Patient Care Technician (PCT) AAH Practice Exam

What is the primary function of the kidneys?

1. Secretion of hormones

2. Production of insulin

3. Filtration of blood

4. Absorption of nutrients

The correct answer is: Filtration of blood

The primary function of the kidneys is the filtration of blood. The kidneys play a crucial role in maintaining the body's internal environment by filtering waste products, excess substances, and toxins from the bloodstream. This filtration process results in the formation of urine, which is then excreted from the body. In addition to filtering blood, the kidneys regulate fluid and electrolyte balance, control blood pressure through the regulation of blood volume, and play a part in maintaining acid-base balance in the body. They also produce hormones that are important for blood pressure regulation and red blood cell production, but these functions are secondary to their primary role as filters. In contrast, the secretion of hormones, production of insulin, and absorption of nutrients are functions performed by other organs in the body. For instance, the pancreas is responsible for producing insulin, and the intestines are primarily responsible for nutrient absorption. While the kidneys may produce certain hormones, such as erythropoietin and renin, their main job remains focused on filtering blood and maintaining homeostasis.