CONNECTIVE TISSUE This resource is licensed under the Creative Commons Attribution Non-Commercial & No Derivative Works License

Objective The main objective is to identify different types of connective tissue cells, protein fibres and connective tissue types that provide unique properties to different tissue varieties.

SLIDE 118 Areolar connective tissue Slide as seen at lowest magnification. Areolar or Loose connective tissue. 1.0 mm

SLIDE 118 Areolar connective tissue Slide as seen at lowest magnification. Areolar or Loose connective tissue. 1.0 mm

SLIDE 118 Areolar connective tissue Area from slide as seen with x4 objective lens. Identify areas of adipose cells, blood vessels and fibroblasts with collagen fibre matrix. 250 µm

SLIDE 118 Areolar connective tissue Area from slide as seen with x4 objective lens. Identify areas of adipose cells, blood vessels and fibroblasts with collagen fibre matrix. connective tissue with fibroblasts and collagen C C : capillaries and small blood vessels C adipose cells 250 µm

SLIDE 118 Areolar connective tissue Area from slide as seen with x4 objective lens. Identify areas of adipose cells, blood vessels and fibroblasts with collagen fibre matrix. connective tissue with fibroblasts and collagen C C : capillaries and small blood vessels C adipose cells 250 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Adipose cells Red and white blood cells Fibroblasts Macrophages Mast cells 50 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Adipose cells Red and white blood cells Fibroblasts Macrophages Mast cells adipose cells 50 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Adipose cells Red and white blood cells Fibroblasts see next picture Macrophages see slide 144 Mast cells follows slide 144 white blood cells (dark stained nuclei) red blood cells adipose cells 50 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Fibroblasts Fibrocytes 25 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Fibroblasts : usually spindle shaped cells, the most representative cell type in Fibrocytes : connective tissue. Inactive fibroblasts termed fibrocytes. fibroblasts 25 µm

SLIDE 118 Areolar connective tissue Try to identify the following cell types: Fibroblasts : usually spindle shaped cells, the most representative cell type in Fibrocytes : connective tissue. Inactive fibroblasts termed fibrocytes. fibrocytes fibroblasts 25 µm

SLIDE 144 Macrophages in spleen (mouse) The tissue on this slide has been injected with carbon particles to label macrophages. You should only observe the macrophages in this section and do not worry about other structures at this stage. Canine Abdomen D S L Sp D : Diaphragm L : Liver S : Stomach Sp : Spleen 25 µm

SLIDE 144 Macrophages in spleen (mouse) The tissue on this slide has been injected with carbon particles to label macrophages. You should only observe the macrophages in this section and do not worry about other structures at this stage. Why do these black macrophages show such variability in cell shape and size? macrophages 25 µm

SLIDE 144 Macrophages in spleen (mouse) The tissue on this slide has been injected with carbon particles to label macrophages. You should only observe the macrophages in this section and do not worry about other structures at this stage. Why do these black macrophages show such variability in cell shape and size? When actively phagocytic, these cells increase in size, their pseudopodia giving them an irregular shape. macrophages 25 µm

DEMONSTRATION SLIDE for Mast cells In this slide mast cells are stained with toluidine blue. The cytoplasm of mast cells is granular, but does not stain in normal H&E sections. The granules will stain metachromatically with stains such as toluidine blue used here. 25 µm

SLIDE 58 Stained spread preparation This slide is not sectioned material, but is a thin spread of tissue stained on the slide. What sort of connective tissue is it? 0.5 mm

SLIDE 58 Stained spread preparation This slide is not sectioned material, but is a thin spread of tissue stained on the slide. What sort of connective tissue is it? Loose connective tissue also called areolar tissue. 0.5 mm

SLIDE 58 Stained spread preparation Areolar connective tissue. You should see two types of protein fibres in this preparation. Which one of these is thinner and branched compared with lighter staining thicker wavy fibres? 100 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. You should see two types of protein fibres in this preparation. Which one of these is thinner and branched compared with lighter staining thicker wavy fibres? Thinner branching elastic fibres and lightly staining wavy collagen fibres. E : elastic fibres C E C : collagen fibres capillary 100 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. What holds these protein fibres and cells together in this preparation? 50 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. What holds these protein fibres and cells together in this preparation? Ground substance, an amorphous gel filling the spaces between cells, fibres and vessels mainly glycoproteins and proteoglycans. A A capillary A : adipocytes A 50 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. How did you distinguish the blood capillaries from the protein fibres? 25 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. How did you distinguish the blood capillaries from the protein fibres? The capillaries are cellular, the endothelial cells forming the walls are visible as are often the circulating red and white blood cells. C C C : capillaries F adipocytes F : fibroblasts C 25 µm

