| Purkinje fibre | <cardiology, pathology> A group of specialised cardiac muscle cells that conduct electrical impulses through the heart and are involved in regulating the heart beat. The fibres form the terminal portion of the heart conduction system and have central granulated protoplasm containing one or two nuclei and a transversely striated peripheral portion. They are the terminal ramifications of the conducting system of the heart found beneath the endocardium of the ventricles. See: conducting system of heart. (10 Jul 2002) |
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| silver cone | Pure silver cone with standard conical shape, used with cement to obturate dental root canals. (05 Mar 2000) |
| spindle fibre | <cell biology> Microtubules of the spindle that interdigitate at the equatorial plane with microtubules of the opposite polarity derived from the opposite pole microtubule organising centre. Usually distinguished from kinetochore fibres that are microtubules that link the poles with the kinetochore, although these could be included in a broader use of the term. (18 Nov 1997) |
| nerve fibre | The axon of a nerve cell, ensheathed by oligodendroglia cells in brain and spinal cord, and by Schwann cells in peripheral nerves. (05 Mar 2000) |
| nerve growth cone | <cell biology> A specialised region at the tip of a growing neurite that is responsible for sensing the local environment and moving toward the neuron's target cell. Growth cones are hand shaped, with several long filopodia that differentially adhere to surfaces in the embryo. Growth cones can be sensitive to several guidance cues, for example: surface adhesiveness, growth factors, neurotransmitters and electric fields (galvanotropism). (18 Nov 1997) |
| stress fibre | <physiology> Long bundles of microfilaments made up of actin subunits. They are involved in the attachment of cultured cells to a substratum, the determination of cell shape and may be involved in cellular mobility. They are found in most cells and have been shown to be contractile, have a periodicity reminiscent of the sarcomere and are anchored at one end to a focal adhesion, although sometimes between two focal adhesions. (17 Jul 2002) |
| nuclear bag fibre | The largest type of intrafusal muscle fibre's in a neuromuscular spindle, containing a central aggregation of nuclei (nuclear bag). (05 Mar 2000) |
| nuclear chain fibre | The shortest and most numerous type of intrafusal muscle fibre's in a neuromuscular spindle, containing a single row of centrally positioned nuclei. (05 Mar 2000) |
| diabetes and fibre | Soluble fibres (oat bran, apples, citrus, pears, peas/beans, psyllium, etc.) slow down the digestion of carbohydrates (sugars), which results in better glucose metabolism. Some patients with the adult-onset diabetes may actually be successfully treated with a high-fibre diet alone, and those on insulin, can often reduce their insulin requirements by adhering to a high-fibre diet. (12 Dec 1998) |
| dietary fibre | <nutrition> The remnants of plant cell walls that are resistant to digestion by the alimentary enzymes of man. It comprises various polysaccharides and lignins. (12 Dec 1998) |
| diverticulosis/diverticulitis and fibre | High fibre diets help delay the progression of diverticulosis and, at least, reduce the bouts of diverticulitis. (12 Dec 1998) |
| drift cyclotron loss cone instabilities | (DCLC) This is an electrostatic microinstability (frequencies at harmonics of the ion cyclotron frequency) which is of major concern in small mirror devices. Mode is driven by radial gradients in the electron density, and causes loss of ions due to non-conservation of magnetic moment (see adiabatic invariant) as they interact with the mode, and are dispersed in velocity space into the loss cone. Stabilisation is accomplished by increasing the plasma size and by partially filling the loss cone with a continuous extermal warm plasma stream. (09 Oct 1997) |
| icecream cone | <radiology> Ball of icecream head of malleus, cone body of incus (12 Dec 1998) |
| implantation cone | <cell biology> Tapering region between a neuron's cell body and its axon. This region is responsible for summating the graded inputs from the dendrites and producing action potentials if the threshold is exceeded. (12 Mar 1998) |
| inverted cone bur | A rotary cutting instrument in the shape of a truncated cone with the smaller end attached to the shaft; generally used for entering carious pits or creating undercuts in cavity preparations. (05 Mar 2000) |