Glucose enters the body with food, then it is absorbed by the digestive system and enters the blood, which, in turn, carries it to all organs and tissues. This is the main source of energy for the human body, it can be found in gasoline, which runs most cars, or electricity, which is necessary for the functioning of equipment. In order to penetrate into cells, while in circulatory system, is placed in an insulin shell.
Insulin is a special hormone produced by the pancreas. Without it, glucose will not be able to get inside the cells, and will not be absorbed. If there is a problem with the production of insulin, the person develops diabetes mellitus. He needs constants. The blood of a diabetic patient will be oversaturated until the body receives the missing hormone from the outside. An insulin capsule is necessary for the absorption of glucose by muscle and fatty tissues and the liver, but some organs are able to receive glucose without it. These are the heart, kidneys, liver, lens, nervous system, including the brain.
IN digestive system glucose is absorbed very quickly. This substance is a monomer that makes up important polysaccharides such as glycogen, cellulose and starch. Glucose is oxidized, resulting in the release of energy, which is spent on various physiological processes.
If an excess amount of glucose enters the body, it is quickly utilized, turning into energy reserves. On its basis, glycogen is formed, which is then deposited in various places and tissues of the body as a reserve source of energy. If there is already enough glycogen in the cell depot, then glucose begins to turn into fat and be deposited in the body.
Glycogen is vital for muscles. It is this that, during decay, provides the energy needed for cell functioning and restoration. It is constantly consumed in the muscles, but the reserves do not decrease. This is due to the fact that new portions of glycogen are constantly supplied from the liver so that its level always remains constant.
The normal fasting blood glucose level is 3.5 to 6.1 mmol/liter. Elevated blood sugar is hyperglycemia. The reasons for this condition may be various diseases, including diabetes mellitus and metabolic disorders. This is usually diagnosed through a urine test, through which the body will eliminate sugar. Short-term hyperglycemia can be caused by various phenomena, such as overexertion, eating large amounts of sweets, and others.
Blood glucose concentration is too low - hypoglycemia. Short-term hypoglycemia occurs when a person eats a lot of quickly digestible carbohydrates, then the sugar level first jumps sharply and then drops sharply. Constant hypoglycemia occurs due to metabolic disorders, liver or kidney diseases, as well as a lack of carbohydrates in the diet. Symptoms - tremors in the limbs, dizziness, hunger, pallor, a feeling of fear.
The correct diagnosis can only be made by a qualified specialist based on the collected medical history and tests performed. To correctly interpret the result “sugar in urine”, it is necessary to know the processes during which certain changes occur in the body, leading to a deviation in determining this indicator in biological material.
The concept of “sugar in urine”
In normal healthy body There is a renal threshold for glucose, that is, a certain amount of blood sugar is reabsorbed by the kidneys in full. Because of this, sugar is in the urine qualitative methods not detected. The established threshold decreases slightly with age. When blood glucose levels increase renal tubules unable to absorb as much sugar from urine into the blood. The consequence of this process is the appearance of sugar in the urine - glucosuria. The presence of sugar in the urine is a dangerous indicator in which it is necessary to identify the cause of its appearance.Physiological glycosuria
Physiological glucosuria is observed with a single detection of sugar in the urine. Depending on the reasons that caused the change in this indicator, several forms of glucosuria are distinguished: nutritional, emotional, physical. A nutritional increase in sugar in the urine is associated with the consumption of foods rich in carbohydrates: chocolate, sweets, sweet fruits. Emotional glycosuria occurs due to stress and overexcitation. The appearance of glucose in the urine can be triggered by excessive physical activity on the eve of the test. It is acceptable to have a small amount of sugar in the urine.Pathological glycosuria
The development of pathological glycosuria is associated with the presence of changes in the body that affect the reabsorption function of the kidneys. Diabetes mellitus is one of the most common causes of this pathology. In this case, when the level of sugar in the blood is sufficiently low, it is determined in the urine in large quantities. This occurs more often in insulin-dependent diabetes mellitus. Acute pancreatitis may cause sugar to be detected in the urine. Brain tumor, meningitis, traumatic brain injury, hemorrhagic stroke or encephalitis can lead to glycosuria.Diseases that are accompanied by fever may be accompanied by febrile glucosuria. An increase in the level of adrenaline, glucocorticoid hormones, thyroxine or somatotropin can lead to the development of endocrine glucosuria. In case of poisoning with morphine, strychnine, chloroform and phosphorus, toxic glucosuria can be determined. Due to a decrease in the kidney threshold, renal glycosuria develops.
Preparing for analysis
On the eve of submitting urine for testing for sugar, you should follow a diet that excludes the consumption of sweet foods and fruits, and drinks containing large amounts of carbohydrates. It is recommended to reduce the level physical activity. If you detect any amount of sugar in your urine, you should immediately consult a doctor.Video on the topic
Ascorbic acid It is extremely necessary for the body for the normal functioning of all organs and systems. It improves immunity, lowers blood sugar levels, prevents the development of heart diseases, etc.
Ascorbic acid or vitamin C is not produced by the human body independently, unlike the animal body. That is why doctors in all countries recommend eating more fruits and vegetables - the main suppliers of this vitamin, or replenishing its deficiency with the help of medicinal complexes. A lack of vitamin C can lead to dire consequences, but why?
The role of vitamin C in the human body
Average, to the human body about 80 mg of ascorbic acid per day is required, while the daily requirement for other vitamins is significantly lower. Why? Yes, because vitamin C normalizes the metabolism of carbohydrates, fats and proteins, increases immune protection, stimulates the formation of antibodies, red blood cells and, to a lesser extent, white cells. In addition, it reduces the concentration of glucose in the blood and increases glycogen reserves in the liver, normalizes the amount of cholesterol in the blood and serves as a cancer prevention.
Ascorbic acid takes part in more than 300 biological processes in organism. Of these, one can especially highlight the synthesis of collagen, a protein that forms connective tissue, which “cements” the intercellular space. Collagen is involved in the formation of tissues, bones, skin, tendons, ligaments, cartilage, teeth, etc. It protects the body from diseases and infections and accelerates wound healing.
Regarding immunity, vitamin C is responsible for the production of antibodies and the functioning of white blood cells. Without it, the formation of interferon, a substance that fights viruses and cancer, is impossible. Ascorbic acid is a powerful natural water-soluble antioxidant that protects against the destructive effects of oxidizing agents. It eliminates potentially harmful reactions in water-saturated parts of the body and protects “good” cholesterol from the effects of free radicals, preventing the development of heart and vascular diseases, early aging and the development of malignant tumors.
What else lies in the area of responsibility of vitamin C?
Ascorbic acid is an important component of hormone synthesis by the adrenal glands. Under stress, the adrenal glands begin to lack this vitamin. In addition, it takes part in the production of cholesterol and its conversion into bile. Ascorbic acid is necessary for the normal functioning of neurotransmitters in the brain. It converts tryptophan into serotonin, tyrosine into dopamine and adrenaline.
