Anatomy is the science of the structure of the normal human body. It can be divided into that which is visible to the naked eye - Gross Anatomy - and that which can be seen only with the aid of a microscope - Microanatomy. The latter can be further divided into Histology - the study of tissues - and Cytology - the study of cells. Microanatomy is a visual discipline, combining observation with reasoning.

Several types of microscope are available for the study of biological material. In most general use is the light microscope using visible light as the light source. Chemically stained sections are examined under the light microscope in order to discern the basic organisation of cells and tissues. Less often used is the transmission electron microscope in which the source of illumination is a beam of high velocity electrons accelerated in a vacuum. The resolving power of the electron microscope is much greater than that of the light microscope and it is thus used to provide information on tissue ultrastructure, or organisation at the subcellular level. In microanatomy practical classes we will be concentrating on the light microscopical appearances of cells and tissues but will see occasional electron micrographs when appropriate.

So why do we need to study microanatomy?

There are three main reasons for this:
Firstly, it complements the study of gross anatomy. It is important to relate what you see in the Dissecting Room at the whole-body or topographical level to what you learn during microanatomy.

Secondly, it provides a structural basis for understanding normal tissue function ie. Physiology. Correlation between structure and function is essential and forms the basis of much of medicine. You will find that if you know about the structure of a tissue or organ you can deduce much about its function. Conversely, if you know about the function of a tissue you can predict what its structure might be.

Thirdly, a knowledge of normal structure and function is a prerequisite for understanding disordered structure and function ie. Pathology.

Primary tissue types

• Epithelium covers surfaces and cavities. It also has secretory and absorptive functions
• Connective tissue forms the supporting framework for epithelia. Cartilage, bones, joints and even blood are specialised connective tissues
• Muscular tissue moves the skeleton, heart and walls of the cardiovascular, gastrointestinal and urogenital systems
• Nervous tissue is derived from embryonic epithelium and retains some epithelial characteristics. It is responsible for the co-ordinated contraction of muscle

Confused?

We will try over the next few weeks to make all of these terms fit into place. But remember, integration of knowledge obtained in the different parts of the course is vital to successfully negotiating this new integrated curriculum. Microanatomy lies at the heart of it all!