Podcast
Questions and Answers
Calcium constitutes about 90% of the composition of bone and teeth.
Calcium constitutes about 90% of the composition of bone and teeth.
False
The recommended dietary allowance of calcium during pregnancy and lactation is 800 mg/day.
The recommended dietary allowance of calcium during pregnancy and lactation is 800 mg/day.
False
Oligosaccharides enhance calcium absorption in the gastrointestinal tract.
Oligosaccharides enhance calcium absorption in the gastrointestinal tract.
False
Increased gastrointestinal motility is a factor that enhances calcium absorption.
Increased gastrointestinal motility is a factor that enhances calcium absorption.
Signup and view all the answers
Calcium binding to albumin constitutes approximately 40-50% of non-diffusible calcium.
Calcium binding to albumin constitutes approximately 40-50% of non-diffusible calcium.
Signup and view all the answers
A higher pH in the bloodstream leads to an increase in ionized calcium levels.
A higher pH in the bloodstream leads to an increase in ionized calcium levels.
Signup and view all the answers
Calcium absorption involves both simple diffusion and active transport processes.
Calcium absorption involves both simple diffusion and active transport processes.
Signup and view all the answers
The calcium to phosphorus ratio in the diet should be between 1:1 and 1:2 for optimal absorption.
The calcium to phosphorus ratio in the diet should be between 1:1 and 1:2 for optimal absorption.
Signup and view all the answers
Hypocalcemia is defined as a serum Ca level below 8 mg/dl.
Hypocalcemia is defined as a serum Ca level below 8 mg/dl.
Signup and view all the answers
Hyperparathyroidism can lead to increased serum Ca levels.
Hyperparathyroidism can lead to increased serum Ca levels.
Signup and view all the answers
Calcitonin has the same effect on plasma PO4 levels as KATACALCIN.
Calcitonin has the same effect on plasma PO4 levels as KATACALCIN.
Signup and view all the answers
Pseudo hypoparathyroidism results in an increased serum PTH level.
Pseudo hypoparathyroidism results in an increased serum PTH level.
Signup and view all the answers
Hypomagnesemia can lead to hypocalcemia by decreasing PTH secretion.
Hypomagnesemia can lead to hypocalcemia by decreasing PTH secretion.
Signup and view all the answers
Hypercalcemia can cause metabolic acidosis as a clinical manifestation.
Hypercalcemia can cause metabolic acidosis as a clinical manifestation.
Signup and view all the answers
Acute pancreatitis is associated with an increased serum calcium level.
Acute pancreatitis is associated with an increased serum calcium level.
Signup and view all the answers
Sarcodosis can lead to hypercalcemia.
Sarcodosis can lead to hypercalcemia.
Signup and view all the answers
The elevated levels of parathyroid hormone suggest that the hypercalcaemia is caused by a parathyroid source.
The elevated levels of parathyroid hormone suggest that the hypercalcaemia is caused by a parathyroid source.
Signup and view all the answers
Renal failure can lead to hypophosphatemia and decreased serum PO4 levels.
Renal failure can lead to hypophosphatemia and decreased serum PO4 levels.
Signup and view all the answers
Hypocalcaemia can present with symptoms such as paraesthesiae and tetany.
Hypocalcaemia can present with symptoms such as paraesthesiae and tetany.
Signup and view all the answers
Prolonged ST segments on ECG are associated with hypocalcemia.
Prolonged ST segments on ECG are associated with hypocalcemia.
Signup and view all the answers
A low plasma 25-hydroxyvitamin D concentration indicates the presence of hypercalcaemia.
A low plasma 25-hydroxyvitamin D concentration indicates the presence of hypercalcaemia.
Signup and view all the answers
Persons with breast carcinoma are not at risk for bone metastases.
Persons with breast carcinoma are not at risk for bone metastases.
Signup and view all the answers
Calcium, phosphate, and magnesium metabolism are independent of each other.
Calcium, phosphate, and magnesium metabolism are independent of each other.
Signup and view all the answers
Osteoporosis is characterized by an increase in bone resorption due to osteoblast activity.
Osteoporosis is characterized by an increase in bone resorption due to osteoblast activity.
