Which of the following cell types would be the first to aid in killing bacteria to prevent infection in his hand?

Correct Answer: B

Rationale: Neutrophils are the first responders to a bacterial infection. They are phagocytes that engulf and destroy bacteria, playing a crucial role in the early stages of the immune response. Eosinophils are primarily involved in combating parasitic infections and allergic reactions, not bacterial infections. Leukotrienes are signaling molecules that contribute to inflammation and immune responses, but they are not cells. Monocytes are another type of white blood cell that differentiates into macrophages and dendritic cells, playing a role in immune response but not as immediate as neutrophils.

Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.

Correct Answer: D

Rationale: Anemia of chronic inflammation is typically characterized by normochromic (normal hemoglobin content) and normocytic (normal cell size) red blood cells. Choice A, hypochromic and microcytic, is incorrect because hypochromic refers to reduced hemoglobin content and microcytic refers to smaller than normal red blood cells, which are not typically seen in anemia of chronic inflammation. Choice B, hypochromic and macrocytic, is also incorrect as macrocytic refers to larger than normal red blood cells. Choice C, normochromic and microcytic, is incorrect because microcytic red blood cells are smaller than normal. Therefore, the correct classification for anemia of chronic inflammation is normochromic and normocytic.

Correct Answer: B

Rationale: The correct answer is that the person is a sickle cell carrier. In HbAS, 'Hb' stands for hemoglobin, 'A' indicates normal hemoglobin, and 'S' indicates the sickle cell trait. Individuals with HbAS are carriers of the sickle cell trait but do not have sickle cell disease. Choice A is incorrect because having the sickle cell trait means carrying the gene for sickle cell disease. Choice C is incorrect as sickle cell anemia is a different condition where individuals have two copies of the abnormal hemoglobin gene, resulting in the disease. Choice D is incorrect because thalassemia is a separate genetic disorder affecting the production of hemoglobin, not related to the sickle cell trait.

Correct Answer: D

Rationale: The correct answer is 'Low-density lipoprotein (LDL) receptor mutation with defects in breakdown.' Primary hypercholesteremia is mainly caused by mutations in the LDL receptor, leading to impaired clearance of LDL cholesterol from the blood. This results in high levels of LDL cholesterol in the bloodstream. Choices A, B, and C are incorrect because they do not directly relate to the primary cause of primary hypercholesteremia.