Topic and Aims. Contractile cells. Nervous system. Muscle tissue is one of the four basic tissue types.

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1 Topic and Aims Contractile cells Muscle tissue is one of the four basic tissue types. You should be able to: 1. Describe and identify the types of contractile cells, and summarise similarities and differences. 2. Compare the functions of each type of contractile cell. 3. Recognise the ultrastructural appearance of contractile cells. 4. Explain the organisation and layers of connective tissue of muscle tissue. 5. Recognise and distinguish between the three types of muscle tissue in transverse and longitudinal sections. 6. Explain the structure and function of skeletal, cardiac and smooth muscle. 7. Identify the myofibrils and cross-striations in striated muscle fibers. 8. Describe a dense body, desmosome, intercalated discs and gap junctions. 9. Define and describe satellite cells. 10. Define and describe a motor unit. 11. Explain the filament model of muscle contraction. 12. Explain fast and slow muscle fibers. 13. Distinguish between smooth muscle and dense regular connective tissue. Name and discuss the five types of contractile elements found in the body. Explain the organization, function and structure of skeletal, cardiac and smooth muscle. Identify and explain the connective tissue associated with muscle cells and fascicles of muscle cells. Compare and contrast skeletal, cardiac and smooth muscle with regards to structure and function. Identify skeletal, cardiac and smooth muscle on a slide and in various tissues and organs. Describe how muscles contract and relax. Explain the relationship between muscle and the nervous system and how this relates to exercise and muscle performance. Define, explain and identify a motor unit and its component parts. Describe, identify and understand the sarcomere and and how this relate to muscle striations. Identify the intercalated disks in cardiac fibers. Discuss the similarities and difference between smooth muscle fibers and collagen fibers of connective tissue. Describe and discuss the functions of each of the components. Nervous system By following this topic, you will find out about the basic structure of nerves, synapses, central and peripheral nervous systems, supporting cells of nervous tissue and the special senses. The following content will be studied in this topic: Neurons: 1. Cell bodies 1. Multipolar 2. Pseudo-unipolar 2. Processes 1. Myelinated 2. Unmyelinated Neuroglia: 1. Astrocytes 2. Ependyma Special sense: 1. Eye 2. Ear 3. Touch Nervous system: 1. Ganglia Spinal Sympathetic Parasympathetic 2. Cerebrum 3. Cerebellum

2 3. Nerve endings 1. Central nervous system 1. Synapse 2. Peripheral nervous system 1. Motor units Motor muscle end plate 2. Sensory endings Pacinian corpuscle Meissner's corpuscle Pacinian corpuscle Meissner s corpuscle 4. Spinal cord Nervous tissues You should be able to: 1. Describe the major divisions of the nervous system. 2. Describe the functional and structural differences between grey and white matter. 3. Describe the basic structure of a neuron. 4. Identify neurons, neuroglia and neuropil. 5. Identify the different types of neurons. 6. Identify and describe the differences between axons and dendrites. 7. Identify and describe myelinated and nonmyelinated nerve axons. 8. Identify and explain the connective tissue arrangements in nervous tissue. 9. Describe the components and organisation of the central and peripheral nervous systems. 10. Describe and identify the supporting cells in the central and peripheral nervous system. 11. Describe the functions of the various cells and structures of the nervous system. 12. Describe the structure of synapses. You should be able to: Identify neurons of the central and peripheral nervous system. Name, describe and differentiate between the different parts of a neuron. Describe and explain the microscopic structure of a nerve fibre, including the myelin sheath and connective tissue layers. Describe myelinated and non-myelinated axons and the process of myelination. Identify and describe the support cells of the central and peripheral nervous system. Identify and describe synapses, neuromuscular junctions and muscle spindles. Identify and describe the structure of muscle spindles, Pacinian and Meissner s corpuscles. Distinguish between and discuss the components, location and organisation of grey and white matter. Describe and discuss the functions of each of the components. Nervous system You should be able to: 1. Distinguish cerebellum from cerebrum in histological sections. 2. Identify the layers of the grey matter in the cerebellum and their constituent cells. 3. Describe and explain the organization and structure of the spinal cord in cross-section. 4. Distinguish and explain the differences between ganglia and nerves. Sensory system You should be able to: 1. Describe different types of sensory receptors 2. Identify different encapsulated sensory receptors. 3. Describe the structures involved in the special senses of taste, smell, hearing, balance, and vision. 4. Describe the means of mechano-reception for hearing and balance.

