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LACRIMATION is the process of the secretion of tears.

LACTASE (Beta-Galactosidase) is an enzyme found in bacteria and many other sources. Lactase produced by bacteria will break down lactose into glucose and galactose. Lactase in humans breaks down gangliosides into simpler compounds which are then further broken down. The lack or low concentrations of lactase is believed to result in gangliosidosis, the symptoms of which are mental retardation, liver enlargement, and skeletal deformations.

LACTIC ACID is a colorless syrupy sour liquid which is produced by the action of bacteria upon sugar or milk.

When the term is used in reference to anatomy/physiology, lactic acid is a chemical formed from pyruvic acid, through a side "shuttle", during increased muscle action and is carried by the blood to the liver, where it is reconverted to glucose and returned as blood glucose to the muscles. It is this elevation of blood lactic acid in sustained strenuous exercise, such as in marathon running, which results in muscle fatigue and pain. Recovery follows when enough oxygen gets to the muscle, part of the lactic acid being oxidized and most of it then being built up once more into glycogen. The metabolic cooperation between contracting skeletal muscle and the liver to support active muscle work is called the Cori cycle.

LACTOSE is a disaccharide of milk which on hydrolysis yields glucose and galactose. Bacteria can convert it into lactic acid and butyric acid, as in the souring of milk. It is used in infant feeding formulas, in other foods and as an osmotic laxative and diuretic. Lactose is not tolerated in many persons after weaning, owing to a reduce lactase activity.

LARGE INTESTINE - The large intestine is a large muscular tube responsible for resorption of water and electrolytes, the formation and expulsion of feces, and the manufacture of certain vitamins, mainly vitamin K.

The large intestine begins at the right side of the abdomen directly above the pelvic girdle. The initial portion, where the appendix is attached, is called the cecum. Beyond the cecum, it is called the ascending colon and extends upward vertically along the right side of the abdomen. At the under face of the liver, the colon turns and crosses the abdominal cavity from the right to left; this portion is called the transverse colon. The descending colon, also called the sigmoid colon because of its S-shape, begins near the spleen and then travels downward until it reaches the pelvic cavity. The rectum is the lowest end of the intestine which leads into the anus.

LAURIC ACID is an unsaturated fatty acid found in milk, coconut, and many other sources. Lauric acid, when joined to a glycerol backbone with other fatty acids and compounds, may form lipids or phospholipids. Lipids and phospholipids are used as cell membranes all over the human body.

LAXATIVE - an agent which acts to loosen the bowels; it is therefore used to treat constipation. Laxatives may act by increasing peristalsis by irritating the intestinal mucosa, lubricating the intestinal walls, softening the bowel contents by increasing the amount of water in the intestines, and increasing the bulk of the bowel content.

LECHER: A stud with liver spots.

LECTINS are proteins found in plants and animals. Lectins have properties which make them resemble antibodies: they have agglutinating and precipitating effect on microorganisms. Two examples of lectins are phytoagglutinins and concanavalin A. Concanavalin A is used in laboratory research, and has a specificity towards certain types of simple carbohydrate molecules which are bound to proteins as polysaccharides.

LEIOMYOMA - A tumor consisting of smooth muscle fibers.

LICORICE is a perennial plant indigenous to southern Europe, the Middle East and northern China; it is cultivated in many parts of the world. The rootstock is brown, wrinkled, and woody, producing an erect striated stem two to five feet in height. The leaves are alternate, odd-pinnate, and have four to seven pairs of ovate, smooth, dark green leaflets. Purplish or yellowish white flowers grow in axillary racemes and bloom from June to August. The medicinal part is the rootstock.

Other common names for this plant are: Italian Juice Root, Lickweed, Spanish Juice Root, Sweet Licorice, Sweet Wood.

For more information see the HERBS section of the Nutrition Notebook.

