What does von Willebrand factor do?

Correct Answer: B

Rationale: Rationale: Von Willebrand factor plays a crucial role in primary hemostasis by binding platelets to the subendothelium at sites of vascular injury, facilitating platelet adhesion and aggregation. This is important for forming a platelet plug to stop bleeding. Choices A and C are incorrect because von Willebrand factor does not directly bind platelets to each other or to a phospholipid surface. Choice D is incorrect because von Willebrand factor does not carry factor VII, but it does carry factor VIII.

Correct Answer: C

Rationale: The correct answer is C, Factor VIII. Vitamin K deficiency primarily affects the synthesis of Factors II, VII, IX, and X. Factor VIII is not dependent on vitamin K for its synthesis since it is a co-factor for Factor IX. Therefore, Factor VIII levels remain unaffected in Vitamin K deficiency. Factors II, VII, and IX are all vitamin K-dependent factors, making them incorrect choices.

Correct Answer: A

Rationale: Correct Answer: A - Low TIBC Rationale: - Pallor, fatigue, koilonychias, and cheilosis are symptoms of iron deficiency anemia. - Low TIBC is not an expected lab finding in iron deficiency anemia. - TIBC measures the total amount of iron that can be carried in the blood by transferrin. In iron deficiency anemia, TIBC is typically elevated, not low. - High serum transferrin, low iron:TIBC ratio, and low serum ferritin are all expected lab findings in iron deficiency anemia indicating low iron stores and increased iron-binding capacity.

Correct Answer: A

Rationale: The correct answer is A: Acute myeloid leukemia. The key clues are the presence of 15% myeloblasts and reduced erythropoiesis. In AML, there is an abnormal increase in myeloblasts in the bone marrow, leading to reduced production of normal blood cells, including erythrocytes. Myelofibrosis (C) is characterized by fibrotic changes in the bone marrow, not an increase in blasts. ALL (B) primarily affects lymphoid cells, not myeloblasts. MDS (D) involves ineffective hematopoiesis and dysplastic changes, but not necessarily a high blast count.

Correct Answer: D

Rationale: The correct answer is D: Schizonticidal activity. Artemisinin targets and kills the asexual blood stage of the malaria parasite Plasmodium falciparum, known as schizonts. This action helps in treating resistant falciparum malaria. Gametocidal activity (A) targets sexual stage parasites, preventing transmission but not directly treating the infection. Preventing hypnozoites (B) is specific to Plasmodium vivax and ovale, not falciparum. Sporontocidal activity (C) targets mosquito-stage parasites, which is not relevant for treating resistant falciparum malaria.