3 Eye You should be able to: 1. Describe the overall organization of the eye. 2. Describe the structural organization and functions of the components of the eyelid and conjunctiva. 3. Describe the components of the three layers of the eye. 4. Explain the relation between structure and function of the layers in the eye. 5. Recognize and describe the retina, fovea, optic disk, and layout of blood vessels in the retina. 6. Recognize and describe the structures of the cornea, iris, lens, vitreous body and ciliary body. 7. Understand the relationship among the choroid and the pigmented and sensory layers of the retina. 8. Understand and describe the sensory cells of the retina and the rest of the optical sensory pathway. Ear You should be able to: 1. Describe the overall organisation of the ear, middle ear and inner ear. 2. Recognise the ear drum, cochlea and its components. 3. Describe and explain the functions of the components of the ear. Revision Contractile cells Name the 3 types of muscle cells. Name and define the striations of skeletal muscle. What is the unit between two Z-lines termed? How are individual cardiac muscle cells linked? Name 2 areas where smooth muscle is found. Name 3 diseases of muscle. Complete the table, listing important differences between the 3 muscle types: Skeletal Cardiac Smooth Cell Elongated Branching Spindle-shaped Nucleus Multiple peripheral Single, central Single, central Striations Cross-striated Cross-striated & Intercalated disk at branching None Motor control Voluntary Involuntary Involuntary Why do smooth muscle fibers in cross section have different diameters and why do some of these fail to show nuclei? Are myofibrils or sarcomeres present in smooth muscle fibers? Explain the following histological observation made in waxembedded, H&E-stained sections: 1. In smooth muscle cut in transverse section, not all profiles contain nuclei. 2. White adipose tissue shows no sign of fat in a wax-embedded section. 3. What do the blue granules in conventional sections of neurones represent?

4 Nervous system What are the 3 layers of the sclera? Name and discuss the 5 layers of the cornea. Name the 4 layers of the iris. What determines eye colour? Name the 8 layers of the retina and what forms them. What is the lens composed of? Name the 3 chambers of the eye. Explain the histological basis of glaucoma. Describe the flow of liquid in the posterior and anterior chambers of the eye. What separates the external and middle ear? Name the three auditory ossicles. What type of joint articulates the ossicles? How is movement detected in the inner ear? How is sound detected in the inner ear? What is the organ of Corti composed of? Name 3 types of neurons. What is a synapse? Name the types of cells which form myelin in the CNS & PNS. Name the 4 specialized support cells of the central nervous system. Name and define the 3 meningeal layers. What is the function of the choroid plexus? Name the 4 components of a peripheral nerve. Where are the endoneurium, perineurium and epineurium located? Which autoimmune disease attacks the myelin of the CNS? Draw a neuron and label its key histological and structural features. Complete the drawings for each slide in the practical workbook. Slides Contractile cells Slide name Slide number Stain Smooth muscle (cross & longitudinal; ureter) Smooth muscle (cross & longitudinal; umbilical cord) Skeletal muscle (cross & longitudinal) Skeletal muscle (cross & longitudinal; tongue) 78 H/E 100 H/E 18 H/E 33 H/E Skeletal muscle 19 Y/H Heart muscle (longitudinal section) 20 H/E Heart muscle (cross section) 77 H/E Heart muscle 86 Y/H

