HISTOLOGY IMAGE GALLERY A simple copyright free pictorial gallery of normal human and animal tissues and organs aimed at undergraduate medical, dental, health science and biological science students • Epithelia • Connective Tissue • Bone & Cartilage • Blood • Muscular Tissue • Nervous Tissue • Sense Organs • Lymphoid Tissues • Skin • Respiratory System • Cardiovascular System • Alimentary Tract • Liver, Pancreas, Gallbladder • Tongue, lip, Salivary Glands • Endocrine Glands • Urinary System • Male Reproductive System • Female Reproductive System Introduction Acknowledgements Quiz Mike Mahon & Jan Wyatt © 1999-2010 Universities of Keele and Manchester, UK (Last updated 9 September 2010) 3g HISTOLOGY IMAGE GALLERY A simple copyright free pictorial gallery of normal human and animal tissues and organs aimed at undergraduate medical, dental, health science and biological science students INTRODUCTION This resource contains images scanned from film transparencies of light micrographs of normal histology slides which Medical, Dental, Health Science, and Bioscience students at Manchester and Keele Universities have used during histology practical classes in multiuser laboratories since 1976. The package is designed as a visual supplement to histology courses for single users or as an aid to group discussion with or without a tutor. Each topic section should take about 20 minutes of study time. Each screen contains an image with a short description or comment. As in all histological study, consider where the section is from, what is shown in the section and which basic cell or tissue types are present, and of course what the tissue does, remember: Structure - Function – Location ! Observe and you will See ! ACKNOWLEDGEMENTS Picture & Text Sources: John Dixon, Philip Harris, Mike Mahon, Jan Wyatt Web Authoring & Digitising: Catriona Rennie, Philip Bentley, Laura Messenger, Mike Mahon, Jan Wyatt Usage: Worldwide Copyright & License free to use, store, network, dissasemble, for non commercial purposes. Please acknowledge. Mike Mahon & Jan Wyatt © 1999-2010 Universities of Keele and Manchester, UK EPITHELIA • One of the four basic tissue types from which all organs are constructed • Characterised largely by the shape and organisation of its cells • LINING / COVERING epithelia forms layers lying on a basement membrane • Simple: a single layer of squamous, cuboidal or columnar cells designed to allow for diffusion of substances through it or for filtration or absorption. Surfaces may be modified with microvilli or cilia • Stratified: multiple layers, designed for protection and replacement named according to the shape of the cells in the surface layer (See this section and also Skin, Alimentary, Respiratory, Cardiovascular, Reproductive topics) Wikimedia Commons • GLANDULAR epithelia secrete mucus, enzymes or hormones • Exocrine: glands with ducts to pass secretions locally • Endocrine: ductless glands which secrete into blood vessels (For glands see: Liver, Pancreas, Salivary, Endocrine, Reproductive topics) 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 1. Simple squamous As seen in Bowman’s capsule of the kidney glomerulus. Q. What is its function here? Q. Simple squamous epithelium is present at two other locations in this micrograph -where? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 2. Simple squamous Endothelium lining blood vessels and lymphatics. Q. Identify three occurrences here. Q. What is its function here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 3. Simple squamous Mesothelium covering organs, e.g. pleura over lungs (pictured), pericardium over heart, peritoneum covering parts of the intestines. Q. What is its role here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 4. Simple squamous A sheet of mesothelium from the mesentery viewed ‘face on’ to show the cell outlines which have been stained with silver. Q. What is its function here? Q. What holds the cells together? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 5. Simple cuboidal These cells line the tubules of the nephrons and collecting ducts in the kidneys. Q. How does their role compare and differ to that of the simple squamous cells in the glomerulus (Image 1)? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 6. Simple cuboidal This a glandular epithelium forming the surface of a thyroid follicle. It lies on a basement membrane and is in close proximity to numerous capillaries. Q. These cells have a complex glandular function. What do they do? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 7. Simple columnar From the gallbladder. Q. Identify the ‘brush border’ (microvilli) at the apices of these cells. Q. What is the function of this epithelium here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 8. Simple columnar This epithelium from the villi of the small intestine has an absorptive, digestive and secertory function. Q. Identify the ‘brushborder’. Q. What are the darker staining flask-shaped cells? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 9. Simple columnar These simple columnar ciliated cells line the uterine (Fallopian) tubes. Q. Identify these cells. Q. What is their function here? Q. Suggest another location for cells of this type. 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 10. Stratified squamous keratinised From the skin of the hand. Q. Identify as many layers as you can. Q. What is its function here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 11. Stratified squamous keratinized High-power of previous image. Note the various cell shapes, some show a ‘prickly’ surface. Q. What do the spiny ‘prickles’ represent? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 12. Stratified squamous nonkeratinized From the oesophagus. Q. What is its function here? Q. Identify the various layers. Q. Where else does this type of epithelium occur? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 13. Stratified columnar Lining the large duct of a salivary gland. Q. What is its function here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 14. Stratified transitional Located in the lining of the urinary tract (urothelium), this epithelium shows variable shapes of its surface cells depending on the degree of stretch. Q. What other properties does this epithelium have in order to carry out its role in the urinary tract? