Glycogen is most abundant in which tissues?

• A. Liver, heart (cardiac muscle cells), womb
• B. Brain and spinal cord
• C. Skin and subcutaneous tissue
• D. Lungs and trachea

Answer: (A)

Glycogen serves as the rapid-energy reserve of glucose in animals, stored where quick access to fuel is needed. The liver holds the largest glycogen pool, preserving glucose to maintain blood sugar levels between meals. Skeletal muscle also stores a substantial amount to power its own activities. Cardiac muscle contains glycogen as well to provide immediate energy for continuous heart contractions. The uterus has some glycogen for secretory activity, but its overall amount is much smaller. Brain and spinal cord rely on constant blood glucose with little stored glycogen, and tissues like skin, subcutaneous tissue, lungs, and trachea have minimal glycogen. So, among the listed tissues, the liver and heart contain the most glycogen, with the uterus contributing a smaller amount.