Calcium Metabolism New 15-6
-
Upload
rejanischandran -
Category
Documents
-
view
143 -
download
0
Transcript of Calcium Metabolism New 15-6
![Page 1: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/1.jpg)
A Seminar
on Calcium Metabolism
![Page 2: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/2.jpg)
contentsIntroductionRole of calciumNormal values,Types,Sources,Daily requirementsAbsorption,Distribution,ExcretionRegulation of blood calcium levelsApplied physiologyImportance of calcium in ProsthodonticsConclusionReferences
![Page 3: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/3.jpg)
Introduction
Most abundant mineral in the body
Calcium interacts with phosphorous forming Calcium phosphate
![Page 4: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/4.jpg)
Role of Calcium
1. Neuronal ActivityCalcium is necessary –
-- For transmission of impulses from pre synaptic to post synaptic region
-- For the release of neurotransmitter from synaptic vescicle
![Page 5: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/5.jpg)
2 Muscular ActivityCalcium mediates excitation-contraction coupling of muscle fibers
Skeletal Muscle - Calcium binds with Troponin c and Tropomyosin
Smooth Muscle – in place of Troponin Calcium binds with Calmodulin
![Page 6: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/6.jpg)
3. Hemostasis
Necessary for activation of clotting factors in blood coagulation
4. Formation of bone and teeth
5. Membrane stabilization
6. Secretary activity of glands
7. Activation of enzymes
![Page 7: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/7.jpg)
Normal Values
Total body Calcium – 1100g(1.5 % of total body weight)
Out of this - 99% in bone
- 4-5 g in soft tissues
- approx 1g in extra cellular fluid
Normal Serum Calcium
- 9-11 mg%
![Page 8: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/8.jpg)
Types 1. Diffusible
Ionised calcium- physiologically active form (50%)
Non Ionised Calcium- Calcium complexed with anions (9%)
2. Non Diffusible (41%)Calcium bound to albuminPhysiologically inactive
Sources Milk, Egg, Fish ,Leafy Vegetables, Cereals
![Page 9: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/9.jpg)
Daily Requirement
Adult - 500 -800mg per day
Children - 1200mg per day
Pregnancy and Lactation -1500mg per day
After age of 50 tendency for osteoporosis may be prevented by-
Calcium (1500mg/day)+ Vitamin D (20mg/day)
![Page 10: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/10.jpg)
Absorption of CalciumMainly from 1st and 2nd part of Duodenum
Absorbed against a concentration gradient
Requires a carrier protein- Calbindin helped by calcium dependent ATPase
Factors Increasing•Vitamin D•Calcitriol•Parathyroid Hormone•Amino Acids..lysine,Arginine
Factors Decreasing• Phytates•Oxalates•Malabsorption Syndrome•High Phosphate content
Factors affecting Absorption
![Page 11: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/11.jpg)
Regulation of Blood Calcium Levels
Three hormones that regulates blood calcium levels
1. Parathyroid hormone
2. 1,25-dihydroxycholecalciferol
3. Calcitonin
![Page 12: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/12.jpg)
1. Parathyroid Hormone(PTH)A polypeptide secreted by chief cells of parathyroid gland
Synthesised from a precursor Prepro-PTH
Acts via activation of adenylyl cyclase
Actions
a. Action on Bones
Increases plasma calcium concentration by promoting bone resorption
Occurs in 2 Phases
Rapid Phase (Early Phase)-Osteolysis
Slow Phase- Activation of Osteoclasts
![Page 13: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/13.jpg)
b. Action on Kidneys
Increases renal tubular reabsorption of calcium
Occurs mainly in the distal tubules, collecting tubules, collecting duct and to a lesser extent in ascending loop of Henle
c. Action on GIT
Increases calcium absorption from intestine-by increasing the formation of 1,25 dihydroxycholecalciferol
![Page 14: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/14.jpg)
2. 1,25 – dihydroxycholecalciferol
Activated form of Vitamin D
Increases calcium absorption from intestine
![Page 15: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/15.jpg)
3. Calcitonin
A peptide hormone secreted by C cells of thyroid gland
Reduces Blood calcium level by acting on-
Bone-deposition of calcium
Kidney-Increases calcium Excretion
Intestine-Prevents Calcium Absorption
![Page 16: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/16.jpg)
Applied Physiology1.Hypoparathyroidism
Decreased secretion of PTH- Hypocalcemia(calcium <8.5mg/dl)
Hypocalcemic tetany – neuromuscular hyper excitability- Occurs if the plasma calcium level falls below 6mg%
Signs and symptoms • Carpopedal Spasm -Trousseau’s Sign(Figure)
• Laryngeal Stridor• ECG Changes• Can be detected by 1, Trousseau’s Sign 2, Chvostek’s Sign 3. Erb Sign
![Page 17: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/17.jpg)
2. Hyperparathyroidism
Increased secretion of PTH-Hyper calcemia
Radiology of hyperparathyroidism
![Page 18: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/18.jpg)
OsteoporosisBone disease characterised by loss of bone matrix and minerals
Due to excessive bone resorption and decreased bone deposition.
Risk factors
1.sedentary life
2.genetic factors
3.early menopause/ ovariectomy
4.excessive alcohol intake
5.prolonged medication with corticosteroids.
6.hypothyroidism,cushings syndrome,
acromegaly, hypogonadism.
![Page 19: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/19.jpg)
3. RicketsBone disease occurring in children due to vitamin D deficiency
![Page 20: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/20.jpg)
4.Osteomalacia(Adult Rickets)
5.Renal OsteodystrophyA consequence of chronic renal failure related to calcium metabolism
![Page 21: Calcium Metabolism New 15-6](https://reader034.fdocuments.us/reader034/viewer/2022042515/5450fbecb1af9f51248b480f/html5/thumbnails/21.jpg)
Importance of calcium in Prosthodontics
Necessary for the normal growth of bone and teeth.
In osteoporosis, - RRR will be more- affect denture retention – frequent relining is needed
Amount and density of available bone in edentulos site is the primary determining factor in predicting the success of an implant.