Histology Certification Microscopy Techniques 2

Question 1

What is the primary advantage of phase contrast microscopy over bright-field microscopy when viewing unstained cells?

Accepted Answer

It converts phase differences into amplitude differences, enhancing contrast

Answer

Phase contrast microscopy converts subtle differences in refractive index into visible contrast differences, allowing unstained living cells to be visualized clearly.

Question 2

In confocal laser scanning microscopy, what is the purpose of the pinhole aperture?

Accepted Answer

To exclude out-of-focus light and improve axial resolution

Answer

The pinhole aperture in confocal microscopy blocks out-of-focus fluorescent light, enabling optical sectioning and high-resolution 3D reconstruction.

Question 3

Which type of objective lens provides the highest numerical aperture and requires immersion oil?

Accepted Answer

100x oil immersion

Answer

The 100x oil immersion objective achieves numerical apertures up to 1.4 by using immersion oil that matches the refractive index of glass, maximizing light collection.

Question 4

What does the term 'parfocal' mean in the context of microscope objectives?

Accepted Answer

Objectives remain approximately in focus when switching between them

Answer

Parfocal objectives require only minor refocusing when switching magnifications because they are designed to maintain approximately the same focal plane.

Question 5

In transmission electron microscopy (TEM), what is the function of the objective aperture?

Accepted Answer

To improve contrast by blocking scattered electrons

Answer

The objective aperture in TEM blocks highly scattered electrons, improving image contrast by allowing only minimally scattered electrons to contribute to the final image.

Histology Certification Practice Test

Histology Certification Practice Test

Histology Certification Microscopy Techniques 2