent of all white blood cells. Neutrophils phagocytize bacteria. Forty to seventy percent of all white blood cells are neutrophil cells. |
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agranular leukocytes
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The tiny granules in the cytoplasm of agranular leukocytes cannot be easily seen when stained.
Monocytes develop into macrophages. These cells comprise approximately four to eight percent of all white blood cells. Macrophages phagocytize both bacteria and viruses. These cells are involved in the inflammatory, antibody-mediated, and cell-mediated responses. Macrophages play an important role in antigen presentation by engulfing the invader and then putting its antigens on the invaders surface to "present" to T lymphocytes. Macrophages also release proteins that activate T cells to release chemicals that will, in turn, transform macrophages into activated macrophages with a license to kill. |
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killer t cells
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also known as cytotoxic T cells. These are involved in the cell-mediated response. They directly attack and kill host cells harboring a virus. Killer T cells remove infected cells to protect uninfected cells.
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helper t cells
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involved in both the antibody- and cell-mediated responses. These cells produce a compound cell, interleukin, which stimulates the rapid division of B cells and killer T cells.
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suppressor t cells
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prevent any unnecessary immune responses. These cells come into play when the invader has been destroyed or inactivated. They release chemicals that inhibit the helper T cells, and so suppress the formation of antibodies and/or killer T cells.
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The largest majority of white blood cells are
A lymphocytes. B basophils. C monocytes. D neutrophils. |
The correct answer is D. Neutrophils comprise 40 – 70 percent of white blood cells. T lymphocytes share 20 – 45 percent with B lymphocytes. Basophils total approximately one percent and monocytes comprise four to eight percent.
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passive immunity
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temporary immunity provided by antibodies transferred during pregnancy and breast feeding
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vaccines
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a preparation containing an antigen used to provide immunity against a specific disease
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active immunity
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immunity produced when an immune system reacts to a stimulus (e.g., bacteria, virus, or vaccine) and produces antibodies and cells that will protect the body from future attacks
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memory cells
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a subset of T and B cells produced by the immune system to respond to second and subsequent infections
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primary immune response
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the immune system's response to the first challenge by an antigen, and the consequent creation of memory T cells ready for second and subsequent attacks
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secondary immune response
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the immune response to the second and subsequent attacks to specific antigen previously encountered
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attenuated virus vaccines
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designed to be recognized as antigens without causing infection. The virus might look the same, but it does not act the same
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Killed or weakened virus vaccines
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derived from the actual viruses. Either heat or chemicals are used to weaken or kill the virus. These vaccines are not as effective as attenuated virus vaccines
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Inactivated by-product vaccines
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made by using the by-products of a virus or bacteria. These by-products are flagged and used to tag invaders, if necessary. For example, the vaccine for tetanus is made from the by-products of the bacteria Clostridium tetani. Genetically engineered virus vaccines use bacteria to make some of the proteins found on the outer covering (capsid) of the virus. Many copies of the outer proteins are made for injection. This is just a copy of the virus housing. Although it does not adversely affect the body, the body does respond as if the virus was real. Examples include vaccines for hepatitis B, rabies, and the flu.
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group or herd immunity
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the resistance of group or community to invasion and spread of an infectious disease, based on the immunity of a high proportion of the group's members
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Vaccines injected into the body produce
A a secondary immune response. B lifelong immunity. C memory cells. D viral mutations |
The correct answer is C. A secondary immune response comes after a second attack of an invader. Lifelong immunity is very rare; vaccine boosters are often necessary. Viral mutations occur during viral reproduction.
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specific defense system
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1 The reaction is systemic—it does not occur in a single place.
(Nonspecific defenses are localized reactions.) 2 Responses are specific to the invader. (The invader type does not matter in nonspecific defenses.) 3 A memory of the invader is created, which allows the body to launch a larger attack the next time of exposure. The specific defense response happens after the host has been exposed to the invader. Once exposed the body creates specific antibodies. |
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2 types of primary immune response
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antibody-mediated and cell mediated
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anti-mediated immune response
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targets extracellular organisms, such as bacteria, viruses, fungus, protozoa, and other parasites. For an antibody to bind to an antigen, the antigen must be present. An antigen cannot be found if the invader is already in one of the body's own cells. The following takes place in a bacterial invasion.
