Microscope

Parfocal lenses

- objective lenses constructed and mounted so that their focal planes are approximately the same: a specimen remains in focus and centered in the field of view when you chage from on parfocal lens to another.

Light - Fluorescent light microscope

For immuno-fluorescent antibody technique

Longer wavelengths of light offer less resolution than short wavelength illumination. Shorter is better. THE BEST EXAMPLE IS Near-ultraviolet light has the shortest usable wavelength and offers the greatest resolution.

Longer wavelengths of light offer less resolution than short wavelength illumination. Shorter is better. THE BEST EXAMPLE IS Near-ultraviolet light has the shortest usable wavelength and offers the greatest resolution.

numerical aperture and light wavelength

Microscope resolution is the most important determinant of how well a microscope will perform and is determined -----

Light - Differential Interference Contrast

Provide 3d image; use diffracted ray seperated by prism. No staining, look color bc of prisms.

Resolving power

The ability to distinguish details of a specimen

Magnification

The amount the specimen is enlarged

Field of view

The area of the slide that can be seen through the microscope

Working Distance

The distance between the top of the coverslip and the low power objective lens (25mm, 8.3, 0.5 mm for 4x 10x and 40x respectively)

Light - Dark field microscope/

The type of microscope that examines living micro-organisms that are invisible in brightfield microscopy, do not stain easily, or become distorted b/c of staining. Frequent use in diagnosis of T.Pallidum (for syphilis disease). organism is light on dark background.

Light- bright field microscope

The type of microscope that observes various specimens or to count microbes but does not resolve small specimens like virus; have bright field to view stain easily

Depth of Focus

The vertical distance the specimen is in focus

Electron- transmission microscope

To examine viruses or ultrastructure (inner structure) of thin cell section (100000X) ; use beam of electron which have shorter wavelength and it PASS THROUGH the specimen

Electron- Scanning miscrope

To study SURFACE features of cell and virus (100000x); use beam of electron that REFLECT from specimen

Total Magnification = Ocular x Objective low power = 10 x 10 = 100X high power = 10 x 45 = 450X *oil immersion = 10 x 100 = 1000X

Total Magnification =

CONFOCAL microscope

Use laser to obtain 2d and 3d images.

Refractive index

a measure of how greatly a substance slows the velocity of light direction and magnitude of bending is determined by the ------ of the two media forming the interface

rheostat

dimmer to change the amount of light that shines on the specimen.

40x

high dry magnification

Refractive index of oil immersion field

light-bending ability of a medium The light may bend in air so much that it misses the small high-magnification lens.

XYLENE AND TOLUENE. Carcinogenic and readily absorped through skin; linked with liver damage and cancer.

oil immerse material

A parfocal lens is a lens that stays in focus when magnification/focal length is changed. There is inevitably some amount of focus error, but small enough to be considered insignificant.

parfocal lens

Scanned-probed: atomic force

provide image of biological molecule in atomic details and molecular processes; use metal and diamond probe. Looks pretty

Scanned-probed : Scanning Tunneling

provides detailed view of MOLECULES INSIDE THE CELL. Use a metal probe and scan the bumps and depression of atoms. RIDICULOUS RESOLVING POWER.

shorter

the higher the resolution the ---- the wavelength

Ocular lens magnification is 10X.

the lens in the eyepiece What magnification?

Magnification is: low power - 10X high power - 40X or 45X oil immersion - 100X

the lens in the nosepiece What magnification

Retinal image

this image is formed by the rays of light striking the retina of your eye.

Virtual image

this is the image that you actually see when you look through the objective lens. It appears both larger and farther away than the specimen on the stage.

1. Use the rheostat (dimmer) to change the amount of light that shines on the specimen. 2. The iris diaphragm can be adjusted so that the opening is larger or smaller, thus allowing in more light. 3. The condenser may be lowered or raised to allow more light to be focused on the specimen.

to change light through

to improve the microscope resolution

to improve the microscope resolution 1) pick better wavelength = shorter the better 2) increase the refractive index which makes speed of light slower and decrease wavelength

Oil immersion microscopy

to view bacteria and protist

Light - Phase-contrast

use a special condenser containing ring-shaped diaphragm (annular diaphragm), does not need staining; use info from direct and diffracted ray. Help examine internal structure of specimen.