2. Dr. D.V.S. REVATH VYAS
PG 1ST YEAR
DEPT OF ORAL MEDICINE
AND RADIOLOGY

3. -INTRODUCTION
-CALCIUM REGULATION IN BODY
-CALCIUM METABOLISM
-FACTORS REGULATING CALCIUM METABOLISM
-TOOTH MINERALISATION
CONTENTS

4. CONTENTS
-PHOSPHOROUS REGULATION IN BODY
-PHOSPHOROUS METABOLISM
-FACTORS REGULATING PHOSPHOROUS
METABOLISM
-APPLIED ASPECTS

7. The rigidity of skeleton which provides support and protection
for soft tissues, muscle contraction , the hardness and fitness
of the teeth, the stability of the cell membranes, as activator
of many hormones and last but not the least the heart beat it
self, is dependent on CALCIUM. With its myriads of functions
and complex mechanisms of control, calcium in both ionized and
unionized form is arguably one of the most important body
components.
INTRODUCTION

8. CALCIUM

9. 1% of total body
calcium

10. TOTAL BODY CALCIUM 1100-1200gms(1.5 % of body weight)
99% in the skeleton
4-5gms in soft tissue
1gm in ECF
NORMAL SERUM CALCIUM 8.8-10.4mg%
PLASMA CALCIUM occurs in 2 forms
Diffusible : 5.36mg% or 54-55%
oIonized 47%
oNon-ionized 5%
Non diffusible : 4.64mg% or 45-46%
MOST ABUNDANT MINERAL OF OUR BODY

11. ESTIMATION OF CALCIUM CONCENTRATION
• Ionized Ca concentration can be estimated from routine
laboratory tests, usually with reasonable accuracy
eg: plasma Ca is often low - Hypoalbuminemia
plasma Ca increases - Multiple myeloma
• Measured total plasma Ca decreases or increases by about 0.8
mg/dL (0.20 mmol/L) for every 1-g/dL decrease or increase in
albumin

13. 8-ounce glass of milk = 300mg of calcium
2 ounces of Swiss cheese = 530mg of calcium
6 ounces of yogurt = 300 mg of calcium
2 ounces of sardines with bones = 240mg of calcium
6 ounces of cooked turnip greens = 220mg of calcium
3 ounces of almonds = 210mg of calcium
“Avoid foods causing calcium loss.. For example excess salt
and caffeine”

14. ADULT MALES AND FEMALES ….800mg
WOMEN DURING PREGNANCY
AND LACTATION ….1200mg
INFANTS UNDER 1 YEAR ….360-540mg
CHILDREN(1-18 YEARS) ….800-1200mg
DAILY REQUIREMENTS OF CALCIUM
.
Dietary calcium intake is inversely related to body weight and body fat
mass. It has the potential to increase faecal fat excretion to an extent
that could be relevant for prevention of weight (re-)gain.
(Nutrition Reviews. 66(10):601-605,
October 2007)

15. Factors Increasing
Absorption :
- Calcitriol
- Paratharmone
- Acidity (Low PH)
- Growth Hormone
- Pregnancy, Lactation
- Lactose, Arginine, Lysine
Factors Decreasing absorption :
- Oxalates & phytates – form Ca salts
- High dietary fats & fibers formm Ca
soaps
- Phosphates
- Alkalinity
- Chronic renal failure ( impaired
activity of vitamin – D)

16. CALCIUM REGULATION IN THE BODY

19. -Before the fifth month of
IUL very little calcium is
found in the fetus because
bone formation is only
starting.
-60% of the total deposition
occurs in the last trimester
which is the period of rapid
and extensive ossification

20. -One year old baby contains about 100 g of calcium, a gain of
70 g over the total calcium content at birth.
-The adult human weighing 70 kg contains about 1.2 to 1.4 kg
of calcium that is 1.5% of the body weight, 99% of which is
present in bones and teeth.
 Mature fetus contains about 30 g of calcium which constitutes
about 3 to 4% of maternal calcium
 Much greater drainage occurs after birth during lactation

21. TYPES OF CALCIUM
Calcium in plasma
3 forms:
Ionized (50%)
Nonionozed (8-10%)
Calcium bound to plasma protein (40-42%)
Calcium in bones:
2 forms:
Rapidly exchangeable calcium
Slowly exchangeable calcium

22. ABSORPTION & EXCRETION OF CALCIUM IN BODY
35-40% of average daily dietary Ca is absorbed
from gut, mainly duodenum and first half of
jejunum by a carrier mediated active transport
under the influence of vitamin D
After oral administration absorption is completed
within 4hrs

