Exam 9: Minerals Essential for Calcified Structures

The serum calcium-to-phosphorus ratio is an inverse relationship. If the calcium level increases, the phosphorus level will increase to match this level.

Each of the following is true of the calcium-to-phosphorus ratio except one. Which one is the exception?

Each of the following characteristics of fluoride are true except one. Which one is the exception?

Magnesium supplements are frequently recommended by dietitians because it is difficult to get enough magnesium from food alone.

During growth periods, the requirement for calcium is unchanged because peak bone mass seems related to depletion of calcium reserves.

Fluoride ions can replace hydroxyl ions in the hydroxyapatite crystal lattice of teeth. This fluoridated hydroxyapatite, or fluorapatite, is more soluble and makes the tooth less resistant to demineralization.

Nourishment for the dentin is provided by:

High levels of calcium within the kidneys is called:

Patients with achlorhydria (absence of hydrochloric acid in the stomach) should not take calcium with meals. Mineral oils and some laxatives can decrease calcium absorption.

Adequate intake of calcium is observed in males and females from 20 to 35 years. Women can continue to increase bone growth and density through their 20s, but do not achieve the bone mass level observed in most men.

Each of the following is true of osteoporosis except one. Which one is the exception?

Which percentage most approximates the dietary phosphorus absorbed in the jejunum?

Fluoride is advantageous to dental health because of its systemic effects before tooth eruption and both systemic and topical effects after toot eruption.

Calcium supplements combined with vitamin D result in small but significant reductions in bone loss. Benefits of this combination are significant because the bioavailability of both vitamin D and calcium is enhanced in combined supplements.

The crystalline structure of enamel makes it:

Magnesium toxicity has been associated with kidney failure because the kidneys regulate plasma magnesium levels.

Each of the following is true of requirements and recommendations for fluoride utilization except one. Which one is the exception?

Mineralization of bone begins prior to collagen formation. Mineralization is the deposition of organic elements on an inorganic matrix.

Rickets cannot occur when calcium levels are sufficient because formation of rickets is solely dependent upon blood (serum) calcium level.

Calcium balance, an intake that equals excretion, depends solely on adequate calcium intake. Although hormones such as PTH are involved in phosphorus balance, hormonal influence on calcium balance is insignificant.