ATI RN
Basic Immune System Quizlet Questions
Question 1 of 5
What is the primary function of platelets?
Correct Answer: C
Rationale: Platelets primarily function in clotting and sealing damaged blood vessels. Firstly, when a blood vessel is injured, platelets rush to the site to form a plug, preventing excessive bleeding. Secondly, platelets release clotting factors to initiate the coagulation cascade, leading to the formation of a stable blood clot. This process is crucial for wound healing and preventing blood loss. Platelets do not produce hormones (choice A), transport gases (choice B), or protect the body from foreign substances (choice D). These functions are carried out by other components of the body's systems.
Question 2 of 5
Which of the following does not describe defensins?
Correct Answer: B
Rationale: The correct answer is B: They function as opsonins. Rationale: 1. Defensins disrupt pathogen membranes by penetrating them (A), not by functioning as opsonins. 2. Defensins are amphipathic (C), having hydrophobic and hydrophilic regions, which aid in membrane disruption. 3. Defensins are contained in neutrophil granules (D), contributing to their role in the immune response. Summary: Choice B is incorrect because defensins do not function as opsonins, which are molecules that enhance phagocytosis of pathogens by immune cells. Choices A, C, and D correctly describe aspects of defensins' mechanism of action and localization.
Question 3 of 5
All of the following can be a consequence of the formation of NETS with the exception of:
Correct Answer: A
Rationale: The correct answer is A because NETs (Neutrophil Extracellular Traps) are released by neutrophils to trap and kill microbes extracellularly. Step 1: NETs are composed of DNA, histones, and antimicrobial proteins. Step 2: They trap microbes at the site of infection. Step 3: The antimicrobial proteins in NETs kill the trapped microbes. Step 4: Neutrophils themselves do not contain microbes inside phagolysosomes, so the killing of microbes contained in phagolysosomes is not a direct consequence of NET formation. Therefore, choice A is the exception. Choices B, C, and D are incorrect as they are all consequences of NET formation.
Question 4 of 5
Which of the following is a characteristic of the constant region of a T cell receptor?
Correct Answer: B
Rationale: The correct answer is B: Anchors the receptor in the T cell membrane. The constant region of a T cell receptor is responsible for anchoring the receptor in the T cell membrane, providing stability and structural support. This region does not mediate antigen binding (choice A), as that function is carried out by the variable region. It also does not directly interact with MHC molecules (choice C), which is primarily the role of the variable region. Lastly, the constant region is not structurally diverse amongst T cell receptors (choice D), as it remains relatively consistent within a specific T cell subtype.
Question 5 of 5
Which of the following is not required for full activation of a naïve lymphocyte?
Correct Answer: A
Rationale: The correct answer is A. Naïve lymphocytes require activation through recognition of specific antigen, costimulatory signaling, and cytokines. Migration into an inflammatory site is not a requirement for full activation. Naïve lymphocytes can be activated in secondary lymphoid organs where antigen presentation occurs. Migration to inflammatory sites occurs after activation to fight infections.