. Anatomy, descriptive and applied. Anatomy. 810 THE NERVE SYSTEM narrower as they divide into many branches in a dichotomous or arborescent manner to end free, according to most observers, or to be joined with the dendrites of other neurones by means of minute fibrillaj (as claimed by Apathy) or by concrescence (Held). The contour of the dendrite, while occasionally irregular in some specimens, with varicosities along its course, is, as a rule, beset with numerous lateral buds called gemmules. ^'arious hypotheses have been advanced in explanation of these appearances, it being held by some in
. Anatomy, descriptive and applied. Anatomy. 810 THE NERVE SYSTEM narrower as they divide into many branches in a dichotomous or arborescent manner to end free, according to most observers, or to be joined with the dendrites of other neurones by means of minute fibrillaj (as claimed by Apathy) or by concrescence (Held). The contour of the dendrite, while occasionally irregular in some specimens, with varicosities along its course, is, as a rule, beset with numerous lateral buds called gemmules. ^'arious hypotheses have been advanced in explanation of these appearances, it being held by some investigators that they are related to- conditions of activity as contrasted to those of repose, while others believe them' to be artefacts produced by the fixing and staining methods at present employed. However, it is no longer disputed that the function of the dendrites is receptive and conductive (or cellulipetal) for nerve impulses, although they probably serve the nutritional requirements of the cell body as well. This functional distinction gives the clue to the correct interpretation of the central and peripheral prolongations of the cerebrospinal ganglionic neurones. The cells of these ganglia are at first bipolar in form, but gradually undergo transformation into apparently unipolar cells by the migration of the cell body to one side and the consequent approximation of the two processes to form a common pedicle in a T-shaped manner so typical of the spinal ganglion cell of the adult (Fig. 586). The central branch invariably remains cellulifugal, the peripheral branch invariably remains cellulipetal, and as such is equivalent to the dendrites of all other neurones. It is merely a modified dendrite in that it courses a longer distance without branching until it reaches the periphery and is usually myelinic. Such a peripheral prolongation of the ganglioa cell is also termed a centripetal nerve fibre or myelinic (medullaied) peripheral axone of an afferent. B. Please note t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
