31. Organic composition of saliva: Produced in salivary glands, human saliva is 98% water, but it contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes. Mucus in saliva mainly consists of mucopolysaccharides and glycoproteins;

 Antibacterial compounds (thiocyanate, hydrogen peroxide, and secretory immunoglobulin A)

 Epidermal growth factor or EGF

 Various enzymes. There are three major enzymes found in saliva.

       - a-amylase (EC3.2.1.1). Amylase starts the digestion of starch and lipase fat before the food is even swallowed.

It has a pH optima of 7.4.

        -lingual lipase. Lingual lipase has a pH optimum ~4.0 so it is not activated until entering the acidic environment

of the stomach.

        -Antimicrobial enzymes that kill bacteria. Lysozym, Salivary lactoperoxidase, Lactoferrin, Immunoglobulin A

       - Proline-rich proteins (function in enamel formation, Ca2+-binding, microbe killing and lubrication)

        Minor enzymes include salivary acid phosphatases A+B, N-acetylmuramoyl-L-alanine amidase, NAD(P)H dehydrogenase

(quinone), superoxide dismutase, glutathione transferase, class 3 aldehyde dehydrogenase, glucose-6-phosphate isomerase,and tissue kallikrein (function unknown).

    Cells: Possibly as much as 8 million human and 500 million bacterial cells per mL. The presence of bacterial products

(small organic acids, amines, and thiols) causes saliva to sometimes exhibit foul odor.

   Opiorphin, a newly researched pain-killing substance found in human saliva.

 

 

32. Inorganic components of saliva: It is a fluid containing:

 

   The saliva can detect the presence of cations: calcium (Ca2 +), magnesium (Mg 2 +), sodium (Na +) and potassium (K +), and the presence of ammonia [13]: 26 (NH 3)neutralizing acidic environment and resulting from the deamination of amino acids (Darginine [8]: 221) from the plaque and gingival fluid.
Among the anions are identified orthophosphate anions (H2PO4-, HPO42-, PO43-) andcarbonate (HCO3-, CO32-) corresponding to the time for buffering properties of saliva(concentration of carbonate also increases with increasing salivary flow, and they arethe main salivary buffer system [8]: 221), chloride anions (Cl-), fluoride (F-), citrate(C6H7O7-,-C6H6O72, C6H5O73-) and  SCN, the latter acting as abactericidal. Water.

 

 

33. Nutritional components:

 

 Personal energy requirement = basic energy requirements + extra energy requirements

 

Basic energy requirements (BER) includes your basal metabolic rate (BMR) and general daily activities

 

    For every Kg of body weight 1.3 Calories is required every hour.

(An athlete weighing 50Kg would require 1.3 × 24hrs × 50Kg = 1560 Calories/day)

 

    For each hours training you require an additional 8.5 Calories for each Kg of body weight.

(For a two hour training session our 50Kg athlete would require 8.5 × 2hrs × 50Kg = 850 Calories)

 

An athlete weighing 50Kg who trains for two hours would require an intake of approximately 2410 Calories

(BER + EER = 1560 + 850)

Energy Fuel

 

the energy we need has to be blended. The blend that we require is as follows:

 

    57% Carbohydrates (sugar, sweets, bread, cakes)

    30% Fats (dairy products, oil)

    13% Protein (eggs, milk, meat, poultry, fish)

 

The energy yield per gram is as follows: Carbohydrate - 4 Calories, Fats - 9 Calories and Protein - 4 Calories.

 

What does a 50 kg athlete require in terms of carbohydrates, fats and protein?

 

    Carbohydrates - 57% of 2410 = 1374 Calories - at 4 Calories/gram = 1374 ÷ 4 = 343 grams

    Fats - 30% of 2410 = 723 Calories - at 9 Calories/gram = 723 ÷ 9 = 80 grams

    Protein - 13% of 2410 = 313 Calories - at 4 Calories/gram = 313 ÷ 4 = 78 grams

 

Our 50kg athlete requires 343 grams of Carbohydrates, 80 grams of Fat and 78 grams of Protein

 

 

34. Digestion in stomach Bolus (masticated food) enters the stomach through the oesophagus via the oesophageal sphincter.

 The stomach releases proteases (protein-digesting enzymes such as pepsin) and hydrochloric acid, which kills or

 inhibits bacteria and provides the acidic pH of 2 for the proteases to work. Food is churned by the stomach through muscular contractions of the wall - reducing the volume of the fundus, before looping around the fundus[3] and the

body of stomach as the boluses are converted into chyme (partially digested food). Chyme slowly passes through the

 pyloric sphincter and into the duodenum, where the extraction of nutrients begins. Depending on the quantity and

contents of the meal, the stomach will digest the food into chyme anywhere between 40 minutes and a few hours.

 

 

 

35. Hydrochloric acid formation: Gastric acid is one of the main secretions of the stomach. It consists mainly of hydrochloric acid and acidifies the stomach content to a pH of 1 to 2.

 

Chloride (Cl-) and hydrogen (H+) ions are secreted separately in the stomach fundus region at the top of the stomach

by parietal cells of the gastric mucosa into a secretory network called canaliculi before it enters the stomach lumen.

 

Gastric acid acts as a barrier against microorganisms to prevent infections and is important for the digestion of food.

 Its low pH denatures proteins and thereby makes them susceptible to degradation by digestive enzymes such as pepsin.

 The low pH also activates the enzyme precursor pepsinogen into the active enzyme pepsin by self-cleavage. After leaving

 the stomach, the hydrochloric acid of the chyme is neutralized in the duodenum by sodium bicarbonate.

 

The stomach itself is protected from the strong acid by the secretion of a thick, protective mucus layer, and by secretin

 induced buffering with sodium bicarbonate. Heartburn or peptic ulcers can develop when these mechanisms fail. Drugs of

 the antihistaminic and proton pump inhibitor classes can inhibit the production of acid in the stomach, and antacids are

 used to neutralize existing acid

 

36. Digestion of proteins in small intestine:   The small intestine is where most chemical digestion takes place. Most of the digestive enzymes that act in the small intestine are secreted by the pancreas and enter the small intestine via the pancreatic duct. The enzymes enter the small intestine in response to the hormone cholecystokinin, which is produced in the small intestine in response to the presence of nutrients. The hormone secretin also causes bicarbonate to be released into the small intestine from the pancreas in order to neutralize the potentially harmful acid coming from the stomach.

The three major classes of nutrients that undergo digestion are proteins, lipids (fats) and carbohydrates:

 Proteins and peptides are degraded into amino acids. Chemical breakdown begins in the stomach and continues in the

large intestine. Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the pancreas and cleave proteins into

smaller peptides. Carboxypeptidase, which is a pancreatic brush border enzyme, splits one amino acid at a time. Aminopeptidase and

dipeptidase free the end amino acid products.

 

 

37. Digestion of carbohydrates in small intestine: Pancreatic amylase breaks down some carbohydrates (notably starch) into oligosaccharides. Other carbohydrates pass undigested into the large

intestine and further handling by intestinal bacteria. Brush border enzymes take over from there. The most important

brush border enzymes are dextrinase and glucoamylase which further break down oligosaccharides. Other brush border

enzymes are maltase, sucrase and lactase. Lactase is absent in most adult humans and for them lactose, like most poly-saccharides are not digested in the small intestine. Some carbohydrates, such as cellulose, are not digested at all, despite being made of multiple glucose units.

