Electrolytes

Electrolytes notes for MLT students

1. MODULE 3 Topic: Electrolytes Sub code : MLT504 Sub Name: Medical Lab Technician -1 (T) Department: Department of MLT, SMAS Faculty: A. Vamsi Kumar Designation : Assistant professor

2. Course outcomes Provide technical information about test results;

3. LEARNİNG OBJECTİVES At the end of this lecture, the student can be able to : List the role of the six most important electrolytes in the body Name the disorders associated with abnormally high and low levels of the six electrolytes Identify the predominant extracellular anion Describe the role of aldosterone on the level of water in the body

4. Contents Introduction to Electrolytes  Electrolyte balance  Homeostasis  Imbalance disorders  Acid –Base Balance  conclusion

5. Metabolic The metabolic definition is still popular with many biologists . It describes a living system as an object with a definite boundary, continually exchanging some of its materials with its surroundings, but without altering its general properties, at least over some period of time. But again there are exceptions. There are seeds and spores that remain, so far as is known, perfectly dormant and totally without metabolic activity at low temperatures for hundreds, perhaps thousands, of years but that can revive perfectly well upon being subjected to more clement conditions. A flame, such as that of a candle in a closed room, will have a perfectly defined shape with fixed boundary and will be maintained by the combination of its organic waxes with molecular oxygen, producing carbon dioxide and water. A similar chemical reaction, incidentally, is fundamental to most animal life on Earth. Flames also have a well-known capacity for growth.

6. Biochemical A biochemical or molecular biological definition sees living organisms as systems that contain reproducible hereditary information coded in nucleic acid molecules and that metabolize by controlling the rate of chemical reactions using proteinaceous catalysts known as enzymes. In many respects, this is more satisfying than the physiological or metabolic definitions of life. There are, however, even here, the hints of counterexamples. There seems to be some evidence that a virus-like agent called scrapie contains no nucleic acids at all, although it has been hypothesized that the nucleic acids of the host animal may nevertheless be involved in the reproduction of scrapie . Furthermore, a definition strictly in chemical terms seems peculiarly vulnerable. It implies that, were a person able to construct a system that had all the functional properties of life, it would still not be alive if it lacked the molecules that earthly biologists are fond of--and made of.

7. Genetic All organisms on Earth, from the simplest cell to man himself, are machines of extraordinary powers, effortlessly performing complex transformations of organic molecules, exhibiting elaborate behavior patterns, and indefinitely constructing from raw materials in the environment more or less identical copies of themselves. How could machines of such staggering complexity and such stunning beauty ever arise? The answer, for which today there is excellent scientific evidence, was first discerned by the evolutionist Charles Darwin in the years before the publication in 1859 of his epoch-making work, the Origin of Species. A modern rephrasing of his theory of natural selection goes something like this: Hereditary information is carried by large molecules known as genes, composed of nucleic acids . Different genes are responsible for the expression of different characteristics of the organism.

8. During the reproduction of the organism the genes also reproduce, or replicate, passing the instructions for various characteristics on to the next generation. Occasionally, there are imperfections, called mutations, in gene replication. A mutation alters the instructions for a particular characteristic or characteristics. It also breeds true, in the sense that its capability for determining a given characteristic of the organism

9. This definition places great emphasis on the importance of replication. Indeed, in any organism enormous biological effort is directed toward replication, although it confers no obvious benefit on the replicating organism. Some organisms, many hybrids for example, do not replicate at all. But their individual cells do. It is also true that life defined in this way does not rule out synthetic duplication. It should be possible to construct a machine that is capable of producing identical copies of itself from preformed building blocks littering the landscape but that arranges its descendants in a slightly different manner if there is a random change in its instructions. Such a machine would, of course, replicate its instructions as well.

10. But the fact that such a machine would satisfy the genetic definition of life is not an argument against such a definition; in fact, if the building blocks were simple enough, such a machine would have the capability of evolving into very complex systems that would probably have all the other properties attributed to living systems. The genetic definition has the additional advantage of being expressed purely in functional terms: it does not depend on any particular choice of constituent molecules. The improbability of contemporary organisms--dealt with more fully below--is so great that these organisms could not possibly have arisen by purely random processes and without historical continuity. Fundamental to the genetic definition of life then is the belief that a certain level of complexity cannot be achieved without natural selection.

