CONNECTIVE TISSUE SCHOOL OF ANATOMICAL SCIENCES Connective consists - PowerPoint PPT Presentation

CONNECTIVE TISSUE SCHOOL OF ANATOMICAL SCIENCES

Connective consists of cells , fibres and ground substance . The cells produce the fibres and ground substance, which together are known as matrix. Connective tissue is classified according to the matrix:  With a solid matrix – cartilage and bone.  With a semi-solid matrix – connective tissue proper.  With a fluid matrix – blood and lymph. In this demonstration note the special staining techniques used to demonstrate specific features.

SEMI-SOLID MATRIX

Slide 120 (400x): Mesentery spread – rat (H, acid fuchsin and elastic) Loose Areolar Connective Tissue The rat from which this connective tissue spread was taken had been injected with India ink (carbon particles). NOTE:  The macrophages filled with ingested carbon particles * in their cytoplasm.  The large, round metachromatic-staining granules of mast cells.  The large round pale nuclei of the mesothelial cells. 400x  Thin, dark, branched elastic fibres. Question  What is the importance of macrophages in connective tissue? * 1000x

Slide 120 (400x): Mesentery spread – rat (H, acid fuchsin and elastic) Loose Areolar Connective Tissue – Mast Cells NOTE:  The large, round metachromatic-staining granules of mast cells.  The large, round, pale nuclei of mesothelial cells.  The thick eosinophilic collagen fibres.  Thin, dark, branched elastic fibres. 400x Question  What is the importance of mast cells in connective tissue? 1000x

Slide 122 (400x): Non-lactating mammary gland (H&E) Dense Irregular Connective Tissue * NOTE:  The irregularly arranged, broad eosinophilic collagen (type?) fibres.  The relatively few, basophilic and flat fibroblast nuclei lying in close 400x apposition to the fibres; and  A capillary * with a simple squamous endothelial lining. Questions  What is the function of dense irregular connective tissue?  What is the function of fibroblasts in connective tissues? * 1000x

Slide 122 (400x): Non-lactating mammary gland (H&E) Adipose Tissue NOTE:  The many adipocytes with large clear spaces.  The thin rim of eosinophilic cytoplasm.  The flattened basophilic nuclei pushed to the periphery.  Loose connective tissue between adipocytes.  Dense irregular CT at the top of the field. Questions  What is contained within the spaces in living Adipose tissue?  What type of fibres are found in the CT between adipocytes?  What is the function of adipose tissue?

Slide 50 (400x): Musculo-tendinous junction (H&E) Dense Regular Connective Tissue Compare with the dense irregular connective tissue (DICT) i.e. non-lactating mammary gland (slide 122). NOTE:  The parallel arrangement of the eosinophilc collagen (type?) fibres.  The flattened basophilic fibroblast nuclei lying between the collagen fibres. Questions  Why are the fibres arranged in parallel?  Is this tissue vascular?

Supplementary slides: Slide 28 (400x): Aorta (Weigert’s elastic technique) Elastic Tissue e.g. Aorta In this section, NOTE:  The concentrically arranged, blue-stained elastic sheets in the wall of the aorta.  The elastic fibres which cross-connect the elastic sheets.  The nuclei of the fibroblasts which secrete the elastin have not been stained. Question  What is the significance of highly developed elastic tissue in large arteries such as the aorta?

Slide 25 (400x): Liver (Silver impregnation) Reticular Tissue e.g. Liver In this section, NOTE the fine, black-stained reticular fibres woven around the cords of liver cells to form a supportive ‘basket’. They have been stained specifically by means of a special (silver) technique. Questions  Can reticular fibres be distinguished in routine H & E sections by their staining reaction or structural features? Explain your answer.

SOLID MATRIX

Slide 32 (400x): Trachea (H&E) Hyaline Cartilage NOTE:  The gradual transition from the eosinophilic, dense fibrous connective tissue of the * perichondrium * to a rigid cartilaginous matrix.  The chondrocytes which are either isolated or in nests; and  The basophilic cartilaginous matrix. Questions  Why is the cartilage matrix basophilic?  What evidence do you have in this field of appositional and interstitial growth?  How are chondrocytes nourished?  What function does the cartilage serve in the trachea?