 

 

 

38. Digestion of lipids: Lipids (fats) are degraded into fatty acids and glycerol. Pancreatic lipase breaks down triglycerides into free fatty  acids and monoglycerides. Pancreatic lipase works with the help of the salts from the bile secreted by the liver and the

gall bladder. Bile salts attach to triglycerides to help emulsify them, which aids access by pancreatic lipase. This

 occurs because the lipase is water-soluble but the fatty triglycerides are hydrophobic and tend to orient towards each

other and away from the watery intestinal surroundings. The bile salts are the "main man" that holds the triglycerides

in the watery surroundings until the lipase can break them into the smaller components that are able to enter the villi

for absorption. Some carbohydrates are degraded into simple sugars, or monosaccharides (e.g., glucogen)

 

 

39. A vitamins is an organic compound required as a nutrient in tiny amounts by an organism.[1] In other words, an organic

chemical compound (or related set of compounds) is called a vitamin when it cannot be synthesized in sufficient quantities

by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid (vitamin C) is a vitamin for humans, but not for most other animals,and biotin and vitamin D are required in the human diet only in certain circumstances. By convention, the term vitamin

 does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids

(which are needed in larger amounts than vitamins), nor does it encompass the large number of other nutrients that

 promote health but are otherwise required less often. Thirteen vitamins are presently universally recognized.

Until the mid-1930s, when the first commercial yeast-extract and semi-synthetic vitamin C supplement tablets were sold,

 vitamins were obtained solely through food intake, and changes in diet (which, for example, could occur during a particular growing season) can alter the types and amounts of vitamins ingested. Vitamins have been produced as commodity chemicals and made widely available as inexpensive semisynthetic and synthetic-source multivitamin dietary

supplements, since the middle of the 20th century.

Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint

 inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs.

It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of

these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage

 

 

 

40. B1 and B2: Thiamine (B1) is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are involved in many cellular processes. The best-characterized form is thiamine pyrophosphate (TPP), a coenzyme in the catabolism of sugars and amino acids. In yeast, TPP is also required in the first step of alcoholic fermentation.

Thiamine is a colorless compound with a chemical formula C12H17N4OS. Its structure contains a aminopyrimidine ring and

 a thiazole ring with methyl and hydroxyethyl side chains linked by a methylene bridge. Thiamine is soluble in water,

 methanol, and glycerol and practically insoluble in acetone, ether, chloroform, and benzene. It is stable at acidic

pH, but is unstable in alkaline solutions] Thiamine, which is a N-heterocyclic carbene, can be used in place

of Cyanide as a catalyst for Benzoin condensation. Thiamine is unstable to heat, but stable during frozen storage. It is unstable when exposed to ultraviolet light and gamma irradiation.Thiamine reacts strongly in Maillard-type reactions.

Thiamine derivatives and thiamine-dependent enzymes are present in all cells of the body, thus a thiamine deficiency would seem to adversely affect all of the organ systems. However, the nervous system and the heart are particularly

sensitive to thiamine deficiency, because of their high oxidative metabolism. Beriberi is a neurological and cardiovascular disease. The three major forms of the disorder are dry beriberi, wet beriberi, and infantile beriberi.

 

Riboflavin, B2, is an easily absorbed micronutrient with a key role in maintaining health in humans and animals. It is the central component of the cofactors FAD and FMN, and is therefor required by all flavoproteins. As such, vitamin B2 is required for a wide variety of cellular processes. It plays a key role in energy metabolism, and for the metabolism of fats, ketone bodies, carbohydrates, and proteins.Riboflavin is continuously excreted in the urine of healthy individuals, making deficiency relatively common when dietary intake is insufficient. However, riboflavin deficiency is always accompanied by deficiency of other vitamins.

 

A deficiency of riboflavin can be primary - poor vitamin sources in one's daily diet - or secondary, which may be a

result of conditions that affect absorption in the intestine, the body not being able to use the vitamin, or an increase

 in the excretion of the vitamin from the body.

 

In humans, signs and symptoms of riboflavin deficiency (ariboflavinosis) include cracked and red lips, inflammation of the lining of mouth and tongue,

mouth ulcers, cracks at the corners of the mouth (angular cheilitis), and a sore throat. A deficiency may also cause dry and scaling skin,

fluid in the mucous membranes, and iron-deficiency anemia. The eyes may also become bloodshot, itchy, watery and sensitive to bright light.