A lack of vitamin C can negatively affect the functioning of all organs and systems of the body, causing muscle pain, weakness, lethargy, apathy, hypotension, disruption of the gastrointestinal tract, dry skin, heart pain, tooth loss, etc.
The main message of most strict diets is “stop passing and you will be happy”! Try to understand the mechanisms of your body and lose weight wisely!
Why are we getting fat?
The answer lies on the surface - day after day we create all the most the necessary conditions. What does our average working day look like? A cup of coffee with a couple of sandwiches, 1.5 hours in traffic jams to the office, 8 hours of sitting on the computer, then again 1.5 hours of traffic jams. Snack on anything during the day and a high-calorie dinner at night. On weekends - wallowing until noon and again a “celebration” of the belly. Rest after all... Okay, maybe not quite like that, and a couple of times a week we work diligently for an hour or two in the gym. But this is a drop in the bucket.
What types of fat are there?
1. Subcutaneous. This is superficial fat that lies under the skin tissue. This is exactly the type of fat that is visible visually and that can be touched and felt. First of all, the human body begins to accumulate fat in the most problematic areas. For men this is the abdominal region and chest, for women it is the thighs, buttocks and sides. As these zones fill, fat begins to occupy new territories.
2. Visceral. This is deep-lying fat, which is located around the internal organs of a person (liver, lungs, heart). A certain amount of visceral fat is necessary, as it provides cushioning for internal organs. But when subcutaneous fat has mastered all possible zones and the stages of obesity have begun, it begins to replenish its reserves visceral fat. Excess visceral fat is very dangerous as it can lead to serious problems with health (diseases of the digestive and cardiovascular systems).
Why can't you just stop eating?
The Internet is filled with offers of various miracle diets that promise to get rid of extra pounds in a matter of months. Their principle is usually to sharply limit the number of calories consumed. But try to understand the body’s response mechanism - the kilograms really go away, but the fat will remain unharmed. All this is explained by the presence of such a hormone as stucco. The level of its content is correlated with the level of fat content - the more fat, the more stucco. So, the process goes like this:
- The number of calories consumed is sharply reduced, glucose levels and insulin production are reduced, and fat is mobilized. Fine!
- There is little glucose, which means the stucco level drops. The brain receives a hunger signal.
- In response to a hunger signal, the body turns on defense mechanism– cessation of synthesis muscle tissue and slowing down fat burning.
- At the same time, the level of cortisol (stress hormone) increases, which further strengthens the protective mechanism.
As you can see, weight loss occurs, but not due to fat loss, but due to a decrease muscle mass. At the end of the diet, the body begins to intensively store calories, storing them in fat (in case the situation repeats). The difference between the light and dark stripes on the tail is clearly pronounced, and the “Volga” is considered ripe if its skin becomes light.
2. Be careful!
If you think that it is too early to buy Russian watermelons at the beginning of August, then you are right. Most varieties reach ripeness by the middle or even the end of August. Anything that is sold earlier most likely either did not have time to ripen, or was generously fertilized to accelerate growth.
The main signs of determining that a watermelon is “stuffed” with nitrates:
- This kind of watermelon cannot be stored for long. Round spots of a darker shade appear on the skin.
- When you cut it, you will see bright red flesh and white seeds, and the fibers will be yellow.
- The pulp may contain compacted lumps up to 2 cm in size and yellowish color- they concentrate harmful substances.
- The pulp of a healthy watermelon, if ground in a glass of water, will make the water only slightly cloudy, but if it is a watermelon, the water will turn pink or red.
3. How dangerous are nitrates?
According to doctors, no one has ever died from nitrate poisoning, but you can get into trouble. If you eat one or two slices of nitrate watermelon, then nothing will happen to you. If you get carried away and eat the whole watermelon, you may end up with liver problems, intestinal upset, or nervous system. If after a nice meal you feel unwell, then immediately call an ambulance.
By the way, invisible nitrates are not as dangerous as bacteria that settle on the surface during transportation and storage. Therefore, before cutting, be sure to wash the fruit thoroughly; for greater effect, you can even scald it; this will not harm the watermelon.
The pulp of a ripened watermelon is dominated by easily digestible glucose and fructose; sucrose accumulates if the fruit is stored for a long time. Watermelons can be eaten if you have diabetes, since the fructose it contains does not cause insulin tension.
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Ministry of Education and Science of the Russian Federation
Federal state budget educational institution higher education
Tambovsky State University named after G.R. Derzhavina
on the topic: The biological role of glucose in the body
Completed:
Shamsidinov Shokhiyorzhon Fazliddin coals
Tambov 2016
1. Glucose
1.1 Features and functions
2.1 Glucose catabolism
2.4 Glucose synthesis in the liver
2.5 Glucose synthesis from lactate
Literatures used
1. Glucose
1.1 Features and functions
Glucose (from the ancient Greek glkhket sweet) (C 6 H 12 O 6), or grape sugar, or dextrose, is found in the juice of many fruits and berries, including grapes, which is where the name of this type of sugar comes from. It is a monosaccharide and six-hydroxy sugar (hexose). The glucose unit is part of polysaccharides (cellulose, starch, glycogen) and a number of disaccharides (maltose, lactose and sucrose), which, for example, digestive tract quickly break down into glucose and fructose.
Glucose belongs to the group of hexoses and can exist in the form of b-glucose or b-glucose. The difference between these spatial isomers is that at the first carbon atom of b-glucose the hydroxyl group is located under the plane of the ring, while for b-glucose it is above the plane.
Glucose is a bifunctional compound because contains functional groups- one aldehyde and 5 hydroxyl. Thus, glucose is a polyhydric aldehyde alcohol.
The structural formula of glucose is:
Abbreviated formula
1.2 Chemical properties and structure of glucose
It has been experimentally established that the glucose molecule contains aldehyde and hydroxyl groups. As a result of the interaction of a carbonyl group with one of the hydroxyl groups, glucose can exist in two forms: open chain and cyclic.
In a glucose solution, these forms are in equilibrium with each other.
For example, in aqueous solution glucose there are the following structures:
The cyclic b- and c-forms of glucose are spatial isomers that differ in the position of the hemiacetal hydroxyl relative to the plane of the ring. In b-glucose this hydroxyl is in the trans position to the hydroxymethyl group -CH 2 OH, in b-glucose it is in the cis position. Taking into account the spatial structure of the six-membered ring, the formulas of these isomers have the form:
IN solid state glucose has a cyclic structure. Ordinary crystalline glucose is the b-form. In solution, the b-form is more stable (at steady state, it accounts for more than 60% of the molecules). The proportion of the aldehyde form in equilibrium is insignificant. This explains the lack of interaction with fuchsinous acid (qualitative reaction of aldehydes).
In addition to the phenomenon of tautomerism, glucose is characterized by structural isomerism with ketones (glucose and fructose are structural interclass isomers)
Chemical properties of glucose:
Glucose has chemical properties, characteristic of alcohols and aldehydes. In addition, it also has some specific properties.
