The use of a microscope is to provide a magnified view of objects (that are
being analysed) that are otherwise to small to be seen by the naked eye. They
can be described according to their illumination and lens arrangement. (i)
Microscopes are able to use either light or electrons as their illumination
source, which are respectively known as light powered and electron microscopes.

(ii) Monocular microscopes have a single eye piece where as binocular
microscopes posses two eye pieces, position side by side for simultaneous
viewing with both eyes. (iii) A simple microscope consists of one single lens
system where as a compound microscope consists of two main lens systems, an
ocular and objective, which are superimposed over each other to provide greater
magnification. In Biology, microscopes can also be described according to some
specific purpose such as dissecting microscopes, which are commonly referred, as
dissectors are especially suitable for use while dissecting very small or
delicate specimens. Microscopes are usually equipped with a series of
interchangeable eyepiece lenses (oculars), each with different individual
magnifications. Majority of ocular magnification is as followed: X4, X5, X6, X7,
X8, X10, X12, and X15. On a typical monocular microscope objectives
magnification found is as followed: X4 = SCANNING POWER = S.P. X10 = LOW POWER =
L.P. X40 = HIGH POWER = H.P. To find the overall magnification factor obtained
when using any microscope is calculated by the following mathematical formula:
OCULAR magnification X OBJECTIVE magnification = OVERALL magnification The
condenser lens is situated below the stage and causes light rays to converge on
to the specimen situated on the stage, thus illuminating is adequately when
magnified by the viewing lens. The amount of light passing through the condenser
lens can be varied by opening and closing the iris diaphragm, situated at the
bottom of the condenser. AIM: (i) To become familiar with the features and
function of the monocular and stereo microscopes. (ii) To gain first hand
experience in sketching scientific diagrams from prepared slides. EQUIPMENT
USED: Monocular microscopes, microscope lamp, lens cleaning tissue,
lens-cleaning fluid, and various prepared slides. PROCEDURE: When using a
monocular microscope, adjust the condenser lens so that it comes to rest against
the bottom of the stage. Wind it down about 2mm below this level; now its in
the ideal position. The iris diaphragm should also be readjusted each time a
slide is moved from S.P to L.P. H.P. Obtain the first of the prepared slides and
examine it under the scanning power. (ALWAYS begin with the S.P. then the L.P.

and finally the H.P.! NEVER the other way round!). Adjust the course focussing
mechanism followed by the fine focus knob this will assure maximum clarity.

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Having adjusted the course focus whilst operating the scanning power setting,
there is no need to use it again with either the L.P. or H.P. magnifications.


Use only the FINE FOCUS with these magnifications. N.B When operating either
focussing mechanism, ALWAYS adjust the two wheels TOWARDS yourself, NEVER away
from you! This will insure that the objective moves AWAY from the side NOT
towards it, therefore the objective it CANNOT be rammed through the specimen
slide! In Scientific sketching, try to keep BOTH eyes open, using one to peer
down the microscope, and using the other eye to draw with. In addition, the
sketches should ALWAYS include: A Title, Magnification factor, Labels (if
possible) and be approximately -1 full page in size. DISCUSSION/CONCLUSION:
Microscopes have many components, but one component was used at all times and
most likely without even noticing you used it. That component is sits at the top
of the microscope, which you look through and it is call the ocular. The ocular
is interchangeable with different individual magnifications including X10, which
was used in examining all prepared slides. Therefore, even if the objective
magnification was X4 (S.P.), X10 (L.P.), or X40 (H.P.) the ocular did not change
it was still the same magnification of X10. By using the mathematic formula of
Ocular times, Objective will equal to the overall magnification you were using
while examining a slide. These magnifications were: OCULAR X OBJECTIVE = OVERALL
MAGNIFICATION FACTOR X10 X X4 = 40 times = S.P. X10 X X10 = 100 times = L.P. X10
X X40 = 400 times = H.P. The specimens that are on slides come in many come
colours and shape it depends on what specimen and which stain is used. In this
experiment the prepared side specimens that were examined were an Ovary and
Testes Colon Appendix that were pink, Striated Muscle was a purple red colour,
and Grass Root Tip came in three colours red light blue and cream. Each slide
was examined with Scanning power, Low power, and High power, there are
tremendous amounts of differences between the sides. Cause of out five the sides
selected four are of from different parts of an animal and one is a plant slide.


The main difference is between the magnification factors, scanning power (S.P.)
is the only one that enables you to view all or most of the specimen section.