11. Thermodynamic Thermodynamics distinguishes between open and closed systems. A closed system is isolated from the rest of the environment and exchanges neither light, heat, nor matter with its surroundings. An open system is one in which such exchanges do occur. The second law of thermodynamics states that, in a closed system, no processes can occur that increase the net order ( or decrease the net entropy) of the system (see thermodynamics). Thus the universe taken as a whole is steadily moving toward a state of complete randomness, lacking any order, pattern, or beauty.

12. This fate has been known since the 19th century as the heat death of the universe. Yet living organisms are manifestly ordered and at first sight seem to represent a contradiction to the second law of thermodynamics. Living systems might then be defined as localized regions where there is a continuous increase in order . Living systems, however, are not really in contradiction to the second law. They increase their order at the expense of a larger decrease in order of the universe outside. Living systems are not closed but rather open. Most life on Earth, for example, is dependent on the flow of sunlight, which is utilized by plants to construct complex molecules from simpler ones. But the order that results here on Earth is more than compensated by the decrease in order on the sun, through the thermonuclear processes responsible for the sun's radiation.

13. Some scientists argue on grounds of quite general open-system thermodynamics that the order of a system increases as energy flows through it, and moreover that this occurs through the development of cycles. A simple biological cycle on the Earth is the carbon cycle. Carbon from atmospheric carbon dioxide is incorporated by plants and converted into carbohydrates through the process of photosynthesis. These carbohydrates are ultimately oxidized by both plants and animals to extract useful energy locked in their chemical bonds. In the oxidation of carbohydrates, carbon dioxide is returned to the atmosphere, completing the cycle.

14. The existence of diverse definitions of life surely means that life is something complicated. A fundamental understanding of biological systems has existed since the second half of the 19th century. But the number and diversity of definitions suggest something else as well. As detailed below, all the organisms on the Earth are extremely closely related, despite superficial differences. The fundamental ground pattern, both in form and in matter, of all life on Earth is essentially identical. As will emerge below, this identity probably implies that all organisms on Earth are evolved from a single instance of the origin of life.

15. Erwin Schrodinger

16. Intracellular Vs Extracellular electrolytes

17. Normal Values of Electrolytes

18. Normal values of electrolytes

19. Functions of Electrolytes

20. 1. Sodium

21. 2. Potassium

22. Potassium

23. Dietary source of potassium

24. Minerals Minerals are essential for normal growth and maintenance of the body. Major elements : Requirement >100 mg /day Calcium Chloride Magnesium Sulphur Phosphorous Fluoride Sodium Potassium

25. Contd…. Trace Elements : Requirement <100mg/day Iron Zinc Iodine Molybdenum Copper Selenium Manganese

26. Contd…. Some are necessary for the body but their exact functions are not known. Ex.: Chromium, Nickel, Bromide, Lithium, Barium Non-Essentials : seen in tissues. Contaminants in food stuffs. Ex.: Rubedium, Silver, Gold, Bismuth Toxic : should be avoided. Ex.: Aluminium, Lead, Cadmium, Mercury

27. CALCIUM (Ca) Total Calcium in human body: 1 – 1.5 Kg In Bones – 99 % In extra cellular fluid – 1 % Sources : - Milk (Cow’s Milk – 100mg/100ml) - Egg, Fish, Vegetables - moderate - Cereals (wheat, rice) - poor source

28. Plasma Calcium Normal Plasma / Serum Calcium : 9 – 11 mg / dl Ionized Calcium : 5 mg/dl Protein bound Calcium : 4 – 5 mg/dl Complexed with phosphate/citrate/ bicarbonate : about 1 mg/dl

29. Daily Requirement Adults : 500 mg/day Children : 1200 mg/day Pregnancy and Lactation : 1500 mg/day >50 yrs. : 1500 mg/day +20µg Vit.D (to prevent osteoporosis)

30. Absorption 1 st and 2 nd part of duodenum Against concentration gradient and requires energy Requires carrier protein

