a small sac adjacent to the liver. The gallbladder stores bile, which is secreted by the liver, and releases it into the small intestine through the common bile duct.
crystals formed by the precipitation of cholesterol or bilirubin in the gallbladder. Gallstones may be asymptomatic (without symptoms) or they may result in inflammation and infection of the gallbladder.
pertaining to the stomach.
a mucus membrane lining of the interior of the stomach that protects the underlying stomach tissue.
Gastroesophageal reflux disease (GERD)
a condition in which stomach contents, including acid, back up (reflux) into the esophagus, causing inflammation and damage to the esophagus. GERD can lead to scarring of the esophagus and may increase the risk of cancer of the esophagus in some patients.
referring to or affecting the digestive tract, which includes the mouth, pharynx (throat), esophagus, stomach, and intestines.
a region of DNA that controls a specific hereditary characteristic, usually corresponding to a single protein.
the process by which the information coded in genes (DNA) is converted to proteins and other cellular structures. Expressed genes include those that are transcribed to mRNA and translated to protein, as well as those that are only transcribed to RNA (e.g., ribosomal and transfer RNAs).
all of the genetic information (encoded in DNA) possessed by an organism.
the period of time between fertilization and birth. In humans, normal gestation is about 40 weeks.
Glomerulus (plural glomeruli)
a tuft of capillaries that makes up part of the filtering unit of the kidney (nephron).
the production of glucose from non-carbohydrate precursors, such as amino acids (the building blocks of proteins).
a six-carbon sugar which plays a major role in the generation of energy for living organisms.
the ability of the body to maintain normal glucose levels when challenged with a carbohydrate load (see impaired glucose tolerance).
a glycoside that contains glucose as its carbohydrate (sugar) moiety.
an excitatory neurotransmitter. Under certain circumstances glutamate may become toxic to neurons. Glutamate excitotoxicity appears to play a role in nerve cell death in some neurodegenerative disorders.
a tripeptide consisting of glutamate, cysteine, and glycine. Glutathione is an endogenous, intracellular antioxidant and is also required for some phase II biotransformation reactions.
glucose-bound hemoglobin. A test for glycated hemoglobin measures the percentage of hemoglobin that is glucose bound. Since glucose remains bound to hemoglobin for the life of a red blood cell (~120 days), glycated hemoglobin values reflect blood glucose control over the past four months.
Glycemic index (GI)
an index of the blood glucose-raising potential of the carbohydrate in different foods. The GI is calculated as the area under the blood glucose curve after a test food is eaten, divided by the corresponding area after a control food (glucose or white bread) is eaten. The value is multiplied by 100 to represent a percentage of the control food.
Glycemic load (GL)
an index that simultaneously describes the blood glucose-raising potential of the carbohydrate in a food and the quantity of carbohydrate in a food. The GL of a food is calculated by multiplying the GI by the amount of carbohydrate in grams provided by a food and dividing the total by 100.
a large polymer (repeating units) of glucose molecules, used to store energy in cells, especially muscle and liver cells.
the metabolic pathway in the cytosol that degrades glucose, producing energy in the form of ATP.
a compound containing a sugar molecule that can be cleaved by hydrolysis to a sugar and a nonsugar component (aglycone).
enlargement of the thyroid gland. Goiter is one of the earliest and most visible signs of iodine deficiency. The thyroid enlarges in response to persistent stimulation by TSH. In mild iodine deficiency, this adaptive response may be enough to provide the body with sufficient thyroid hormone. However, more severe cases of iodine deficiency result in hypothyroidism. Thyroid enlargement may also be caused by factors other than iodine deficiency, especially in iodine sufficient countries, such as the US.
a substance that induces goiter formation by interfering with thyroid hormone production or utilization.
a condition characterized by abnormally high blood levels of uric acid (urate). Urate crystals may form in joints, resulting in inflammation and pain. Urate crystals may also form in the kidney and urinary tract, resulting in kidney stones. The tendency to develop elevated blood uric acid levels and gout is often inherited.
the layer of the epidermis below the stratum corneum.
the darker-colored tissue in the central nervous system that contains mostly cell bodies and dendrites.
guanosine triphosphate. A high-energy molecule, required for a number of biochemical reactions, including nucleic acid and protein synthesis (formation).
a set of DNA variations (polymorphisms) at adjacent locations on a chromosome; these DNA variations are inherited together.
a genetic disorder resulting in defective absorption of the amino acid, tryptophan.
high-density lipoproteins. HDL transport cholesterol from the tissues to the liver where it can be eliminated in bile. HDL-cholesterol is considered “good cholesterol,” because higher blood levels of HDL-cholesterol are associated with lower risk of cardiovascular disease.
the percentage of red blood cells in whole blood.
the branch of medicine that studies the nature, function, disorders, and diseases of the blood, spleen, and lymph glands.
