Why do our bodies need calcium in the blood?What happens when there is not enough? What happens when there is too much?

Blood needs to have calcium since it is
responsible for the transmission of messages by the nerves, for muscle contractions and
for blood to clot. A decline of blood calcium level will enable the parathyroid gland,
located in the throat to release parathyroid hormone, which has the capacity to
activitae osteoclast. Then osteoclasts or bone-destroying cells would break down bone
matrices to release calcium in the
blood.

However, if there is
too much blood calcium level, also known as hypercalcemia, the excess amount of calcium
are just deposited into bone matrix as hard calcium salts.