Reed-Sternberg cells infrequent, popcorn cells present. Hodgkin’s type?

Correct Answer: C

Rationale: The correct answer is C: Lymphocyte predominance. Reed-Sternberg cells are characteristic of Hodgkin's lymphoma. In this type, Reed-Sternberg cells are infrequent, and popcorn cells are present. This presentation is typical of lymphocyte predominance subtype. Nodular sclerosis (A) is characterized by bands of collagen separating nodules, mixed cellularity (B) has a mixed cell population with frequent Reed-Sternberg cells, and lymphocyte depleted (D) has few lymphocytes and more Reed-Sternberg cells.

Correct Answer: C

Rationale: Platelets play a crucial role in the process of hemostasis after vascular injury. When a blood vessel is damaged, platelets adhere to the site and change shape to form a plug, a process known as platelet aggregation. This is important for stopping bleeding. Vasodilation (choice A) typically occurs after vasoconstriction to help with blood flow. Clotting factors (choice B) are essential in the coagulation cascade but not directly involved in platelet aggregation. Serotonin (choice D) is released by platelets during aggregation but does not directly stimulate the process. Therefore, the correct answer is C as platelets changing shape is a key step in platelet aggregation during vascular injury.

Correct Answer: D

Rationale: The correct answer is D: Thymus. The thymus is a primary lymphoid organ where T lymphocytes mature. It plays a crucial role in the development of the immune system. Lymph nodes (A), spleen (B), and Peyer's patches (C) are considered secondary lymphoid organs where immune responses are initiated but not where lymphocytes mature. Thymus is the only choice that fits the criteria of being a primary lymphoid organ.

Correct Answer: A

Rationale: The correct answer is A: Antibodies are opsonins. Antibodies are proteins produced by B-cells that can bind to antigens, marking them for destruction by phagocytic cells. Opsonins enhance phagocytosis by promoting the binding of pathogens to phagocytes. This statement is correct because antibodies can act as opsonins. B: B-cells can't recognize naive antigen - Incorrect. B-cells can recognize and respond to naive antigens through their B-cell receptors. C: T-cells recognize naive antigen - Incorrect. T-cells also recognize and respond to naive antigens through their T-cell receptors. D: T-helper cells not important for cytokines - Incorrect. T-helper cells play a crucial role in orchestrating the immune response by producing cytokines that regulate immune cell activities.

Correct Answer: A

Rationale: The correct answer is A because older people tend to have lower levels of plasma proteins, such as antibodies, which play a crucial role in immune function. This results in a weaker immune response to pathogens. Explanation: 1. Plasma proteins are essential for immune defense. 2. Aging leads to a decline in plasma protein levels. 3. Lower plasma protein levels weaken the immune system's ability to fight infections. Summary: B and C are incorrect because bone marrow and platelets are not directly related to immune system weakening in older individuals. D is incorrect as lymphocytes becoming more reactive would actually suggest a stronger immune response, not a weaker one.