Nokea
The intestinal epithelial cells that specialize in the production of antimicrobial peptides are called:
- A. Goblet cells
- B. Enterocytes
- C. Paneth cells
- D. Epithelial stem cells
Correct Answer: C
Rationale: The correct answer is C: Paneth cells. Paneth cells are specialized intestinal epithelial cells located in the small intestine that produce antimicrobial peptides to help defend against pathogens. They play a crucial role in maintaining gut homeostasis. Goblet cells (A) secrete mucus, enterocytes (B) absorb nutrients, and epithelial stem cells (D) are responsible for cell regeneration, but they do not produce antimicrobial peptides like Paneth cells do.
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What defect in cellular proliferation is involved in the development of cancer?
- A. A rate of cell proliferation that is more rapid than that of normal body cells
- B. Shortened phases of cell life cycles with occasional skipping of G1 or S phases
- C. Rearrangement of stem cell RNA that causes abnormal cellular protein synthesis
- D. Indiscriminate and continuous proliferation of cells with loss of contact inhibition
Correct Answer: D
Rationale: Cancer involves indiscriminate and continuous proliferation of cells with loss of contact inhibition, which allows cells to grow uncontrollably.
In LN naïve T cells and activated dendritic cells interact in the
- A. Subcapsular sinus
- B. Cortex
- C. Paracortex
- D. Medulla
Correct Answer: C
Rationale: The correct answer is C: Paracortex. Naïve T cells circulate through the blood and lymphatic system until they encounter antigens presented by activated dendritic cells in the paracortex of lymph nodes. The paracortex is the region where T cell activation and proliferation occur, leading to an immune response. The subcapsular sinus (A) is primarily involved in filtering lymph fluid, the cortex (B) contains B cell follicles, and the medulla (D) contains plasma cells and macrophages. Thus, the paracortex is the specific site of interaction between naïve T cells and activated dendritic cells in lymph nodes.
T-cell antigen receptors are distinguished from antibodies by which of the following
- A. T-Cell receptors are glycosylated
- B. T-cell receptors must interact with antigen uniquely presented by other cells but not with free antigen
- C. T-Cell receptors bind various cytokines
- D. T-Cell receptors bind complement to lyse cells
Correct Answer: B
Rationale: The correct answer is B. T-cell receptors must interact with antigens uniquely presented by other cells but not with free antigen. This is because T-cell receptors recognize antigens that are processed and presented on the surface of other cells via major histocompatibility complex (MHC) molecules. T-cell receptors specifically bind to the antigen-MHC complex, allowing T-cells to respond to specific foreign antigens.
A: T-cell receptors are not distinguished from antibodies by glycosylation. Both T-cell receptors and antibodies can be glycosylated, so this does not differentiate them.
C: T-cell receptors do not bind various cytokines. Cytokine receptors are separate entities that mediate cellular responses to cytokines.
D: T-cell receptors do not bind complement to lyse cells. Complement activation is a separate immune response mechanism not involving T-cell receptors.
What is the primary mechanism by which innate immunity differentiates between self and non-self?
- A. Somatic recombination
- B. Recognition of PAMPs via PRRs
- C. Presentation of antigens by MHC molecules
- D. Production of antibodies
Correct Answer: B
Rationale: The correct answer is B: Recognition of PAMPs via PRRs. Innate immunity distinguishes self from non-self by recognizing Pathogen-Associated Molecular Patterns (PAMPs) via Pattern Recognition Receptors (PRRs). This recognition triggers an immediate response to eliminate potential threats. Choices A, C, and D are incorrect because somatic recombination is a process in adaptive immunity, MHC molecules present antigens for recognition by T cells in adaptive immunity, and antibody production is part of adaptive immunity involving B cells.
Which of the following should a client with autoimmune disorder be advised to avoid?
- A. Rest during the periods of severe exacerbation
- B. Regular exercise during the periods of remission
- C. Being in crowds during the periods of immunosuppression
- D. Humid environment during the periods of remission
Correct Answer: C
Rationale: Clients with autoimmune disorders especially during immunosuppression should avoid crowds to reduce the risk of infections.