5 Nervous system Slide name Slide number Stain Nervous tissue Neuron Cell bodies Multipolar - spinal cord 26 H/E Multipolar - spinal cord 82 Silver Multipolar- cerebellum 60 Silver Pseudo-unipolar - spinal 26 H/E ganglion Nervous tissue Neuron Fibres Myelinated - peripheral 32 H/E nerve Myelinated- myelin sheath 59 Osmium Nervous tissue Neuron Nerve endings Central nervous system Synapse 82 Silver Nervous tissue Neuron Nerve endings Peripheral nervous system Motor endings Motor end plate 44 Gold Sensory endings Pacinian corpuscles 93 H/E Meissner s corpuscles 24 Silver Nervous tissue Neuroglia Astrocytes cerebrum Demonstration Silver Ependyma choroid plexus 98 H/E Nervous System Nervous System Ganglia Spinal 26 H/E Spinal 82 Silver Sympathetic 103 H/E Sympathetic Demonstration Silver Parasympathetic 37 H/E Parasympathetic 41 H/E Parasympathetic 42 H/E Nervous System Structures Cerebrum 61 Silver Cerebellum 60 Silver Spinal cord 26 H/E Neuromuscular bundle 69 H/E

6 Tasks Slide 78: Ureter This slide is a cross section of the ureter. H/E 1. View the slide at low magnification. You should see the complete organ with a lumen in the middle. 1. What type of epithelium lines blood vessels? 2. What type of epithelium lines the ureter? 2. Identify the following: 1. The lumen of the ureter. 2. The circular wall of the ureter. 3. The muscle layers of the ureter. 1. What is typical of the lumen of the urether? 3. View the slide at appropriately higher levels of magnification. Identify the following: 1. Lumen 2. Epithelium 3. Mucosa 4. M. externa 5. Adventitia 6. The different layers of the epithelium. 7. The shape of the cells in the different layers of the epithelium. 1. How many layers can be identified in urothelium? 2. How does the shape of the cells in each layer of urothelium change? 3. What is characteristic of the luminal layer of urothelium? Why? 4. Make annotated drawings: 1. A line diagram of the different layers of the ureter. 2. A cut-out to illustrate the epithelium. Show the shapes of the cells in the different layers. 1. How many layers of muscle are found along the length of the ureter? 2. How are these muscular layers arranged? Slide 100: Umbilical cord This specimen is a cross section through the umbilical cord. It consists mainly of gelatinous connective tissue. The three large blood vessels present inside the umbilical cord are used as examples of smooth muscle. 1. View the slide at low magnification. You should be able to see three dark stained areas within the confines of the umbilical cord. Name the blood vessels found in the umbilical cord. What is the main component of the wall of blood vessels in general? What epithelium lines blood vessels? 2. Identify: 1. The three large blood vessels of the umbilical cord. 2. The lumens of each of the blood vessels. H/E

7 3. The lighter stained areas around the blood vessels. What are the three components of connective tissue? Which area of a cell is stained with haematoxillin? What colour is haematoxillin generally? 3. View the slide at higher magnification. 4. In the lighter area, using appropriate magnification, identify the following: 1. Nuclei stained purple. 2. Fibroblasts. 3. Collagen fibers. 4. Amorphous ground substance. What are the function/s of fibroblasts? What are the function/s of collagen fibers? What are the function/s of amorphous ground substance? What are the relative proportions of each as seen in the umbilical cord? 5. In the blood vessels, identify the following: 1. Nuclei stained purple. 2. Longitudinally sectioned smooth muscle fibers. 3. Cross sectioned smooth muscle fibers. Imagine a balloon. What happens if the balloon is compressed from all sides? How is a balloon analogous to a muscle fibre and the nucleus within a muscle fibre? 6. Make annotated drawings of the following: 1. A line diagram, showing the orientation of the blood vessels in the umbilical cord. 2. The three components of gelatinous connective tissue in the correct ratio. Draw an additional fibroblast showing its microscopic detail (at higher magnification). 3. A few longitudinal and cross sectioned smooth muscle fibers. Note the shape and different diameters of the smooth muscle fibers. What is the shape of the fibroblasts and their nuclei? What is the shape of the smooth muscle fibre and their nuclei? Compare fibroblasts with smooth muscle fibres. How is the collagen arranged? How do the collagen fibers appear? How does the amorphous substance appear and how does it stain? What is characteristic of the cellular and nuclear shapes? How does the nucleus appear in a contracted smooth muscle fibre? What is found between the muscle fibres?