1. Glucose is a polyhydric alcohol.
Glucose with Cu(OH) 2 gives a solution of blue color(copper gluconate)
2. Glucose is an aldehyde.
a) Reacts with an ammonia solution of silver oxide to form a silver mirror:
CH 2 OH-(CHOH) 4 -CHO+Ag 2 O > CH 2 OH-(CHOH) 4 -COOH + 2Ag
gluconic acid
b) With copper hydroxide it gives a red precipitate Cu 2 O
CH 2 OH-(CHOH) 4 -CHO + 2Cu(OH) 2 > CH 2 OH-(CHOH) 4 -COOH + Cu 2 Ov + 2H 2 O
gluconic acid
c) Reduced with hydrogen to form hexahydric alcohol (sorbitol)
CH 2 OH-(CHOH) 4 -CHO + H 2 > CH 2 OH-(CHOH) 4 -CH 2 OH
3. Fermentation
a) Alcoholic fermentation (to produce alcoholic beverages)
C 6 H 12 O 6 > 2CH 3 -CH 2 OH + 2CO 2 ^
ethanol
b) Lactic acid fermentation (sour milk, fermentation of vegetables)
C 6 H 12 O 6 > 2CH 3 -CHOH-COOH
lactic acid
1.3 Biological significance glucose
Glucose is a necessary component of food, one of the main participants in metabolism in the body, it is very nutritious and easily digestible. During its oxidation, more than a third of the energy resource used in the body is released - fats, but the role of fats and glucose in the energy of different organs is different. The heart is used as fuel fatty acid. Skeletal muscles need glucose to “start”, but nerve cells, including brain cells, work only on glucose. Their need is 20-30% of the generated energy. Nerve cells Energy is needed every second, and the body receives glucose when eating. Glucose is easily absorbed by the body, so it is used in medicine as a strengthening agent. remedy. Specific oligosaccharides determine blood type. In confectionery for making marmalade, caramel, gingerbread, etc. Great importance have glucose fermentation processes. So, for example, when pickling cabbage, cucumbers, and milk, lactic acid fermentation of glucose occurs, as well as when ensiling feed. In practice, alcoholic fermentation of glucose is also used, for example, in the production of beer. Cellulose is the starting material for the production of silk, cotton wool, and paper.
Carbohydrates are really the most common organic matter on Earth, without which the existence of living organisms is impossible.
In a living organism, during metabolism, glucose is oxidized, releasing a large amount of energy:
C 6 H 12 O 6 +6O 2 ??? 6CO 2 +6H 2 O+2920kJ
2. Biological role of glucose in the body
Glucose is the main product of photosynthesis and is formed in the Calvin cycle. In the human and animal body, glucose is the main and most universal source of energy for metabolic processes.
2.1 Glucose catabolism
Glucose catabolism is the main supplier of energy for the body's vital processes.
Aerobic breakdown of glucose is its extreme oxidation to CO 2 and H 2 O. This process, which is the main path of glucose catabolism in aerobic organisms, can be expressed by the following summary equation:
C 6 H 12 O 6 + 6O 2 > 6CO 2 + 6H 2 O + 2820 kJ/mol
Aerobic breakdown of glucose includes several stages:
* aerobic glycolysis is the process of glucose oxidation with the formation of two molecules of pyruvate;
* general path of catabolism, including the conversion of pyruvate to acetyl-CoA and its further oxidation in the citrate cycle;
* chain of electron transfer to oxygen, coupled with dehydrogenation reactions occurring during the breakdown of glucose.
In certain situations, oxygen supply to tissues may not meet their needs. For example, on initial stages intense muscle work under stress, heart contractions may not reach the desired frequency, and the muscles' oxygen needs for aerobic breakdown of glucose are high. In such cases, a process is activated that occurs without oxygen and ends with the formation of lactate from pyruvic acid.
This process is called anaerobic breakdown, or anaerobic glycolysis. Anaerobic breakdown of glucose is energetically ineffective, but this process can become the only source of energy for muscle cell in the described situation. Later, when the supply of oxygen to the muscles is sufficient as a result of the heart switching to an accelerated rhythm, anaerobic breakdown switches to aerobic.
Aerobic glycolysis is the process of oxidation of glucose to pyruvic acid, which occurs in the presence of oxygen. All enzymes that catalyze the reactions of this process are localized in the cytosol of the cell.
1. Stages of aerobic glycolysis
Aerobic glycolysis can be divided into two stages.
1. Preparatory stage, during which glucose is phosphorylated and split into two phosphotriose molecules. This series of reactions takes place using 2 molecules of ATP.
2. Stage associated with ATP synthesis. Through this series of reactions, phosphotrioses are converted to pyruvate. The energy released at this stage is used to synthesize 10 mol of ATP.
2. Aerobic glycolysis reactions
Conversion of glucose-6-phosphate into 2 molecules of glyceraldehyde-3-phosphate
Glucose-6-phosphate, formed as a result of phosphorylation of glucose with the participation of ATP, is converted into fructose-6-phosphate in the next reaction. This reversible isomerization reaction occurs under the action of the enzyme glucose phosphate isomerase.
Pathways of glucose catabolism. 1 - aerobic glycolysis; 2, 3 - general path of catabolism; 4 - aerobic breakdown of glucose; 5 - anaerobic breakdown of glucose (in the frame); 2 (circled) - stoichiometric coefficient.
Conversion of glucose-6-phosphate to triose phosphates.
Conversion of glyceraldehyde 3-phosphate to 3-phosphoglycerate.
This part of aerobic glycolysis includes reactions associated with ATP synthesis. The most complex reaction in this series of reactions is the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate. This transformation is the first oxidation reaction during glycolysis. The reaction is catalyzed by glyceraldehyde-3-phosphate dehydrogenase, which is an NAD-dependent enzyme. The significance of this reaction lies not only in the fact that a reduced coenzyme is formed, the oxidation of which in the respiratory chain is associated with the synthesis of ATP, but also in the fact that the free energy of oxidation is concentrated in the high-energy bond of the reaction product. Glyceraldehyde-3-phosphate dehydrogenase contains a cysteine residue in the active center, the sulfhydryl group of which is directly involved in catalysis. Oxidation of glyceraldehyde-3-phosphate leads to the reduction of NAD and the formation, with the participation of H 3 PO 4, of a high-energy anhydride bond in 1,3-bisphosphoglycerate at position 1. In the next reaction, the high-energy phosphate is transferred to ADP with the formation of ATP
The formation of ATP in this manner is not associated with the respiratory chain, and it is called substrate phosphorylation of ADP. The formed 3-phosphoglycerate no longer contains a high-energy bond. In the following reactions, intramolecular rearrangements occur, the meaning of which is that a low-energy phosphoester is converted into a compound containing a high-energy phosphate. Intramolecular transformations involve the transfer of a phosphate residue from position 3 in phosphoglycerate to position 2. Then, a water molecule is cleaved from the resulting 2-phosphoglycerate with the participation of the enolase enzyme. The name of the dehydrating enzyme is given by the reverse reaction. As a result of the reaction, a substituted enol is formed - phosphoenolpyruvate. The resulting phosphoenolpyruvate is a high-energy compound, the phosphate group of which is transferred in the next reaction to ADP with the participation of pyruvate kinase (the enzyme is also named for the reverse reaction in which phosphorylation of pyruvate occurs, although such a reaction does not take place in this form).
