The system regulates the volume of water in the blood and also has an important role in eliminating wastes.
a. Respiratory
b. Nervous
c. Excretory
d. Endocrine
The correct answer and explanation is :
The correct answer is: c. Excretory
Explanation (Approximately 300 words):
The excretory system plays a crucial role in maintaining the internal balance of the body, particularly in regulating the volume of water in the blood and eliminating waste products from the body. This system is made up of organs including the kidneys, ureters, bladder, and urethra.
One of the primary functions of the excretory system is to filter blood through the kidneys, removing nitrogenous wastes like urea, uric acid, and creatinine. These waste products are byproducts of cellular metabolism and must be eliminated to prevent toxicity. The kidneys also regulate electrolyte balance, pH levels, and the volume and pressure of blood by adjusting the amount of water and salts excreted in urine.
The kidneys play a central role in water regulation. They respond to hormones like antidiuretic hormone (ADH) and aldosterone, which help control the amount of water reabsorbed into the blood. When the body is dehydrated, ADH levels increase, prompting the kidneys to reabsorb more water and produce concentrated urine. Conversely, when water levels are sufficient, less ADH is released, and the kidneys excrete more dilute urine, lowering blood volume and pressure.
In addition to water regulation, the excretory system helps eliminate toxins, drugs, and metabolic byproducts, maintaining a stable internal environment—a process known as homeostasis. This balance is vital for the proper functioning of other systems, such as the cardiovascular and nervous systems.
While other systems like the endocrine and respiratory systems support homeostasis and waste removal (e.g., lungs excreting carbon dioxide), it is the excretory system that is directly responsible for regulating water volume in the blood and removing liquid and soluble wastes from the body.
Thus, the excretory system is essential for cleansing the body and ensuring that fluid levels remain within healthy limits.