8 Skin Various Slides of the skin is used to study skin as an organ and several structures contained within skin. Sensory nerve endings are present in the papillae of the dermis (Meissner's corpuscles) and fatty tissue (Pacinian corpuscles). The dermis serves as an example of loose connective tissue, irregular dense connective tissue and fatty connective tissue. Compare thin and thick skin and note the differences between them. The slides is also used to study two types of epithelium, namely stratified squamous keratinizing epithelium and endothelium. Some structures are more distinctive on some slides. View all four slides and compare the views on each. 1. Slide 24: Meissner's corpuscle this is a section through skin from the palm, stained with silver to illustrate sensory nerve endings of the peripheral nervous system. 2. Slide 93: Thick skin this slide is a section through the skin of the palm of the hand. 3. Slide 94: Thin Skin this slide is a section through skin from the thigh region. 4. Slide 95: Thin skin from the scalp this slide is a section through skin from the scalp. Structures to look at are the following: 1. Skin as an organ and its cells; as well as the layers of skin and the structures contained within each layer. 2. Simple squamous epithelium (endothelium). Slide 41 can also be used to study simple squamous epithelium. The blood vessels can be found in the dermis or hypodermis of the skin or in the submucosa of the ileum. 3. Fatty connective tissue is present everywhere in the body. In skin, the hypodermis contain good examples of fatty connective tissue. 4. Pacinian corpuscle, sensory nerve endings of the peripheral nervous system, are present between the fatty connective tissue. 5. Meissner's corpuscles are located in the papillary layer of the dermis. 6. The papillary layer of the dermis consists of loose connective tissue. 7. The other part of the dermis consists of dense irregular connective tissue. 1. View the slides at low magnification. You should be able to see several layers, stained different colours and intensities. For a standard haematoxillin and eosin stained slide, there are three layers: A dark pink to red scalloped area the epidermis. A central light pink eosinophilic area the dermis. A very thick light pink area the hypodermis. 1. Look at the palm of your hand and fingertips. The thickened outer layer is the outer layer of stratified squamous keratinized epithelium. 2. Compare and describe the visual differences seen between the skin of the palm of your hand, the back of your hand, your forearm and scalp. 3. Make a list of structures you expect to find in skin using the microscope. 2. Compare the different textures and intensity of stained layers of skin. What colours are seen in the slide stained with haematoxillin and eosin? What colours are seen in the slide stained with silver? List the layers and subdivisions of each layer found in skin in general. Using the terms thin, medium and thick, describe the thickness of each of the three layers of skin in each of the four slides.

9 3. View the slides at higher magnification. At this magnification, structural detail should be clear. Cell borders and nuclei should be visible at highest magnification. Adjust the view as appropriate to differentiate the various structures. Name the three components found in all types of connective tissues. Which cell secretes collagen? What is the specific fibre component of loose connective tissue? What is the function of reticular fibres? What cells are expected in dense connective tissue? List the differences between the nuclei of fat cells, endothelium and fibroblasts. 4. Identify the following structures, in order: 1. The three main layers of skin, epidermis, dermis and hypodermis. The epithelium of skin, stratified squamous keratinising epithelium. 2. Loose connective tissue in the papillary layer of the dermis. Meissner's corpuscles. 3. Blood vessels. Lumen of the blood vessel. Endothelial cells against the lumen Nuclei of the endothelial cells Cytoplasm Layers of the blood vessel wall 4. Irregular dense connective tissue in the reticular layer of the dermis. Collagen fibers sectioned in different planes. Nuclei of the connective tissue cells. Fibroblast nuclei. 5. Subcutaneous fat, or fatty connective tissue in the hypodermis. Pacinian corpuscles. Individual fat cells and their nuclei. Connective tissue septa, dividing subcutaneous fat cells into small lobules. 6. The different layers of the epithelium which form the epidermis. The shape of the cells in the different layers of epidermis. 7. The layers of the scalp and the subcutaneous tissue. Sweat glands. The different layers of a hair follicle, and hair. Sebaceous glands. Arrector pili muscle. 1. What is the function of the arrector pili muscle in animals? 5. Make annotated drawings as indicated below of the structures studied above: 1. Cells: A few endothelial cells. A few epithelial cells of each layer of the stratified squamous keratinised epithelium. Clearly indicate the different cell shapes. A single fat cell. 2. Tissues: Collagen fibers sectioned in different directions also indicate the different connective tissue nuclei. Dense irregular connective tissue. Indicate the collagen fibers sectioned in different planes. 3. Organs:

10 The layers of the skin, including the associated structures, subcutaneous tissue and sweat glands. A diagram showing the scalp with associated structures. 4. Structures: A line diagram of the bloodvessel and endothelial cells. A Meissner's corpuscle. A line diagram of a few lobules of fatty tissue. In one of the lobules draw fat cells as well as the surrounding connective tissue septa. A Pacinian corpuscle. A detailed diagram of a cross-section through a hair follicle. 1. What is characteristic of endothelial cells? 2. What is characteristic of the cytoplasm of endothelial cells? And the nuclei? 3. What is sometimes seen in the lumen next to endothelial cells? 4. Describe a Meissner's corpuscle. 5. What is the difference between a Meissner's and Pacinian corpuscle? 6. Approximately how many cell layers are present in thin and thick skin respectively? 7. How does the shape of the epithelial cells of skin in each layer change? 8. How does the junction between this epithelium and the underlying support structures (connective tissue) appear? 9. How does the appearance of fat cells stained with H/E differ from those that were stained with Sudan IV? 10. Describe the Pacinian corpuscle. 11. What is the capsule of the Pacinian corpuscle made from? 12. What are the different layers of the dermis, and what type of support tissue is found here? 13. What is characteristic of the subcutis (hypodermis)? 14. What is characteristic of the ducts of the sweat glands? 15. How does one distinguish between the secretory part and the tubular part of sweat glands? 16. How do the sectioned collagen fibers differ from those of the mesenterium when spread out (view slide 6)? 17. What is the relative composition of this loose connective tissue, with regard to % fibers, cells and amorphous ground substance? 18. How does the fibers of dense irregular connective tissue differ from loose connective tissue in a tissue section? 19. Are there more or less cells in dense irregular than in loose connective tissue? 20. What is characteristic of skin from the thigh region? 21. How can one distinguish between scalp, thigh and thick skin? 22. What is characteristic of tissue from the scalp? 23. Where do the sebaceous glands open? 24. Classify sebaceous glands. 25. What is characteristic of sebaceous glands? 26. What is characteristic of hair follicles? 27. What is characteristic of hair? 28. In which layers of skin are hair follicles found?

11 Slide 18: Skeletal muscle (Striated) A longitudinal and cross section of skeletal muscle. See also Slide 33, a section through the tip of the tongue in which the skeletal muscle is sectioned longitudinally, obliquely and crosswise. To view the striations of skeletal muscle in an H/E specimen, the condenser of the microscope must be turned down to obtain as much contrast as possible. Remember to turn the condenser back to its original position after you have finished. Identify microscopically: A Longitudinal section Skeletal muscle fibers Nuclei of the skeletal muscle fibers and connective tissue Cross striations Connective tissue B Cross section Skeletal muscle fibers arranged in bundles Size, shape and diameter of the muscle bundles Nuclei of the skeletal muscle fibers Myofibrils Connective tissue A longitudinal AND cross section of skeletal muscle: 1. What is characteristic of skeletal muscle? 2. What is characteristic of the nuclei of skeletal muscle and how do they differ from those of smooth muscle? 3. How does skeletal muscle differ in longitudinal and cross section from smooth muscle? 4. What are skeletal muscle fibre bundles called? 5. Can all the subdivisions of muscle connective tissue be seen on this specimen? What is the connective tissue is called? H/E

12 Slide 19: Skeletal muscle (striated) This is a section through the tip of the tongue stained to show the cross striations. Identify microscopically: 1. Longitudinal section of skeletal muscle 2. The different bands in the longitudinal section that form the cross striations 3. Nuclei of the skeletal muscle and connective tissue A skeletal muscle fibre. Indicate al the different components in detail. 1. How many of the cross striation of skeletal muscle are visible under the light microscope? 2. Can all the bands be seen? 3. How does each band appear? Y/H