Conversion of 3-phosphoglycerate to pyruvate.
3. Oxidation of cytoplasmic NADH in the mitochondrial respiratory chain. Shuttle systems
NADH, formed by the oxidation of glyceraldehyde-3-phosphate in aerobic glycolysis, undergoes oxidation by transfer of hydrogen atoms to the mitochondrial respiratory chain. However, cytosolic NADH is unable to transfer hydrogen to the respiratory chain because the mitochondrial membrane is impermeable to it. Hydrogen transfer through the membrane occurs using special systems called "shuttle". In these systems, hydrogen is transported across the membrane with the participation of pairs of substrates bound by corresponding dehydrogenases, i.e. There is a specific dehydrogenase on both sides of the mitochondrial membrane. There are 2 known shuttle systems. In the first of these systems, hydrogen from NADH in the cytosol is transferred to dihydroxyacetone phosphate by the enzyme glycerol-3-phosphate dehydrogenase (NAD-dependent enzyme, named for the reverse reaction). The glycerol-3-phosphate formed during this reaction is further oxidized by the enzyme of the inner mitochondrial membrane - glycerol-3-phosphate dehydrogenase (FAD-dependent enzyme). Then protons and electrons from FADH 2 move to ubiquinone and further along the CPE.
The glycerol phosphate shuttle system operates in white muscle cells and hepatocytes. However, mitochondrial glycerol-3-phosphate dehydrogenase is absent in cardiac muscle cells. The second shuttle system, which involves malate, cytosolic and mitochondrial malate dehydrogenases, is more universal. In the cytoplasm, NADH reduces oxaloacetate to malate, which, with the participation of a transporter, passes into the mitochondria, where it is oxidized to oxaloacetate by NAD-dependent malate dehydrogenase (reaction 2). NAD reduced during this reaction donates hydrogen to the mitochondrial CPE. However, oxaloacetate formed from malate cannot leave the mitochondria into the cytosol on its own, since the mitochondrial membrane is impermeable to it. Therefore, oxaloacetate is converted to aspartate, which is transported to the cytosol, where it is again converted to oxaloacetate. The transformations of oxaloacetate into aspartate and vice versa are associated with the addition and elimination of an amino group. This shuttle system is called malate-aspartate. The result of its work is the regeneration of cytoplasmic NAD+ from NADH.
Both shuttle systems differ significantly in the amount of ATP synthesized. In the first system, the P/O ratio is 2, since hydrogen is introduced into the CPE at the KoQ level. The second system is energetically more efficient, since it transfers hydrogen to the CPE through mitochondrial NAD+ and the P/O ratio is close to 3.
4. ATP balance during aerobic glycolysis and the breakdown of glucose to CO 2 and H 2 O.
ATP release during aerobic glycolysis
The formation of fructose-1,6-bisphosphate from one molecule of glucose requires 2 molecules of ATP. Reactions associated with ATP synthesis occur after the breakdown of glucose into 2 phosphotriose molecules, i.e. at the second stage of glycolysis. At this stage, 2 substrate phosphorylation reactions occur and 2 ATP molecules are synthesized. In addition, one molecule of glyceraldehyde-3-phosphate is dehydrogenated (reaction 6), and NADH transfers hydrogen to the mitochondrial CPE, where 3 molecules of ATP are synthesized by oxidative phosphorylation. IN in this case the amount of ATP (3 or 2) depends on the type shuttle system. Consequently, the oxidation of one glyceraldehyde-3-phosphate molecule to pyruvate is associated with the synthesis of 5 ATP molecules. Considering that 2 phosphotriose molecules are formed from glucose, the resulting value must be multiplied by 2 and then subtracted 2 ATP molecules spent in the first stage. Thus, the ATP yield during aerobic glycolysis is (5H2) - 2 = 8 ATP.
The release of ATP during the aerobic breakdown of glucose to final products as a result of glycolysis produces pyruvate, which is further oxidized to CO 2 and H 2 O in OPC. Now we can evaluate the energy efficiency of glycolysis and OPC, which together constitute the process of aerobic breakdown of glucose to final products. Thus, the ATP yield from the oxidation of 1 mol of glucose to CO 2 and H 2 O is 38 mol of ATP. During the aerobic breakdown of glucose, 6 dehydrogenation reactions occur. One of them occurs in glycolysis and 5 in the OPC. Substrates for specific NAD-dependent dehydrogenases: glyceraldehyde-3-phosphate, fatty acid, isocitrate, b-ketoglutarate, malate. One dehydrogenation reaction in the citrate cycle by succinate dehydrogenase occurs with the participation of the coenzyme FAD. Total ATP synthesized by oxidative phosphorylation is 17 mol of ATP per 1 mol of glyceraldehyde phosphate. To this must be added 3 moles of ATP synthesized by substrate phosphorylation (two reactions in glycolysis and one in the citrate cycle). Considering that glucose breaks down into 2 phosphotrioses and that the stoichiometric coefficient of further transformations is 2, the resulting value must be multiplied by 2, and from the result subtract 2 mol of ATP used in the first stage of glycolysis.
Anaerobic breakdown of glucose (anaerobic glycolysis).
Anaerobic glycolysis is the process of breaking down glucose to form lactate as the final product. This process occurs without the use of oxygen and is therefore independent of the mitochondrial respiratory chain. ATP is formed due to substrate phosphorylation reactions. Overall process equation:
C 6 H 12 0 6 + 2 H 3 P0 4 + 2 ADP = 2 C 3 H 6 O 3 + 2 ATP + 2 H 2 O.
Anaerobic glycolysis.
During anaerobic glycolysis, all 10 reactions identical to aerobic glycolysis occur in the cytosol. Only the 11th reaction, where pyruvate is reduced by cytosolic NADH, is specific for anaerobic glycolysis. The reduction of pyruvate to lactate is catalyzed by lactate dehydrogenase (the reaction is reversible, and the enzyme is named after the reverse reaction). This reaction ensures the regeneration of NAD+ from NADH without the participation of the mitochondrial respiratory chain in situations involving insufficient oxygen supply to cells.
2.2 Importance of glucose catabolism
The main physiological purpose of glucose catabolism is to use the energy released in this process for the synthesis of ATP
Aerobic breakdown of glucose occurs in many organs and tissues and serves as the main, although not the only, source of energy for life. Some tissues are most dependent on glucose catabolism as a source of energy. For example, brain cells consume up to 100 g of glucose per day, oxidizing it aerobically. Therefore, insufficient supply of glucose to the brain or hypoxia is manifested by symptoms indicating impaired brain function (dizziness, convulsions, loss of consciousness).
