Calcium Balance

Question 1

Calcium is the most abundant mineral in the body. A typical person has

Answer 1

1-2 kg (2.2-4.4lbs)

Question 2

Calcium ions play key roles in

Answer 2

Controlling muscular and neural activities,
in blood clotting,
as cofactors for enzymatic reactions, and as second messengers.

Question 3

Calcium homeostasis primarily reflects an interplay between

Answer 3

The reserves in bone, the rate of absorption across the digestive tract, and the rate of loss by the kidneys

Question 4

The hormones parathyroid hormone, Calcitrol, and calcitonin maintain

Answer 4

Homeostasis in the ECF

Question 5

Parathyroid hormone and Calcitrol increase

Answer 5

Calcium concentration. Their actions are opposed by calcitonin.

Question 6

An adult must absorb

Answer 6

0.8 - 1.2 g per day

Question 7

PTH from the Parathyroid glands and Calcitrol from the kidneys stimulate

Answer 7

Calcium absorption by the digestive tract and calcium reabsorption along the distal convoluted tubule

Question 8

Hypercalcemia exists when the calcium concentration of the ECF exceeds

Answer 8

5.3 mEq/L

Question 9

The primary cause of hypercalcemia in adults is

Answer 9

Hyperparathyroidism

Question 10

Hyperparathyroidism

Answer 10

A condition resulting from PTH oversecretion

Question 11

Less common causes of hypercalcemia are

Answer 11

Malignant cancer’s of the breast, lung, kidney, bone marrow.

Excess use of calcium or vitamin D supplements

Question 12

Severe hypercalcemia (12-13mEq/L) causes

Answer 12

Fatigue, confusion, cardiac arrhythmias, calcification of the kidneys and soft tissues

Question 13

Hypocalcemia

Answer 13

Calcium concentrations under 4.3 mEq/L

Question 14

Hypocalcemia can be caused by

Answer 14

Hypoparathyroidism, vitamin D deficiency, or chronic renal failure

Question 15

Signs of hypocalcemia are

Answer 15

Muscle spasms, sometimes with generalized convulsions, weak heartbeats, cardiac arrhythmias, and osteoporosis