13 Slide 20: Heart muscle This is a longitudinal section through heart muscle. To view the cross striations the condenser of the microscope must be turn downward to produce contrast. Identify microscopically: 1. Muscle fibers and branchings 2. Nuclei of the heart muscle fibers and connective tissue 3. Intercalary discs and cross striations 4. Connective tissue A heart muscle fibre. Indicate the characteristic components in detail. 1. What is characteristic of heart muscle fibers? 2. How do heart muscle fibers differ from skeletal and smooth muscle? 3. What is the connective tissue found between the heart muscle fibers called? H/E

14 Slide 26: Spinal cord multipolar neurons This is a cross section through the spinal cord and spinal ganglion. The spinal cord serves as an example of multipolar neuron cell bodies. 1. Identify: Macroscopic The orientation of the spinal cord, identifying the H-shaped grey matter, the white matter and the spinal ganglion. 2. Microscopic The multipolar neuron cell bodies found in the grey matter. (i) Cell body. Nucleus Nissl-substance Axon hillock Nuclei of the neuroglia 3. A multipolar neuron cell body. Indicate the components of the neuron in detail. 1. What characteristic of the cell bodies is used in the identification of multipolar neurons? 2. What is characteristic of the nuclei of the neurons? 3. How does the Nissl-substance appear and what is it in reality? 4. What is characteristic of the axon hillock? H/E

15 Slide 26: Spinal cord pseudo-unipolar neurons This is a cross section through the spinal cord and spinal ganglion. The spinal ganglion is used as an example to demonstrate pseudo-unipolar neuron cell bodies. 1. Identify: Macroscopic The orientation of the spinal ganglion identifying the spinal ganglion next to the spinal cord. The pseudo-unipolar neurons are found in the spinal ganglion. 2. Microscopic Cell bodies Nuclei Nissl-substance 3. A pseudo-unipolar neuron. 1. What is characteristic of the shape of a pseudo-unipolar neuron in comparison to that of multipolar neurons? 2. How do the granules of the Nissl-substance of pseudo-unipolar neurons differ from those of the multipolar neurons? H/E

16 Slide 32: Peripheral nerve myelinated fibers This is a cross section through a peripheral nerve. H/E Identify microscopically: 1. Epi-, peri- and endoneurium 2. Axon 3. Neurilemma 4. Schwann cell nuclei A line diagram of the nerve in which the connective tissue components and nerve bundles are indicated. Draw a few cross sectional axons with their sheaths. 1. How do the axons appear? 2. How do the myelin sheaths appear? 3. How does one distinguish between Schwann cell and fibroblast nuclei? 4. How do unmyelinated fibers appear?

17 Slide 33: Skeletal muscle (striated) This is a section through the tip of the tongue in which the skeletal muscle is sectioned longitudinally, obliquely and crosswise. See also slide 18, a longitudinal and cross section of skeletal muscle. To view the striations of skeletal muscle in an H/E specimen, the condenser of the microscope must be turned down to obtain as much contrast as possible. (Remember to turn the condenser back to its original position after you have finished). Identify microscopically: A Longitudinal section Skeletal muscle fibers Nuclei of the skeletal muscle fibers and connective tissue Cross striations Connective tissue B Cross section Skeletal muscle fibers arranged in bundles Size, shape and diameter of the muscle bundles Nuclei of the skeletal muscle fibers Myofibrils Connective tissue A longitudinal and cross section of skeletal muscle: 1. What is characteristic of skeletal muscle? 2. What is characteristic of the nuclei of skeletal muscle and how do they differ from those of smooth muscle? 3. How does skeletal muscle differ in longitudinal and cross section from smooth muscle? 4. What are skeletal muscle fibre bundles called? 5. Can all the subdivisions of muscle connective tissue be seen on this specimen? What is the connective tissue is called? H/E

18 Slide 33: Tongue: papilla circumvalata This slide is a coronal section through the tongue. H/E Identify microscopically: 1. Papilla circumvalata 2. Glands of Ebner 3. Taste buds A circumvallate papilla and associated gland. 1. What is the shape of this papilla? 2. Where do the glands of Ebner open? 3. What type of gland is the gland of Ebner? 4. Where are the taste buds found?

