What is the fundamental principle behind the disector counting rule for estimating the number of particles?
Consider the comparison between two parallel planes separated by a known distance.
Why is counting 2D profiles per unit area (NA) considered a ‘naive’ and incorrect method for estimating the number of 3D objects?
Consider how the size of an object affects the likelihood of it being cut by a scalpel.
When using an optical disector, what equipment is essential for accurately measuring the distance travelled along the z-axis?
This device is used to verify the height h of the 3D scan.
What geometric property of the particles is generally required for the simplified application of the optical disector?
Think about how easy it is to define a single ‘vertex’ for each object.
Why is the use of high numerical aperture (NA) objectives, such as ×60 or ×100 oil immersion objectives, crucial for the optical dissector?
Consider the relationship between the numerical aperture and the thickness of the ‘slice’ of space that is in focus at a given instant t.
With regard to the unbiased counting frame, how is a profile that touches the ‘forbidden line’ handled?
This rule ensures that each object in a frame mosaic is counted only once.
What is the main practical difficulty encountered when implementing a physical disector compared with an optical disector?
Consider the time it takes for two images from different sections to align perfectly.
When using an optical dissector on a thick section, why is it advisable to ignore the first few micrometres of the section’s surface?
Consider the physical condition of the tissue immediately after it has passed through the microtome blade.
How does the ‘fractionator’ manage to estimate the total number of objects without needing to know the reference volume or the tissue retraction?
Think about what happens to a slice of cake if the whole cake shrinks in the oven.
What is the correct definition of a ‘transect’ according to the terminology used in the chapter?
This is what you actually see under a microscope when you look at a tissue section.
