Glycemia

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Glycemia

Glycemia or glycæmia is the concentration of glucose

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
in the blood

Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's Cell s ? such as nutrients and oxygen ? and transports waste products away from those same cells....
. It is usually expressed in milligrams per deciliter (mg/dl) in the US and other countries. It may also be expressed in millimol per decilitre (mmol/dl) especially in Europe. Both of these are SI units. It is one of the most important controlled variables in the internal milieu of animals (homeostasis

Homeostasis

Homeostasis is the property of a system, either open system or closed system, that regulates its internal environment and tends to maintain a stable, constant condition....
), as it was first proposed by French

France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
physiologist Claude Bernard

Claude Bernard

Claude Bernard was a France physiologist. Historian of science I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science"....
(1813-1878).

Physiological regulation
Glycemia is controlled by several physiological

Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
processes.

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Encyclopedia

Glycemia or glycæmia is the concentration of glucose

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
in the blood

Blood

Homeostasis

France

Claude Bernard

Claude Bernard was a France physiologist. Historian of science I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science"....
(1813-1878).

Physiological regulation

Glycemia is controlled by several physiological

Physiology

Stomach

In most mammals, the stomach is a hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication....
and intestinal absorption of carbohydrate

Carbohydrate

Carbohydrates or saccharides are the most abundant of the four major classes of biomolecules. They fill numerous roles in living things, such as the storage and transport of energy and structural components ....
s of low molecular weight present in the diet

Diet (nutrition)

In nutrition, the diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat....
or broken down from other kinds of foodstuffs, such as starch

Starch

File:Amylose2.svgFile:Amylopektin Sessel.svgStarch or amylum is a polysaccharide carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds....
es (polysaccharide

Polysaccharide

Polysaccharides are relatively complex carbohydrates. They are polymers made up of many monosaccharides joined together by glycosidic bonds. They are therefore very large, often branched, macromolecules....
s), and to lower levels with usage by catabolism

Catabolism

Catabolism is the set of metabolic pathways which break down molecules into smaller units and release energy. In catabolism, large molecules such as polysaccharides, lipids, nucleic acids and proteins are broken down into smaller units such as monosaccharides, fatty acids, nucleotides and amino acids, respectively....
, particularly after stress

Stress (medicine)

Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or body threats to the organism, whether actual or imagined....
, temperature regulation and physical exertion. Another input to glycemia levels is gluconeogenesis

Gluconeogenesis

Gluconeogenesis is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactic acid, glycerol, and glucogenic amino acids....
, whereby glycogen

Glycogen

Glycogen is a polysaccharide of glucose which functions as the secondary short term energy storage in animal cells. It is made primarily by the liver and the muscles, but can also be made by the brain and stomach....
stored in the liver

Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
and skeletal muscle

Skeletal muscle

They generally contract voluntarily , although they can contract involuntarily through Reflex action. The whole muscle is wrapped in a special type of connective tissue, epimysium....
s, or amino acid

Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s and lipid

Lipid

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins , monoglycerides, diglycerides, phospholipids, and others....
s are converted to glucose via several metabolic chains. Excess glucose is converted to glycogen or to triglyceride

Triglyceride

is a glyceride in which the glycerol is esterified with three fatty acids. It is the main constituent of vegetable oil and animal fats....
s for energy storage.

Glucose is the most important source of metabolic energy for the majority of cells

Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
, particularly for some cells (e.g., neuron

Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s and erythrocytes) which are almost totally dependent on it. The brain

Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
requires a fairly stable glycemia in order to function normally. Concentrations of less than about 30 mg/dl or greater than about 300 mg/dl can produce confusion

ConFusion

ConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association....
, unconsciousness

Unconsciousness

Unconsciousness, more appropriately referred to as loss of consciousness or lack of consciousness, is a dramatic alteration of mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli....
and convulsion

Convulsion

A convulsion is a medical condition where body muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body....
s.

Several hormones are involved in the regulation of glucose metabolism, such as insulin

Insulin

Insulin is a hormone with extensive effects on both metabolism and several other body systems . Insulin causes most of the body's cells to take up glucose from the blood , storing it as glycogen in the liver and muscle, and stops use of fat as an energy source....
, glucagon

Glucagon

Glucagon is an important hormone involved in carbohydrate metabolism. Produced by the pancreas, it is released when the glucose level in the blood is low , causing the liver to convert stored glycogen into glucose and release it into the bloodstream....
(secreted by the pancreas

Pancreas

The pancreas is a gland Organ in the digestive system and endocrine system of vertebrates. It is both an endocrine gland , as well as an exocrine gland, secreting pancreatic juice containing Digestion enzymes that pass to the small intestine....
), epinephrine

Epinephrine

Epinephrine is a hormone and neurotransmitter.Epinephrine increases the "fight or flight" response of the Sympathetic nervous system of the autonomic nervous system....
(adrenaline secreted by the adrenal gland

Adrenal gland

In mammals, the adrenal glands are the star-shaped endocrine glands that sit on top of the kidneys; their name indicates that position . They are chiefly responsible for regulating the stress response through the biosynthesis of corticosteroids and catecholamines, including cortisol and adrenaline, respectively....
s), glucocorticoids and steroid hormones (secreted by the gonads and adrenal glands).

