Carbohydrates ( CC1 Lab)

Carbohydrates

Organic compounds that serve as the primary source of energy for the brain, erythrocytes, and retinal cells. They are also a major food source and energy supply for the body. Carbohydrates can be stored as glycogen in the liver and muscles. They can be classified based on the number of carbons, properties such as size and location of functional groups, number of sugar units, and stereochemistry of the compound.

Monosaccharides

Simple sugars that contain more than three carbons. Common examples include glucose, fructose, and galactose.

Disaccharides

Two monosaccharides joined by glycosidic linkages. Common examples include maltose, sucrose, and lactose.

Oligosaccharides

Chains of 2 to 10 sugar units.

Polysaccharides

Linkages of many monosaccharide units. Common examples include starch and glycogen.

Glycolysis

The metabolic pathway that converts glucose into pyruvate or lactate for the production of energy.

Gluconeogenesis

The formation of glucose-6-phosphate from non-carbohydrate sources.

Glycogenolysis

The breakdown of glycogen into glucose.

Glycogenesis

The conversion of glucose into glycogen.

Lipogenesis

The conversion of carbohydrates into fatty acids.

Lipolysis

The decomposition of fats.

Insulin

A hypoglycemic agent and hormone responsible for the entry of glucose into the cell. It is synthesized by the cells of the Islets of Langerhans and increases glycogenesis, lipogenesis, and glycolysis while inhibiting glycogenolysis.

Glucagon

A hyperglycemic agent and primary hormone responsible for increasing glucose levels. It is synthesized by the A cells of the Islets of Langerhans and promotes glycogenolysis and gluconeogenesis.

Epinephrine

Released by the adrenal medulla, it increases plasma glucose by inhibiting insulin, promotes glycogenolysis, and stimulates lipolysis.

Cortisol

Produced by the adrenal cortex and stimulated by ACTH, it increases plasma glucose by decreasing intestinal entry into the cell and promotes gluconeogenesis and lipolysis.

Growth hormone

Stimulated by decreased glucose and inhibited by increased glucose, it increases glucose levels by decreasing the entry of glucose into the cell and increases glycolysis.

ACTH

If low, the pituitary gland is stimulated to release cortisol, which increases glucose levels by promoting gluconeogenesis and the conversion of glycogen to glucose.

Thyroxine

Increases plasma glucose levels by increasing glycogenolysis and gluconeogenesis.

Somatostatin

Inhibits insulin, glucagon, and growth hormone.

Hyperglycemia

An increase in plasma glucose levels. It is commonly associated with diabetes mellitus.

Diabetes Mellitus

A metabolic disorder characterized by a defect in insulin secretion or action. It can be classified into Type I, Type II, and other specific types.

Type I Diabetes

Pancreatic islet B cell destruction resulting in insulin secretion deficiency. It typically occurs in childhood or adolescence and is insulin-dependent and prone to ketosis. Symptoms include polydipsia, polyphagia, polyuria, weight loss, hyperventilation, mental confusion, and loss of consciousness. Complications include nephropathy, neuropathy, retinopathy, and heart disease.

Type II Diabetes

Due to insulin resistance with an insulin secretory defect. It is commonly associated with obesity, age, and lack of exercise.

Other specific types of Diabetes

Includes genetic defects, pancreatic diseases, and drug or chemical-induced diabetes.

Gestational Diabetes Mellitus

Diabetes recognized during pregnancy, typically occurring between 24 to 28 weeks of gestation. It is associated with metabolic and hormonal changes and can lead to complications in the baby such as respiratory distress, hypocalcemia, and hyperbilirubinemia.