Anaerobic breakdown of glucose occurs in muscles, in the first minutes of muscular work, in red blood cells (which lack mitochondria), as well as in various organs under conditions of limited oxygen supply, including tumor cells. The metabolism of tumor cells is characterized by acceleration of both aerobic and anaerobic glycolysis. But predominant anaerobic glycolysis and an increase in lactate synthesis serve as an indicator increased speed cell division when they are insufficiently supplied with a system of blood vessels.
In addition to the energy function, the process of glucose catabolism can also perform anabolic functions. Glycolysis metabolites are used to synthesize new compounds. Thus, fructose-6-phosphate and glyceraldehyde-3-phosphate are involved in the formation of ribose-5-phosphate - structural component nucleotides; 3-phosphoglycerate can be included in the synthesis of amino acids such as serine, glycine, cysteine (see section 9). In the liver and adipose tissue, acetyl-CoA, formed from pyruvate, is used as a substrate in the biosynthesis of fatty acids and cholesterol, and dihydroxyacetone phosphate is used as a substrate for the synthesis of glycerol-3-phosphate.
Reduction of pyruvate to lactate.
2.3 Regulation of glucose catabolism
Since the main significance of glycolysis is the synthesis of ATP, its rate must correlate with energy expenditure in the body.
Most glycolytic reactions are reversible, with the exception of three, catalyzed by hexokinase (or glucokinase), phosphofructokinase and pyruvate kinase. Regulatory factors that change the rate of glycolysis, and hence the formation of ATP, are aimed at irreversible reactions. An indicator of ATP consumption is the accumulation of ADP and AMP. The latter is formed in a reaction catalyzed by adenylate kinase: 2 ADP - AMP + ATP
Even a small consumption of ATP leads to a noticeable increase in AMP. The ratio of the level of ATP to ADP and AMP characterizes the energy status of the cell, and its components serve as allosteric rate regulators as common path catabolism and glycolysis.
A change in the activity of phosphofructokinase is essential for the regulation of glycolysis, because this enzyme, as mentioned earlier, catalyzes the slowest reaction of the process.
Phosphofructokinase is activated by AMP but inhibited by ATP. AMP, by binding to the allosteric center of phosphofructokinase, increases the enzyme's affinity for fructose-6-phosphate and increases the rate of its phosphorylation. The effect of ATP on this enzyme is an example of homotropic aschusterism, since ATP can interact with both the allosteric and the active site, in the latter case as a substrate.
At physiological values The ATP active center of phosphofructokinase is always saturated with substrates (including ATP). An increase in the level of ATP relative to ADP reduces the reaction rate, since ATP under these conditions acts as an inhibitor: it binds to the allosteric center of the enzyme, causes conformational changes and reduces the affinity for its substrates.
Changes in phosphofructokinase activity contribute to the regulation of the rate of glucose phosphorylation by hexokinase. Decreased phosphofructokinase activity during high level ATP leads to the accumulation of both fructose-6-phosphate and glucose-6-phosphate, and the latter inhibits hexokinase. It should be recalled that hexokinase in many tissues (with the exception of the liver and pancreatic β-cells) is inhibited by glucose-6-phosphate.
When ATP levels are high, the rate of the cycle decreases citric acid and the respiratory chain. Under these conditions, the process of glycolysis also slows down. It should be recalled that allosteric regulation of OPC enzymes and the respiratory chain is also associated with changes in the concentrations of key products such as NADH, ATP and some metabolites. Thus, NADH, accumulating if it does not have time to oxidize in the respiratory chain, inhibits some allosteric enzymes of the citrate cycle
Regulation of glucose catabolism in skeletal muscles Oh.
2.4 Glucose synthesis in the liver (gluconeogenesis)
Some tissues, such as the brain, require a constant supply of glucose. When the intake of carbohydrates in food is insufficient, the blood glucose level is maintained within normal limits for some time due to the breakdown of glycogen in the liver. However, glycogen reserves in the liver are low. They decrease significantly by 6-10 hours of fasting and are almost completely exhausted after a daily fast. In this case, de novo glucose synthesis begins in the liver - gluconeogenesis.
Gluconeogenesis is the process of synthesis of glucose from non-carbohydrate substances. Its main function is to maintain blood glucose levels during periods of prolonged fasting and intense physical activity. The process occurs mainly in the liver and less intensely in the renal cortex, as well as in the intestinal mucosa. These tissues can provide the synthesis of 80-100 g of glucose per day. During fasting, the brain accounts for most of the body's need for glucose. This is explained by the fact that brain cells are not capable, unlike other tissues, of meeting energy needs through the oxidation of fatty acids. In addition to the brain, tissues and cells in which the aerobic breakdown pathway is impossible or limited, for example, red blood cells (they lack mitochondria), cells of the retina, adrenal medulla, etc., need glucose.
The primary substrates of gluconeogenesis are lactate, amino acids and glycerol. The inclusion of these substrates in gluconeogenesis depends on physiological state body.
Lactate is a product of anaerobic glycolysis. It is formed under any conditions of the body in red blood cells and working muscles. Thus, lactate is constantly used in gluconeogenesis.
Glycerol is released during the hydrolysis of fats in adipose tissue during fasting or prolonged physical activity.
Amino acids are formed as a result of the breakdown of muscle proteins and are included in gluconeogenesis during prolonged fasting or prolonged muscle work.
2.5 Glucose synthesis from lactate
Lactate formed in anaerobic glycolysis is not the end product of metabolism. The use of lactate is associated with its conversion in the liver to pyruvate. Lactate as a source of pyruvate is important not so much during fasting as during normal functioning of the body. Its conversion to pyruvate and the further use of the latter is a way to utilize lactate. Lactate formed in intensively working muscles or in cells with a predominant anaerobic method of glucose catabolism enters the blood and then into the liver. In the liver, the NADH/NAD+ ratio is lower than in contracting muscle, so the lactate dehydrogenase reaction proceeds in the opposite direction, i.e. towards the formation of pyruvate from lactate. Next, pyruvate is included in gluconeogenesis, and the resulting glucose enters the blood and is absorbed by skeletal muscles. This sequence of events is called the "glucose-lactate cycle", or "Cori cycle". Corey cycle completes 2 essential functions: 1 - ensures utilization of lactate; 2 - prevents the accumulation of lactate and, as a consequence, a dangerous decrease in pH (lactic acidosis). Part of the pyruvate formed from lactate is oxidized by the liver to CO 2 and H 2 O. The energy of oxidation can be used for the synthesis of ATP, necessary for gluconeogenesis reactions.
Cori cycle (glucosolactate cycle). 1 - entry of layugate from the contracting muscle with the blood flow to the liver; 2 - synthesis of glucose from lactate in the liver; 3 - the flow of glucose from the liver through the bloodstream into the working muscle; 4 - the use of glucose as an energy substrate by the contracting muscle and the formation of lactate.