Viewing in S.P. the specimen section structure is very cramped with every thing
very close together (refer to sketches). When changing to low power (L.P.) the
specimen section structure is larger where the section is a lot more free
enabling the viewer to view in between the sections components (refer to
sketches). High power (H.P.) is where the specimen section structures is huge
and more unattached compared to those of the S.P. and L.P. Therefore, in H.P.

the structure can look total different from S.P. and L.P., the specimen section
almost like its a completely different slide altogether. By examining the
sides specimens and the sketches, this was drawn while the slides specimens were
under the microscope. Through these sketches and titles, it gave out enough
information to seek out and research the suitable reference to complete this
report. OVARY Cortex The cortex of the ovary is covered by a modified
mesothelium, the germinal epithelium. Deep to this simple cuboidal to simple
squamous epithelium is the tunica albuginea, the fibrous connective tissues
capsule of the ovary. The remainder of the ovarian connective tissue is more
cellular and is referred to as the stroma. The cortex houses the ovarian
follicles in various stages of development. Primordial Follicles Primordial
follicles consist of a primary oocyte surrounded by a single layer of flattened
follicular (granulosa) cells. Primary Follicular (A) Unilaminar Primary
Follicles consists of a primary oocyte surrounded by a single layer of
cuboidal follicular cells. Primary Follicular (B) Multilaminar Primary
Follicles consists of a primary oocyte surrounded by several layers of
follicular cells. The zona pellucida is visible. The theca interna is beginning
to organised. Secondary (Vesicular) Follicle The secondary follicle is
distinguished from the primary multilaminar follicles by its larger size, by a
well-established theca interna and theca externa. Especially by the presence of
follicular fluid in small cavities formed from intercellular space of the
follicular cells. These fluids filled cavities are known as Call Exner
bodies. Graafian (Mature) Follicles the graafian follicles is very large,
the Call Exner bodies have coalesced into a single space and the antrum is
filled with follicular fluid. The wall of the antrum is referred to as the
membrane granulosa and the region of the oocyte and the follicular cells jutting
into the antrum is the cumulus oophorus. The single layer of follicular cells
immediately surrounding the oocyte is the corona radiata. Long apical processes
of these cells extend into the zona pellucida. The theca interna and theca
externa are well developed; the former displays numerous cells and capillaries,
where as the latter is less cellular and more fibrous. Atretic Follicles (A)
Atretic follicles are in the state of degeneration. They are characterised in
later stages by the presence of fibroblasts in the follicle and a degenerated
oocyte. Medulla (B) The Medulla of the ovary is composed of a relativity
loose fibroblastic connective tissue housing and extensive vascular supply
including spiral arteries and convoluted veins. Corpus Luteum (C) Subsequent
to the extrusion of the secondary oocyte with its attendant follicular cells,
the remnant of the Graafian follicle becomes partly filled with blood and is
known as the corpus hemorrhagicum. Cells of the membrane granulosa are
transformed into large granulosa lutein cells. Moreover, the cells of the theca
interna also increase in size to become theca lutein cells, although they remain
smaller than the granulosa lutein cells. Corpus Albicans (D) The corpus
albicans is a corpus luteum that is in the process of involution a
hyalinization. It becomes fibrotic with few fibroblasts among the intercellular
materials. Eventually, the corpus albicans will become scar tissue on the
ovarian surface. TESTES Capsule The fibromuscular connective tissue capsule
of the testes is known as the tunica albuginea, whose inner vascular layer is
the tunica vasculosa. The capsule is thickened at the mediastinum testis from
which septa emanate subdividing the testis into approximately 250 incomplete
lobuli testis, with each containing one to four seminiferous tubules embedded in
a connective tissue stroma. Seminiferous Tubules Each highly convoluted
seminiferous tubule is composed of a fibromuscular tunica propria, which is
separated from the seminiferous epithelium by a basal membrane. Seminiferous
Epithelium The seminiferous epithelium is a composed of sustentacular
sertoli cells and a stratified layer of developing male gametes. Sertoli cells
establish a blood testis barrier by forming occluding junctions with each
other, thus subdividing the seminiferous tubule into adluminal and basal
compartments. The basal compartments house spermatogonia A (both light and
dark), spermatogonia B, and the basal aspects of sertoli cells. The adluminal
compartment contains the apical portions of sertoli cells primary spermatocytes,
secondary spermatocytes, spermatids, and spermatozoa. Tunica Propria The
tunica propria consist of loose collagenous connective tissue, fibroblasts, and
myoid cells. Stroma loose, vascular, connective tissue stroma surrounding
seminiferous tubules houses small clusters of large, vacuolated appearing
endocrine cells, in the interstitial cells (of leydig). COLON, APPENDIX Mucosa
the mucosa presents no specialised folds. It is thicker than that of the
small intestine. Epithelium (A) The simple columnar epithelium has goblet
cells and columnar cells. Lamina Propria (B) The crypts of lieberkhn of
the lamina propria are longer than those of the small intestine. They are
composed of numerous goblet cells, a few APUD cells, and stem cells. Lymphatic
nodules are frequently present. Muscularis Mucosae (C) The muscularis
mucosae consist of inner circular and outer longitudinal smooth muscle layers.


Submucosa The submucosa resembles that of the jejunum or ileum. Muscularis
Externa The muscularis externa is composed of inner circular and outer
longitudinal smooth muscle layers. The outer longitudinal muscle is modified
into teniae coli, three flat ribbons of longitudinally arranged smooth muscle.


