FIBRES may be medullated or non-medullated, but, whichever they are, they consist of thelong
See also:process or axon of a nerve
See also:cell; in a non-medullated nerve this process is either naked or enclosed in a delicate membrane called the
See also:primitive sheath or neurilemma, but in a medullated nerve the process or
See also:axis cylinder is encased by a
See also:white fatty substance called myelin, and so the
See also:term " myelinated " is often used instead of " medullated " for these nerves (see fig . 1) . Axis Outside this white sheath the neurilemma is cylinder
See also:present in most nerves, but is lost when they are massed to
See also:form the white
See also:matter of the central
See also:system and in the optic nerve . Myelin At
See also:regular intervals the myelin is interrupted by some substance which stains deeply with
See also:silver nitrate, and these breaks are known as nodes of Ranvier . They do not, however, affect the axis cylinder . In a large nerve, such as the median, the nerve fibres are collected into small Primitive bundles called funiculi, enclosed in a connective sheath tissue sheath, the perineurium, and separated from it by a
See also:lymph space . From this sheath delicate processes penetrate among the fibres, and these are known as the endoneurium . The funiculi are collected into bundles called fascicuti, and the whole nerve consists of a variable number of fasciculi surrounded by a dense fibrous sheath, the epineurium . The various bundles do not remain distinct, but break up and re-arrange themselves, so that following them up with the scalpel is a difficult and tedious
See also:work . The nerve fibres, however, never join one another and are often several feet in length .
FIBRES (or FIBERS, in American spelling; from Lat. ...
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