23. 1000 mg/day

24. INCREASED BY DECREASED BY
 Acidity in stomach
 Calcium phosphate ratio
 Hypocalcemia during
pregnancy & lactation
 Vitamin D3- (1, 25-DHCC)
 Parathyroid hormone
 Lactose
 Intestinal alkalinity
 Excess of oxalate
 Excess of phytic acid
 Hypercalcemia
 Fats
 Alcohol and smoking
 Lack of exercise
 Emotional stability
 Glucocorticoids
FACTORS AFFECTING CALCIUM ABSORPTION FROM GIT

25. EXCRETION
• As calcium is both filtered and reabsorbed but not secreted, the
rate of renal calcium excretion is calculated as
Renal calcium excretion= calcium filtered – calcium reabsorbed
99% of filtered calcium (Glomerulus) is
reabsorbed by the tubules, 1% gets excreted
 65% is reabsorbed in proximal tubules, 25-30% in loop
of henle and 4-9% in distal and collecting tubules
 Daily loss of Ca in sweat is about 15mg.

29. FACTORS CONTROLLING EXCRETION
• Calcium concentration in the body
• PTH (loop of henle and distal tubules)
• Plasma concentration of phosphate
↓CALCIUM EXCRETION
↑ PTH
↓ Extracellular fluid volume
↓ Blood pressure
↑ Plasma phosphate
↑CALCIUM EXCRETION
↓ PTH
↑ Extracellular fluid volume
↑ Blood pressure
↓ Plasma phosphate

30. HORMONES INFLUENCING CALCIUM ABSORPTION
• GROWTH HORMONE
• “PROLACTIN (Prolactin has been shown to stimulate
intestinal calcium absorption, increase bone turnover, and
reduce renal calcium excretion)”
Canadian Journal of Physiology & Pharmacology. 85(6):569-581, June 2007)
• GLUCOCORTICOIDS

31. FUNCTIONS OF CALCIUM
• Bone and teeth formation
• Neuronal activity
• Muscle activity
• Cardiac activity
• Cell division and growth
• Blood coagulation
• Excitability of nerves and muscles
• Maintains integrity of cell membrane

33. Constituent of bone and teeth
• Calcium and phosphorous are the principal constituent
minerals of bone and teeth.
• They occur in the bone matrix, enamel, dentin and cementum
of teeth mainly as rod shaped or platelet shaped crystals of
calcium hydroxyapatites. These give the hardness, strength
and concrete like elastic modulus to these tissues

34. Physiology of bone
• Bone is composed of tough organic matrix that is greatly
strengthened by deposits of calcium salts
• Average compact bone contains by weight about 30% matrix
and 70% salts
• Organic matrix of bone:

35. BONE SALTS
 The crystalline salts deposited in the organic matrix of bone are
composed principally of calcium and phosphate.
 The major crystalline salt is known as hydroxyapatite
[Ca10(PO4)6(OH)2].

36.  Bone is constantly being reabsorbed and reformed,
under the cellular control….
 Osteoblasts
 Osteocytes
 Osteoclasts.

37. Neuronal activity

38. Excitation-contraction coupling of all types
of muscles
THE ATTACHMENT OF CALCIUM TO TROPONIN
AND MOVEMENT OF TROPONIN-TROPOMYSIN
COMPLEX RESULTING IN EXPOSURE OF
BINDING SITES ON ACTIN MYOSIN
CROSS BRIDGING CAUSING A POWER
STROKE

40. Muscle contraction

41. Membrane permeability
• Ca2+ reduces membrane permeability to ions and water,
probably by binding with calmodulin of cell membranes and
consequently changing the conformation and hydration of
membrane proteins.

46. Blood coagulation

51. factors REGULATING CALCIUM METABOLISM
Vitamin D
Calcitonin
Parathyroid hormone

52. PARATHORMONE
-it provides a powerful mechanism for controlling extracellular calcium
and phosphate concentrations
Secreted by Chief cells of parathyroid gland

53. On blood calcium level:
1. Increases bone resorption/absorbtion
2. Increases renal Ca ++ absorption in distal tubules
3. Increases absorption of intestinal Ca++
On blood phosphate level:
1. Stimulates resorption of phosphate from bone
2. Increases urinary excretion
3. Increases absorption of phosphate from GIT through calcitriol
ACTIONS OF PTH

54. ↓ BONE RESORPTION
↑ URINARY LOSS
↓ 1,25,(OH)2 D
PRODUCTION
↓
NORMAL BLOOD CALCIUM
↑
↑ BONE RESORPTION
↓ URINARY LOSS
↑ 1,25,(OH)2 D
PRODUCTION
SUPPRESS PTH
RISING BLOOD CALCIUM
FALLING BLOOD CALCIUM
STIMULATE PTH