SLIDE 58 Stained spread preparation Areolar connective tissue. How did you distinguish the blood capillaries from the protein fibres? The capillaries are cellular, the endothelial cells forming the walls are visible as are often the circulating red and white blood cells. The protein fibres are generally thinner and acellular. C C C : capillaries F adipocytes F : fibroblasts C 25 µm

SLIDE 116 Subcutaneous tissue (subcutis) What sort of connective tissue is it? 1.0 mm

SLIDE 116 Subcutaneous tissue (subcutis) What sort of connective tissue is it? Subcutaneous connective tissue is another example of loose connective tissue. This section also contains large clusters of purple staining lymphoid tissue. areas of adipocytes lymphoid tissue 1.0 mm

SLIDE 116 Subcutaneous tissue Section showing a large cluster of purple staining lymphoid tissue. protein fibres and cells adipocytes lymphoid tissue 250 µm

SLIDE 116 Subcutaneous tissue There is an abundance of protein fibres staining deep blue in this section. What sort of protein fibre is it and how is it arranged? 25 µm

SLIDE 116 Subcutaneous tissue There is an abundance of protein fibres staining deep blue in this section. What sort of protein fibre is it and how is it arranged? Bundles of type 1 collagen fibres running in many directions. What are the red cells? transverse bundles of collagen longitudinal bundles of collagen 25 µm

SLIDE 116 Subcutaneous tissue There is an abundance of protein fibres staining deep blue in this section. What sort of protein fibre is it and how is it arranged? Bundles of type 1 collagen fibres running in many directions. What are the red cells? Mostly fibroblasts but also macrophages and mast cells have stained purple/red. transverse bundles of collagen red/purple staining cells longitudinal bundles of collagen 25 µm

SLIDE 121 Tendon (Dense regular connective tissue) This section contains both the muscle and the tendon. What colour are the muscle cells? Equine Hindlimb La : Lateral Digital Extensor Muscle Belly & Tendon Lo : Long Digital Extensor Muscle Belly & Tendon 1.0 mm

SLIDE 121 Tendon (Dense regular connective tissue) This section contains both the muscle and the tendon. What colour are the muscle cells? Deep pink. tendon muscle 1.0 mm

SLIDE 121 Tendon (Dense regular connective tissue) What is the most abundant constituent of the tendon? 50 µm

SLIDE 121 Tendon (Dense regular connective tissue) What is the most abundant constituent of the tendon? Mainly thick collagenous fibres, collagen type 1. What is the orientation of protein fibres in the tendon? collagen bundles fibroblasts or tenocytes 50 µm

SLIDE 121 Tendon (Dense regular connective tissue) What is the most abundant constituent of the tendon? Mainly thick collagenous fibres, collagen type 1. What is the orientation of protein fibres in the tendon? Parallel bundles of closely packed collagen fibres. collagen bundles fibroblasts or tenocytes 50 µm

SLIDE 121 Tendon (Dense regular connective tissue) A higher magnification view showing the deep pink staining striated muscle with tendon cells insinuated between the bundles of protein fibres. collagen tendon cells fibroblasts muscle 25 µm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) Why is this connective tissue described as irregular? 1.0 mm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) Why is this connective tissue described as irregular? It consists of bundles of fibres running in a random orientation. epidermis dermis : area of dense irregular connective tissue hypodermis : subcutaneous 1.0 mm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) What are the pale pink stained dense interwoven bundles of protein fibres composed of? 100 µm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) What are the pale pink stained dense interwoven bundles of protein fibres composed of? Mostly collagen type 1. collagen bundles in the dermis 100 µm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) What is the purple staining major cell type found beneath the surface epidermis? 50 µm

SLIDE 78 Dermis of skin (Dense irregular connective tissue) What is the purple staining major cell type found beneath the surface epidermis? Fibroblasts are the predominant cell type present. fibroblasts collagen 50 µm

SLIDE 122 Ligamentum Nuchae (Elastic connective tissue) Most of the protein fibres have stained yellow in this section. Nuchal Ligament Preparation 100 µm