Lactic acidosis. The term "acidosis" means an increase in the acidity of the body's environment (decrease in pH) to values beyond normal limits. In acidosis, either proton production increases or proton excretion decreases (in some cases, both). Metabolic acidosis occurs when the concentration of intermediate metabolic products (acidic in nature) increases due to an increase in their synthesis or a decrease in the rate of breakdown or excretion. When the acid-base state of the body is disturbed, they quickly turn on buffer systems compensation (after 10-15 minutes). Pulmonary compensation ensures stabilization of the ratio of HCO 3 -/H 2 CO 3, which normally corresponds to 1:20, and decreases with acidosis. Pulmonary compensation is achieved by increasing the volume of ventilation and, therefore, accelerating the removal of CO 2 from the body. However, the main role in compensating for acidosis is played by renal mechanisms involving the ammonia buffer. One of the causes of metabolic acidosis may be the accumulation of lactic acid. Normally, lactate in the liver is converted back into glucose through gluconeogenesis or oxidized. In addition to the liver, other consumers of lactate are the kidneys and heart muscle, where lactate can be oxidized to CO 2 and H 2 O and used as an energy source, especially when physical work. The level of lactate in the blood is the result of a balance between the processes of its formation and utilization. Short-term compensated lactic acidosis occurs quite often even in healthy people during intense muscular work. U untrained people Lactic acidosis during physical work occurs as a result of a relative lack of oxygen in the muscles and develops quite quickly. Compensation is carried out by hyperventilation.
With uncompensated lactic acidosis, the lactate content in the blood increases to 5 mmol/l (normally up to 2 mmol/l). In this case, the blood pH can be 7.25 or less (normally 7.36-7.44). An increase in blood lactate may be a consequence of impaired pyruvate metabolism
Disorders of pyruvate metabolism in lactic acidosis. 1 - violation of the use of pyruvate in gluconeogenesis; 2 - violation of pyruvate oxidation. glucose biological catabolism gluconeogenesis
Thus, during hypoxia, which occurs as a result of a disruption in the supply of oxygen or blood to tissues, the activity of the pyruvate dehydrogenase complex decreases and the oxidative decarboxylation of pyruvate decreases. Under these conditions, the equilibrium of the pyruvate-lactate reaction is shifted towards the formation of lactate. In addition, during hypoxia, ATP synthesis decreases, which consequently leads to a decrease in the rate of gluconeogenesis, another pathway for lactate utilization. An increase in lactate concentration and a decrease in intracellular pH negatively affect the activity of all enzymes, including pyruvate carboxylase, which catalyzes the initial reaction of gluconeogenesis.
The occurrence of lactic acidosis is also facilitated by disturbances in gluconeogenesis in liver failure. of various origins. In addition, lactic acidosis may be accompanied by hypovitaminosis B1, since a derivative of this vitamin (thiamine diphosphate) performs a coenzyme function as part of the MDC during the oxidative decarboxylation of pyruvate. Thiamine deficiency can occur, for example, in alcoholics with poor diet.
So, the reasons for the accumulation of lactic acid and the development of lactic acidosis may be:
activation of anaerobic glycolysis due to tissue hypoxia of various origins;
liver damage (toxic dystrophies, cirrhosis, etc.);
impaired use of lactate due to hereditary defects in gluconeogenesis enzymes, glucose-6-phosphatase deficiency;
disruption of the MPC due to enzyme defects or hypovitaminosis;
application of a number medicines, for example biguanides (gluconeogenesis blockers used in the treatment of diabetes mellitus).
2.6 Glucose synthesis from amino acids
Under starvation conditions, some muscle tissue proteins break down into amino acids, which are then included in the catabolic process. Amino acids, which during catabolism are converted into pyruvate or metabolites of the citrate cycle, can be considered as potential precursors of glucose and glycogen and are called glycogenic. For example, oxaloacetate, formed from aspartic acid, is an intermediate product of both the citrate cycle and gluconeogenesis.
Of all the amino acids entering the liver, approximately 30% are alanine. This is explained by the fact that the breakdown of muscle proteins produces amino acids, many of which are converted directly into pyruvate or first into oxaloacetate and then into pyruvate. The latter turns into alanine, acquiring an amino group from other amino acids. Alanine from the muscles is transported by the blood to the liver, where it is again converted into pyruvate, which is partially oxidized and partially included in glucoseogenesis. Therefore, there is the following sequence of events (glucose-alanine cycle): muscle glucose > muscle pyruvate > muscle alanine > liver alanine > liver glucose > muscle glucose. The entire cycle does not increase the amount of glucose in the muscles, but it solves the problems of transporting amine nitrogen from the muscles to the liver and prevents lactic acidosis.
Glucose-alanine cycle
2.7 Glucose synthesis from glycerol
Glycerol can only be used by tissues that contain the enzyme glycerol kinase, such as the liver and kidneys. This ATP-dependent enzyme catalyzes the conversion of glycerol to b-glycerophosphate (glycerol-3-phosphate). When glycerol-3-phosphate is included in gluconeogenesis, it is dehydrogenated by NAD-dependent dehydrogenase to form dihydroxyacetone phosphate, which is further converted into glucose.
Conversion of glycerol to dihydroxyacetone phosphate
Thus, we can say that the biological role of glucose in the body is very large. Glucose is one of the main sources of energy in our body. It is an easily digestible source of valuable nutrition that increases the body's energy reserves and improves its functions. The main importance in the body is that it is the most universal source of energy for metabolic processes.
Use in the human body hypertonic solution glucose promotes vasodilation, increased contractility of the heart muscle and increased urine volume. Glucose is used as a general tonic for chronic diseases which are accompanied by physical exhaustion. The detoxification properties of glucose are due to its ability to activate the liver’s functions to neutralize poisons, as well as a decrease in the concentration of toxins in the blood as a result of an increase in the volume of circulating fluid and increased urination. In addition, in animals it is deposited in the form of glycogen, in plants - in the form of starch, the polymer of glucose - cellulose is the main component of the cell walls of all higher plants. In animals, glucose helps survive frosts.
In short, glucose is one of the vital substances in the life of living organisms.
List of used literature
1. Biochemistry: textbook for universities / ed. E.S. Severina - 5th ed., - 2014. - 301-350 art.
2. T.T. Berezov, B.F. Korovkin "Biological chemistry".
3. Clinical endocrinology. Guide / N. T. Starkova. - 3rd edition, revised and expanded. - St. Petersburg: Peter, 2002. - pp. 209-213. - 576 p.
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The name “carbohydrates” has been preserved since those times when the structure of these compounds was not yet known, but their composition was established, which corresponds to the formula Cn(H 2 O) m. Therefore, carbohydrates were classified as carbon hydrates, i.e. to compounds of carbon and water - “carbohydrates”. Nowadays, most carbohydrates are expressed by the formula C n H 2n O n.
