Where are the majority of the body's calcium stores located?

Where are the majority of the body's calcium stores located?

• A. Blood plasma
• B. Liver
• C. Muscle tissue
• D. Skeleton

Answer: (D)

Most of the body's calcium is stored in the skeleton. Calcium is a major component of bone mineral, largely as hydroxyapatite, which gives bones their strength. The skeleton serves as a huge reservoir that buffers blood calcium levels, keeping them within a narrow range needed for nerve signaling, muscle contraction, and blood clotting. About 99% of total body calcium is in bone, while only a small amount circulates in the blood and inside cells. The body can release calcium from bone when needed, under hormonal control (such as parathyroid hormone) to raise blood calcium, or rebuild bone when calcium is abundant. Other tissues like liver and muscle contain calcium, but in much smaller amounts, so they are not the body's major calcium store.

Most of the body's calcium is stored in the skeleton. Calcium is a major component of bone mineral, largely as hydroxyapatite, which gives bones their strength. The skeleton serves as a huge reservoir that buffers blood calcium levels, keeping them within a narrow range needed for nerve signaling, muscle contraction, and blood clotting. About 99% of total body calcium is in bone, while only a small amount circulates in the blood and inside cells. The body can release calcium from bone when needed, under hormonal control (such as parathyroid hormone) to raise blood calcium, or rebuild bone when calcium is abundant. Other tissues like liver and muscle contain calcium, but in much smaller amounts, so they are not the body's major calcium store.