To identify parenchyma and sclerenchyma tissues in plants Video Lecture - Class 9

to identify parenchyma and sclerenchyma
tissues in plants striped muscles fibers
and nerve cells in animals from prepared
slides and to draw their label diagrams
materials required permanent slides of
parenchyma tissues sclerenchyma tissues
striped muscle fibers and nerve cells
compound microscope procedure observe
the permanent slides one by one under a
compound microscope
observation one plant tissues a
parenchyma tissues
the slide shows numerous cells the
parenchyma two cells are ISO diametric
from ISO diametric it implies that
almost all cells are equal in length and
width at the corners of the cells are
present intercellular spaces each cell
possesses a large central vacuole each
cell has peripheral cytoplasm with a
prominent nucleus each cell has thin
cell wall
inference parenchyma two cells make
simple tissues parenchyma two cells are
living cells and a precursor of all
other cells these cells are present in
the soft areas of plants such as stems
leaves roots flowers and fruits the
important function of these cells is
photosynthesis or storage or helping in
flotation
be sclerenchyma our tissues sclerenchyma
two cells are dead cells they have
evenly thickened heart cell walls they
have very little or no protoplasm they
have hard lignified secondary walls they
can be divided into two types a fibrous
sclerenchyma B scleroids fibrous
sclerenchyma one they are highly
elongated narrow and spindle shaped with
pointed end walls two adjacent fibers
have simple oblique bits three the only
function they perform is to provide
mechanical strength otherwise these
fibers are empty and dead scared's 1
they are highly thickened dead
sclerenchyma 2 cells which have very
narrow cavities - they may occur singly
or in groups and are isoda metric in
nature 3 they are sometimes called grit
or stone cells they provide stiffness to
the plant wherever they occur
inference the sclerenchyma to cells
being thick-walled and having deposition
of lignin give mechanical strength to
the plant
- animal tissues a striped muscle fibers
the slide shows large number of long
cylindrical fibers that are enclosed in
a membrane called
sarcolemma the fibers are non tapering
and wide the fibers are multinucleated
the nuclei lied towards the periphery of
the fibers the cytoplasm of each fiber
is called sarcoplasm it is divided into
large number of myofibrils each
myofibril bears alternate light and dark
band thus these cells show longitudinal
and transverse striations the cells are
surrounded and held by connective tissue
inference the observation of slide shows
the presence of striated muscles it is
because they are long cylindrical fibers
having myofibrils which make striations
tightly packed the muscles give contra
tract ability and strength to the
voluntary muscle these muscles work
according to our will they get tired
when overworked
be nerve cell
a nerve cell or a neuron has a large
body called site on the site on has a
prominent nucleus site on has
cytoplasmic projections called dendrites
one of the dendrite is long and is
called axon a group of axons held
together by a connective tissue is
called a nerve the axons are covered
with medullary sheath or myelin sheath
at the nodes of ranvier the myelin
sheath is absent a membrane called Nuri
lemma surrounds the sheath the nerve
endings are attached to muscles
inference from the above observation it
is clear that a nerve cell of a large
site on with the prominent nucleus such
that site on has cytoplasm projections
called dendrites one of the dendrite is
long and is called axon the axons or
fibers are packed together to make a
nerve for the transfer of impulses