Which one of the following human tissues contains the greatest amount of body glycogen?
## **Core Concept**
The human body stores glycogen primarily in the liver and muscles. Glycogen serves as a readily mobilizable storage form of glucose. The liver and muscles have different capacities and purposes for glycogen storage.
## **Why the Correct Answer is Right**
The correct answer, **liver**, contains the greatest amount of body glycogen, approximately 100 grams, with a total body content of about 400 grams. The liver plays a crucial role in glucose homeostasis and can store and release glycogen as needed to maintain blood glucose levels.
## **Why Each Wrong Option is Incorrect**
* **Option A: Adipose tissue** - While adipose tissue is crucial for fat storage, it does not significantly store glycogen. Its primary role is in lipid metabolism.
* **Option B: Muscle** - Muscle tissue does store glycogen, which is used locally for energy during muscle contraction. However, the total amount stored in muscles is less than in the liver.
* **Option C: Kidney** - The kidneys do not store significant amounts of glycogen compared to the liver. Their primary functions include filtration, reabsorption, and secretion.
* **Option D: Brain** - The brain does not store glycogen. It relies on a constant supply of glucose from the blood for energy.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that liver glycogen can be depleted in about 12-18 hours of fasting, whereas muscle glycogen stores last about 18-24 hours. The liver's ability to synthesize and break down glycogen makes it critical for glucose homeostasis.
## **Correct Answer: B. Liver**