1. Carbohydrates have been used since ancient times - the very first carbohydrate (more precisely, a mixture of carbohydrates) that man became acquainted with was honey.
2. Sugarcane is native to northwestern India-Bengal. Europeans became familiar with cane sugar thanks to the campaigns of Alexander the Great in 327 BC.
3. Beet sugar pure form was discovered only in 1747 by the German chemist A. Marggraff.
4. Starch was known to the ancient Greeks.
5. Cellulose like component wood, used since ancient times.
6. The term “sweet” and the ending - osa - for sugary substances was proposed by the French chemist J. Dula in 1838. Historically, sweetness was the main feature by which a particular substance was classified as a carbohydrate.
7. In 1811, the Russian chemist Kirchhoff first obtained glucose by hydrolysis of starch, and the Swedish chemist J. Bertzemus proposed the correct empirical formula for glucose for the first time in 1837. C 6 H 12 O 6
8. The synthesis of carbohydrates from formaldehyde in the presence of Ca(OH) 2 was carried out by A.M. Butlerov in 1861
Glucose is a bifunctional compound because contains functional groups - one aldehyde and 5 hydroxyl. Thus, glucose is a polyhydric aldehyde alcohol.
The structural formula of glucose is:
The shortened formula is:
The glucose molecule can exist in three isomeric forms, two of which are cyclic, one is linear.
All three isomeric forms are in dynamic equilibrium with each other:
cyclic [(alpha form) (37%)]<-->linear (0.0026%)<-->cyclic [(beta form) (63%)]
The cyclic alpha and beta forms of glucose are spatial isomers that differ in the position of the hemiacetal hydroxyl relative to the plane of the ring. In alpha-glucose, this hydroxyl is in a trans position to the hydroxymethyl group -CH 2 OH, in beta-glucose - in a cis position.
Chemical properties of glucose:
Properties due to the presence of an aldehyde group:
1. Oxidation reactions:
a) with Cu(OH) 2:
C 6 H 12 O 6 + Cu(OH) 2 ↓ ------> bright blue solution
2.Recovery reaction:
with hydrogen H2:
Only the linear form of glucose can take part in this reaction.
Properties due to the presence of several hydroxyl groups (OH):
1. Reacts with carboxylic acids to form esters(five hydroxyl groups of glucose react with acids):
2. How a polyhydric alcohol reacts with copper (II) hydroxide to form copper (II) alcohol:
Specific properties
Of great importance are the processes of glucose fermentation that occur under the influence of organic catalysts-enzymes (they are produced by microorganisms).
a) alcoholic fermentation (under the influence of yeast):
b) lactic fermentation (under the influence of lactic acid bacteria):
d) citric acid fermentation:
e) acetone-butanol fermentation:
Obtaining glucose
1. Synthesis of glucose from formaldehyde in the presence of calcium hydroxide (Butlerov reaction):
2. Hydrolysis of starch (Kirhoff reaction):
Biological significance of glucose, its use
Glucose- an essential component of food, one of the main participants in metabolism in the body, very nutritious and easily digestible. During its oxidation, more than a third of the energy resource used in the body is released - fats, but the role of fats and glucose in the energy of different organs is different. The heart uses fatty acids as fuel. Skeletal muscles need glucose to “start”, but nerve cells, including brain cells, work only on glucose. Their need is 20-30% of the generated energy. Nerve cells need energy every second, and the body receives glucose when eating. Glucose is easily absorbed by the body, so it is used in medicine as a strengthening remedy. Specific oligosaccharides determine blood type. In confectionery for making marmalade, caramel, gingerbread, etc. Glucose fermentation processes are of great importance. So, for example, when pickling cabbage, cucumbers, and milk, lactic acid fermentation of glucose occurs, as well as when ensiling feed. In practice, alcoholic fermentation of glucose is also used, for example, in the production of beer.
Carbohydrates are indeed the most common organic substances on Earth, without which the existence of living organisms is impossible. In a living organism, during metabolism, glucose is oxidized, releasing a large amount of energy:
Glucose is a natural monosaccharide, otherwise called grape sugar.. Contained in some berries and fruits. A large amount of the substance is included in grape juice, which is where its name comes from. How is glucose useful for humans, what significance does it have for health?
Importance for the body
Glucose is a colorless substance with a sweet taste that can dissolve in water. Penetrating into the stomach, it is broken down into fructose. Glucose in the human body is needed to carry out photochemical reactions: It transports energy to cells and is involved in the metabolic process.
Useful properties of the crystalline substance:
- promotes the smooth functioning of cellular structures;
- entering cells, the monosaccharide enriches them with energy, stimulates intracellular interactions, resulting in oxidation and biochemical reactions.
The element can be synthesized independently in the body. Made from simple carbohydrates medical supplies, designed to replenish its deficiency in the body.
Release form
Grape sugar is produced in different forms:
- In tablet form. Glucose tablets are useful for improving overall well-being, increasing physical and mental abilities.
- In the form of a solution for placing droppers. Used to normalize water-salt and acid-base balance.
- In solution for intravenous injections. Used to increase osmotic pressure, as a diuretic and vasodilator.
Opinions about grape sugar are controversial. Some argue that the substance provokes obesity, others consider it a source of energy, without which healthy person not even a day can do it. What are the benefits and harms of glucose for the body?
Benefit
The substance must always be present in the human circulatory system. A simple carbohydrate penetrates into internal organs along with food.
Dissolving in the digestive tract, food decomposes into fats, protein compounds and carbohydrates. The latter, in turn, are broken down into glucose and fructose, which, penetrating the bloodstream, spread throughout the cells and internal organs.
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The product has positive properties:
- participates in metabolic processes. With its deficiency, people feel malaise, loss of strength and drowsiness;
- is the main source of energy. By taking a small amount of glucose-containing food, you can restore strength;
- normalizes heart function;
- used in medical purposes in the treatment of many diseases: hypoglycemia, poisoning, brain pathologies, liver diseases, infectious diseases;
- nourishes the brain. This monosaccharide is the main food for the brain. With its deficiency, deterioration of mental abilities and difficulties with concentration may occur;
- satisfies the feeling of hunger;
- relieves stress.
Carbohydrates can correct the psycho-emotional state, improve mood and calm the nervous system.
Harm
Glucose can harm the body. Patients with metabolic disorders, as well as older people, should not abuse foods containing large amounts of carbohydrates. An excess of a substance can lead to negative consequences:
- the occurrence of fat deposits, obesity;
- metabolic disorder;
- disruption of the pancreas, which, in turn, negatively affects the synthesis of insulin;
- increased amount of cholesterol in the blood, atherosclerosis;
- the formation of blood clots;
- the appearance of allergic reactions.
Norm and consequences of deviation
The required level of glucose in the body is 3.4-6.2 mmol/l. Any deviation from acceptable limits may result in severe disorders.