31. Factors promoting Ca absorption Vitamin – D (calcitriol) synthesis of carrier protein calbindin – facilitates absorption Parathyroid Hormone – ↑ Ca transport from intestinal cells Acidity – favors Ca absorption Amino acids – Lysine and Arginine

32. Factors Inhibiting Ca absorption Phytates and oxalates - form insoluble calcium oxalates High dietary phosphates - precipitate as calcium phosphate High pH - (alkaline) High dietary fiber Mal absorption syndrome - Fatty acids not absorbed and form insoluble calcium salts of fatty acid

33. Functions 1. Bones & Teeth : Formation of bone & teeth . Bones are reservoir for Ca in the body. Osteoblasts → bone deposition Osteoclasts → demineralization.

34. Muscle Contraction : Ca mediates excitation & contraction of muscle fibers. Ca interacts with Troponin -C to trigger muscle contraction. Ca activates ATPase , ↑ interaction between actin and myosin.

35. Nerve Conduction : Transmission of nerve impulses from pre-synaptic to post-synaptic region. Secretion of hormones : Mediates the secretion of Insulin, PTH, Calcitonin, Vasopressin etc.

36. Second Messenger : Ca & cyclic AMP are 2 nd messengers of different hormones. Eg: Glucogan Membrane integrity & Permeability : Influences transport of number of substances across the membranous barrier.

37. Blood Coagulation : Factor IV in blood coagulation cascade. prothrombin → Thrombin Action on Heart : Ca prolongs Systole . ↑ Ca concentration → ↑ myocardial contractility

38. The Calcium-Binding Region of Prothrombin Prothrombin binds calcium ions with the modified amino acid g-carboxyglutamate ( red ).

39. 9. Activation of Enzymes : Calmodulin – Ca binding regulatory protein. Binds with 4 Ca ions and leads to activation of enzymes.

40. Calmodulin contains four similar units in a single polypeptide chain shown in red, yellow, blue, and orange. Each unit binds a calcium ion (shown in green).

41. Homeostasis of Ca The major factors that regulate the plasma Calcium Calcitriol Parathyroid hormone Calcitonin

42. Calcitriol ↑ intestinal absorption of Ca. Stimulates Ca uptake by osteoblasts and promotes Calcification.

43. P T H Elevates serum Ca Demineralization of bone (Osteoclasts) Increases Ca reabsorption by renal tubules Increases intestinal absorption of Ca by promoting synthesis of Calcitriol

44. Calcitonin secreted by Para follicular cells of Thyroid gland Lowers the serum Ca levels Calcification of bone (by osteoblasts) Increases the excretion of Ca into urine Calcitonin & PTH are directly antagonistic

45. Calcitriol PTH Calcitonin Blood calcium ↑ ↑ ↓ Main action Absorption from gut Deminerali-zation Oppose demineraliza-tion

46. Disorders of Calcium Metabolism Hypercalcemia : > 11 mg/dl causes : Hyperparathyroidism - Parathyroid adenoma ectopic parathyroid secreting tumor Multiple myeloma Paget’s disease Metastatic carcinoma of bone.

47. Hypocalcemia TETANY Ca < 8.5 mg/dl → mild tremors < 7.5 mg/dl → typical Tetany Causes : Accidental removal of parathyroid glands Autoimmune disease

48. Symptoms : Neuromuscular irritability Carpopedal spasms Laryngismus → stridor ( noisy breathing) laryngeal spasms may lead to death . Signs : Chovstek’s sign + Trousseau’s sign + ↑ Q-T interval in ECG

49. Chovstek’s sign A twitch of the facial muscles following gentle tapping over the facial nerve in front of the ear that indicates hyperirritability of the facial nerve

50. Trousseau’s sign A test for latent tetany in which carpal spasm is induced by inflating a sphygmomanometer cuff on the upper arm to a pressure exceeding systolic blood pressure for 3 minutes.

