Oregon Certified Nursing Assistant State Practice Exam

Which system is primarily responsible for waste elimination in the body?

1. Digestive system

2. Endocrine system

3. Respiratory system

4. Urinary system

The correct answer is: Urinary system

The urinary system is primarily responsible for waste elimination in the body. It plays a crucial role in filtering and removing waste products and excess substances from the bloodstream. This system includes key organs such as the kidneys, ureters, bladder, and urethra, which work together to produce, transport, store, and excrete urine. The kidneys filter blood to create urine, which contains waste, toxins, and excess water, thus maintaining the body's internal environment and homeostasis by regulating fluid and electrolyte balance. While the digestive system also plays a role in eliminating waste, particularly by processing solid waste from food, its primary function is nutrient absorption. The respiratory system is involved in gas exchange rather than waste elimination, primarily expelling carbon dioxide. The endocrine system regulates bodily functions through hormones but does not serve a direct role in waste removal. Thus, the urinary system stands out as the principal system designated for waste elimination.