With a deficiency of insulin, a hormone produced by the pancreas, the substance is not absorbed in the body, does not penetrate the cells and is concentrated in the circulatory system. This leads to starvation of cellular structures and their death. This condition is a serious pathology, and in medicine is called diabetes mellitus.
With an unbalanced diet, long-term diets, as well as under the influence of certain diseases, a person’s blood sugar level may decrease. This threatens the deterioration of mental abilities, anemia, and the development of hypoglycemia. Lack of sugar negatively affects the functioning of the brain and also adversely affects the functioning of the entire body.
An excess of monosaccharide is fraught with the development of diabetes mellitus, damage to the nervous system and visual organs.
Excess substances, penetrating into the bloodstream, negatively affect blood vessels, which entails a deterioration in the functions of vital organs. Subsequently, this can lead to atherosclerosis, heart failure, blindness, and kidney pathology.
That is why Glucose-containing foods should be consumed within the permissible norm.
The daily glucose requirement is calculated based on the patient’s weight: a person weighing 70 kg needs 182 g of the substance. To calculate your need for sugar, you need to multiply your body weight by 2.6.
Who is prescribed
In some cases, additional glucose intake is required. More often specialists prescribe the drug in tablets for poor nutrition
. In addition, it is used:
- during pregnancy, with insufficient fetal weight;
- during intoxication with narcotic and chemical drugs;
- at hypertensive crisis, strong fall blood pressure, as well as deterioration of blood supply to some organs;
- to restore the body after poisoning and dehydration resulting from diarrhea and vomiting;
- V recovery period after operations;
- when the amount of sugar in the blood drops, hypoglycemia, diabetes mellitus;
- for liver pathologies, intestinal infections, increased bleeding;
- after prolonged infectious diseases.
Ascorbic acid with glucose is especially useful for a growing organism. A deficiency of the product during active growth of children can lead to skeletal muscle dystrophy and tooth decay.
Besides, The use of tablets will help replenish lost vitamin C in smokers who lose it during smoking.
Overdose
Very unpleasant consequences For a person's life, it can result in exceeding the permissible norm by 4 times. Excessive consumption of sugar and other sugar-containing products may result in flatulence, vomiting, and diarrhea.
An overdose of glucose is extremely dangerous for diabetics, which can cause various complications. You can suspect an overabundance of an element based on the symptoms:
- frequent need to urinate;
- heart failure;
- visual impairment;
- disturbance of consciousness;
- dry mouth;
- intense thirst;
- lethargy, loss of strength;
- itching of the skin.
These signs appear, as a rule, in isolated cases of exceeding the dose.
People with diabetes have an increased risk of complications from the disease. Most often, diabetics are concerned about difficult-to-heal wounds, brittle bones, blood clots, painful sensations in muscles, increased cholesterol.
Thus, the blood glucose level must be at a certain level. Any deviations from the norm provoke work disorder endocrine system and metabolic disorders, which, in turn, negatively affect the general condition.
The energy supplier for our body can be fats, proteins and carbohydrates. But of all the substances that our body uses for its energy needs, glucose occupies the main place.
What is glucose?
Glucose or dextrose is a colorless or white, odorless, finely crystalline powder with a sweet taste. Glucose can be called a universal fuel, since most of the body's energy needs are covered by it.
This substance must be constantly present in our blood. Moreover, both its excess and its deficiency are dangerous for the body. So, during hunger, the body begins to “use for food” what it is built from. Then muscle proteins begin to be converted into glucose, which can be quite dangerous.
Color scale of indicator visual test strips
These test strips are used to detect blood sugar abnormalities at home.
Official blood glucose standards approved by WHO.
Food-glucose-glycogen system
Glucose enters the human body with carbohydrates. Once in the intestines, complex carbohydrates are broken down into glucose, which is then absorbed into the blood. Some of the glucose is used for energy needs, another part can be stored as fat reserves, and some is stored as glycogen. After the food is digested and the flow of glucose from the intestines stops, the reverse conversion of fats and glycogen into glucose begins. This is how our body maintains constant blood glucose concentration.
Conversion of proteins and fats into glucose and back is a process that takes a lot of time. But the interconversion of glucose and glycogen occurs very quickly. Therefore, glycogen plays the role of the main storage carbohydrate. In the body it is deposited in the form of granules in various types cells, but mainly in the liver and muscles. Glycogen reserve in an average person physical development can provide it with energy throughout the day.
Hormone regulators
The conversion of glucose to glycogen and vice versa is regulated by a number of hormones. Insulin lowers the concentration of glucose in the blood. And increases - glucagon, somatotropin, cortisol, hormones thyroid gland and adrenaline. Disturbances in the passage of these reversible reactions between glucose and glycogen can lead to serious illnesses, the best known of which is diabetes mellitus.
Measuring blood glucose
The main test for diabetes is measuring blood glucose.
Concentration glucose is different in capillary and venous blood and fluctuates depending on whether a person has eaten or is hungry. Normally, when measured on an empty stomach (at least 8 hours after the last meal), the glucose content in capillary blood is 3.3 - 5.5 (mmol/l), and in venous blood 4.0 - 6.1 (mmol/l). ). Two hours after eating, the glucose level should not exceed 7.8 (mmol/l), for both capillary and venous blood. If during the week, when measuring on an empty stomach, the glucose level does not fall below 6.3 mmol/l, then you should definitely contact an endocrinologist and carry out additional examination body.
Hyperglycemia - a lot of glucose in the blood
Hyperglycemia develops most often in diabetes mellitus. Glucose levels may increase if:
- diabetes mellitus
- stress, strong emotional tension
- diseases of the endocrine system, pancreas, kidneys
- myocardial infarction
Endocrinologist
At stressful situations Blood glucose may increase. The fact is that the body, in response to an acute situation, releases stress hormones, which, in turn, increase blood glucose.
Hyperglycemia occurs:
- light - 6.7 mmol/l
- moderate severity - 8.3 mmol/l
- severe - more than 11.1 mmol/liter
- coma state - 16.5 mmol/l
- coma - more than 55.5 mmol/l
Hypoglycemia - low blood glucose
Hypoglycemia A condition is considered when the blood glucose concentration is below 3.3 mmol/l. Clinical manifestations of hypoglycemia begin after the sugar level drops below 2.4 - 3.0 mmol/l. With hypoglycemia the following are observed:
- muscle weakness
- impaired motor coordination
- confusion
- increased sweating
Glucose levels decrease when:
- diseases of the pancreas and liver
- some diseases of the endocrine system
- eating disorders, starvation
- overdose of hypoglycemic drugs and insulin
With very severe hypoglycemia, it can develop.
Glucose in medicine
Glucose solution is used in the treatment of a number of diseases, for hypoglycemia and various intoxications, as well as for diluting certain medications when administered into a vein.
Glucose- an essential substance that plays a very important role in the functioning of our body.
An Israeli doctor refuted the stereotype that sugar provokes the development of diabetes and named other causes of the disease