51. Carpopedal spasm

52. IRON (F e ) MINERALS

53. INTRODUCTION Total body iron content : 3 - 5 gm Iron is present in almost all cells Heme containing proteins: Hb, myoglobin, cytochromes, cytochrome oxidase, catalase, peroxidase, xanthine oxidase & Trp pyrrolase

54. Contd …. 75% of total Fe is in Hb & 5% in myoglobin Non-heme iron containing proteins : ferritin, transferrin, hemosiderin, lactoferin (milk) & neutrophils

55. BIOCHEMICAL FUNCTIONS Tissue Respiration : Iron can change readily between Ferrous and Ferric states and function in electron transfer reactions. Cytochromes NADH dehydrogenase Succinate dehydrogenase

56. Contd.… Transport of gases : Able to bind with molecular O 2 and CO 2 . The main function is to coordinate the O 2 molecule into heme of hemoglobin, so that it can be transported from the lungs to the tissues.

57. Contd …. Oxidative Reactions : Component of various oxidoreductase enzymes -vital role in oxidative reactions.

58. Contd …. Immune Response : Required for effective activity of lysosomal enzyme peroxidase – helps in phagocytic and bactericidal activity of neutrophils.

59. Requirement Indian diet contain >10 – 20 mg of Iron. only about 10% of it is absorbed. 1 mg is eliminated each day from human body by shredding of skin epithelial cells & cells lining urinary tract & small extent in urine + sweat.

60. Requirement is high in women 20-40 mg - blood loss in each menstrual cycle. ↑ daily demand to 3-4 mg in pregnant & lactating women. 900 mg – diversion of Iron to foetus in pregnancy. blood loss during delivery subsequent breast feeding

61. Requirement Children : 10 mg/day Adults Males : 10-12 mg/day Women Premenopausal : 18 mg/day Postmenopausal : 10 mg / day Pregnant & Lactating : 40 mg/day

62. Source Good sources: Leafy vegetables (20mg/100g), pulses (10mg/100g), cereals (5mg/100g), liver (5mg/100g), meat (2mg/100g), fish, dried fruits, jaggery and iron cookware Poor sources: Milk (0.1 mg/100 ml), wheat, polished rice

63. Absorption Ferric ions are reduced with the help of gastric HCl, ascorbic acid, cys. and -SH groups of pro. --------- favors absorption. Ca, Cu, Zn, Pb ------------- inhibit absorption. Phytates (in cereals), oxalates (leafy veg) & phosphates in the diet reduce absorption by forming insoluble iron salts. Marginal ↓ by t ea & eggs.

64. Regulation of Absorption Mucosal block theory Absorbed by upper part of duodenum Homeostasis is maintained at the level of absorption Iron stores depleted - absorption ↑ Iron stores adequate - absorption ↓ Only Fe ++ (ferrous) form is absorbed and not Fe +++ (ferric) form.

65. Contd …. Ferrous Iron binds to mucosal cell protein called Divalent Metal Transporter - 1 (DMT-1). This bound Iron is then transported into the mucosal cell. Unabsorbed Iron is excreted.

66. Lumen of GIT Mucosal cells of GIT Plasma Tissues Food Fe Apoferritin Apotransferrin HCl Organic acids Ferritin Transferrin (Fe +++ ) Fe +++ Fe +++ Ferro- Fe +++ Ascorbic acid reductase Cysteine Ferroxidase Fe++ Ceruloplasmin or Ferroxidase II Fe ++ Fe ++ Fe ++ Iron absorption and transport Liver Ferritin hemosiderin Bone marrow (Hb) Muscle (Mb) Other tissues

67. Inside the mucosal cell….. Iron oxidized to ferric state. complexed with apoferritin to form Ferritin . Ferric Iron is released, reduced to Ferrous state crosses the cell membrane.

68. Lumen of GIT Mucosal cells of GIT Plasma Tissues Food Fe Apoferritin Apotransferrin HCl Organic acids Ferritin Transferrin (Fe +++ ) Fe +++ Fe +++ Ferro- Fe +++ Ascorbic acid reductase Cysteine Ferroxidase Fe++ Ceruloplasmin or Ferroxidase II Fe ++ Fe ++ Fe ++ Iron absorption and transport Liver Ferritin hemosiderin Bone marrow (Hb) Muscle (Mb) Other tissues

69. In the blood stream…. Reoxidized to Ferric state by Ceruloplasmin Ferric Iron bound with Transferrin and transported to tissues.

