Understanding Organ-System Analogies: Stomach and Kidney

The question asks us to find the relationship between the third and fourth words based on the relationship between the first and second words. The given analogy is: Stomach : Digestive system : : Kidney : ?

Let's analyze the first pair:

• Stomach : Digestive system

Here, the Stomach is a vital organ that is part of the larger Digestive system. The Digestive system is responsible for breaking down food, absorbing nutrients, and eliminating waste.

Now we need to apply the same relationship to the second pair:

• Kidney : ?

We are looking for the body system that the Kidney belongs to. The Kidney is an organ known for its role in filtering waste products from the blood and producing urine.

Let's examine the given options:

1. Nervous system: This system includes the brain, spinal cord, and nerves. It controls communication and coordination throughout the body. The Kidney is not part of the Nervous system.
2. Circulatory system: This system includes the heart, blood vessels, and blood. It is responsible for transporting oxygen, nutrients, and waste products throughout the body. While the Kidneys are supplied with blood by the Circulatory system, they are not considered a primary component of the system itself.
3. Respiratory system: This system includes the lungs, trachea, and bronchi. It is responsible for the exchange of oxygen and carbon dioxide. The Kidney is not part of the Respiratory system.
4. Excretory system: This system is responsible for eliminating waste products from the body. Key organs include the Kidneys, ureters, bladder, and urethra. The Kidneys are the primary filtering organs of the Excretory system.

Based on this analysis, the Kidney is a crucial organ within the Excretory system, performing the function of filtering waste, similar to how the Stomach is an organ within the Digestive system, performing the function of digestion.

Therefore, the correct relationship is that the Kidney is a part of the Excretory system.

Revision Table: Organ Systems

Additional Information: The Excretory System

The Excretory system is vital for maintaining homeostasis in the body. It removes metabolic wastes, excess salts, and water. The main components of the Excretory system in humans include:

• Kidneys: The primary organs, responsible for filtering blood and producing urine.
• Ureters: Tubes that carry urine from the kidneys to the bladder.
• Bladder: A sac that stores urine.
• Urethra: A tube that carries urine from the bladder out of the body.

Other organs like the lungs (excreting carbon dioxide) and skin (excreting sweat) also play roles in excretion, but the Kidneys are central to filtering liquid waste from the blood.