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 15. Pseudo-stratified ciliated columnar Lining of the upper respiratory tract. Q. Why is it called pseudo-stratified? Q. Why do these cells have cilia? Q. What are the pale cells interspersed in the epithelium? Q. Can you identify a second type of epithelium here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 16. Pseudo-stratified ciliated columnar Same as previous image but from a thinner (1µm thick) plastic section showing more detail. Note the pseudostratification of this simple epithelium. Q. Identify cilia, nuclei, mitochondria, mucus. Q. What is its function here? 1 2 3 4 14 15 16 16a 5 6 7 8 9 10 11 12 13 EPITHELIA 16a. Pseudo-stratified ciliated columnar Separated cells from the respiratory epithelium shown in the previous two slides. Note the luminal cilia and basal processes. Q. What is the function of these cells? Q. To what do the basal processes attach? 1 2 3 4 5 6 7 8 9 10 11 12 13 Next Topic ► 14 15 16 16a CONNECTIVE TISSUE • One of the four basic tissue types from which all organs are constructed Characterised by the major cell type present and especially the extracellular matrix • Cells: highly variable (e.g. fibrocytes, adipocytes, mast cells, chondrocytes, osteocytes). Developing and active cells are –blasts. (See also Blood and Immune Defence/Lymphoid cells) • Matrix: highly variable, usually comprises fibrous and amorphous gel components • Loose connective tissues form packing between other tissues and between organs • Areolar: variety of cells in scant fibrous and fluid matrix; abundant • Adipose: dominant cell is the adipocyte; found under skin and around some organs • Fibrous: dominant matrix fibre is collagen; strong, often surrounds organs • Elastic: dominant matrix fibre is elastin; elastic, often around tubes • Reticular: dominant matrix fibre is reticulin; branched fibre cradling loose cells • Dense connective tissues usually provide protection and support • Irregular: withstand forces in various directions (e.g. dermis) • Regular: withstand forces in specific direction (e.g. tendon) • Specialised Dense connective tissues include cartilage and bone 17 18 19 29 30 31 20 32 20a 21 22 23 24 (See topic: Bone & Cartilage) 25 26 27 28 CONNECTIVE TISSUE 17. Primitive mesenchymal C.T. The cells have processes which appear to connect with those of neighbouring cells so forming a sponge like structure. Q. From which embryonic germ layer does this tissue arise? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 18. Primitive mesenchyme showing condensation The closely packed nuclei are probably developing into an area which will become a dense mass of connective tissue. Mitotic figures will also occur in these condensed areas as cells proliferate. Q. Where might you see this in an embryo? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 19. Dense irregular fibrous C.T. The nuclei are fibrocyte nuclei. The pink staining material is collagen. Q. Why is the collagen arranged in this manner? Q. Give an example location of this tissue in the body. 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 20. Dense regular C.T. Human tendon in longitudinal section. The long thin cells are fibrocytes. Q. Why is the collagen arranged in this manner? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 20a. Dense regular C.T. Human tendon in cross section. Compare to previous image. Q. The investing layers of looser connective are called epitendineum, peritendineum and endotendineum. Where do they lie? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 21. Loose areolar C.T. Identify the very active fibroblasts in this healing wound. Note the rich vascular supply and presence of numerous leucocytes. Q. How do these fibroblasts compare to the fibrocytes in image 20 (Tendon L.S.)? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 22. Loose areolar C.T. Another example of Identify active fibroblasts in a healing wound. Note the rich vascular supply and presence of numerous leucocytes. Q. Which features of the nuclei and cytoplasm are indicative of activity? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 23. Loose areolar C.T. Elastic fibres in spread of loose areolar (subcutaneous) tissue. Q. How do elastic fibres differ from collagen fibres? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 24. Elastic tissue Identify the thin internal and thick external layers of darkly stained elastic fibres in the wall of this artery. Q. What is its function here? Q. Which cell type produces this material? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 25. Elastic tissue Elastic fibres are tightly arranged in multiple fenestrated sheets in the wall of the aorta close to the lumen. Q. What is its function here? Q. What happens to this material on ageing? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 26. Elastic tissue Elastic fibres (stained black here) are prominent in the lungs and are especially noticeable towards the edges. Q. Why is this tissue prominent here? Q. What will be the difference in a lung from an elderly person? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 27. Reticular tissue A web of highly branched reticular fibres (stained black) is clearly visible in this lymph node from which most of the lymphocytes have been washed away. Note - some large pale granular cells are also visible. Q. What is the function of the reticulin and associated reticuloendothelial cells here? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 28. Collagen The red staining shows the presence of collagen fibres in the layer between the epithelium and muscle in this section of the wall of the small intestine. Van Gieson stain. Q. What is the role of this connective tissue layer? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 29. Adipose tissue In this section of tissue embedded in paraffin wax the fat has been lost leaving each cell as an unstained region surrounded by cytoplasm and a nucleus (‘cygnet ring’ shape). Q. Name two body sites where you might find an abundance of this tissue. 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 30. Adipocytes Fat cells in a spread of mesentery (stained with Oil Red 0 - a fat soluble dye). Note their size compared to other cells. Q. What preparative technique has been used to preserve the fat content here compared to that in the previous image (29)? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 31. Loose areolar C.T. Macrophages in subcutaneous tissue previously injected with a carbon suspension. Q. The macrophages contain large quantities of carbon particles in their cytoplasm - Why? Q. What other cells and matrix components can you see here? 17 18 19 29 30 31 20 32 20a 21 22 23 24 25 26 27 28 CONNECTIVE TISSUE 32. Loose areolar C.T. Mast cells (granules stained red) lie close to a blood vessel. Q. What is the role of mast cells? Q. What do mast cells contain in their granules? 17 18 19 20 20a 21 22 23 24 25 26 27 28 Next Topic ► 29 30 31 32 End of Images Quit