Mineral Metabolism Flashcards
Function of Calcium
Ionized Calcium is the physiological active form
Important co-enzyme in coagulation cascade
Role in heart, muscle, and nerve excitability
Suppresses neuromuscular excitability
Plays a role in transport across membranes
Structure and Concentration of Calcium
99% located in bone as CaPo4 complex
- Hydroxyapatite
Location of Calcium in body
Bone - 99%
Other sites - 1%
Calcium Analysis
Two types of tests
Total serum calcium
Protein bound (albumin and globulins)
Complexed to ions (Citrate, phosphate, bicarbonate, sulfate)
Ionized Ca2+
Phosphorus Function
Tied up with calcium in skeleton
Other Functions:
- High intracellular phosphate concentration
- Carbohydrate metabolism: ATP
- Component of nucleic acids, phospholipids, and nucleotides
- Phosphate buffer important in balancing acid in urine
Magnesium Function
Found in 50% of bone with calcium and phosphorus
Rest is found with potassium inside cell
Acts as a co-enzyme in enzyme reactions
Regulation not fully understood
Elevated Magnesium
Intoxication
Renal Failure - unable to filter appropriately
Low Magnesium
Impaired absorption or intake
Excessive renal loss
Organs Involved in regulation of Ca and PO4
Parathyroids
Thyroid
Kidneys
Liver
Skeletal system
Intestine
Parathyroid Produces
PTH (Parathyroid Hormone)
Regulating Calcium and Phosphorus Concentrations
Thyroid Produces
C-cells
Calcitonin
Kidneys Function for Ca and PO4
Hydroxylate Vitamin D
Control Ca and PO4 absorption
Liver Creates
Hydroxylated Vit D
Parathyroids Info
Lobe of the thyroid gland
4 glands are present
Calcitonin
Produced by C-cells of Thyroid
Acts antagonistically to PTH
Stimulated by elevated Ca2+
Found in children who also have high Alkaline Phosphatase
Responsible for laying down crystalline bone
Bone and ECF ions are in balance with one another
Osteoclasts
Osteoblasts
Osteoclasts
Involve in bone resorption
PTH breaks down CaPO4 component