70. Lumen of GIT Mucosal cells of GIT Plasma Tissues Food Fe Apoferritin Apotransferrin HCl Organic acids Ferritin Transferrin (Fe +++ ) Fe +++ Fe +++ Ferro- Fe +++ Ascorbic acid reductase Cysteine Ferroxidase Fe++ Ceruloplasmin or Ferroxidase II Fe ++ Fe ++ Fe ++ Iron absorption and transport Liver Ferritin hemosiderin Bone marrow (Hb) Muscle (Mb) Other tissues

71. Excretion One-way element (very little of it is excreted) Almost no iron is excreted through urine Any type of bleeding will cause the loss Normal level in plasma -------- 50 - 175 µg/dl

72. Deficiency Iron deficiency anemia is the most common nutritional deficiency diseases Characterized by microcytic hypochromic anemia (blood Hb <12 g/dl)

73. Iron deficiency anemia Clinical Manifestations: Anemia, Apathy Achlorhydria Impaired attention, Irritability, Lowered memory Koilonychia (spoon nails)

74. Koilonychia

75. Causes of deficiency Hookworm infection Nephrosis Repeated pregnancy Lack of absorption Nutritional deficiency of Fe Chronic blood loss (piles, peptic ulcer, uterine hemorrhage)

76. Toxicity HEMOSIDEROSIS --------- uncommon Occurs in persons receiving repeated blood transfusion (in hemophilia, hemolytic anemia). Common in Bantu tribe , because of staple diet, corn, is low in phosphates, and their habit of cooking foods in iron vessels.

77. It is manifested when total body iron is >25-30 gm, where hemosiderin is deposited in almost all tissues.

78. Hemochromatosis Primary Hemochromatosis : - genetic disorder – excessive storage of Iron in tissues → tissue damage. Secondary Hemochromatosis : - repeated blood transfusions - excessive oral intake of Iron eg. as in African Bantu tribes

79. Bronze diabetes Deposition of iron Liver cell death ------ cirrhosis Pancreatic cell death -------- diabetes Deposits under the skin cause yellow-brown discoloration ---------- hemochromatosis The triad of cirrhosis, diabetes and hemochromatosis ------- bronze diabetes

80. PHOSPHOROUS

81. The total body phosphate – 1 kg 80 % - Bone & Teeth 10 % - Muscles Mainly Intracellular ion – seen in all cells.

82. Functions Formation of bone & teeth Production of high energy phosphates: ATP CTP GTP creatine phosphate Synthesis of nucleoside co-enzymes: NAD + and NADP + DNA and RNA synthesis: Phosho-diester linkages –backbone of structure

83. Contd…. Formation of phosphate esters: Glucose 6-phosphate, phospholipids Formation of phosphoprotein: Casein Activation of enzymes by phophorylation Phosphate buffer system of blood: maintain the pH of blood at 7.4.

84. Requirement & Sources 500 mg/day Milk - good source cereals Nuts moderate source Meat Calcitriol increases phosphate absorption

85. Serum levels Normal adults - 3 – 4 mg/dl Children - 5 – 6 mg/dl Whole blood phosphate – 40 mg/dl Decrease in phosphate levels: Hyperparathyroidism Rickets

86. SODIUM

87. Chief cation of Extracellular fluid. Total body Sodium – 4000 mEq 50 % in bones 40 % in extracellular fluid 10 % in soft tissues

88. Biochemical Functions Sodium (as sodium bicarbonate) regulates the body acid base balance. Sodium regulates ECF volume : Sodium pump is operating in all cells, so as to keep Sodium extracellular . This mechanism is ATP dependent .

89. Required for maintenance of osmotic pressure and fluid balance. Necessary for normal muscle irritability and cell permeability.

90. Daily requirement Normal diet contains 5 – 10 gm of sodium mainly as sodium chloride Sources : Common salt used in cooking medium Bread whole grains Nuts leafy vegetables Eggs Milk

91. Absorption Readily absorbed in the GI tract . very little < 2 % is found in faeces. In Diarrhea – large quantities of sodium is lost in faeces.

92. Excretion Kidney – major route of sodium excretion 800 gm/day of Na filtered in glomuruli 99 % - reabsorbed by proximal convoluted tubule. ↑ reabsorption in distal tubules controlled by aldosterone.

