Covers how to recognise a placenta slide stained with H&E, starting with the staining colours and the exchange role of the organ. It then goes through the features to look for: chorionic villi with fetal capillaries in a connective tissue core, maternal blood in the intervillous space, and the trophoblast layers. It also notes late-pregnancy changes such as syncytial knots, fibrinoid and decidual cells.
Inside: 1 section · 1 min
Topic 126 of 127 in the MU Sofia syllabus for Cytology (Dental Medicine, Year 1). The free AceMed note covers it in 1 section, about 111 words (1 min of reading).
In this note
Introduction
Introduction
The placenta is where fetal and maternal blood exchange substances without mixing.
Stain
H&E: cytoplasm pink, nuclei blue-purple, red blood cells red.
How to recognise it
Many round or oval sections of chorionic villi.
Maternal blood in the intervillous space around the villi.
Each villus has a connective tissue core with fetal capillaries containing fetal blood cells.
The villi are covered by trophoblast: an outer syncytiotrophoblast (dark, many nuclei, no cell borders) and, mainly early in pregnancy, an inner layer of single cytotrophoblast cells.
In late pregnancy: clumps of syncytial nuclei (syncytial knots), and pink fibrinoid. Large pale decidual cells lie on the maternal side.
Theory: topics 79–80 (fetal membranes, placenta).
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