Medical brain notes 25

  MINERALS Introduction Mineral elements are inorganic substances. They are found in all body tissues and fluids. They are supplied by the diet as their salts; for example, sodium chloride. They may also be combined with organic compounds like iron in hemoglobin and sulphur in almost all proteins. Unlike carbohydrates, fats and proteins, mineral elements do not furnish energy but they may influence the rate of biological reactions through enzymes. The mineral elements are not destroyed in food preparations un like vitamins. However, they are soluble in water so that some loss will occur if cooking liquids are discarded. Classification Minerals are classified into two main groups : macro elements and micro elements. Macro elements are required in large amount (>100 mg/day) and present in large quantities in the body, whereas micro elements are required in small quantity (<100 mg/day) and also present in small amount in tissues and body fluids. 1. Macro elements or Bulk element...

  Calcium Functions ·             About 99% of the body calcium is found in the bones and teeth where it is combined with phosphorus and other elements to give rigidity to the bone. ·             The bones also serve as the store house for calcium which is needed for a number of cellular functions. ·             Calcium is required for the complex process of blood coagulation. ·             Together with other elements it regulates the passage of ions into and out of cells. ·             It controls the transmission of nerve impulses, brings about the normal contraction of muscles, including the heart. ·             It also activate certain enzymes like aden...

  Phosphorus Functions Probably no mineral element has more functions than phosphorus. It is essential for the formation of ·             bones and teeth. ·             phospholipids that regulates the absorption and transport of fats. ·             DNA and RNA, which are nucleic acids essential for protein synthesis and genetic coding. ·             ATP and ADP, which are necessary for storing and releasing energy according to the body needs. ·             enzymes that are required to metabolise carbohydrates, fats, and proteins and buffer salts in the regulation of acid-base balance. Blood content of phosphorus The inorganic phosphorus content of blood in normal human adults ranges from 2.5 to 4.0 mg /100 ml a...

  Sodium Functions ·             It is the major component of the cations of extracellular fluid and exists in the body in association with the anions like chloride, bicarbonate, phosphate and lactate. ·             Sodium ion is mainly associated with chloride and bicarbonate in the regulation of acid-base equilibrium. It maintains osmotic pressure of the body fluids and thus protects the body against excessive fluid loss. ·             It plays an important role in the absorption of glucose and nutrients from small intestine. ·             Sodium ions are involved in the maintenance of heart beat. ·             It maintains the normal neuromuscular functions and it functions in the permeability functioning of ...

  Potassium It was given the name potassium because it was obtained from potash. It is an indispensible constituent of the body cells. Functions ·             Potassium is an important intracellular cation and needed for all cellular functions. ·             It maintains the alkalinity of the bile and blood. ·             It plays an important role in the regulation of acid-base balance in the cell. ·             It influences cardiac muscle activity. ·             The glycolytic enzyme pyruvate kinase requires potassium for its maximal activity. Sources Most foods contain potassium. Animal sources include meat, fish , egg, milk, cheese. Vegetables like onion and carrot, fruits like banana, grapes and legumes su...

  Chlorine Functions ·             As a component of sodium chloride (NaCl), chloride ion is an essential for acid-base equilibrium. ·             Chloride ion regulates the water balance and osmotic pressure. ·             It is also important in the production of hydrochloric acid in the gastric juice. ·             Chloride ion is important as an activator of amylase enzyme. Sources Sodium chloride is the main source for chlorine. Requirements The requirements of sodium chloride depend on the climate and occupation and on the salt content of the diet. Animal foods contain more NaCl than those of plant foods. Normal requirement of chloride is 5-10g /day as NaCl. Absorption and excretion Chloride is completely absorbed from the gastro intestinal tract. Chloride is ...

  Magnesium Functions About 70 percent of the total magnesium content of the body is combined with calcium and phosphorus in the complex salts of bone. The reminder is in the soft tissues and body fluids. It is the principal cation of the soft tissues. Magnesium ions act as an activators for many of the phosphate group transferring enzymes and it also functions as a co-factor for oxidative phosphorylation. Blood content of magnesium The normal level of magnesium in blood is 1-3 mg/100 ml. Sources Milk, egg, cauliflower, cabbage and fruits are rich sources of magnesium. Requirements Infants - 100-150 mg/day Children - 150 -200 mg/day Adults - 200-300 mg/day Absorption and excretion Like calcium the salts of magnesium are rather insoluble and greater part of the daily ingested magnesium is not absorbed. Parathyroid hormone increases the magnesium absorption. Very high intake of fat, phosphate and calcium decrease the absorption of magnesium. The major quantity of magnesium is excrete...

  Sulphur Functions Sulphur is present in the amino acids such as methionine, cystine and cysteine. Thus, it is present in all proteins in the body. Especially connective tissue, skin, hair and nails are rich in sulphur. Also thiamine and biotin which are B-complex vitamins contain sulphur in their molecules. Sources Sulphur intake is mainly in the form of cystine and methionine present in protein. Other compounds present in the food contribute small amounts of sulphur. Requirements A diet that is adequate in protein supplies required amounts of sulphur. Absorption and excretion Inorganic sulphate (So 4 2-) is absorbed as such from the intestine into the portal circulation. Sulphur is excreted in the urine. Deficiency No specific sulphur deficiency has been observed in human beings.

  Micro elements or Trace elements The important micro elements essential for normal body functions are iron, copper, iodine, fluorine, zinc, cobalt, manganese, chromium, molybdenum, selenium etc.   Iron Functions The total content of iron in the adult body is only 3 to 5 grams. Most of the iron is present in hemoglobin, a protein that consists of an iron-containing compound, heme, attached to a protein globin. Hemoglobin is carried in the circulation by the red blood cells. It picks up oxygen in the lungs and transports the oxygen to the tissues so that oxidation reactions can take place in the cells. From the cells the hemoglobin carries CO 2  to the lungs to be exchanged. Myoglobin is an iron-containing protein similar to hemoglobin and is present in muscle tissue. Iron is also a constituent of many enzymes that are required for oxidation of glucose and fatty acids for energy production. Sources Among the richest animal sources of iron are beef, liver, heart, kidneys, ...