A patient is suffered from vitamin K deficiency. Which of the coagulation factors will not be affected?

Correct Answer: C

Rationale: The correct answer is C: Factor VIII. Factor VIII is not dependent on vitamin K for its synthesis, so its levels will not be affected by vitamin K deficiency. Factor II, VII, and IX are all vitamin K-dependent factors, so their levels will decrease with vitamin K deficiency, leading to impaired blood clotting. This is due to the role of vitamin K in the post-translational modification of these factors, which is necessary for their activation. Therefore, Factor VIII is the only factor that will not be affected by vitamin K deficiency.

Correct Answer: B

Rationale: The correct answer is B: Basophilic stippling. Hookworm infection can lead to anemia due to chronic blood loss. Basophilic stippling is a characteristic finding in the peripheral blood smear of patients with iron deficiency anemia, which can result from hookworm infection. Basophilic stippling represents the aggregation of ribosomes and is seen in erythrocytes that contain denatured ribosomal RNA. Howell-Jolly bodies are remnants of nuclear material and are typically seen in patients with functional asplenia. Target cells are seen in conditions like liver disease or hemoglobinopathies. Spherocytes are seen in immune hemolytic anemias.

Correct Answer: D

Rationale: The correct answer is D: Aplastic anemia. Aplastic anemia is characterized by pancytopenia, which includes low hemoglobin levels leading to anemia. The dry tap marrow indicates bone marrow failure, which is a hallmark of aplastic anemia. The subcutaneous petechiae are due to thrombocytopenia, another feature of this condition. Iron deficiency anemia (A) typically presents with microcytic hypochromic red blood cells and is not associated with bone marrow failure. Megaloblastic anemia (B) is characterized by macrocytic red blood cells and is usually due to deficiencies in vitamin B12 or folate. Hemolytic anemia (C) involves the premature destruction of red blood cells and is not typically associated with bone marrow failure.

Correct Answer: C

Rationale: The correct answer is C, Microangiopathic hemolytic anemia. Schistocytes are fragmented red blood cells caused by mechanical damage as they pass through narrowed vessels. This occurs in conditions like thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, which are types of microangiopathic hemolytic anemia. Sickle cell trait (A) and Thalassemia (B) are genetic disorders affecting red blood cell structure and production, not causing mechanical fragmentation. Idiopathic thrombocytopenic purpura (D) is a disorder characterized by low platelet count, unrelated to RBC fragmentation.

Correct Answer: C

Rationale: The correct answer is C: Platelets change their shape during the process of platelet aggregation in vascular injury. Platelets undergo shape change from a discoid to a spiky form, leading to the exposure of their glycoprotein receptors, which then bind to fibrinogen and other platelets to form a platelet plug. This process is crucial for hemostasis and preventing excessive bleeding. Explanation for why other choices are incorrect: A: There will be initial vasodilation - Vasodilation is not a direct result of platelet aggregation but rather an initial response to vascular injury to increase blood flow to the area. B: Clotting factors play no role in its formation - Clotting factors are essential for the later stages of hemostasis, but platelet aggregation is primarily driven by platelet activation and shape change. D: Serotonin stimulates platelet aggregation - While serotonin is released from platelets upon activation, it does not directly stimulate platelet aggregation.