Signup and view all the answers
Osteomalacia results from a failure of mineralization of bone.
Osteomalacia results from a failure of mineralization of bone.
Signup and view all the answers
A common cause of rickets is a deficiency of vitamin C.
A common cause of rickets is a deficiency of vitamin C.
Signup and view all the answers
Renal osteodystrophy is associated with increased serum calcium levels.
Renal osteodystrophy is associated with increased serum calcium levels.
Signup and view all the answers
Hypoalbuminemia can lead to falsely low measured calcium levels.
Hypoalbuminemia can lead to falsely low measured calcium levels.
Signup and view all the answers
The serum phosphate levels in a patient with primary hyperparathyroidism are typically elevated.
The serum phosphate levels in a patient with primary hyperparathyroidism are typically elevated.
Signup and view all the answers
An adjusted calcium level of 2.18 mmol/L indicates that specific treatment is required.
An adjusted calcium level of 2.18 mmol/L indicates that specific treatment is required.
Signup and view all the answers
The diagnosis of primary hyperparathyroidism may be associated with a parathyroid adenoma.
The diagnosis of primary hyperparathyroidism may be associated with a parathyroid adenoma.
Signup and view all the answers
Renal rickets occurs due to impaired vitamin metabolism and is marked by increased serum calcium.
Renal rickets occurs due to impaired vitamin metabolism and is marked by increased serum calcium.
Signup and view all the answers
The biochemical findings in rickets include decreased serum calcium and increased urine phosphate.
The biochemical findings in rickets include decreased serum calcium and increased urine phosphate.
Signup and view all the answers
Phosphorus is more concentrated in the extracellular fluid (ECF) compared to the intracellular fluid (ICF).
Phosphorus is more concentrated in the extracellular fluid (ECF) compared to the intracellular fluid (ICF).
Signup and view all the answers
Calcitonin is secreted by the C-cells of the parathyroid gland.
Calcitonin is secreted by the C-cells of the parathyroid gland.
Signup and view all the answers
Vitamin D enhances the reabsorption of phosphorus in the kidneys.
Vitamin D enhances the reabsorption of phosphorus in the kidneys.
Signup and view all the answers
A normal calcium-phosphorus product (Ca x P) is considered to be 40.
A normal calcium-phosphorus product (Ca x P) is considered to be 40.
Signup and view all the answers
The primary site for phosphorus absorption in the body is the ileum.
The primary site for phosphorus absorption in the body is the ileum.
Signup and view all the answers
Parathormone inhibits renal dihydroxylation of vitamin D.
Parathormone inhibits renal dihydroxylation of vitamin D.
Signup and view all the answers
Collagenase activity is enhanced by parathormone, which promotes bone resorption.
Collagenase activity is enhanced by parathormone, which promotes bone resorption.
Signup and view all the answers
The body contains approximately 1% of phosphorus in adults.
The body contains approximately 1% of phosphorus in adults.
Signup and view all the answers
High calcium levels stimulate the secretion of calcitonin.
High calcium levels stimulate the secretion of calcitonin.
Signup and view all the answers
Phosphorous turnover in the body refers to the daily synthesis of phosphates exclusively from dietary sources.
Phosphorous turnover in the body refers to the daily synthesis of phosphates exclusively from dietary sources.
Signup and view all the answers
Study Notes
Calcium and Phosphorus
- Calcium is primarily found in the extracellular fluid (ECF), with about 99% in bones and teeth. In serum, it exists in two forms.
- 50% of diffusible free calcium ionizes, and 10% is complex calcium.
- 40-50% of calcium is non-diffusible and protein-bound.
pH and Calcium
- Increased pH leads to decreased calcium.
- Decreased pH leads to increased calcium.
- Non-diffusible calcium is 50% bound to albumin.
