Minerals and Human Health

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Questions and Answers

Which of the following is NOT a major element?

Molybdenum

Sulfur

Calcium

Iodine (correct)

What percentage of total calcium in the human body is extracellular?

10%

1% (correct)

0.1%

What is the recommended daily intake of calcium for an adult?

800 mg

1000 mg

200 mg

500 mg (correct)

Which of the following is a minor element?

Iodine Signup and view all the answers

What is the primary source of calcium?

Milk Signup and view all the answers

What is the role of vitamin D in calcium absorption?

It induces the synthesis of the carrier protein Signup and view all the answers

What is the effect of phytic acid on calcium absorption?

It reduces calcium absorption Signup and view all the answers

Which of the following minerals is toxic and should be avoided?

Aluminium Signup and view all the answers

What is the effect of cooking on phytate content?

Reduces phytate content Signup and view all the answers

Oxalates are commonly found in which type of vegetables?

Leafy vegetables Signup and view all the answers

What is the function of calcium in muscle contraction?

Mediates excitation and contraction of muscle fibers Signup and view all the answers

What is the normal range of calcium levels in blood?

8.5-10.5 mg/dl Signup and view all the answers

What is the function of calcium in the transmission of nerve impulses?

Necessary for transmission of nerve impulses Signup and view all the answers

What is the role of calcium in the coagulation cascade?

Known as factor IV in blood coagulation cascade Signup and view all the answers

What is the effect of vitamin D on calcium absorption?

Enhances calcium absorption Signup and view all the answers

What is the function of calcitriol in the body?

Induces a carrier protein in the intestinal mucosa Signup and view all the answers

What is the effect of vitamin D on osteoblasts?

It increases the number and activity of osteoblasts Signup and view all the answers

Which cells secrete parathyroid hormone (PTH)?

Chief cells of the gland Signup and view all the answers

What is the effect of PTH on bones?

It causes bone resorption Signup and view all the answers

What is the effect of calcitonin on serum calcium level?

It decreases serum calcium level Signup and view all the answers

What is the relationship between PTH and calcitonin?

They are antagonistic Signup and view all the answers

What is the effect of calcitonin on osteoclasts?

It decreases the activity of osteoclasts Signup and view all the answers

What is the effect of PTH on kidney function?

It decreases renal excretion of calcium Signup and view all the answers

What is the effect of PTH when blood calcium levels are low?

It is stimulated Signup and view all the answers

What is the term for when the blood calcium level is more than 10.5 mg/dl?

Hypercalcemia Signup and view all the answers

What is the major cause of hypercalcemia?

Hyperparathyroidism Signup and view all the answers

What is the condition characterized by a serum calcium level less than 8 mg/dl?

Hypocalcemia Signup and view all the answers

What can be a life-threatening consequence of hypocalcemia?

Tetany Signup and view all the answers

What is a possible consequence of chronic calcium deficiency?

Deformities of weight-bearing bones Signup and view all the answers

Which of the following does not cause tetany?

Vitamin D deficiency Signup and view all the answers

Study Notes

Minerals for Normal Growth and Maintenance

The human body requires certain minerals for normal growth and maintenance.
Minerals are classified into two groups: major elements (required in amounts > 100 mg/day) and minor elements or trace elements (required in amounts < 100 mg/day).

Major Elements

Calcium (Ca++)
Magnesium
Phosphorus
Sodium
Potassium
Chloride
Sulfur
Fluoride

Minor Elements (Microminerals or Trace Elements)

Iron
Iodine
Copper
Manganese
Zinc
Molybdenum
Selenium

Toxic Minerals to Avoid

Aluminium
Lead
Cadmium
Mercury

Calcium (Ca++)

Sources of Calcium

Milk (good source)
Egg, fish, and vegetables (medium sources)
Cereals (wheat, rice) (small amount)

Daily Requirement of Calcium

Adult: 500 mg/day
Child: 1200 mg/day
Pregnancy and lactation: 1500 mg/day

Absorption of Calcium

Takes place in the first and second parts of the duodenum
Requires a carrier protein helped by calcium-dependent ATPase
Factors affecting absorption:
- Vitamin D (induces synthesis of carrier protein)
- Parathyroid hormone (increases calcium transport)
- Acidity (favors calcium absorption)
- Phytic acid (reduces uptake of calcium)
- Oxalates (reduce absorption)
- Phosphate (precipitates calcium phosphate)

Functions of Calcium

Activation of enzymes
Muscle contraction and relaxation
Transmission of nerve impulses
Secretion of hormones
Second messenger (with cyclic AMP)
Coagulation (factor IV in blood coagulation cascade)
Myocardium function
Bone and teeth formation

Calcium in Blood

Normal level: 8.5-10.5 mg/dl
Ionized calcium: 5 mg/dl (metabolically active)

Factors Regulating Blood Calcium Level

Vitamin D (increases calcium absorption and bone formation)
Parathyroid hormone (increases calcium transport and bone resorption)
Calcitonin (decreases serum calcium level and bone resorption)

Hypercalcemia

Blood calcium level > 10.5 mg/dl
Causes: hyperparathyroidism
Effects: osteoporosis, bone resorption, and pathological fractures

Hypocalcemia and Tetany

Serum calcium level < 8 mg/dl (hypocalcemia)
Serum calcium level < 7.5 mg/dl (tetany, a life-threatening condition)
Causes: accidental surgical removal of parathyroid glands, vitamin D deficiency, and dietary deficiency of calcium
Effects: mild tremors, increased neuromuscular irritability, and laryngeal spasm

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Description

Learn about the importance of minerals for human growth and maintenance, including major and minor elements, and their daily requirements.