Histological Techniquies

Histology 2016-2017
Department of Anatomy &Histology: Dr.Rajaa Ali
*************************************************************
HISTOLOGICAL TECHNIQUES

INTRODUCTION:
Before we study the various histological techniques, let us quickly familiarise ourselves with the basics of histology.
The term Histology is derived from the Greek words, histos, meaning “web” (tissue) and logos meaning “the study of”.
Today the term histology is used not only for the study of tissue alone but also for the study of cells and fi ne structure of organs and can collectively be called microscopic anatomy. The study of histology provides a structural basis for functional correlation of an organ or tissue and is a necessary prerequisite to the study of the abnormal tissue (pathology).

GENERAL ARCHITECTURE OF THE BODY
Cells are the functional and building units of all living organisms and are held together b _ y intercellular junctions and m atrix.
_ In multicellular organisms, tissues are collections of specialised cells with associated intercellular matrix for performing specifi c functions.
_ There are four basic types of tissues in the body and each one performs a specifi c function:
1. Epithelial tissue – protection
2. Connective tissue – support
3. Muscular tissue – contraction
4. Nervous tissue – conduction
Thus the tissues form building blocks of the organs (e.g. kidney, liver, ovary) and they constitute the various functional systems of the body (e.g. digestive system, urinary system, reproductive system, etc.).
? Cells
? Tissues
? Organs
? Systems
? Body



UNITS OF MEASUREMENT USED IN HISTOLOGY:
For Light Microscopy
_ The term micrometer (?m) is being used nowadays instead of micron (?).
_ 1 micrometer or micron = 0.001 mm or 10–6 m.
For Electron Microscopy
_ The term nanometer (nm) is being used nowadays instead of angstrom (A°).
_ 1 nanometer = 0.001 (?m or 10–9 m.
_ 1 angstrom = 0.1 nm or 10–10 m.