MORPHOLOGY OF WOOL FIBRE

1. 1

2. WOOL FIBRE
. The wool fiber is an organized structure growing from a
root situated in the dermis.
The animal fiber consists of three morphological
components :-
1. Cuticle
2. Cortex
3. Medulla
 In fine wool, the medulla is absent, and even in coarse
wool only some of the fibers are partially medullated.
Thus a wool fiber generally consists only of cuticle and
cortex.

3. Outer layer of the fibre made up of flat irregular horny
cells or scales .
Scales 30 μ length , .5 μ thickness , scale loose end tip
of fibre , covers about 1/6 in wool and 5/6 in hair .
Cuticle variations in shape , contour & arrangement of
scales .
The most common type of scale structures are:
Coronal Pattern
Each scale forms a complete ring around the fiber, the top
of one scale overlapping the bottom of the next like a
column of flower pots set into one another. Truly coronal
scale arrangements appear in very fine fibers particularly
those in merino wools.
CUTICLE ( EPIDERMIS )

4. Coronal-Reticulate Scaling
In this, scale edges forms a band around the fiber, but
each band contains more than one scale, so that lateral as
well as axial overlapping occurs. The bands may be
transverse to the fiber axis or run diagonally across the
fiber. This type of scaling is found in the coarse merinos,
in luster and down wools, and in some kemp fibers.
Reticulate Scaling
The scales form an irregular network over the surface of
fiber. This type of pattern is found only in coarse fibers.
The scale pattern is useful tools for distinguishing
certain fibre types e.g. fine wool and cashmere, medium
wool and mohair

5. The structure of cuticle can further be subdivided into
3 regions i.e. Epicuticle , Exocuticle and Endocuticle.
CORONAL
PATTERN
CORONAL RETICULATE
PATTERN
RETICULATE

6. CORTEX
This cell layer which constitute the principal body of
wool fibre lies immediately below the epidermis.
It is made of long flattened more or less twisted
spindle like cells
Cortical cells :- irregular , polygonal , longitudinally
oriented fibrils comprising fibrillae.
Intercellular cementing substances held the cells
together .
Cortex cells 100 microns long and 2-4 microns wide.
Cortical cells impart strength & elasticity to the fibre

7. Based on the arrangements of fibrils, 3 types of
cortical cells have been identified
Ortho-cortical cells: have discrete microfibrilis
which appear to be twisted about their sound axis.
Para-cortical cells: have fused poorly defined
microfibrilis especially around periphery of cells.
Meso-cortical cells: Is para cortex like but have
less extensively defined microfibrilis.

9. MEDULLA
Medulla consists of network of hallow air filled cell walls,
which in some case collapses completely to give a hollow tube.
Heavy medullation increases the reflection of light by the
fiber and results in a white chalky appearance.
Medullation is rare in fibers less than 35 microns thick.
In general, the incidence of Medullation increases with fiber
diameter.
In fine wool, the medulla is absent, and even in coarse wool
only some of the fibers are partially medullated.

10. THANK
YOU