BIOL325 - Ca2+ Homeostasis Vocab

Ca2+

Calcium ions; an important mineral ion in the body and bone.

Plasma

Liquid portion of blood in which Ca2+ is transported.

Parathyroid

Glands that produce and secrete parathyroid hormone (PTH).

Thyroid

Gland that produces and secretes calcitonin.

Calcitonin

Hormone that lowers plasma Ca2+ by inhibiting osteoclast activity.

PTH

Parathyroid hormone; hormone that increases plasma Ca2+ partly by increasing bone resorption.

RANK ligand (RANKL)

Signal produced by osteoblasts that promotes osteoclast development and activity.

Osteoprotegerin (OPG)

Protein produced by osteoblasts that binds RANKL and reduces osteoclast activity.

OPG gene

Gene that controls production of osteoprotegerin.

Osteocytic-osteoblastic bone membrane

Membrane formed by osteocytes and osteoblasts that covers bone surfaces and helps regulate Ca2+ exchange.

Mineralized bone

Bone matrix containing mineral, including hydroxyapatite.

Labile pool of Ca2+

Readily exchangeable Ca2+ associated with bone that can rapidly move between bone and plasma.

Fast exchange

Rapid movement of Ca2+ between the labile bone pool and plasma.

Slow exchange

Slower movement of Ca2+ between mineralized bone and plasma through remodeling.

Vitamin D3 (cholecalciferol)

Form of vitamin D produced in the skin in response to ultraviolet light.

Vitamin D2 (calcidiol)

Vitamin D form produced after vitamin D is modified in the liver.

Calcitriol

Active form of vitamin D that increases intestinal absorption of Ca2+.

Ultraviolet light

Light that initiates production of vitamin D3 in the skin.

Precursor molecule

Molecule that can be converted into another molecule through a chemical process.

Rickets

Disorder in children caused by inadequate mineralization of growing bone.

Osteomalacia

Disorder in adults caused by inadequate mineralization of bone.