Human Anatomy and Physiology : Innate Immunity

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #1 : Innate Immunity

What is the purpose of basophils?

Possible Answers:

They aid in destroying parasites and addressing allergic reactions

They cause inflammation in order to allow more leukocytes to migrate to the affected area

They release antibodies for one specific antigen

They engulf bacteria and pathogens in the body

Correct answer:

They cause inflammation in order to allow more leukocytes to migrate to the affected area

Explanation:

Basophils are part of the innate immunity, and are a key player for stimulating inflammation. Basophils release histamine, which dilates blood vessels and increases the permeability of capillaries. This allows an infection to be walled off in the affected area and helps other white blood cells migrate to the area.

Eosinphils are involved in parasitic immunity and allergic reactions. Neutrophils, macrophages, and monocytes are responsible for phagocytosing foreign pathogens. B-lymphocytes release antibodies against a specific antigen.

Example Question #2 : Innate Immunity

Which of the following leukocytes is NOT a granulocyte?

Possible Answers:

Lymphocyte

Eosinophil

Neutrophil

Basophil

Correct answer:

Lymphocyte

Explanation:

White blood cells can be classified by whether or not they have granules in their cytoplasm (granulocytes and agranulocytes). There are three types of granulocytes, and all of them end in the suffix "-phil." Neutrophils, basophils, and eosinophils are considered granulocytes. Lymphocytes are agranulocytes, and do not have granules present in their cytoplasm.

Example Question #1 : Innate Immunity

Which white blood cell type will notably increase during allergies and parasitic infections?

Possible Answers:

Eosinophils

Basophils

Lymphocytes

Monocytes

Neutrophils

Correct answer:

Eosinophils

Explanation:

The white blood cells are typically categorized into several major types. Each of these types have specific roles in the body, and their proportions will change during specific body conditions. Basophils are used to dilate blood vessels by releasing histamine and eosinophils become elevated during parasitic infections and allergy season. Neutrophils play an important role in recruiting other immune cells to damaged tissues. Lymphocytes include B-cells and T-cells and are involved in the adaptive immune response. Monocytes are the preliminary cells that differentiate into macrophages, which are involved in non-specific phagocytosis.

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?

Possible Answers:

NADPH oxidase

Peroxidase

Superoxide dismutase

Catalase

Enolase

Correct answer:

NADPH oxidase

Explanation:

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?

Possible Answers:

Neural

Microglia

Astrocyte

Epithelial

Macrophage

Correct answer:

Neural

Explanation:

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?

Possible Answers:

CD8 T-cells

Polymorphonuclear cells

CD4 T-cells

B-cells

Macrophages

Correct answer:

Polymorphonuclear cells

Explanation:

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 #1 : Innate Immunity

Which of the following is involved in the innate immune system?

Possible Answers:

Memory B-cells

C1qrs

Plasma cells

C3b

Correct answer:

C3b

Explanation:

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 #2 : Innate Immunity

Which of the following is not involved in phagocytosis?

Possible Answers:

Plasma cells

Neutrophils

Macrophages

C3b

Correct answer:

Plasma cells

Explanation:

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 : Innate Immunity

Which of the following cells is not part of the innate immune system? 

Possible Answers:

Macrophages 

Neutrophils 

B cell 

Mast cells 

Natural killer cells

Correct answer:

B cell 

Explanation:

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 : Innate Immunity

Which of the following describes mast cells?

Possible Answers:

Cells that target specific infected cells

Antibody-producing 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

Correct answer:

Cells that contain granules that cause inflammation when released and attract other cells to an area

Explanation:

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.

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