MORPHOLOGY OF WOOL FIBRE

MORPHOLOGY OF WOOL FIBRE

1. COLLEGE OF VETERINARY & ANIMAL SCIENCE , NAVANIA, VALLABHNAGAR,UDAIPUR (RAJ.) 1 SUBMITTED TO : DR.UMESH S. SURADKAR , DR. RAMESH CHAND JAT SUBMITTED BY : ASHISH KUMAR MORPHOLOGY OF WOOL FIBRE ASSIGNMENT : LPT – 312 (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 :- Cuticle Cortex 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 .

8. 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 .

9. THANK YOU