PRACTICAL ROADMAP

CONNECTIVE TISSUE PROPER

A. JOVANOVIĆ

Cells

Extracellular matrix which includes:

Fibers and

Ground substance

Connective tissue’s main constituents

Classification of connective tissue proper

CONNECTIVE TISSUE PROPER

Loose or Areolar Connective Tissue

Dense Connective Tissue

Dense regular Connective Tissue

Dense Irregular Connective Tissue

• Slides: 120 – 1, 120 – 2, 120 – 3

Loose (areolar) connective tissue – Mesentery spread

Stain: Haematoxylin, acid fuchsin and elastic stain

This is a whole mount spread of mesenchymal tissue. It consists of a sheet of loose connective tissue with simple squamous epithelium - mesothelium on each side and a thin “filling” of loose connective tissue in between them. Look at the schematic drawing of the mesentery available in your histology practical manual in order to understand the “sandwich” concept!

Mesentery spread Slide: 120 - 3

In the following slide it will be difficult to distinguish between mesothelial cells and fibroblasts. Fibroblasts generally have more flattened nuclei while mesothelial cells have faded, oval nuclei (you will see mesothelial cells faded, as you will be looking through the loose areolar connective tissue which is a “filling inside a sandwich”.

Elastic fiber

Mast cell

Ground substance

Capillary

Fibroblast nucleus

Mesothelial cell nucleus

Slide: 120 - 2 Macrophages with ink inclusions

Elastic fiber Collagen fiber

Slide: 122 Non lactating mammary gland Dense irregular connective tissue

Mammary gland ducts

Adipose tissue Dense irregular connective tissue

Elastic fibres cannot be distinguished with H and E. See slide 28 where aorta was stained with elastic stain.

Adipose tissue

Randomly arranged

collagen fibres

Fibroblast nucleus situated on the edge of

the collagen fibres

Mammary gland duct

Small arteriole

Capillaries

Fibroblast nucleus

Randomly arranged collagen fibers

Randomly arranged collagen fibers

Ground substance

Randomly arranged collagen

fibers

Fibroblast nucleus

Slide: 50 Musculo-tendinous junction (H and E) Tendon - Dense regular connective tissue

Tendon (Dense regular

connective tissue)

Muscle (Striated skeletal

muscle)

Note the difference in fibre density, ground substance and cellularity seen in the basic three types of connective tissue proper. These criteria are used to classify the type of connective tissue.

Regular arrangement of collagen fibers

Ground substance Fibroblast nucleus

Note the junction (dashed line) between the tendon on the left and the muscle on the right. Note the single direction and regular organisation of the collagen fibres of the tendon. The fibroblast nuclei are arranged along the edge of the collagen fibres within the very restricted ground substance.

Slide: 28 Aorta (Elastic stain) Elastic tissue The inset shows the wall of a aorta which has been stained with elastic stain for visualization of elastic fibres.

The wall of the aorta is made up of numerous dark staining, wavy elastic fibres. In between the elastic fibres are smooth muscle cells (not visible in the tissue stained with elastic stain) which produce and maintain the elastic fibres.

Elastic fiber Smooth muscle

Slide: 25 Liver (Silver impregnation method) Reticular tissue

Liver parenchyma Portal tract

The majority of the tissue is stained light brown with silver stain and represents the hepatocytes (liver cells) organized in cords. The reticular fibres are seen as a dark brown meshwork surrounding and supporting the hepatocytes

Hepatocytes

Reticular fibres