55. ON BONE:
- RAPID PHASE
- SLOW PHASE
ON KIDNEYS:
ON GASTROINTESTINAL
TRACT

56. Role of PTH in the activation of VITAMIN D
VITAMIN D IS A HORMONE BY CLASSIC CRITERIA: MADE
IN ONE PLACE (OR SEQUENTIALLY SEVERAL PLACES!),
AND ACTING IN OTHER
DAILY DIETARY ALLOWANCE RECOMMENDED:
- From infancy till puberty is 10 mcg of cholecalciferol (400
IU of vitamin D)
- In young adulthood, its 7.5 mcg
- After 25 yrs, 5 mcg required
Pregnancy and lactation 10 mcg

57. ACTIVATION Of VITAMIN D

59. BONE
STIMULATE TERMINAL DIFFERENTIATION OF
OSTEOCLASTS
STIMULATE OSTEOBLASTS TO STIMULATE
OSTEOCLASTS TO MOBILIZE CALCIUM
KIDNEY
IT INCREASES RE-ABSORPTION OF Ca FROM DCT &
INCREASES RE-ABSORPTION OF PHOSPHATE ION
FROM PCT

60. ACTIONS OF 1,25-Dihydroxycholecalciferol
1.Increases absorption of Ca from intestine
2.Increases synthesis of Ca induced ATPase in the
intestinal epithelium
3.Increases synthesis of alkaline phosphatase in the
intestinal epithelium
4.Increases absorption of phosphate from intestine.

61. Role of Ca ion in regulating 1,25 Dihydroxycholecalciferol
ca ion 25 Dihydroxycholecalciferol
ca ion - PTH secretion

62. Regulation of PTH secretion:
Blood level of calcium:
-inversely proportional
conditions when PTH secretion decreases
Blood level of phosphate:
- directly proportional

63. CALCITONIN
• It is a 32 amino – acid polypeptide, secreted from clear
cells or parafollicular cells of thyroid glands therefore
also, known as THYROCALCITONIN
• It is not secreted until the plasma calcium exceeds
9.5mg/dl
• Normal secretion is 0.5mg/day;
• half life less than 15 mins;
• molecular weight 3000;
• Normal plasma level 0.2ngm/ml

64. ACTIONS
ON BLOOD CALCIUM LEVEL-
It reduces the blood calcium concentration
ON BONE
Stimulates osteoblastic activity
Inhibits osteoclastic activity
Increases excretion of Ca through urine
Inhibits reabsorption of Ca from renal tubules
ON GIT
Inhibits intestinal absorption of
Ca++and PO4
---
ON KIDNEYS

65. ON BLOOD PHOSPHATE LEVEL-
On bones:
Inhibits resorption of phosphate from bone
On kidneys:
Increases excretion of phosphate through urine

66. PTH 1,25-DHCC CT
ON BONE Bone resorption
increases
Mobilize Ca &
P
Bone resorption
decreases
ON GIT Ca & P absorption
increases
Ca & P
absorption
increases
Ca & P absorption
decreases
ON KIDNEY P absorption
decreases
Ca reabsorption
increases
Ca resorption
increases
1,25-DHCC
decreases
Ca & P excretion
increases
ON S.Ca+2 Increases Increases Decreases
ON S.PO4-3 Decreases Increases Decreases

67. Applied physiology –
Disorders of parathyroid glands ( two types )
1. HYPOPARATHYROIDISM
-causes: Parathyroidectomy
Thyroidectomy
Deficiency of receptor for PTH
1. HYPERPARATHYROIDISM
Primary hyperparathyroidism
Secondary hyperparathyroidism
Tertiary hyperparathyroidism

68. Hypoparathyroidism- Hypocalocemia
Hypocalcemic tetany:
signs and symptoms
1. hyper-reflexia and convulsions
2. carpopedal spasm
3. laryngeal stridor
4. cardiovascular changes
5. other features
Late or subclinical tetany:
1. trousseau’s sign
2. chvostek’s sign
3. erb sign

69. Hyperparathyroidism- hypercalcemia
signs and symptoms:
1. depression of the nervous system
2. sluggishness of reflex activities
3. reduced ST segment and QT interval in ECG
4. lack of appetite
5. constipation
Parathyroid function tests:
Measurement of blood Ca level
Chvostek’s sign and trousseau’s sign for hypoparathyroidism

