GENERAL HISTOLOGY

Detailed explanation-1: -Samples destined for the SEM aren’t cut into thin sections, because the SEM visualises the surface of three-dimensional objects. Instead, SEM samples are coated with a thin layer of metal (usually gold or gold-palladium). The metal coating makes samples conductive.

Detailed explanation-2: -Due to the requirement for transmitted electrons, TEM samples must be very thin (generally less than 150 nm) and in cases that high-resolution imaging is required, even below 30 nm, whereas for SEM imaging, there is no such specific requirement.

Detailed explanation-3: -Due to their high conductivity, coating materials can increase the signal-to-noise ratio during SEM imaging and therefore produce better quality images.

Detailed explanation-4: -Because electrons cannot pass through glass, the lenses that are used are electromagnetic. They simply consist of coils of wires inside metal pole pieces. When current passes through the coils, a magnetic field is generated.