Slide 79 (400x): Meniscus of the knee (H&E) Fibrocartilage NOTE:  The presence of chondrocytes in lacunae * which are arranged at random, either singly or in * clusters between eosinophilic collagen fibres. * Questions  Why does fibrocartilage have such a high proportion of collagen fibres? Why is it called ‘fibrocartilage’?  Where does fibrocartilage occur? What is its function there?  How does fibrocartilage ‘grow’?  How is cartilage nourished?

Slide 1 (100x): Long bone (Decalcified, H&E) Compact Bone This is a transverse section through long bone. NOTE:  The arrangement of lamellae in the bone matrix.  The Haversian systems/Osteons.  The periosteum covering on the left side of the bone.  Sharpey’s fibres inserting into the bone at the top of the field.  A Volkmann’s canal * .  Lacunae in the bone matrix. * Questions  Why is bone considered a connective tissue?  What are the functions of the different bone cells?  What is the main organic component in bone matrix?  What are the inorganic salts responsible for bone hardening?  What is the function of the periosteum, endosteum and Sharpey’s fibres?

Slide 3 (400x): Long bone (Ground bone & silver impregnation) Compact Bone This transverse section through a long bone shows an Haversian system. NOTE:  The lacunae in the concentric lamellae of the Haversian system; and  The canaliculi radiating from the lacunae. Questions  What is a lacuna? And what is its function?  How do the osteocytes in the lacunae of the outer lamellae of the Haversian system obtain their nourishment?  What is meant by a Haversian system?  What do Haversian canals contain in living bone?  Is there any evidence of osteocytes in lacunae in this field?  How is it that bone has a lamellar structure?  How are the lamellae arranged in this compact bone?  Explain the presence of interstitial lamellae.  What is the function of the Volkmann’s canal in living bone?  How was the section on this slide prepared?

Slide 67 (400x): Nasal cavities & air sinus (Decalcified, H&E) Spongy (Cancellous) Bone This field shows a trabeculum of eosinophilc spongy (cancellous) bone from the nasal cavity. NOTE:  The parallel lamellae.  The endosteum with fibroblast nuclei lining the marrow cavity.  The osteocytes in lacunae. Questions  What does the word ‘trabeculum’ mean?  Describe the contents of the marrow spaces.  How does the spongy bone differ in structure from compact bone?

Supplementary slide: Slide 51 (400x): External auditory meatus (H&E and elastic) Elastic Cartilage In this section, NOTE:  The features which this type of cartilage shares with hyaline cartilage.  The branching elastic fibres, which form a dense network throughout the matrix. Question  What function does this cartilage serve in the external auditory meatus?

FLUID MATRIX

Slide 70 (1000x): Blood smear (Romanowsky & Leishman’s) Blood: Eosinophil Eosinophils constitute 2-4% of circulating leucocytes. NOTE:  The size – 1.5x larger than an erythrocyte.  The bi-lobed nucleus.  The large, eosinophilic, spherical refractile granules – all approximately the same size. Question  What are the functions of eosinophils?

Slide 70 (1000x): Blood smear (Romanowsky & Leishman’s) Blood: Neutrophil Neutrophils constitute 60-70% of circulating leucocytes. They are 12-15µm in diameter, with a nucleus consisting of 2-5 (usually 3) lobes linked by fine threads of chromatin. In females, the inactive X-chromosome appears as a drumstick-like appendage as one of the lobes of the nucleus although this is not obvious in all neutrophils. NOTE:  The size of the neutrophil –larger than an erythrocyte.  The multi-lobed nucleus with clumped chromatin.  The ‘drumstick’ i.e. Barr Body and the fine neutrophilic granules in the cytoplasm. Question  What is the function of neutrophils?

Slide 70 (1000x): Blood smear (Romanowsky & Leishman’s) Blood: Basophil * Basophils make up less than .1% of blood leucocytes and are therefore difficult to locate in smears. NOTE:  The size – slightly larger than an erythrocyte.  The nucleus – obscured by the overlying basophilic granules.  The irregular shape of the granules.  The presence of a lymphocyte *. Question  What do the basophilic granules contain?

Slide 70 (1000x): Blood smear (Romanowsky & Leishman’s) Blood: Monocyte & Eosinophil NOTE:  The size of the monocyte – very large.  The large, basophilic nucleus.  The pale, basophilic, frosted-glass appearance of the cytoplasm. Question  To what connective tissue cells do monocytes give rise?