What is Histology ?
Histology is the scientific study of the fine detail of biological cells and tissues using microscopes to look at specimens of tissues that have been carefully prepared using special processes.
It is a discipline that is essential for the understanding and advancement of biology, medicine, veterinary medicine and many sub-disciplines within those scientific subjects.
Uses of Histology
- Education – Histology slides are often used in teaching laboratories to help students learn about the microstructures of human (and animal) biological tissues.
- Diagnosis for treatment – Biological tissue samples taken from a patient (human or pet) may be studied in detail to enable medical or veterinary experts to learn more about the patient’s condition and hence perhaps understand its causes and make recommendations for treatment or management of the condition.
- Forensic investigations – Forensic histology, immunohistochemistry and cytology involving microscopic study of biological tissues using various stains can help clarify the cause of sudden unexpected deaths and other issues in forensic science.
- Autopsy – Biological tissues from a deceased person or animal can be studied using histological techniques enabling experts to learn about the circumstances and possibly cause of death.
- Archaeology – Study of biological cells and tissues recovered from archaeological sites can provide information about history, even ancient history. The state of preservation of the biological material is critical and sometimes sufficient e.g. for bone histology and dental histology.
Who does what?
Biomedical Scientists are people which have and use the special skills necessary to process samples of biological tissue in histology laboratories. They undergo training set out by the Health and Care Professions council (HCPC) and the Institute of Biomedical Scientists.
Histopathologists are medical experts trained in interpreting tissue at the microscopic level and are governed by the General Medical Council and the Royal college of Pathologists.
Tissue obtained from the patient is processed using a series of techniques to prepare thin sections of the tissue samples mounted onto glass slides and stained with chemicals. The initial stain carried out is a Haematoxylin and Eosin which stains the nuclei blue and all other structures different shades of pink. this allows the histopathologists to ascertain if the tissue is normal or diseased and if required can request extra staining on new sections of the tissue to highlight features which aid in the diagnoses.
Images below: Grocott; fungi spores are stained with silver which gives them a black colour, Haematoxylin and Eosin; standard stain on kidney tissue, ZN; this stain highlights TB bacteria red, Immumnohistochemistry for CD20; hihglights B-lympocytes