Anatomy Practice Exam

Which system is responsible for cleansing blood and maintaining water balance?

1. Lymphatic system

2. Digestive system

3. Urinary system

4. Endocrine system

The correct answer is: Urinary system

The urinary system is primarily responsible for cleansing the blood and maintaining water balance in the body. This system includes the kidneys, ureters, bladder, and urethra. The kidneys filter the blood, removing waste products and excess substances, including water, electrolytes, and toxins. This filtration process results in the formation of urine, which is then excreted from the body, thereby helping to regulate blood composition and volume. Additionally, the urinary system plays a critical role in maintaining homeostasis by adjusting the concentration of urine depending on the body's hydration status. When the body is dehydrated, the kidneys conserve water, producing concentrated urine, while in a hydrated state, they excrete excess water to maintain balance. Overall, the urinary system is essential for the removal of waste and the regulation of fluid levels, thereby supporting overall health and well-being. In contrast, other systems mentioned serve different primary functions— the lymphatic system is mainly involved in immune function and fluid balance but does not directly cleanse blood; the digestive system breaks down food and absorbs nutrients but does not filter blood; and the endocrine system regulates bodily functions through hormones, rather than directly managing waste or water balance.