Both B and T cells are originally derived from cells of the:
gut-associated lymphoid tissue.
bone marrow.
Thymus.
lymph nodes.
The Correct Answer is B
A. Gut-associated lymphoid tissue (GALT): GALT is a component of the mucosa-associated lymphoid tissue (MALT) and refers to the immune cells found in the gastrointestinal tract. These cells play a significant role in local immune responses in the gut.
B. Bone marrow: The bone marrow is the primary site of blood cell production in the body. It contains stem cells that can differentiate into various blood cells, including B cells. B cells mature in the bone marrow.
C. Thymus: The thymus is an organ located near the heart and is crucial for the development of T cells. T cells mature in the thymus, where they learn to recognize self from non-self antigens.
D. Lymph nodes: Lymph nodes are small, bean-shaped structures that produce and store cells that help fight infection. While they are essential parts of the immune system, B and T cells are not originally derived from lymph nodes.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. "Cephalosporins are assigned to generations based on their relative costs to administer."
This statement is incorrect. The classification of cephalosporins into generations is based on their antimicrobial spectrum and activity against specific bacteria, not their cost.
B. "Later generations of cephalosporins have lower resistance to destruction by beta-lactamases."
This statement is not accurate. In fact, later generations of cephalosporins have increased resistance to destruction by beta-lactamases, which are enzymes produced by bacteria that can break down certain antibiotics.
C. "Cephalosporins have increased activity against gram-negative bacteria with each new generation."
This statement is correct. Cephalosporins are grouped into generations (first to fifth) based on their antibacterial spectrum. As the generations progress, there is an increase in activity against gram-negative bacteria, among other improvements in their spectrum.
D. "First-generation cephalosporins have better penetration of the cerebrospinal fluid."
This statement is generally true. First-generation cephalosporins have better penetration into the cerebrospinal fluid, making them useful for treating certain central nervous system infections.
Correct Answer is C
Explanation
A. Delayed hypersensitivity reaction: This type of hypersensitivity reaction, also known as Type IV hypersensitivity, involves a delayed response by the immune system and is mediated by T cells. It does not necessarily involve a failure of self-tolerance.
B. Antibody-mediated reaction: This type of hypersensitivity reaction, also known as Type II hypersensitivity, involves antibodies targeting specific antigens on cell surfaces, leading to cell destruction. It doesn't directly indicate a failure of self-tolerance but rather an immune response against specific cells or tissues.
C. Autoimmune reaction: In autoimmune reactions, the immune system fails to recognize certain body tissues or substances as "self," leading to an immune response against the body's own cells or tissues. This results from a breakdown in self-tolerance, where the immune system mistakenly targets its own body.
D. Immediate hypersensitivity reaction: This type of hypersensitivity reaction, also known as Type I hypersensitivity, involves an immediate response by the immune system to an allergen. It includes conditions like allergies and anaphylaxis, where the immune system reacts strongly to substances that are normally harmless. This response does not necessarily indicate a failure of self-tolerance but rather an exaggerated response to specific antigens.
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