PRACTICAL 1 BY NANA ABOAGYE ACHEAMPONG CELL STRUCTURE (BIOL 151) PRACTICAL 1 BY NANA ABOAGYE ACHEAMPONG

OUTLINE GENERAL LABORATORY PRACTICES PRECAUTIONS HANDLING OF MICROSCOPE IDENTIFICATION OF VARIOUS PARTS OF THE MICROSCOPE FOCUSSING

GENERAL LAB PRACTICE 1

GENERAL LAB PRACTICE

GENERAL LAB PRACTICE 2

GENERAL LAB PRACTICE 3

4 5 6 GENERAL LAB PRACTICE Never carry out unauthorized experiments Come to the lab prepared Follow directives strictly 5 6

MICROSCOPE CARE

PICK UP Always carry the microscope with 2 hands…..one on the arm and the other under the base in an upright position

SET UP Place the microscope at least 6 inches from the edge of your laboratory table (or flat surface). 6 inches

SET UP Don’t bang the microscope Clean only with a soft cloth/ tissue (preferably with a lens paper)

SET UP Do not tamper with or remove any part.

SET UP Do not handle the lenses with your fingers.

SET UP Do not allow liquids, particularly acids and alcohol, to come into contact with any part of the microscope

SET UP Always use a cover glass when examining objects or organisms mounted in water or other fluids.

SET UP Always lower the stage sufficiently before placing a slide on or removing a slide from the microscope stage.

PACK UP Remove immersion oil from the microscope with lens paper

PACK UP When disconnecting the light source, do not pull on the wire, but grasp the plug firmly to remove it from the socket.

PACK UP After use, wrap the wire around its base; send it back to the place of storage and cover it with its protective case.

Microscope Anatomy & Physiology Head Body

OCULAR (EYEPIECE) Uppermost series of lenses. Magnifies the image of the specimen

INTERPUPILLARY ADJUSTMENT In-between the ocular lenses Facial adjustment.

BODY TUBE (BARREL) Main cylindrical part Holds oculars, conducts light rays from specimen.

REVOLVING NOSEPIECE Movable, usually circular plate at bottom of body tube. Holds objectives in place.

SCANNING OBJECTIVE Shortest objective, usually magnifies 4x. Magnifies the specimen. Resolves the specimen

LOW POWER OBJECTIVE Short intermediate- sized objective, usually magnifies 10X. Magnifies the specimen. Resolves the specimen

HIGH POWER OBJECTIVE Long intermediate sized objective, usually magnifies 40x. Magnifies the specimen. Resolves the specimen

OIL IMMERSION OBJECTIVE Longest objective, usually magnifies 100X Magnifies the object. Resolves the specimen

PROPERTIES OF THE OBJECTIVE LENSES Parfocal Alignment of all objectives along the same focal plane

MECHANICAL STAGE Platform upon which specimens for examinations are placed. Specimen support and manipulation.

STAGE CLIPS & SLIDE HOLDER Located on top of the stage Control devices which permit movement of slide. Manipulation of specimen’s location.

APERTURE Hole in the centre of the stage. Opening in the condenser unit. Allows light penetrations through the specimen.

CONDENSER Lens system located below central stage opening. Concentrates and directs light beam through specimen.

CONDENSER

COMPLEX SYSTEM OF LENSES

IRIS DIAPHRAGM Located beneath stage in association with condenser unit, controlled with a lever. Regulates brightness or intensity of light passing through lenses. Field and Aperture diaphragm.

COARSE ADJUSTMENT KNOB Generally located below stage. Use for preliminary and coarse focusing by raising or lowering the stage.

FINE ADJUSTMENT KNOB Located below stage, usually at the centre of the coarse adjustment knob. Used for final or fine focussing by raising or lowering the stage

CONDENSER ADJUSTMENT KNOB Control knob located below stage Used to obtain full illumination by raising or lowering condenser.

STAGE ADJUSTMENT KNOB Located below the stage Used to manoeuvre the specimen (stage) sideways and back to front.

BASE Heavy, bottom portion on which instrument rests. Microscope support.

ARM Somewhat curved portion of microscope used in carrying instrument. Microscope support.

LIGHT SOURCE Situated at the base, directly beneath the condenser unit. Diascopic (from below). Emits light rays through the specimen to produce an image.

LIGHT INTENSITY CONTROL Located at the base. Regulates the intensity of light.

ON/OFF SWITCH On the side of the base. Turns light source on or off.

COMMON VOCABULARY OF THE MICROSCOPE Magnification Resolution Contrast Image size Image details Image distinction

TOTAL MAGNIFICATION Total magnification 10 x 4 = 40 10 x 10 = 100 Ocular power multiplied by objective power Total magnification 10 x 4 = 40 10 x 10 = 100 10 x 40 = 400 10 x 100 = 1000 Ocular = 10x Scanning = 4x Low = 10x High = 40x Oil = 100x

FOCUSSING THE MICROSCOPE

FOCUSSING THE MICROSCOPE Wipe all lenses with lens paper. Move the scanning objective into working position. Connect your light source and turn it on.

FOCUSSING THE MICROSCOPE Mount your specimen slide on the mechanical stage. Using the stage control knobs, move the specimen to the centre of the condenser opening in the stage. Using the coarse adjustment knob, raise the stage to the upmost limit.

FOCUSSING THE MICROSCOPE Using the condenser adjustment knob, raise the condenser as far as it will go. While looking into the ocular, use the diaphragm lever to regulate illumination. Locate your specimen. Using the coarse and fine adjustment knob, move the stage downward to focus.

FOCUSSING THE MICROSCOPE To change objectives, simply turn the nosepiece to bring the desired objective into place. ie. PARFOCAL Observe with both eyes.

AFTER USING THE MICROSCOPE After use, the ff. steps should be performed: Remove any slide from the stage. Clean the instrument to remove any fluid from specimens. Open the diaphragm. Raise the condenser to its highest position. Move the scanning objective into working position. Wrap the electrical cord around the base. Return the microscope to its proper storage place. Cover it.

MICROSCOPIC TECHNIQUES Use depth of field and/ or depth of focus to highlight features. Use the diaphragm to improve upon image quality. Use the stage calibrations for quick re- focusing.

THANK YOU!!!