Histology techniques involve permanently mounting tissue specimens on slides for microscopic examination. There are two main types of mounting media: resinous and aqueous. Resinous media are hydrophobic and adhesive, using solvents like benzene to harden. They are most commonly used. Aqueous media are hydrophilic and non-adhesive, using water-based solutions. When preparing slides, mounting media is applied before lowering a coverslip onto the specimen to avoid bubbles and allowing it to harden under warmth. Permanent mounting preserves tissue samples for long-term examination.

1. HISTOLOGY TECHNIQUES
PERMANENT MOUNTING
BY
SYEDA SADAFWAJAHAT

2. introduction
❖Histology also known as “Microanatomy” is
the study of cells, tissues and organs under
the microscope (Light microscope or
Electron microscope).
❖It is related to Cell biology (Cytology),
Anatomy, Physiology and Pathology.

4. Types of tissueS

5. Types of tissueS

6. SOURCES OF SPECIMEN
❖Specimens received for histological
examination may come from a number of
different sources.
1. Excision specimens (surgical biopsies),
where whole organs or affected areas are
removed at operation.

7. 2. Incisional biopsy specimens, where tissue is
removed for diagnosis from within an affected
area.
3. Punch biopsies, where punches are used to
remove a small piece of suspicious tissue for
examination (often from the skin).

8. 4. Shave biopsies, where small fragments of
tissue are “shaved” from a surface (usually skin)
5. Curetting, where tissue is removed in small
pieces from the lining of the uterus or cervix .
6. Core biopsies, where a small tissue sample is
removed using a special needle sometimes
through the skin (percutaneously).

9. PERMANENT MOUNTING
❖In histology or a pathology, mounting is the
last procedure in the series that ends with a
permanent histological preparation on the
table, well after the tissue processing and
staining.

10. PROCEDURE

12. PROPERTIES OF AN IDEAL
MOUNTING MEDIA
❖Refractive index (RI) should be as close as
possible to that of glass, i.e., 1.5.
❖ It should be colorless and transparent.
❖It should be dry to a non-stick consistency
and harden relatively quickly.

13. ❖It should be able to completely permeate
and fill tissue interstices.
❖It should have no adverse effect on tissue
components.
❖It should be resistant to contamination.

14. CLASSIFICATION OF
MOUNTING MEDIA
❖There are two types of mounting medium.
1. Resinous media (hydrophobic/adhesive).
2. Aqueous media (hydrophilic/non-adhesive).

15. 1. Resinous MEDIA
(hydrophobic/adhesive)
❖These are natural or synthetic resins
dissolved in benzene, toluene or xylene.
❖Used when a permanent mount is required.

16. ❖Adhesives harden through solvent
evaporation and thereby fix the
accompanying coverslip to the slide.
❖Resinous mountants are the type most
frequently used.
❖It is further divided into

17. 1. Natural resinous media like Candida
Balsam, Phenol Balsam and Dammar
Balsam.
2. Synthetic resinous media like DPX
(dibutyl phthalate and xylene), Permount
and Histamount.

19. 2.AQUEOUS MEDIA
(HYDROPHILIC/NON-
ADHESIVE)
❖Aqueous media are used for mounting
sections from distilled water when the stains
would be removed by alcohol and xylene.
❖These media are of three types: The syrups,
Gelatin media and Gum Arabic media.

20. ❖Aqueous mounting media require the
addition of bacteriostatic agents such as
phenol or crystal of thymol to prevent the
growth of fungi.
❖Examples are Water, Glycerine jelly,
Glycerine-Glycerol and Polyvinyl alcohol.

21. ❖There are many commercial mounting media
which are available for mounting sections from
water.

22. PREPARING PERMANENTLY
MOUNTED SECTIONS
❖Place 2-3 drops of resin (mounting media)
over the section.
❖To avoid entrapping air bubbles, lower the
cover slip slowly from one side of the droplet.

23. ❖Place the slide on the slide warmer and
carefully place a lead weight on top of the
coverslip.
❖Leave slides on the warmer
for at least 24 hours.

24. ❖Observe the tissue section under the
microscope.

25. CONCLUSION
❖To conclude various commercial
manufacturers have various mounting
media. You should select a mounting media
that suits the viewing and preserving the
required sections for further research.