What is the medical term for the formation of abnormal red blood cells?

Correct Answer: D

Rationale: The correct answer is D: Anemia. Anemia is the medical term for a condition where there is a decrease in the number of red blood cells or hemoglobin in the blood. The formation of abnormal red blood cells can lead to anemia, affecting the oxygen-carrying capacity of the blood. Leukocytosis (A) is an increase in white blood cells, thrombocytosis (B) is an increase in platelets, and hemolysis (C) is the breakdown of red blood cells, none of which specifically refer to the formation of abnormal red blood cells.

Correct Answer: A

Rationale: The correct answer is A: Selectins expressed on endothelial cells. Rolling of neutrophils on endothelial cells is a crucial step in the process of inflammation and immune response. Selectins are cell adhesion molecules expressed on endothelial cells that facilitate the initial interaction between leukocytes (such as neutrophils) and endothelial cells. This interaction allows for the rolling of neutrophils along the endothelial surface, which is essential for the subsequent steps of adhesion and transmigration into the tissues. Integrins (Choice B) are involved in the firm adhesion of leukocytes to endothelial cells, not in the initial rolling process. Chemokines (Choice C) such as CXCL-8 are signaling molecules that help in the recruitment of leukocytes but do not directly mediate the rolling process. TNF (Choice D) is a pro-inflammatory cytokine but is not directly involved in the rolling of neutrophils on endothelial cells.

Correct Answer: C

Rationale: The correct answer is C because secondary lymphoid tissues, like lymph nodes and spleen, are where lymphocytes encounter antigens and become activated. This process leads to the proliferation and differentiation of lymphocytes, enabling them to mount an immune response against specific pathogens. Choices A, B, and D are incorrect because A pertains to primary lymphoid tissues, B describes a localized immune response, and D refers to the process of gene rearrangement that occurs in the primary lymphoid tissues during lymphocyte development.

Correct Answer: C

Rationale: After engagement of pattern recognition receptors, dendritic cells upregulate expression of the B7 molecule, which is essential for co-stimulation of naïve T cells. This step is crucial for activating T cells. MHC class I molecules present antigens to CD8+ T cells, not CD4+ T cells, so choice A is incorrect. Dendritic cells already have high antigen uptake ability, so choice B is not directly related to activation. PAMP-induced proliferation is not a typical response of dendritic cells after pattern recognition receptor engagement, making choice D incorrect.

Correct Answer: C

Rationale: The correct answer is C because celiac disease primarily involves an abnormal adaptive immune response to gluten, not an innate response. Here's the rationale: 1) Celiac disease is characterized by a T-cell mediated response to gluten peptides in genetically susceptible individuals. 2) The adaptive immune system, particularly T cells, plays a crucial role in the pathogenesis by recognizing gluten peptides presented by HLA-DQ2 or HLA-DQ8 molecules. 3) This adaptive immune response leads to inflammation and damage to the intestinal mucosa. 4) In contrast, the innate immune system may also be activated, but it is not the primary driver of the disease. Summary: A: Correct - There is a strong genetic association with HLA alleles. B: Incorrect - Celiac disease is primarily driven by an adaptive immune response, not just features of autoimmunity. D: Incorrect - While gluten exposure triggers the immune response, the disease is not solely driven by gluten intake.