Nokea
Which of the following sentences concerned with lymph node structure is incorrect?
- A. naïve B lymphocytes are found in the cortex
- B. naïve T lymphocytes are found in the paracortex
- C. naïve lymphocytes enter the lymph node through the efferent lymphatic vessel
- D. Antigens can enter the lymph node through afferent lymphatic vessels
Correct Answer: C
Rationale: Rationale:
C is incorrect because naïve lymphocytes actually enter the lymph node through the afferent lymphatic vessel, not the efferent. A carries lymphocytes into the lymph node, and D is true since antigens enter through afferent vessels. B is correct, as naïve T cells are found in the paracortex.
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What is the primary goal of palliative care in cancer treatment?
- A. Cure the disease
- B. Extend life expectancy
- C. Relieve suffering and improve quality of life
- D. Prevent disease recurrence
Correct Answer: C
Rationale: Palliative care focuses on relieving suffering and improving quality of life for patients with advanced cancer.
Which of the following white blood cells is small,present in blood and migrates to tissue as necessary?
- A. Neutrophils
- B. Leukocytes
- C. Monocytes
- D. Lymphocytes
Correct Answer: D
Rationale: Lymphocytes are small white blood cells that circulate in the blood and migrate to tissues as needed to participate in immune responses.
A 21-year-old patient says no one in his family has type 1 diabetes mellitus but he has had it since childhood. He asks how his diabetes was transmitted to him. The nurse should explain to him that this disease is
- A. a single gene disorder
- B. a chromosome disorder
- C. an acquired genetic disorder
- D. a multifactorial genetic disorder
Correct Answer: D
Rationale: Type 1 diabetes is considered a multifactorial genetic disorder influenced by multiple genes and environmental factors rather than being caused by a single gene or chromosome.
The epitopes recognized by T cells are always:
- A. Conformational
- B. Linear
- C. On the antigen surface
- D. Buried inside the antigen
Correct Answer: B
Rationale: The correct answer is B: Linear. T cells recognize linear epitopes, which are sequences of amino acids displayed in a linear fashion on the antigen's surface. This recognition occurs through the T cell receptor binding to the linear epitope. Conformational epitopes (A) involve multiple amino acid residues brought together in a specific three-dimensional structure. Epitopes on the antigen surface (C) are correct, but not all T cell epitopes are necessarily on the surface. Epitopes buried inside the antigen (D) are not accessible to T cell receptors for recognition. Thus, the correct choice is B due to the linear presentation of epitopes for T cell recognition.
Which of the following is a feature of antigen recognition by B cells?
- A. Their antigen receptors are never secreted
- B. Their antigen receptors recognize a fragment of protein in combination with an MHC molecule
- C. Their receptors each have two identical antigen binding sites
- D. They recognize pattern associated molecular structures (PAMPs) that are unique to a particular pathogen
Correct Answer: C
Rationale: The correct answer is C because B cell receptors, known as antibodies, are Y-shaped proteins with two identical antigen-binding sites. This feature allows B cells to bind to specific antigens with high specificity. Each B cell receptor can bind to a unique antigen, leading to the initiation of an immune response.
Choice A is incorrect because B cell receptors can be secreted as antibodies to target antigens outside the cell.
Choice B is incorrect because B cell receptors recognize antigens directly, not in combination with MHC molecules.
Choice D is incorrect because B cells primarily recognize specific antigens rather than general PAMPs associated with pathogens.