Human Anatomy and Physiology : Immune Physiology
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Example Question #41 : Immune Physiology
The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.
Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.
CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.
Polymorphonuclear cells are the first cells that typically migrate to the site of infection. They are central in phagocytosing invading pathogens. Once ingested, pathogens are killed via the generation of hyper-reactive oxygen radicals. Which of the following is most likely to mediate the first step in radical oxidation in these cells?
NADPH oxidase
Peroxidase
Superoxide dismutase
Catalase
Enolase
NADPH oxidase
NADPH oxidase is the first enzyme that can be expected to generate radicals from molecular oxygen. Once the radicals have been generated, they react with another enzyme to generate hydrogen peroxide, a more stable molecule. This generation of a stable intermediate protects the polymorphonuclear cell itself from damage.
The final step mediated by myeloperoxidase generates hypochlorite, or bleach, that ultimately kills the ingested pathogens.
Example Question #42 : Immune Physiology
The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.
Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.
CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.
In contrast to adaptive immunity, innate immunity mounts both active and passive responses to potential infections. Which of the following would least likely be included among relevant cell types for the innate immune system?
Neural
Microglia
Astrocyte
Epithelial
Macrophage
Neural
The innate immune system includes structures that prevent infection, as well as those that take on a non-specific, but active role. A macrophage would be a good example of a non-specific, active innate immune cell. The remainder of the options, with the exception of a neuron, are also preventive structures. Epithelial cells form a barrier to the outside, potentially contaminated environment. Microglia are monocyte-derived, macrophage-like cells in the central nervous system. Astrocytes form the blood-brain barrier, preventing potentially infectious material in the blood from getting to the central nervous system. As neurons lie behind this barrier, they would play the least important role in any kind of innate immunity.
Example Question #1 : Help With Cells Of Innate Immunity
The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.
Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.
CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.
Mutations in the enzyme superoxide dismutase have been implicated in cases of amyothrophic lateral sclerosis. This enzyme is part of the radical burst reaction, and is most likely found in which cells?
CD8 T-cells
Polymorphonuclear cells
CD4 T-cells
B-cells
Macrophages
Polymorphonuclear cells
Superoxide dismutase is in the same radical pathway that involves NADPH oxidase. As a result, it is most likely to be found in nonspecific cells of the innate immune system, such as polymorphonuclear cells.
Example Question #4 : Help With Cells Of Innate Immunity
Which of the following is involved in the innate immune system?
Memory B-cells
C1qrs
Plasma cells
C3b
C3b
C3b is involved in coating bacteria to tag them for degradation by phagosomes, and is activated by the complement system. The alternative complement pathway is activated during innate immunity and activates C3b.
All B-cells are involved in adaptive immunity, including memory B-cells and plasma cells (which as derived from B-cells). C1qrs is involved in the classical complement pathway, but requires antibody-antigen interaction from the adapative immune system.
Example Question #3 : Innate Immunity
Which of the following is not involved in phagocytosis?
Neutrophils
Macrophages
Plasma cells
C3b
Plasma cells
Plasma cells are the only answer option that is not involved with phagocytosis. Plasma cells are derived from B-cells and serve as the primary source of antibody production during the adaptive immune response.
C3b coats bacteria so that macrophages target them for ingestion. Neutrophils are also capable of causing cell lysis and phagocytosis.
Example Question #3 : Help With Cells Of Innate Immunity
Which of the following cells is not part of the innate immune system?
Macrophages
Natural killer cells
B cell
Mast cells
Neutrophils
B cell
The innate immune system is the non-specific immune system that you are born with. Cells of the innate immune system include mast cells, macrophages, neutrophils (and other white cells), natural killer cells, and complement (a group of proteins found in the blood). The B cells are associated with the adaptive immune system, producing antibodies, and providing a memory component of the immune system. The innate immune system does not have a memory component.
Example Question #4 : Help With Cells Of Innate Immunity
Which of the following describes mast cells?
Antibody-producing cells
Cells that target specific infected cells
Lymphocytes that form plasma cells and antibodies when they recognize specific antigens
Cells that contain granules that cause inflammation when released and attract other cells to an area
Cells that contain granules that cause inflammation when released and attract other cells to an area
A mast cell is similar to a basophil in that their granules, which contain histamine and heparin, produce inflammation when released. Also, mast cells play a role in angiogenesis during wound healing. A T-cell is a cell that targets infected cells to destroy. Plasma cells are antibody-producing cells. B-cells form plasma and antibodies in response to specific antigens.
Example Question #1211 : Human Anatomy And Physiology
What is the purpose of mast cells?
To process proteins in lymph fluid
To engulf cell debris or infectious organisms
To form plasma cells
To release granules, which cause inflammation and attract other cells to the area
To release granules, which cause inflammation and attract other cells to the area
Mast cells contain granules which are released to cause inflammation and attract other cells to the area. B-cells that form plasma cells and antibodies when a specific antigen is recognized. Dendritic cells are those that process proteins in lymph fluid, they have long "arms." Macrophages are the cells that engulf and consume cell debris or infectious organisms.
Example Question #1212 : Human Anatomy And Physiology
Which of the following is not a cell of innate immunity?
Basophils
Natural killer cells
B-lymphocytes
Monocytes
B-lymphocytes
B-lymphocytes are part of the adaptive immunity system, they create plasma cells and antibodies when they recognize a specific antigen. Monocytes are what macrophages are before they leave the bloodstream. Basophils contain granules of histamine which produce an inflammation response when released. Natural killer cells attack infected or cancerous cells.
Example Question #1213 : Human Anatomy And Physiology
Which of the following cell types produces antibodies?
T-Cell
Basophil
Natural killer cell
B-Cell
B-Cell
B-cells are stimulated by antigens, which in turn leads to antibody production. Antibodies then are used to neutralize invaders or tag them for destruction. T-cells are divided into helper T-cells, killer T-cells, regulatory T-cells types. Natural killer cells destroy cells that have become infected with pathogens and additionally also cancer cells. Basophils are a type of granulocyte that are active in allergic and inflammatory responses.
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