Measurement

For clinical evaluation purposes, there are two ways of measuring glycemia:

Fasting glycemia: measured in a blood sample taken after 8 hours of complete fasting
Fasting

Fasting is primarily the act of willingly abstaining from some or all food, drink, or both, for a period of time. A fast may be total or partial concerning that from which one fasts, and may be prolonged or intermittent as to the period of fasting....
;
Blood glucose tolerance test
Glucose tolerance test

A glucose tolerance test in medical practice is the administration of glucose to determine how quickly it is cleared from the blood. The test is usually used to test for Diabetes mellitus, insulin resistance, and sometimes reactive hypoglycemia....
(OGTT): measured in several blood samples taken at intervals following a given glucose load (oral intake or endovenous injection).

In certain conditions, it is recommended that blood glucose monitoring

Blood glucose monitoring

Blood glucose monitoring is a way of testing the concentration of glucose in the blood .It is important in the care of diabetes mellitus. A blood glucose test is performed by piercing the skin to draw blood, then placing the blood on a chemically active disposable strip which indicates the result either by changing colour, or changing an...
be performed regularly, usually by the patient himself, who is trained to do a digital venipuncture

Venipuncture

In medicine venipuncture or venepuncture is the process of obtaining a sample of Vein blood. Usually a 5 ml to 25 ml sample of blood is adequate depending on what blood tests have been requested....
and use a small portable glucometer device to evaluate glycemia levels instantly.

Glycemia fluctuates physiologically within a narrow range. Excessively low levels (e.g. a fasting glycemia of 70 mg/dl or below) are classed as hypoglycemia

Hypoglycemia

Hypoglycaemia or hypoglycemia is the medical term for a Pathology state produced by a lower than normal level of Blood glucose. The term hypoglycemia literally means "under-sweet blood" ....
. These may result from poor diet, or as a side effect of diabetes medication. Excessively high levels (e.g., 250 mg/dl or more) are classed as hyperglycemia

Hyperglycemia

Hyperglycemia, hyperglycaemia, or high blood sugar is a condition in which an excessive amount of glucose circulates in the blood plasma....
and are a particular threat to diabetes sufferers.

70-100 mg/dl: Normal
101-125 mg/dl: Impaired fasting glucose
126 mg/dl and above: Risk of diabetes

Abnormal values

Many forms of severe stress and trauma

Physical trauma

Physical trauma refers to a body injury. A trauma patient is someone who has suffered serious and life-threatening physical injury with the potential for secondary complications such as Shock , respiratory failure and death....
, stroke

Stroke

A stroke is the rapidly developing loss of brain function due to a disturbance in the blood supply to the brain. According to the National Stroke Association, a "stroke" occurs when a blood clot blocks and artery or a blood vessel breaks, interrupting blood flow to an area of the brain....
, heart attack

Myocardial infarction

Myocardial infarction , commonly known as a heart attack, occurs when the Blood flow to part of the heart is interrupted. This is most commonly due to occlusion of a coronary artery following the rupture of a Vulnerable plaque, which is an unstable collection of lipids and white blood cells in the wall of an artery....
, and surgery

Surgery

Surgery is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, to help improve bodily function or appearance, or sometimes for some other reason....
can temporarily increase glucose levels. Glycemia can also be increased by certain drugs

Medication

A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease....
such as antidepressants, corticosteroids, diuretics, estrogen

Estrogen

Estrogens are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone....
s, lithium

Lithium

Lithium is a chemical element with the symbol Li and atomic number 3. It is a soft alkali metal with a silver-white color. Under standard conditions for temperature and pressure, it is the lightest metal and the least dense solid element....
, phenothiazine

Phenothiazine

Phenothiazine is the organic compound with the formula S2NH. This yellow tricyclic compound is soluble in acetic acid, benzene, and ether....
, phenytoin

Phenytoin

Phenytoin sodium is a commonly used antiepileptic. Phenytoin acts to dampen the unwanted, runaway brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage gated sodium channels....
and Salicylic acid

Salicylic acid

Salicylic acid is a beta hydroxy acid with the chemical formula C6H4COOH, where the OH group is adjacent to the carboxylic acid....
s, or decreased by others, such as acetaminophen, alcohol

Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
, steroids, clofibrate

Clofibrate

Clofibrate is a fibrate. Clofibrate is a lipid lowering agent used for controlling the high cholesterol and triacylglyceride level in the blood....
, gemfibrozil

Gemfibrozil

Gemfibrozil is the generic name for an oral drug used to lower lipid levels. It belongs to a group of drugs known as fibrates. It is most commonly sold as the brand name, Lopid....
.

However, the disease most directly associated to chronic increase of glycemia is diabetes mellitus

Diabetes mellitus

Diabetes mellitus , often referred to simply as diabetes , is a syndrome of disordered metabolism, usually due to a combination of genetic disorder and environmental causes, resulting in abnormally high blood sugar levels ....
, due to a decrease in the secretion of insulin, excess of its breakdown or decreased capacity of cells to transport it across its membranes

Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
(insulin resistance

Insulin resistance

Insulin resistance is the condition in which normal amounts of insulin are inadequate to produce a normal Insulin#Physiological_effects from fat, muscle and liver cell ....
).

External links

. Medline Plus.
. Medline Plus.
. Medline Plus.

Glycemia

Physiological regulation

Measurement

Abnormal values

See also

External links