compounds of iron complexed in a characteristic ring structure known as a porphyrin ring.
the process of removing blood from an artery, removing waste products from the blood through dialysis, and returning blood to the body through a vein. Hemodialysis is used to treat end-stage renal failure.
the oxygen-carrying pigment in red blood cells.
the main fraction of glycated (glucose-bound) hemoglobin. Since glucose remains bound to hemoglobin for the life of a red blood cell (~120 days), hemoglobin A1C values reflect blood glucose control over the past four months.
rupture of red blood cells.
anemia resulting from hemolysis.
excessive or uncontrolled bleeding.
a stroke that occurs when a blood vessel ruptures and bleeds into the brain.
the arrest of bleeding.
relating to the liver.
literally, inflammation of the liver. Hepatitis caused by a virus is known as viral hepatitis. Other causes of hepatitis include toxic chemicals and alcohol abuse.
the most common type of primary liver cancer.
a genetic disorder that results in iron overload despite normal dietary intake of iron.
a hereditary form of anemia characterized by abnormally shaped red blood cells which are spherical and abnormally fragile. The increased fragility of these red blood cells leads to hemolytic anemia (anemia caused by the rupture of red blood cells).
a dimer or complex of two different molecules, usually proteins.
variability in study design and outcomes; the quality of being diverse and not comparable.
possessing two different forms (alleles) of a specific gene.
the study of cells and tissues at the microscopic level.
protein that binds to DNA and packages it into compact structures to form nucleosomes.
human immunodeficiency virus; the virus that causes AIDS.
a state of balance.
a sulfur-containing amino acid, which is an intermediate in the metabolism of another sulfur-containing amino acid, methionine. Elevated homocysteine levels in the blood have been associated with increased risk of cardiovascular disease.
a dimer or complex of two of the same molecule, usually a protein.
having the same appearance, structure, or evolutionary origin.
possessing two identical forms (alleles) of a specific gene.
a chemical released by a gland or a tissue, which affects or regulates the activity of specific cells or organs. Complex bodily functions, such as growth and sexual development, are regulated by hormones.
sensations of heat in the skin, particularly the face, neck, and chest; also known as hot flashes. Hot flushes are most often related to declining estrogen levels during the perimenopause (period surrounding menopause).
Human papilloma virus (HPV)
a group of viruses that may cause papillomas (growths or warts) on the skin or other parts of the body, including the genitals and the larynx (voice box). Infection with particular strains of HPV is associated with increased risk of cervical cancer.
an inherited degenerative disorder of the brain. Its symptoms include movement disorders and impaired cognitive function. Symptoms of Huntington’s disease, previously known as Huntington’s chorea, typically develop in the fourth decade of life and progressively deteriorate over time.
cleavage of a chemical bond by the addition of water. In hydrolysis reactions, a large compound may be broken down into smaller compounds when a molecule of water is added.
a molecule that has a high affinity for water and will readily dissolve in water.
a molecule that repels water and thus will not dissolve in water.
a calcium phosphate salt. Hydroxyapatite is the main mineral component of bone and teeth and is what gives them their rigidity.
a chemical reaction involving the addition of a hydroxyl (-OH) group to a compound.
an abnormally high blood glucose concentration; symptoms include increased thirst, increased urination, and general fatigue.
abnormally elevated blood levels of homocysteine; associated with increased risk of cardiovascular disease.
excessively high levels of plasma homocysteine.
irregular thickening of the stratum corneum due to increased number of corneocyte layers.
an abnormally high concentration of lipids in the blood.
refers to increased interactions between ß-amyloid peptides and copper in Alzheimer’s disease.
excessive growth of bone tissue.
excess secretion of parathyroid hormone by the parathyroid glands resulting in the disturbance of calcium metabolism. Symptoms may include increased blood levels of calcium (hypercalcemia), decreased blood levels of phosphorus, loss of calcium from bone, and kidney stone formation.
excessive cell growth.
high blood pressure. Hypertension is defined by the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure as a systolic blood pressure of 140 mm Hg or higher and/or a diastolic blood pressure of 90 mm Hg or higher.
an excess of thyroid hormone which may result from an overactive thyroid gland or nodule, or from taking too much thyroid hormone.
an abnormally low blood glucose concentration. Symptoms may include nausea, sweating, weakness, faintness, confusion hallucinations, headache, loss of consciousness, convulsions, or coma.
a deficiency of parathyroid hormone, which may be characterized by low blood calcium levels (hypocalcemia).
an area at the base of the brain that regulates bodily functions, such as body temperature, hunger, and thirst.
an educated guess or proposition that is advanced as a basis for further investigation. A hypothesis must be subjected to an experimental test to determine its validity.
a deficiency of thyroid hormone that is normally made by the thyroid gland, located in the front of the neck.