Knowra Calcium homeostasis Calcium homeostasis Calcium homeostasis is the regulation of calcium concentrations in blood and tissues within ranges that support vital functions, including nerve signaling, muscle contraction, and bone maintenance.
Parathyroid hormone : A hormone secreted by the parathyroid glands that raises blood calcium and regulates phosphate balance. It is the main rapid hormonal signal for correcting low blood calcium.
Calcium ion : A calcium atom that has lost two electrons, written Ca²⁺, and functions as an electrolyte and cellular signal. Homeostatic mechanisms regulate this biologically active form.
Hypercalcemia : An abnormally high concentration of calcium in the blood. It is the high-calcium failure state that homeostatic controls normally prevent.
Magnesium homeostasis : The regulation of magnesium concentrations in the body through intestinal absorption, kidney handling, and tissue exchange. Magnesium status can alter parathyroid hormone secretion and calcium responses.
Calcitriol : The active form of vitamin D, a hormone that increases intestinal calcium absorption and affects bone and kidney function. It helps restore calcium by increasing absorption from food.
Ionized calcium : The unbound calcium fraction in blood, available to cells and sensed by calcium-regulating systems. It is the fraction most directly relevant to physiological signaling.
Hypocalcemia : An abnormally low concentration of calcium in the blood. It is the low-calcium failure state that can disrupt nerves and muscles.
Sodium homeostasis : The regulation of sodium balance and extracellular sodium concentration through thirst, hormones, and kidney function. Sodium is regulated chiefly through water balance, unlike calcium’s strong bone reservoir.
Calcitonin : A hormone produced by thyroid C cells that can lower blood calcium by inhibiting bone resorption. It provides a countervailing signal when blood calcium rises.
Calcium signaling : The use of changes in intracellular calcium concentration to control processes such as secretion, contraction, and gene expression. Small local changes in cellular calcium serve as signals, distinct from blood-level regulation.
Show all 22