70. CALCIUM AND DENTAL CARIES
if it occurs when teeth are still forming, following
abnormalities may occur:
-Enamel hypoplasia
-Poorely mineralised dentin
-Malformed teeth
-Elongated pulp chambers
-Anodontia or impacted teeth

71. CALCIUM AND SALIVA
• Calcium content of submandibular saliva is almost double the
parotid content. This probably contributes to marked
prevalence of calculus on lingual aspect of mandiblular
incisors
• Concentration of calcium lessens as salivary flow increases.
This probably results from the increased parotid contribution
in rapid salivary flow rates
-Principal salivary calcium phosphates salts are dicalcium
phosphate dihydrate, octacalcium phosphate, tricalcium
phosphate and hydroxyapatite

72.  Symbol : P
 Atomic number: 15
 Atomic mass:
30.97376amu
 Melting point: 44.1o C
(317.25K, 111.38o F)
 Boiling point: 280.0oC
(553.15K, 536.0oF)
 Colour
 Classification: Non-metal

73. • Key element in all the known forms of life
• Plays a major role in biological molecules such as RNA and DNA
• Main structural component of all the cellular membranes
• Living cells also utilize phosphate to transport cellular energy via
ATP
• Average person contains little less than 1 kg of phosphorous,
about 3quater present in bones and teeth in form of apatite
crystal

74.  It is found in ATP, cAMP, 2, 3-DPG (diphosphoglyceric
acid)
 Total body phosphate is 500-600gms,
 80-85% is in skeleton
 Remaining is in intracellular phosphate pool.
 Serum inorganic phosphate level:
 In adults: 2.5-4mg%
 In children: 5-6mg%

75. Sources of Phosphorus

76. Adequate Intake
•0-6 months 100 mg/day
•6-12 months 275 mg/day
Estimated Average Requirements
•1-3 years 380 mg/day
•4-8 years 405 mg/day
•9-18 years 1,055 mg/day
•19-70+ years 580 mg/day
•Pregnant & Same as for nonpregnant &
lactating women nonlactating women
Reference : Dietary Reference Intakes, Food and Nutrition
Board, National Academy of Sciences-Institute of Medicine, 1997

77. Total phosphate:500-800
mg
Bones and teeth
80-85%
Inorganic
(0.5-
1mg/dl)
(Adults:3-
4mg/dl)
(children:5-6mg/dl)
Normal plasma levels:
2.5-4.5 mg/dl
Organic

78. Mechanism– co-transport Na
 P is absorbed in duodenum and
other parts of small intestine by
active transport and passive
diffusion.

79.  Approximately 3mg/kg/day of Phosphorous enters the bone
.
In plasma is filtered in glomeruli of which 85-95% gets
reabsorbed actively in PCT. Its excretion in urine is:
INCREASED BY:
Vitamin D excess;
hyperparathyroidism;
high phosphate diet.
DECREASED BY:
GH, during lactation;
hypoparathyroidism;
low phosphate diet.

80. EXCRETION OF PHOSPHOROUS
• It is excreted in urine and feaces
• Urine phosphate constitutes about 60% of total excretion and
rest is excreted in feaces.
Infant 240 - 400mg
Children 800 - 1200mg/day
Adults 800mg/day
Pregnancy & Lactation 1200mg/day

81.  IN BONE
 STRUCTURAL COMPONENT
 INTERMEDIATE METABOLISM
 GENETIC MATERIAL
FUNCTIONS OF PHOSPHOROUS

82.  Important Functions to note
are………..
 Gives rigidity to bones and teeth
 Helps in regulation of pH of blood
 In regulation of glycolysis and energy
metabolism
 Forms a part of DNA, RNA, Phospholipids &
nucleotides.

84. PHOSPHATE
TURNOVER

85. Overview of Phosphate Balance

86. Conditions arising from
disruption / irregularities
of phosphate metabolism

87. Etiologies of Hyperphosphatemia
Increased GI Intake :
Fleet’s Phospho-Soda
Decreased Urinary Excretion :
Renal Failure
Low PTH (hypoparathyroidism)
Thyroidectomy
Autoimmune hypoparathyroidism
Cell Lysis :
Rhabdomyolysis
Tumor lysis syndrome

88. Etiologies of Hypophosphatemia
Decreased GI Absorption
Decreased dietary intake
Diarrhea / Malabsorption
Phosphate binders (calcium acetate, Al & Mg
containing antacids)
Decreased Bone Resorption / Increased Bone Mineralization
Vitamin D deficiency / low calcitriol
Hungry bones syndrome
Osteoblastic metastases

89. Increased Urinary Excretion
Elevated PTH (as in primary hyperparathyroidism)
Vitamin D deficiency / low calcitriol
Fanconi