STUDY OF MICROSCOPE
Aim:
To study the structure, working, use and care of compound microscope.
Theory:
The compound microscope is called so because, in contrast to a single magnifying convex lens, it has two such lenses – the objective and the eyepiece. t magnifies the image of an object that is not visible to the naked eye to an extent where it can be seen.
The microscope is one of the most commonly used instruments in medical and life sciences colleges and in clinical laboratories.
Types of Microscope:
Various types of microscopes have been specially introduced for particular purposes over the past many decades. Some of these are:
(i) Binocular Microscope: It is a compound bright field microscope but has two eyepieces instead of one so that both eyes are used simultaneously. It prevents eyestrain.
(ii) Dissection Microscope: It is a binocular microscope used for microdissection under magnification.
(iii) ”Dark-Field” Microscope: It employs a special condenser that causes right waves to cross on the material under study rather than passing through it. It is used in microbiology to study spirochetes.
(iv) Phase-Contrast Microscope: Since the living cells are mostly transparent, they must be stained with vital stains, or they must be first fixed in alcohol and then stained with acid or basic dyes. Unstained wet preparation can be studied by using this microscope.
(v) Interference -Contrast Microscope: In this, a special prism that can split a beam of light is added to the condenser.
(vi) Polarising Microscope: It has a polarizer (filter) which is usually placed between the light source and the specimen. Such a system is used to study tissues that have the property of birefringence (e.g. Muscle fibres).
(vii) Fluorescence Microscope: A fluorescent dye is used to stain tissues which are then studied under a microscope.
(viii) Transmission Electron Microscope (TEM): This microscope was invented by Knoll and Ruskain in 1940. The TEM uses a strong beam of electrons instead of light.
(ix) Scanning Electron Microscope (SEM): This microscope achieves a resolution of about 30 Å. Though similar to TEM, the SEM employs a different technique.
PARTS OF THE COMPOUND MICROSCOPE
Eyepiece:
The eyepiece is the lens; the viewer looks through, to see the specimen. It usually contains a 10X or 15X power lens.
Body Tube (Head):
The body tube connects the eyepiece to the objective lens.
Arm:
The arm connects the body tube to the base of the microscope.
Coarse Adjustment:
Brings the specimen into general focus.
Fine Adjustment:
Fine adjustment tunes the focus and increases the details of the specimen.
Nosepiece:
It is a rotating turret that houses the objective lenses. The viewer spins the nosepiece to select different objective lenses.
Objectives Lenses:
These lenses are one of the most important parts of a compound microscope, as they are the lenses closest to the specimen. It is usually of power 10X, 45X, 100X.
Stage:
The flat platform where the slide is placed.
Stage Clips:
Metal clips that hold the slide in place.
Stage Control:
These knobs move the stage left and right or up and down.
Aperture:
The hole in the middle of the stage allows light from the illuminator to reach the specimen.
On/Off Switch:
This switch on the base of the microscope turns the illuminator OFF and ON.
Iris Diaphragm:
Adjusts the amount of light that reaches the specimen.
Condenser:
Gathers and focuses light from the illuminator onto the specimen being viewed.
Base:
The base supports the microscope.
PRECAUTIONS AND ROUTINE CARE
1. Select a stool or chair of suitable height so that your eyes are at a level slightly above the eyepiece. This will ensure comfortable working for long periods.
2. Ensure that all the lenses are clear and free from dust and smudges. Do not touch them with your fingers, nor blow on them to remove dust.
3. Check the position of the objective, condenser and diaphragm, to ensure optimal illumination.
4. Once a specimen has been focused, continuously “rack” the microscope.
5. Cover the microscope with the plastic cover after use.
Remedial Biology Practicals
- Introduction to experiments in biology a) Study of Microscope b) Section cutting techniques c) Mounting and staining d) Permanent slide preparation 2. Study of cell and its inclusions 3. Study of Stem, Root, Leaf, seed, fruit, flower and their modifications 4. Detailed study of frog by using computer models 5. Microscopic study and identification of tissues pertinent to Stem, Root Leaf, seed, fruit and flower 6. Identification of bones 7. Determination of blood group 8. Determination of blood pressure 9. Determination of tidal volume
First Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise
First Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise