Mineral Metabolism: Calcium Absorption Influencing Factors

Study Notes

Calcium Roles and Absorption

Calcium has various biological roles, excluding:
- Blood clotting
In the plasma, blood calcium is present in 3 fractions, excluding:
- Albumin-bound fraction

Calcium Absorption

Factors that diminish intestinal transport of calcium:
- Oxalic acid and phytic acid
In a normal adult, extra calcium absorbed from the intestine is:
- Deposited in bones
Vitamin D's influence on calcium absorption:
- Increases calcium absorption
Organic acids, lactose, and basic amino acids in the diet:
- Increase calcium absorption
Dietary factor that decreases calcium absorption:
- Phosphorus
High calcium intake's effect on its absorption:
- Decreases absorption efficiency
Main consequence of a decrease in ionized calcium in the serum:
- Tetany (muscle cramps)

Calcium Balance and Excretion

Average calcium absorbed from the diet:
- 200-300 mg/day
Average calcium excreted as fecal calcium:
- 150-200 mg/day
Primary route of excretion for calcium in the body:
- Kidneys (via urine)
Vigorous physical exercise's effect on calcium loss:
- Increases calcium loss in the body, particularly in the urine

Description

This quiz covers the factors influencing calcium absorption, including the effects of parathyroid hormone, adrenal glucocorticoids, aging, and kidney threshold. It also tests knowledge on the excretion of excess calcium in a normal adult.