1 When bacteria enter the body, their invasion triggers a general inflammatory response and macrophages engulf some of the bacterial cells by phagocytosis. Bacteria are transported via endocytic vesicles into the cytoplasm of the macrophages. The endocytic vesicles fuse with lysosomes and the enzymes digest the bacterial cells without destroying their surface antigens. These antigens are then transported via exocytic vesicles to the macrophages' cell membrane surface. There, the fragments bind to the macrophages' MHC markers, and are now called antigen-MHC complexes. 2 Helper T cells make contact with the macrophages, and the helper T cells' membrane antigen receptors bind to the macrophage antigen-MHC complexes. The occurrence of this binding causes the macrophages to secrete the compound interleukin that stimulates the helper T cells to secret their own interleukins. Helper T cell interleukins activate B cells to divide. 3 B cells originate and mature in the red bone marrow. While each B cell is maturing, it makes many copies of one type of antibody that no other B cell makes. Each antibody reacts to only one type of antigen. While the B cell is maturing, some of the antibodies it produces become positioned at the cell's surface where they bind to a specific antigen. When a B cell is released into circulation, it is called a virgin B cell, since its antibodies have not yet made contact with an antigen. When a virgin B cell interacts with a specific antigen that matches its antibodies, the B cell is activated. If an activated B cell interacts with the appropriate interleukin-producing helper T cell, the B cell begins dividing quickly, giving rise to a clonal population of identical B cells. 4 Part of this clonal population differentiates into plasma cells, which secrete thousands of copies of the antibody produced by the initial virgin B cell. These antibodies leave the plasma cells, but do not destroy invaders directly; instead, they attach to the invader's antigens. In doing so, the invader is made visible to macrophages, increasing the chance of attack by the macrophages. 5 The other part of the B cell clonal population differentiates into memory B cells, which are used in the secondary immune response. All B cells have the same genes for coding the amino acids in the chain but each maturing B cell shuffles the genetic code into one of millions of possible combinations, so the sequence of the amino acids is shuffled. This changes the order of the amino acids, which changes the shape of the protein. Because of this ability, B cells can give rise to virtually an unlimited number of shapes of antibodies. So when a virgin B cell comes into contact with "its" antigen, it really just happened to be there. The virgin B cells are not produced due to the invasion, they are already there. It is our genes that determine what specific foreign substances our immune system will be able to recognize and fight. |
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cell-mediated immune response
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deals with viruses and other pathogens that are already in the host cell (intracellular) and hidden from antibodies. In the cell-mediated immune response, the host cells are killed by killer T cells before the pathogens can replicate and spread to the other cells. The following occurs in a viral infection.
1 Killer T cells in the thymus produce antigen receptors that become positioned on the surface of the cells. These receptors are not antibodies, yet they are similar. 2 The thymus gland releases killer T cells into circulation. 3 When a virus infects a cell, viral proteins become associated with the MHC markers on the host cell's surface. 4 The receptors on the killer T cells bind to the antigen-MHC complexes of the infected cells or macrophages. 5 The killer T cells secrete perforins—a protein that punches holes in the membrane of an infected cell. This kills the infected cell and prevents the reproduction and spread of the virus. As in the antibody-mediated response, this stimulation of macrophages causes them to produce interleukins, thus stimulating the production of more killer T cells. This again creates a clonal population of killer T-cells—all with the same antigen receptor as the original killer T cell. Some of these clones become memory T cells, which are important in the secondary immune response. When the body rejects an organ transplant or skin graft, killer T cells are one of the reasons why. They recognize the foreign MHC markers on the transplanted organ cells and attack. This is why organ recipients are given immuno-suppressor drugs, which can compromise the body's attempt to mount immune responses to other pathogens. |
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autoimmune disorders
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disorder resulting from the body is attacked by its own immune system; examples are rheumatoid arthritis and system lupus erythematosus
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rheumatoid arthritis
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body destroying its joints.
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lupus erythematosus
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body creating antibodies against the individual's own DNA. This can affect the skin and various body systems, including musculoskeletal, cardiovascular, and neural.
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multiple sclerosis
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attacks the brain and spinal cord.
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Graves' disease
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thyroid producing too much thyroxin. A symptom is extremely large, buggy eyes.
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Juvenile diabetes
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pancreas producing not enough insulin to regulate blood sugar levels. It is a lifelong disease.
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immunodeficiency
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the body's decreased ability to fight infection and disease; also called immune deficiency
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AIDS
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caused by a virus—human immunodeficiency virus (HIV). This virus is spread through blood-to-blood contact. It works by destroying the helper T cells that are so important in immunity. When T cell levels are lowered, the efficiency of the immune system is compromised. There are no flags to show immune system cells where to go for attack. Thus, the immunodeficiency has now been acquired.
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antigens
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a foreign substance invading the human body and initiating an immune system response
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immunogenity
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an antigen's or vaccine's ability to stimulate an immune response
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