The nurse knows that a diagnosis of rheumatoid arthritis involves inflammation of which part of the joint?

A strain refers to an injury involving a muscle or tendon, where the fibers are stretched or torn due to excessive force or overuse. It affects the structure that connects muscle to bone, not the ligament. Ligaments, which connect bone to bone and provide joint stability, are involved in a sprain when they are stretched or torn.

A. Iron deficiency: Iron deficiency anemia results from inadequate iron for hemoglobin synthesis, leading to microcytic, hypochromic red blood cells. Bone marrow function is usually intact and responsive. It does not cause failure of all blood cell lines.

B. Folate deficiency: Folate deficiency leads to megaloblastic anemia characterized by impaired DNA synthesis and enlarged red blood cells. The bone marrow is typically hypercellular rather than underactive. It does not result in pancytopenia from marrow failure.

C. Vitamin B deficiency: Vitamin B12 deficiency also causes megaloblastic anemia due to defective DNA synthesis. White blood cells and platelets may be affected secondarily, but the marrow is not hypoplastic. The primary issue is ineffective cell production, not marrow failure.

D. Bone marrow hypoplasia: Aplastic anemia is caused by bone marrow hypoplasia or aplasia, resulting in decreased production of red blood cells, white blood cells, and platelets. This leads to pancytopenia and symptoms related to anemia, infection risk, and bleeding. It reflects a failure of hematopoietic stem cells.