93. In edema – water & sodium content of the body increase. Diuretic drugs – excrete Na also along with water.

94. Normal Values In plasma - 136 – 145 mEq/L In cells - 35 mEq/L Mineralocorticoids influence Na metabolism in adrenocortical insufficiency ↓ plasma Na ↑ urinary excretion of Na

95. Hypernatremia Cushing’s disease Prolonged cortisone therapy In dehydration – water predominantly lost the blood volume decreased with apparent ↑conc. of sodium

96. Hyponatremia Vomiting Diarrhea Burns Addison’s disease (adrenal insufficiency) In severe sweating, Na is lost considerably - muscle cramps & headache.

97. Biochemical estimation Flame photometer Ion selective electrodes

98. POTASSIUM

99. Principal intraracellular cation. Total body Potassium – 3500 mEq 75 % in skeletal muscle Required for regulation of acid base balance and water balance in cells . Maintains intracellular osmotic pressure. Required for transmission of nerve impulse.

100. Enzyme – Pyruvate kinase (of glycolysis) depend on K + for optimal activity. Adequate intracellular concentration of K + is necessary for proper biosynthesis of proteins by ribosomes. Extracellular K + influences cardiac muscle activity.

101. Dietary requirement 3 – 4 g / day Sources : Banana Potato Orange Beans Pineapple Chicken Liver Tender coconut water – rich source

102. Absorption & excretion Absorption: From GI tract – very efficient (90%) In diarrhea – good proportion of K + is lost in feces Excretion : Through urine Aldosterone ↑excretion of potassium.

103. Normal values In plasma : 3.4 – 5.0 mEq/L In whole blood : 50 mEq/L Either high or low concentrations are dangerous since K + affects contractility of cardiac muscle

104. Hypokalemia Over activity of Adrenal cortex (Cushing’s syndrome) Prolonged cortisone therapy Prolonged diarrhea & vomiting Diuretics used for CCF may cause K + excretion S/S: irritability, muscular weakness, tachycardia, cardiomegaly & cardiac arrest ECG - flattened waves with T ↓

105. Hyperkalemia Renal failure Adrenocortical insufficiency (Addison’s disease) Diabetic coma S/S : depression of CNS mental confusion numbness bradycardia - cardiac arrest ECG - T ↑

106. Fluorine (F) Prevents dental caries Increases hardness of bones and teeth Sources : drinking water Requirements Children : 0.5-2.5 mg/day Adults : 2.0-5.0 mg/day Safe limit of fluoride : 1 ppm (parts per million) 1 ppm: 1 gm of F in million gm of water, which is equal to 1 mg per 1000ml

107. Deficiency & Toxicity Dental caries: < 0.5 ppm Dental fluorosis: > 2 ppm In children ; mottling of enamel & discoloration of teeth. In adults ; chronic intestinal upset, loss of weight, loss of appetite & gastroenteritis Skeletal fluorosis: >20 ppm; toxic Osteoporosis & osteosclerosis, with brittle bones

108. Contd. Ligaments of spine & collagen of bones get calcified Genu valgum: advanced cases of skeletal fluorosis (stiff joints) Plasma : normal value : 4 µg/dl fluorosis : 50 µg/dl

109. Iodine Total body iodine : 25-30 mg (80% in thyroid gland) Formation of thyroid hormones (T 3 & T 4 ) Requirements: Children : 40-120 µg/day Adults : 100-150 µg/day Pregnant women : 175 µg/day

110. Commercial source : seaweeds Other sources : drinking water, vegetables, fruits, iodized salt Absorption : small intestine only 30% of iodine in food is absorbed Goiterogenous substances prevent absorption of iodine Eg : i , Cabbage & tapioca contain thiocyanate , which inhibits iodine uptake by thyroid ii, Mustard seed contains thiourea , which inhibits iodination of thyroglobulin

111. Storage : iodothyroglobulin (glycoprotein) Excretion : mainly through urine and also through bile, saliva and skin Plasma : 4-10 µg/dl Deficiency: Children : cretinism Adults : goiter, hypothyroidism, myxedema

112. Zinc Total body Zn: 2 gm (99% is intracellular) 60% in skeletal muscle 30% in bones Prostate gland contains 100 µg/g & liver 50 µg/g Sources : grains, beans, nuts, cheese, eggs, milk, meat & shell fish

113. Absorption : duodenum Cu, Ca, Cd, Fe & phytate interfere absorption. Storage : in liver with a specific protein, metallothionine.

