Vacuum infiltration is used for various tissue types; which pairing is correct?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Vacuum infiltration hinges on how easily embedding medium can penetrate tissue spaces that vary in porosity. Spongy tissues have lots of air-filled or open spaces, so air pockets can block infiltration; using vacuum removes that air and lets resin or paraffin flow into these spaces, preserving structures like alveolar walls in the lung and the intervillous spaces in the placenta. Dense tissues are compact, with little interstitial air, so the infiltrant must be forced into tight gaps between cells and fibers; vacuum helps drive the medium into these small spaces. Fatty tissue, such as breast, is made up of large lipid-filled cells with surrounding connective tissue, which can trap air pockets and create uneven infiltration unless air is removed and the medium is driven through. Cellular tissues like spleen and lymph nodes are highly cellular with narrow intercellular channels, so vacuum ensures the infiltrant penetrates those small spaces evenly.

This combination matches how the porosity and architecture of each tissue type affect infiltration, making that pairing the best fit. Other options mix tissue types whose structural characteristics don’t align as well with the needs of vacuum infiltration.