Calcium RDA
- Adult RDA: 400-500 mg/day
- Children RDA: 800 mg/day
- Pregnancy & Lactation RDA: 1200 mg/day
Calcium Absorption Factors
-
Enhancing Factors:
- 1,25-dihydroxycholecalciferol
- Acidity of digestive mass
- Presence of lactose
- The need for calcium
- Ca:P ratio of 1:1 to 1:2
-
Depressing Factors:
- Oxalic and phytic acid
- Increased GIT motility
- Lack of exercise
- Emotional instability
- Unabsorbed fatty acids
Calcium Absorption Method
- Active transport
- Simple diffusion
Calcium Metabolism Summary
- Diet intake: 1 gram
- Absorption: 400 mg
- Secretion: 200 mg
- Bone Formation
- Resorption: 10 mg/100 ml plasma
- Urine excretion: 200 mg/day
- Tissue
Calcium Physiological Functions
- Blood Clotting: Involved in the process of blood clotting. Calcium, injury, platelet, and thrombopastin are involved. Prothrombin converts to thrombin, which then converts fibrinogen to fibrin. Fibrin forms the blood clot.
- Bone and Teeth Formation: Calcium phosphates (CaHPO4) and calcium hydroxyapatite (Ca3(PO4)2.Ca(OH)2) are critical components of bone and teeth structure.
- Muscle Contraction: Essential for muscle contraction.
- Membrane Permeability: Influences membrane permeability.
Phosphorus
- In adults, phosphorus constitutes about 1% of the body's total mass.
- In intracellular fluid (ICF), phosphorus is 50 times more abundant than in ECF.
- Phosphorus in blood includes inorganic, organic/ester (e.g., glycerophosphate, nucleotide phosphate), and lipid forms (e.g., lecithin, cephalin, sphingomyclin).
Phosphorus RDA
- 2 times the calcium RDA for adults.
- 2/3 of the calcium RDA for infants before 6 months.
Phosphorus Absorption and Excretion
- Primarily absorbed in the jejunum.
- 30-40% of intake is excreted either in urine or feces.
Phosphorus Physiological Functions
- Energy release regulation
- Nutrient absorption and transport
- Part of essential body compounds (DNA, RNA, enzymes, vitamins)
- Bone and teeth calcification (80% of phosphorus)
- Acid-base balance regulation
Phosphorus Turnover
- Daily diet intake: 1200 mg
- Absorption: 960 mg
- Secretion: 180 mg
- Feces excretion: 420 mg
- Urine excretion: 780 mg
Factors Influencing Calcium and Phosphorus Levels
- Vitamin D: 7-dehydrocholesterol to cholecalciferol to 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol. Conversion in liver and kidney.
- Other hormones: Parathyroid hormone (PTH) and Calcitonin
Parathyroid Hormone (PTH)
- Function: Regulates calcium and phosphorus levels.
- Secretion: From parathyroid gland, 84 amino acids, molecular weight ~9500 daltons.
- Stimulated by low calcium levels.
- Actions on bone: Increases bone resorption, osteoclast activity; inhibits osteoblast activity. Leads to pH lowering, stimulating bone dissolution.
- Actions on kidneys: increases calcium reabsorption; inhibits phosphate reabsorption; increases vitamin D production.
- Action on gut: indirectly increases calcium absorption through vitamin D.
Calcitonin
- Function: Regulates calcium levels.
- Secreted by C cells of thyroid gland, polypeptide with 32 amino acids, molecular weight ~3500 daltons.
- Stimulated by high calcium levels.
- Actions: Inhibits bone resorption; increases calcium and phosphate excretion; increases osteoblast activity.
Other Calcium-Related Conditions
- Hypocalcemia: Serum calcium <8 mg/dL while a normal serum calcium range is 8.5-10.5 mg/dL. Causes may include hypoparathyroidism, or post-surgery disorders.
- Hypercalcemia: Serum calcium >12 mg/dL on repeated occasions. Causes may include primary hyperparathyroidism.
- Hypophosphatemia and hyperphosphatemia: abnormal levels of phosphate in the blood. Renal osteodystrophy is a common condition related to impaired calcium and phosphate metabolism. Associated with chronic renal failure.
- Renal rickets: impaired Vitamin D metabolism in children with chronic renal failure.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers essential topics related to calcium, including its role in bone and teeth composition, dietary recommendations during pregnancy, and factors influencing calcium absorption. Test your knowledge of serum calcium levels, the impact of hormones, and dietary ratios for optimal health.
