Which of the following refers to an excessive amount of blood in a body part due to blockage or decreased venous drainage?

The term that accurately describes an excessive amount of blood in a body part due to blockage or decreased venous drainage is passive hyperemia. This condition occurs when blood accumulates in the venous system, typically as a result of an obstruction that impairs the normal drainage of blood from that area. This excess blood causes the affected tissues to become engorged, leading to symptoms such as swelling and discoloration.

In contrast, hypoxia refers to a deficiency in the amount of oxygen reaching the tissues, which is not directly related to blood volume. Anemia, on the other hand, involves a reduced number of red blood cells or hemoglobin, leading to decreased oxygen-carrying capacity of the blood, again not indicative of excess blood. Lastly, ischemia is characterized by a lack of blood supply to a tissue, often due to arterial blockage, which leads to insufficient oxygen and nutrient delivery rather than an excess of blood.

Thus, passive hyperemia is specifically focused on the accumulation of blood due to impaired outflow, making it the correct choice in this context.