Ch. 7: Which of the following is NOT a function of the urinary system?
a) it regulates blood volume
b) it stabilizes blood pH
Oc) it produces erythropoietin
d) it eliminates nitrogenous wastes
e) it regulates electrolyte balance
f) it excretes excess proteins such as albumin
The Correct Answer and Explanation is :
The correct answer is:
f) it excretes excess proteins such as albumin
Explanation:
The urinary system plays a critical role in maintaining homeostasis by filtering the blood and forming urine. It consists of the kidneys, ureters, bladder, and urethra, and its main functions include waste elimination, fluid and electrolyte balance, and hormone production.
- Regulating Blood Volume (Option A)
The kidneys regulate blood volume by adjusting the amount of water excreted in urine. This helps maintain proper blood pressure and fluid balance in the body. - Stabilizing Blood pH (Option B)
The urinary system helps maintain acid-base balance by excreting hydrogen ions (H⁺) and reabsorbing bicarbonate (HCO₃⁻). This keeps blood pH within a narrow range (7.35-7.45). - Producing Erythropoietin (Option C)
The kidneys produce erythropoietin (EPO), a hormone that stimulates red blood cell production in the bone marrow. This is crucial for maintaining oxygen transport in the blood. - Eliminating Nitrogenous Wastes (Option D)
The urinary system removes metabolic waste products such as urea, creatinine, and uric acid, which are produced from protein metabolism and must be excreted to prevent toxicity. - Regulating Electrolyte Balance (Option E)
The kidneys maintain proper levels of sodium, potassium, calcium, and other electrolytes, ensuring normal nerve and muscle function. - Excreting Excess Proteins such as Albumin (Option F – Incorrect Choice)
Normally, the kidneys do not excrete significant amounts of proteins like albumin. The filtration barrier in the kidneys prevents large molecules from being lost in urine. If albumin appears in urine (albuminuria), it indicates kidney damage or a disease like nephrotic syndrome.
Thus, option F is NOT a function of the urinary system under normal conditions, making it the correct answer.