THE MICROSCOPE AND ITS PARTS AND FUNCTIONS

The three structural parts of the microscope

The three structural parts of the microscope

• Head

• Base

• Arm

Head

- carries the optical parts in the upper part of the microscope

Base

- acts as the microscope's support; it also carries the microscopic illuminators

Arms

- connects the base to the head and the eyepiece tube to the base of the microscope; it gives support to the head and used when carrying the microscope

Eyepiece or oculars

is the part of the microscope that magnifies the image produced by the microscope's objective so that it can be seen by the human eye.

Eyepiece rubbers

prevents scratching of lens by the user's eyeglass or vice versa

Numbers on the eyepiece

– for differences in eye grading especially for those wearing prescription glasses

Interpupillary control

– used to adjust the lateral separation of the oculars for everyone

Revolving nosepiece

- holds two or more objective lenses and can be rotated to easily change power

Knob/screw at the back of the microscope

- controls the height limit of the stage to prevent breakage of glass slides

Inner knob before the coarse adjustment knob

• Also known as the coarse tension adjustment knob

• Prevents the stage from going down and losing focus on the specimen

Numbers on the objectives

- refers to the thickness of the coverslip to be used; coverslip to be used must be compatible with the objective to be used for microscopic examination

Aperture

– a hole on the microscope stage through which the transmitted light from the source reaches the stage

Objective Lenses

magnifies the image, also it has several objective lenses that the user can rotate to view the object at varying levels, or “powers,” of magnification.

Mechanical stage

- the place where you put the slide

Stage numbers

determines the positioning of the cells under the microscope; provides the coordinates or location of important cell

Stage clip

hold the slides in place

Condenser

- is used to collect and focus the light from the illuminator on to the specimen. It is located under the stage often in conjunction with an iris diaphragm

Condenser numbers

– must be the same with the magnification of the objective for better viewing of the specimen details

Condenser Knob

moves the condenser up or down to control the light focus on the specimen

Iris Diaphragm

- controls and adjust the amount of light reaching the specimen through the condenser.

Coarse adjustment knob

A rapid control which allows for quick focusing by moving the objective lens or stage up and down.

Coarse adjustment knob

- a knob that are used in scanning and low power lenses

Fine adjustment knob

A slow but precise control used to fine focus the image when viewing at the higher magnifications.

Fine adjustment knob

- a knob that are used in high power and oil immersion

Brightness adjustment knob/ Microscopic illuminator

- adjust the brightness

Types of Objective Lenses

• Scanning

• Low power

• High Power

• Oil Power

Total Magnification of Scanning

40x

Total Magnification of Low power

100x

Total Magnification of High power

400x

Total Magnification of Oil Immersion

1000x

FN20

- refers to the number field/ diameter of the immersion in mm.

Scanning Objective

Function: It provides a low level of magnification to quickly scan and locate the specimen on the slide. It is often used for initial examination and to find areas of interest.

Low Power Objective

Function: It is used for a more detailed examination of the specimen after it has been located with the scanning objective. It provides a higher level of magnification for a closer look at the overall structure of the specimen

High Power Objective

Function: It provides even greater magnification for a detailed examination of specific structures within the specimen. It is commonly used for a more in-depth analysis of cellular or microstructural details.

Function: It is used for the highest level of magnification and resolution. To achieve this, a drop of immersion oil is placed between the objective lens and the specimen. This oil has a refractive index similar to that of glass, reducing light refraction and improving image quality. It is typically used for fine details, such as observing bacteria or studying intricate cellular structures.