SLIDE 122 Ligamentum Nuchae (Elastic connective tissue) What are these protein fibres composed of? 50 µm

SLIDE 122 Ligamentum Nuchae (Elastic connective tissue) What are these protein fibres composed of? Elastin. Also note the presence of fibroblasts that have stained black. fibroblasts 50 µm

SLIDE 118 Adipose unilocular (white) Look for the cytoplasm and the nucleus. Where is the nucleus situated in these cells? Canine Abdomen Spleen retracted to expose gastrosplenic ligament (G) containing much adipose tissue. 50 µm

SLIDE 118 Adipose unilocular (white) Look for the cytoplasm and the nucleus. Where is the nucleus situated in these cells? Flattened nucleus at the side of the cell. What is the major component of these cells? Look for the cytoplasm and the nucleus. Where is the nucleus situated in these cells? nuclei of adipocytes 50 µm

SLIDE 118 Adipose unilocular (white) Look for the cytoplasm and the nucleus. Where is the nucleus situated in these cells? Flattened nucleus at the side of the cell. What is the major component of these cells? Lipid. Why do they appear empty in this section? L nuclei of adipocytes L L L : site of lipid droplets 50 µm

SLIDE 118 Adipose unilocular (white) Look for the cytoplasm and the nucleus. Where is the nucleus situated in these cells? Flattened nucleus at the side of the cell. What is the major component of these cells? Lipid. Why do they appear empty in this section? Lipids require special fixatives (such as osmium). In most preparations lipid is lost during processing. L nuclei of adipocytes L L L : site of lipid droplets 50 µm

SLIDE 86 Adipose multilocular (brown) Why is this tissue called multilocular? Whole slide 1.0 cm 250 µm

SLIDE 86 Adipose multilocular (brown) Why is this tissue called multilocular? Cells contain multiple lipid droplets. Whole slide 1.0 cm 250 µm

SLIDE 86 Adipose multilocular (brown) Are all the adipocytes multilocular in this preparation or do you find any interspersed unilocular adipocytes as well? 50 µm

SLIDE 86 Adipose multilocular (brown) Are all the adipocytes multilocular in this preparation or do you find any interspersed unilocular adipocytes as well? Most appear to be multilocular, possibly some unilocular could be present. lipid droplets variable in size 50 µm

SLIDE 21 Reticular fibres in liver Liver lobules at low magnification. Canine Liver Diaphragmatic surface G – Gall Bladder 250 µm

SLIDE 21 Reticular fibres in liver Reticular fibres are only visible with special staining techniques. In this example a silver stain has been used. 100 µm

SLIDE 21 Reticular fibres in liver Note the loose interwoven network created by the reticular fibres that are stained black. What is this protein fibre composed of? 50 µm

SLIDE 21 Reticular fibres in liver Note the loose interwoven network created by the reticular fibres that are stained black. What is this protein fibre composed of? Collagen type III. 50 µm

SLIDE 21 Reticular fibres in liver Note the loose interwoven network created by the reticular fibres that are stained black. Why is this protein fibre most appropriate in these tissues? 25 µm

SLIDE 21 Reticular fibres in liver Note the loose interwoven network created by the reticular fibres that are stained black. Why is this protein fibre most appropriate in these tissues? Reticular fibres support tissues and organs, protecting cells and structures subjected to volume changes. hepatocytes reticular fibres sinusoids 25 µm

SLIDE 125 Reticular fibres in lymph node Dog Head The larger of the two sections on this slide. Under very low magnification. M M- Mandibular Lymph Node 2.5 mm

SLIDE 125 Reticular fibres in lymph node Under low magnification. 1.0 mm

SLIDE 125 Reticular fibres in lymph node Note the loose interwoven network created by the reticular fibres that are stained black. What is it composed of? 50 µm

SLIDE 125 Reticular fibres in lymph node Note the loose interwoven network created by the reticular fibres that are stained black. What is it composed of? Collagen type III. reticular fibres 50 µm

Lecturer. Dr Tej Dhoot. First Year Histology. 003. Connective Tissue. J.Bredl. 31-07-03. Gross Anatomy Correlates. Dr S.Frean. 05-09-03. Histology Slides and Stains. Tanya Hopcroft. modified 30-10-03, 2003/4/5. Compressed version 2006, 2007.