Fats are the richest source of energy, also they are the most rich energy stores.
Fats provide the body with the essential fatty acids
Fats provide the body with a group of vitamins called “The fat soluble vitamins”.
Biochemical importance of inorganic constituents
The human body requires about eight principal mineral elements which include: calcium, phosphorus , magnesium , sodium , potassium , sulphur , iron and chlorine . These are called bulk or main elements . Certain other elements including: copper , zinc , cobalt , selenium , manganese and iodine are needed in micro amounts and are called “ trace elements ”.
The importance of the inorganic constituents are
Formation of certain tissues for example calcium and phosphorous for formation bones.
clotting of blood needs calcium ions.
Formation of hydrochloric acid ( HCl ) in the stomach , through a process needs sodium chloride ( NaCl ).
Biosynthesis of some hormones needs some trace elements , for example iodine for thyroxin and zinc for insulin .
Biosynthesis of hemoglobin and myoglobin needs iron .
Water Importance total body water is about 45 liters
It acts as an excellent solvent inside the body.
It is very important for regulation of body temperature .
It is suitable medium for the different metabolic pathways.
Many waste products are excreted as soluble form in water .
It enters in the processes of digestion
It is comparatively more essential to life than foods.
Severe dehydration is dangerous hence , death happens if about 20 % of the body water is lost.
Total body water is About 45 liters Extracellular fluid (outside cells , 15 liters) Intracellular fluid (inside the cell 30 liters) tissue fluid (12 liters) Plasma (3 liters) introduction
1-They are composed of a great number of monosaccharide units
2-They are economically important beside their great importance in nutrition. Some important industries are dependent on polysaccharides, e.g.:
Manufacture of textiles.
Manufacture of artificial silk.
Manufacture of paper.
Classification of polysaccharides carbohydrate Examples: gums, pectin and mucopolysaccharides Examples: starch, dexterines, dextrans, glycogen and cellulose Contain different Sugar Formed of only one type of sugar B-Heteropolysaccharides A-Homopolysaccharides
During fasting the liver first uses glycogen degradation, then gluconeogenesis (glucose synthesis) due to increase in the secretion of glucagon and stress hormones which are glucose increasing hormones to maintain blood glucose levels to sustain energy metabolism of brain and other glucose-requiring tissues. .
Glucose is continuously filtered by renal system, under normal conditions glucose completely return to circulation by reabsorptive renal system, when blood glucose level abnormally elevated and exceed the capacity of the reabsorptive renal system ( renal threshold is 180 mgdl ) glucose appear in urine ( glucosuria ).
Insulin is a key regulatory enzyme of blood glucose level, it is a polypeptide hormone produced by the beta cells of the islets of langerhans of the pancreas . Insulin decreases the production of glucose by inhibiting gluconeogenesis and the breakdown of glycogen.
It increases glucose uptake by increasing the number of glucose transporters in the cell membrane.
The intravenous administration of insulin thus causes an immediate decrease in the concentration of blood glucose.
The disease is characterizec by an absolute deficiency of insulin caused by an autoimmune attack on the cells of the pancreas. This destruction requires a stimulus from the environment (such as a viral infection) and a genetic predisposition.
The metabolic abnormalities of type 1 diabetes mellitus include hyperglycemia , ketoacidosis , and hypertriglyceridemia . They result from a deficiency of insulin . Type 1 diabetics must intake exogenous insulin injected subcutaneously to control hyperglycemia
It has a strong genetic component . Results from a combination of insulin resistance and dysfunctional cells .
Insulin resistance is the decreased ability of target tissues, such as liver, adipose tissue and muscle, to respond properly to normal circulating concentrations of insulin. Obesity is the most common cause of insulin resistance.
change in glucose blood level in diabetes mellitus: >200 mgdl Range from 140-200 mgdl Range from 70-140 mgdl Two hours postprandial >126 mgdl Range from 110-120 mgdl Range from 110-120 mgdl Fasting blood glucose Diabetic Impaired glucose utilization Normal