These are responsible for the formation of haustra coli (sacculation).


Auerbachs plexus occupies its position between the two layers. Serosa (A)
The colon possesses both serosa and adventitia. The serosa presents small, fat
filled pouches, the appendices epiploicae. Appendix (B) The lumen of the
appendix is usually stellate shaped, and it may be obliterated. The simple
columnar epithelium covers a lamina propria rich in lymphatic nodules and some
crypts of lieberkhn. The muscularis mucosae, submucosa, and muscularis externa
conform to the general plan of the digestive tract. It is covered by serosa.


Anal Canal (C) The anal canal presents longitudinal folds, anal columns,
that become jointed at the orifice of the anus to form anal valves and
intervening anal sinuses. The epithelium changes from the simple columnar of the
rectum, to simple cuboidal at the anal valves, to epidermis at the orifice of
the anus. Circumanal glands, hair follicles, and sebaceous glands are present
here. The submucosa is rich in vascular supply, while the muscularis externa
forms the internal anal sphincter muscle. An adventitia connects the anus to the
surrounding structures. STRIATED MUSCLES Longitudinal Section (A) Connective
tissue elements are clearly identifiable because of the presence of the nuclei
that are considerably smaller than those of cardiac muscle cells. The connective
tissue is rich in vascular components, especially capillaries. The endomysium is
present but indistinct. Longitudinal Section (B) Cardiac muscle cells from
long, branching, and anastomosing muscle fibers Bluntly oval nuclei are large,
are centrally located within the cell, and appearing somewhat vesicular. A and I
bands are present but are not as clearly defined as in skeletal muscle.


Intercalated discs, marking the boundaries of contiguous cardiac muscle cell,
may be indistinct unless special staining techniques are used. Purkinje fibers
are occasionally evident. ROOT TIP As root tissues differentiate behind the
growing tip, they form a pattern of cylinders (tubes) within the cylinders. Each
cylinder is composed of tissue that has a specific role to play for the plant.


Epidermis The outermost cylinder is only cell in thickness and is called the
epidermis. This encloses and protects the underlying tissues. Some epidermis
cells differentiate into hair cells. These stick out into surrounding soil
spaces and absorb water and selected mineral ions. Cortex Parenchyma A very
thick cylinder is found just under the epidermis. This called the cortex or
cortex parenchyma. Parenchyma cells store excess nutrients, usually in the form
of starch. These cells are loosely packed so that the spaces between them can
direct water and mineral ions coming from root hairs and cortex spaces and
directs them into the central vascular core. Pericycle Another thin cylinder
is found under the endodermis, the pericycle. Pericycle cells can function like
meristem and mitotically produce secondary or branch roots. The pericycle also
constitutes the outer boundary of the vascular core, a structure that contains
the internal, liquid transport highways of the plant in the form of highly
specialised tube like or conducting tissues. Vascular Cylinder The vascular
cylinder is comprised of tissues that transport nutrients. Water and mineral
ions taken in by root hairs and concentrated into the core by the endodermis are
transported up into the plant shoot by xylem tubes. Sugar rich fluid,
sucrose, made in the leaves as glucose is transported by phloem sieve tubes into
the root core, where it is distributed to root cells for energy production or
storage as starch in the cortex parenchyma. Xylem and phloem tissues are
excellent examples of how cell structure dictates function. Xylem Cells (A)
Xylem cells have to die before they can serve the transport needs of the plant.


Dead xylem cells leave behind a thick, hollow, tubular wall, which joins end to
end with other xylem walls to form a microscopic but strong and fixable tube,
which extends from root to leaf. Xylem walls have slit like openings or
pits, which provide for the sideways transfer of water and mineral ions into
surrounding tissue. Close examination of these wall shows that their thickness
is due to cellulose and a cement like substance call lignin. Lignin creates the
wood in woody plants some walls are reinforced with internal rings or spirals.


These rings of lignin help to support the plant. Xylem tubes are sometimes
called vessels, i.e. composed of vessel cells, or elements. Primitive plants
such as pines and firs have tracheid xylem which thinner walls and tapered ends.


Phloem (B) Phloem is made up of two basic cell types, both of which are
living when they serve the transport needs of the plant. The lager cell type is
a sieve tube member; the small is a companion cell. The sieve tubes member,
though living, does not have a nucleus and therefore does not control its own
metabolism. What the needs it has are apparently provide for by the tiny
companion cell that is attached to the sieve tube member. Sieve tubes members
are very much smaller and have thinner walls than xylem, but like xylem, they
join end to end to form sieve tubes that extend leaves to roots. These take
their name from the tiny, sieve like pores in their walls and the larger pores
called sieve plates that separate one member from another. Pores provide for the
horizontal and vertical movement of the sugar rich sap that slowly moves
down from the leaves, supplying energy, and elements to all plant tissues. Large
parenchymal cells called pith may also be associated with the vascular cylinder
phloem.

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