LIGAND - An organic molecule that donates the necessary electrons to form coordinate covalent bonds with metallic ions. When this occurs in food particles the ligand deposits its charged metallic ion/s at the appropriate receptor site in the gastrointestinal tract, and then because of its charge picks up some other metal ion, usually one of the heavy metals that are toxic. It then continues on through the gastrointestinal tract until it is excreted.

LIGAMENTS are strong fibrous cords composed mainly of collagen fibers which extend from one bone to another. They reinforce joint capsules and restrict unwanted movement. Capsular ligaments are distinct thickenings of the joint capsule. Extrinsic ligaments are found in the joint cavity connecting articular surfaces of the bones.

LIGNIN is a polymer of conferyl alcohol found in wood. Lignin may be oxidized to gave vanillin. Vanillin is used as a rubber strengthener, and in laboratories to precipitate proteins.

LIMONENE is a volatile oil found in pine needle oil, lemon oil, and other plants. Limonene has antiviral and antibacterial properties. It is a skin irritant and sensitizer. Limonene is used in the manufacturing of resins and as a solvent.

LINALOOL is a volatile oil found in vois de rose, lavender, and other plants. Linalool has anticonvulsant, spasmolytic, and weak tumor-forming properties on laboratory animals. Linalool has also shown antimicrobial properties. Linalool has also shown antimicrobial properties. Linalool is used in perfumery in place of lavender compound because the odor is similar.

LINOLENIC ACID is an essential fatty acid found in vegetables, peanut oil, and other plants. A linolenic acid deficiency will result in hair loss, poor wound healing, and scaly dermatitis. Linolenic acid is used in the manufacture of paints, coatings, and vitamins. Linolenic acid is also used therapeutically as some vitamins.

LIPASE is a fat-splitting enzyme widely distributed in the animal and vegetable worlds. It is found in the pancreatic juice of animals and in oily seeds. Lipase causes the hydrolysis of fats in glycerin and fatty acids.

LIPID - any of a group of organic substances, including fatty acids, neutral fats, waxes, steroids, and phosphatides, which are insoluble in water, but soluble in alcohol, ether, chloroform, and other fat solvents; lipids are a source of body fuel and an important constitutent of cells.

LIPOPROTEINS - the freight trucks which move fats and cholesterol from one part of the body to another. Lipoproteins are called high density if they have a lot of protein, low fat, and little capacity for cholesterol. They are called low density if they are fatty and carry much cholesterol - can be over 60% by weight. Lipoproteins only carry incoming fat and cholesterol from the liver into the arterial system. The high density ones have the backhauling and garbage collection contract. They can actually pick up the cholesterol from your arterial walls and transport it to the liver, where it is broken down into bile acids and flushed out of the body. Dietary strategy should be to eat foods which increase HDLs. Omega-3 can help to accomplish this.

LIVER - The liver weighs about three and one-third pounds, making it the heaviest gland in the body. It is located in the upper right side of the abdominal cavity under the diaphragm.

Apart from the lungs, it is the only organ which receives both arterial and venus blood. Arterial blood supplies nutrients to the liver tissue; it also receives nutrient-rich but oxygen poor venus blood from the digestive organs, spleen, pancreas, and gallbladder. The liver takes in these nutrients and can store them in the form of glycogen or fat, use them to synthesize proteins, or use them to alter fats.

The liver converts proteins and fats into carbohydrates, a more usable form of energy. The liver also converts nitrogenous wastes into less harmful substances. The spleen breaks down red blood cells; some of the components of these cells flow, via blood vessels, to the liver. The liver combines these components with other compounds to produce bile, which is important in fat digestion. It also acts as a storage area for vitamin A, vitamin B-12, and vitamin D.

LYMPH is the yellowish, transparent fluid that is collected from the tissues of the body, courses through the lymph vessels and slowly passes (passage speeded by exercise) through the lymph nodes before joining the venous blood circulation. It carries numerous white blood cells (mainly lymphocytes), few red blood cells and in some vessels a milky emulsive fat after meals.

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