2. Phosphorus

3. INTRODUCTION
Phos is the second most abundant mineral in the body, after calcium.
It has many functions in human body.
85% of phos in the body is found in bones, and the remaining 15 % is spread throughout soft tissues.
3Ca3(PO4)2Ca(OH)2 with carbonates absorbed on it.

4. INTRODUCTION
It is essential for the normal function of every cell, performing a variety of functions.
Phosphorus is absorbed in the small intestine and stored in bones.
Excess phosphorus is excreted by the kidneys.
Because phosphorus occurs in many foods, deficiency is rare.

5. Functions It is required for energy production and storage.
Helps your body change protein, fat and carbohydrate into energy.
As a component of DNA and RNA, phosphorus is also involved in the storage and transmission of genetic material.

6. FUNCTIONS
It activates,Enzymes, Vitamins, hormones and cell-signaling molecules through phosphorylation.
Phosphorus also helps maintain normal acid-base, or pH, balance by acting as a buffer.

7. Learning Objectives Dietary sources Daily Requirements Metabolism
Important functions and
Deficiency diseases

8. Phosphorous P At. No. 15 Atomic Mass: 30.77

9. PHOSPHORUS

10. Dietary Source
Present in all foods, Dietary deficiency is therefore unknown.
Distribution is similar to Ca++ . Adequate, intake of one ensures that of the other.
Best sources (Milk and milk products)
Lean meat is also a good source.

11. Recommended Dietary Allowance
Infants Up to 6 months mg
6 m – 1.0 year mg
Children 1 – mg
4 – mg
7 – mg

12. Recommended Dietary Allowance
Adults (Male/Females)
11 – mg
15 – mg
19 – mg
23 – mg mg
Pregnant and lactating women should take an additional 400 mg.

13. Absorption and Metabolism
Normally about 70% of dietary P is absorbed
(For calcium 10 – 30%)
Mid jejunum is the main site of absorption for free PO4 .
In ileum absorption occurs via active process.

14. Absorption and Metabolism
Most of phosphorus in food is in combined form, absorption requires splitting off of PO4 by intestinal enzymes (Phosphatases)
is hydrolyzed in GIT by Pancreatic & intestinal enzymes.

15. Absorption and Metabolism
Inorganic phosphorus is released and absorbed
Its absorption decreases during period of increased utilization of carbohydrate

16. Phosphate metabolism
Phosphates are absorbed from foodstuff. Specialized channel proteins called sodium-phosphate transporters 2b (or NaPi2b) located at the surface of the epithelial cells of the small intestine are performing the task.
About 1.5 g of phosphate are captured daily by this process by a normal adult.   

18. Once in the bloodstream, phosphates can be absorbed by organs and tissues.
A major part of it is stored in bones.
Then, phosphates reach the kidneys where most of it is filtered out of the blood.
But before being eliminated in the urine, another channel protein (NaPi2a) similar to the one that capture phosphate from foodstuff bring it back to bloodstream in a process called 'reabsorption'.
This steps of filtration and reabsorption taking place in the kidney are crucial for the maintenance of phosphate levels.

19. Factors affecting absorption
Similar to Calcium like:
Enhancement by Vit D and PTH
Inhibition by binding agents i.e. Iron and Aluminium.
Ca : P ratio in diet.
Excess of one causes, an increased excretion of other.

20. Ratio of P : Ca
Ideal 1 : 1 , Specially during the period of rapid growth (childhood), pregnancy and lactation.
Ratio in other age groups if different, have no serious adverse effect

21. In Infants
Care should be exercised as kidneys can’t handle high phosphate load.
For Prevention of hypocalcemic tetany Ca : P ratio be 1.5 : 1
Ratio should be reduced to 1:1 by age 1 yr

22. Distribution Phosphorus accounts for about 1% of TBW.
¼th of total body mineral matter
80 – 90% joined with Ca++ in bones and teeth as a component of calcium phosphate and is being constantly deposited and liberated from bone structure.
10 – 20% present in all cells as phosphate ion (PO=4)

23. FUNCTIONS
Phos works closely with calcium to build strong bones and teeth in the form of cal- phosphate.
Adequate intake of phosphorus and calcium is essential during infancy , childhood and puberty, when bone mass is laid down.
For adult women, requirements increase again during pregnancy and lactation and in postmenopause, when the protective effect of estrogen on bone is depleted.
It is important to have a balance of phosphorus and calcium in the diet.
Having more phosphorus than calcium may lead to osteoporosis and gum and teeth problems.

24. Functions
Component of many compounds involved in many metabolic reactions.
Sugar – PO4 linkage in DNA and RNA
Phospholipids  Transport of fat in blood
Phospholipids  cell membrane control transport of substances into and out of cell

25. Cell Structure
Phosphorus combines with lipids – usually glyceride to form various types of phospholipids.
Phospholipids are a major structural component of all cell membranes, or walls, throughout the body.
They are essential for optimal brain health, helping brain cells communicate and influencing receptor function.
Phospholipids in brain cells also control which minerals, nutrients and drugs go in and out of the cell.

26. Functions Phosphorylation
Necessary for glucose absorption from intestine
Glucose uptake by individual cells
Resorption of glucose by kidney

27. Functions
Monosaccharides are Phosphorylated several times during metabolic break down to yield energy.
Involved in storage and release of Energy through high energy phosphate bond of ATP and ADP.

28. Functions Essential part of body’s delicate buffer system
Many B vitamins becomes active only when combine with phosphate.

29. Hypo-Phosphatemia Diminished Supply: Starvation Malnutrition
Vit D – Deficiency
Increased excretion / loss
Hyperparathyroidism
Hyper thyroidism
Renal defects

30. Hypo-Phosphatemia Intracellular shift of phosphorus
Glucose induced
Insulin induced
Respiratory alkalosis
Electrolytes administration
Hypercalcaemia
Hypomagnesimia

31. Hyper-Phosphatemia Endocrine disease 2. Renal Diseases
Increased growth hormones (acromegaly)
Hypo parathyroidism low calcium
Pseudo hypo parathyroidism
2. Renal Diseases
Chronic renal insufficiency
Acute renal failure

32. Hyper-Phosphatemia 3. Catabolic states Excess intake or Absorption
Stress or injury
Chemotherapy for malignant disease
Excess intake or Absorption
Laxatives or Enemas containing phosphate
Hyper vitaminosis – D

33. Excretion Phosphate level is regulated by urinary excretion
2 mg / dl is the renal thresh hold
mg / day is excreted in urine

34. Excretion General factors affecting intestinal absorption
Plasma concentration and Hydrolysis of PO4 esters by phosphatases in the kidney.
Decrease Ca++ intake will increase urinary PO4 excretion

35. Clinical Importance

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