114. Biochemical functions Cofactor for more than 300 enzymes eg: carboxy peptidase, carbonic anhydrase, ALP, LDH, ADH, superoxide dismutase & glutamate dehydrogenase. Participate in the metabolism of carbohydrates, lipids, proteins & nucleic acids. Required for transcription and translation.

115. Stabilizes insulin , when stored in β - cells of pancreas. Promotes the synthesis of retinol binding protein. Gusten , Zn containing protein in saliva, is important for taste sensation. Role in growth, reproduction & wound healing.

116. Requirement : Children : 5-10 mg/day Adults : 10-15 mg/day Pregnancy & lactation : 15-20 mg/day Deficiency: Hypogonadism Growth failure Impaired wound healing Decreased taste and smell acuity Plasma : 50-150 µg/dl

117. COPPER (Cu) MINERALS

118. Introduction Total body Cu is 100 mg; quantitatively this is next to iron and zinc It is seen in muscles, liver, bone marrow, brain, kidney, heart and hair Cu containing enzymes: Ceruloplasmin, cyt. oxidase, cyt. C, tyrosinase, lysyl oxidase, ALA synthase, monoamine oxidase, cytosolic superoxide dismutase, uricase and phenol oxidase

119. Requirement & Sources Infants & children : 1.5-3 mg/day Adults : 2-3 mg/day Sources : Cereals, meat, liver, kidney, egg yolk, nuts and green leafy vegetables Milk is a poor source

120. Absorption Mainly from duodenum and is mediated by a Cu binding protein ( metallothionein ) Only about 10% of dietary Cu is absorbed Rate of absorption is reduced by phytates, Ca, Fe, Zn and Mo in the intestines Storage : liver & bone marrow Transport : albumin

121. Excretion : bile Urine doesn't contain Cu in normal circumstances Plasma copper: 100-200 µg/dl 95% is tightly bound to ceruloplasmin Small fraction (5%) is loosely held to histidine residues of albumin Normal serum conc. of ceruloplasmin: 25-50 mg/dl

122. Deficiency microcytic normochromic anemia Fragility of arteries, deminiralization of bones, demyelination of neural tissue, myocardial fibrosis, hypopigmentation of skin, greying of hair Minke’s kinky hair syndrome: results from defective cross linking of connective tissue due to Cu deficiency

123. Wilson’s hepatolenticular degeneration Rare (1 in 50,000) Cu deposition Liver : hepatic cirrhosis Brain (lenticular nucleus): brain necrosis Kidney : renal damage Chronic toxicity may lead to diarrhea and blue-green discoloration of saliva.

124. Selenium (Se) Least abundant and most toxic of essential elements Sources Plants (varies with soil content), meat, sea foods Requirements Children : 10-30 µg/day Adult male : 40-70 µg/day female : 45-55 µg/day Pregnancy & lactation : 65-75 µg/day

125. Biochemical functions Acts as a nonspecific intracellular antioxidant by providing protection against peroxidation in tissues and cell membranes. Complementary to vit. E ; availability of vit. E reduces the Se requirement. Glutathione peroxidase protects the cells against the damage caused by H 2 O 2 . Protects from developing liver cirrhosis. Conversion of T 4 to T 3 by 5´- deiodinase .

126. Plasma Se Normal value : 13 µg/dl Most of the Se in blood is a part of glutathoine reductase . Inside the cells, it exists as selenocysteine and selenomethionine . Absorption : duodenum Se is carcinogenic in animals, its oncogenic influence in man is not established.

127. Deficiency Marginal deficiency; when soil content is low. In animals ; hepatic necrosis, retarded growth, muscular degeneration, infertility. In humans ; congestive cardiomyopathy ( Keshan disease) in China. Toxicity : selenosis ( 900 µg/day) Hair loss, dermatitis, irritability, purple streaks in nails, falling of nails, diarrhea and garlicky odor in breath (dimethyl selenide ).