Introduction

All body parts are made up of four basic tissues:

• Epithelial tissue
• Connective tissue
• Muscle
• Nervous tissue

The properties of these four basic tissue types are covered in the topic on 'tissue types'.

Tissues are made up of

• cells
• extracellular (outside cells) matrix
• body fluids

The basic properties of cells is covered in the topic 'cells'.

The extracellular material, or matrix is made by cells in the matrix. Some extracellular material is very strong, such as bone. Extracellular matrix is covered in the topic on tissue types 'extracellular matrix'.

Body fluids are made up of blood, interstitial fluid and lymph. You can find out more about blood in the topic 'blood'. You can find out more about interstitial fluid and lymph in the topic 'lymphoid tissues'.

Histological methods are used to study the detailed structures of tissues.

Most cells are colourless and transparent, and therefore histological sections have to be stained in some way to make the cells visible. The techniques used may either be non-specific, staining most fo the cells in much the same way, or specific, selectively staining particular chemical groupings or molecules within cells or tissues.

See the topic 'How to make histological sections' to find out how histological sections are made, and cells can be stained.