Final answer:
The nuclear remnants seen as small, round basophilic structures in RBCs associated with regenerative anemia are called Howell-Jolly bodies. They represent immature erythrocytes or reticulocytes responding to anemia by increasing the production of RBCs. The correct option is d.
Step-by-step explanation:
Nuclear remnants that appear as small, round basophilic structures in red blood cells (RBCs), and are increased in animals with regenerative anemia, are known as Howell-Jolly bodies.
These structures are indicative of the presence of immature erythrocytes, or reticulocytes, in the bloodstream. Reticulocytes are the nascent stage of RBCs, having recently exited the red bone marrow and usually still containing some remnants of organelles.
They typically make up about 1-2 percent of the erythrocyte count and, when present in higher percentages, suggest a regenerative response to anemia.
Anemia is characterized by a deficiency in RBCs or hemoglobin, leading to a reduced ability to transport oxygen throughout the body. The body compensates for anemia by increasing the production of RBCs, manifesting an increase in reticulocytes and Howell-Jolly bodies in a complete blood count. The correct option is d.