Bone Mineralization-----------------------------------EXAM2 Flashcards
What is balance?
Long term adjustments to maintain total Ca2+ [ ]
What are osteoclasts responsible for?
Removal of bone matrix
What are osteoblasts responsible for?
Produce bone matrix , control mineralization
- What are the two major mineral constituents?
Calcium
phosphate
T/F: Small amounts of Ca exist in the free/active form?
True
- What percent of phosphate exists in crystalline form?
85%
Name the two 1o regulators for calcium/phosphate?
Parathyroid Hormone
Vitamin D
- What are the 2o regulators for calcium/phosphate?
Calcitonin, Glucocorticoids, Estrogen
Parathyroid H
- Main Goals? *****
Inc calcium
Dec phosphate
Effects on the Kidneys?
Increase Calcium, Magnesium reabsorption
Decrease Phosphate reabsorption at distal tubule
Stimulate the production of Calcitriol (1,25 [OH]2D)
PTH
Effects on Intestines?
No Direct Effect
Indirectly promotes absorption of Calcium through
stimulation of Vitamin D
Vitamin D
T/F. When pts aren’t exposed to UV light you may supplement with Vitamin D
T
Vitamin D
Activation of Vitamin D is?
Endogenous Production
Sun-Liver-Kidney
- What is the active form of Vitamin D
Clcitriol
Doesnt need hydrox in kidney to be active
Main Goals of Vitamin D?
Increase Calcium
Increase Phosphate
- Sites of Action
Vitamin D
Intestine, Bone, and Kidneys
What is Paget’s Disease?
Local areas of bone become Hyperactive
Replace normal matrix w/ softened & enlarged bone
Seen mainly in males and bowed legs
What is the normal total serum concentration of Ca2+?
The normal ionized serum Ca2+ concentrations?
** calcium must be adjusted for hypoalbuminemia
8.5 – 10.5 mg/dL
4.6 – 5.1 mg/dL
- T/F. Calcium must be adjusted for hypo-albuminemia.
T
. What are the effects of alkalosis?
Decreased calcium concentrations (because calcium protein binding increased)
Calcium protein binding increased
What are the effects of acidosis?
Increased calcium concentrations
Calcium protein binding decreased
Hypocalcemia
- What is the hallmark sign of hypocalcemia? ****
Tetany
- T/F. Hypocalcemia associated with hypo-albuminemia does not need treatment?
T
What is the goal of therapy in acute hypocalcemia?
Administer 200 – 300mg
of Ca2+ by IV
What Ca2+ agent is preferred to correct hypocalcemia?
Calcium gluconate (2-3 grams)
What are some ADRs with rapid administration (IV) of calcium?
Hypotension
Bradycardia
Cardiac asystole