In human anatomy, what is considered the heaviest internal organ of the human body by weight although the skin is the largest organ overall?

Introduction / Context:
Organs in the human body can be compared by size and weight. The skin is the largest organ overall by surface area and weight, but it is external. When focusing on internal organs, one stands out as the heaviest. This question asks which internal organ has the greatest weight under normal conditions.

Given Data / Assumptions:

• Skin is considered the largest organ but is external.
• We focus on internal organs located inside the body cavities.
• Options include lungs, heart, liver, skin, and kidneys.
• We assume healthy adult anatomy without disease enlargement.

Concept / Approach:
Among internal organs, the liver is the largest and heaviest. It is located in the right upper quadrant of the abdomen and performs many vital functions including metabolism, detoxification, storage, and bile production. While lungs, heart, and kidneys are substantial in size, they are lighter than the liver. The skin, although the largest organ, is not classified as an internal organ. Therefore, the liver is considered the heaviest internal organ.

Step-by-Step Solution:
Step 1: Recall that the skin is the largest organ by area and weight but lies externally, covering the body. Step 2: Focus only on organs inside the body cavities, such as liver, lungs, heart, and kidneys. Step 3: Recognize that the liver occupies a large volume in the upper abdomen and has high mass due to its dense tissue. Step 4: Compare relative sizes, noting that the heart is smaller and the lungs, although large in volume, are filled with air spaces and therefore relatively light. Step 5: Identify the liver as the heaviest internal organ among the listed options.

Verification / Alternative check:
Anatomy texts and clinical references usually state that an adult human liver weighs about one and a half kilograms on average, making it heavier than other internal organs. The lungs, although large, are spongy and lighter. The heart and kidneys weigh less than the liver. Surgeons and pathologists handling organs confirm this practical observation.

Why Other Options Are Wrong:
Option A, skin, is not an internal organ, so it does not answer the question even though it is the largest organ overall. Option B, lungs, are large but less dense and generally lighter than the liver. Option C, heart, is much smaller and lighter than the liver. Option E, kidneys, are significant organs but individually and together are lighter than the liver.

Common Pitfalls:
Students sometimes choose skin because they think of overall size rather than the restriction to internal organs. Others may be misled by the large volume of lungs without considering their low density. It is important to pay attention to the wording that specifies internal organ.

Final Answer:
The heaviest internal organ in the human body is the Liver.