Fibre Health Dictionary

See ROUGHAGE.... fibre, dietary

The transmission of images through bundles of thin, flexible glass or plastic threads which propagate light by total internal reflection. This means that all the light from a powerful external source travels the length of the fibre without losing its intensity. Fibre-optics have led to the development of endoscopes, which enable structures deep within the body to be viewed directly.... fibre-optics

A visualising technique enabling the operator to examine the internal organs with the minimum of disturbance or damage to the tissues. The procedure has transformed the management of, for example, gastrointestinal disease. In chest disease, ?breoptic bronchoscopy has now replaced the rigid wide-bore metal tube which was previously used for examination of the tracheo-bronchial tree.

The principle of ?breoptics in medicine is that a light from a cold light source passes down a bundle of quartz ?bres in the endoscope to illuminate the lumen of the gastrointestinal tract or the bronchi. The re?ected light is returned to the observer’s eye via the image bundle which may contain up to 20,000 ?bres. The tip of the instrument can be angulated in both directions, and ?ngertip controls are provided for suction, air insu?ation and for water injection to clear the lens or the mucosa. The oesophagus, stomach and duodenum can be visualised; furthermore, visualisation of the pancreatic duct and direct endoscopic cannulation is now possible, as is visualisation of the bile duct. Fibreoptic colonoscopy can visualise the entire length of the colon and it is now possible to biopsy polyps or suspected carcinomas and to perform polypectomy.

The ?exible smaller ?breoptic bronchoscope has many advantages over the rigid tube, extending the range of view to all segmental bronchi and enabling biopsy of pulmonary parenchyma. Biopsy forceps can be directed well beyond the tip of the bronchoscope itself, and the more ?exible ?breoptic instrument causes less discomfort to the patient.

Fibreoptic laparoscopy is a valuable technique that allows the direct vizualisation of the abdominal contents: for example, the female pelvic organs, in order to detect the presence of suspected lesions (and, in certain cases, e?ect their subsequent removal); check on the development and position of the fetus; and test the patency of the Fallopian tubes.

(See also ENDOSCOPE; BRONCHOSCOPE; LARYNGOSCOPE; LAPAROSCOPE; COLONOSCOPE.)... fibreoptic endoscopy

A diet high in rich carbohydrate foods with sufficient protein to promote efficient elimination and supply vital trace elements in the form of minerals. Such foods produce moist bulky stools easy to pass and reduce blood cholesterol. It reduces LDLs and increases HDLs.

Fibre-deficient foods lead to poor elimination of body wastes and constipation, disposing the colon to a toxic state. This induces depression, a coated tongue and tiredness during the day. Such foods bring about a change in the balance of bowel bacterial flora, and form gas which may cause pouches of diverticulitis to develop. One of its less obvious effects is to enhance the risk of tooth and gum disease. Soon calcium is expelled by the urine and the intake of magnesium reduced, thus favouring the development of stone.

All plant material; leaves, stalks, seeds etc contain fibre. High-fibre foods include: whole grains, wholemeal bread, wholemeal flour (100 per cent extraction rate), crispbreads, biscuits (digestive, bran, oatmeal or coconut), raw green salad materials, potatoes boiled in their jackets, breakfast cereals (porridge, muesli, All-Bran, Shredded Wheat), brown rice, bran (2 teaspoons thrice daily; increase if necessary), fresh or dried fruit once or twice daily. ... diet - high fibre

(roughage) nonstarch polysaccharides (NSP), which cannot be digested and absorbed to produce energy; specifically, sources of NSP that do not contain lignin or resistant starch. Fibre is divided into two types: insoluble (cellulose and hemicelluloses) and soluble (pectins). Highly refined foods, such as sucrose, do not contain dietary fibre. Foods with a high fibre content include wholemeal cereals, vegetables, nuts, and fruit. A diet high in insoluble fibre (e.g. wheat bran, wholegrain and wholemeal bread and cereals) may help prevent bowel diseases, such as constipation, diverticulitis, and colon cancer. Soluble fibre (e.g. oats, barley, beans, pulses, fruit, and vegetables) slows the reabsorption of *bile salts and so helps to lower cholesterol as well as dampening the glycaemic response to glucose (see glycaemic index). A high-fibre diet used to be the first-line advice for irritable bowel syndrome; however, a low *FODMAP diet can be more effective.... dietary fibre

n. an *endoscope that uses *fibre optics for the transmission of images from the interior of the body. Fibrescopes have a great advantage over the older endoscopes as they are flexible and can be introduced into relatively inaccessible cavities of the body.... fibrescope

(myelinated nerve fibre) see myelin.... medullated nerve fibre

the long fine process that extends from the cell body of a *neuron and carries nerve impulses. Bundles of nerve fibres running together form a *nerve. Each fibre has a sheath, which in medullated nerve fibres is a relatively thick layer containing the fatty insulating material *myelin.... nerve fibre

see atrioventricular bundle.... purkinje fibres

microscopic, almost nonelastic, branching fibres of *connective tissue that join together to form a delicate supportive meshwork around blood vessels, muscle fibres, glands, nerves, etc. They are composed of a collagen-like protein (reticulin) and are particularly common in lymph nodes, the spleen, liver, kidneys, and muscles.... reticular fibres