19 Slide 37: Stomach fundus This slide is a cross section through the fundus of the stomach. H/E Identify: A Macroscopic The rugae with the naked eye. B Microscopic Foveolae Mucosa Gastric glands Submucosa M. externa Serosa Ganglia A line sketch of the stomach where the detail of a number of foveolae and gastric glands are shown. 1. How deep do the foveolae extend into the mucosa? 2. Which layers comprise the mucosa? 3. What are the identifying characteristics of the epithelium which lines the foveolae and surface? 4. What is typical of the extent, areas and types of cells of the gastric glands? 5. What is typical of the submucosa? 6. What are the identifying characteristics of the M. externa? 7. What does the serosa comprise of, and how does it differ from the adventitia? 8. Where are the ganglia found, and of what do they form a part of?

20 Slide 41: Ileum This slide is a longitudinal section through the ileum. This specimen is used to study the ileum (organ) and endothelium (structure) as seen in the blood vessels (structure) within the ileum. The blood vessels can be found in the submucosa of the ileum. 1. View the slide at low magnification. At this magnification, the lumen should be visible. A rough appearing mucosa borders the lumen and below that two additional layers, the submucosa and muscular layer is visible. Depending on the tissue, components of the serosa could be visible. 2. Identify the following layers to orientate yourself: 1. Epithelium 2. Mucosa 3. Submucosa 4. Muscle layer 5. Serosa 6. Lymphocyte infiltration. 3. View the slide at high magnification. On this view, structural and cellular details should be visible. 4. Identify the following structures: 1. Border areas between the main layers and sub-layers as identified at low magnification. 2. Blood vessels in the submucosa. 5. In the blood vessels, identify the following: 1. Lumen of the blood vessel 2. Endothelial cells against the lumen 3. Nuclei of the endothelial cells 4. Cytoplasm 5. Layers of the blood vessel wall 6. Make annotated drawings of the following: 1. A line diagram of the blood vessel and endothelial cells. 2. A line diagram of the ileum, showing the different layers and sublayers. 1. What is characteristic of the endothelial cells? 2. What is characteristic of the cytoplasm of these endothelial cells? And the nuclei? 3. What is sometimes seen in the lumen? 4. What are the similarities and differences between the ileum and duodenum? H/E

21 Slide 42: Large intestine This specimen is a longitudinal section through the large intestine. This specimen is used to study the colon (organ) and different types of connective tissue cells (cells). 1. View the slide on low magnification. You should see the lumen and several layers of colon tissue. 1. List the cells found in the colon. 2. List the tissues found in the colon. 3. List the structures found in the colon. 2. Identify the following: 1. The longitudinally sectioned colon. 2. The luminal surface. 3. A dark pink zone, the mucosa. 4. The epithelium of the colon. 5. Lamina propria of the mucosa. 6. A central lighter coloured area, with fine pink coloured structures, the submucosa. 7. And outer irregular area, the outer muscular layer. 1. What is a single cell gland? 2. Describe a simple tubular gland. 3. What cells line a simple tubular gland? 4. What are the subdivisions of the mucosa? 3. View the slide at appropriate magnification, and identify the following: 1. A single cell gland, the goblet cell. 2. A simple tubular gland in longitudinal and cross section. 1. What cells line the simple tubular gland? 4. View the slide at higher magnification. 5. The mucosa comprises an epithelial layer and a loose connective tissue layer, the lamina propria. In the lamina propria, locate as many of the following cells as possible: 1. Fibroblasts 2. Plasma cells 3. Macrophages 4. Mast cells 5. Eosinophils 6. Lymphocytes 7. Smooth muscle fibers 1. What are the functions of each of the cells listed? 2. What is a distinguishing feature of each of the cells listed? 3. What is characteristic of a goblet cell? 6. Make an annotated drawing of each of the cell types. List their distinguishing characteristics, the function of each cell and other tissues, organs and structures where they can be expected to occur. 7. Make an annotated drawing of a goblet cell as well as a simple tubular gland (with goblet cells and columnar epithelial cells), as seen in longitudinal section. H/E

22 1. What are the distinguishing characteristics of the crypts as far as their structure and arrangement are concerned? 2. What is typical of the outer layer of M. externa? 3. What are the similarities and differences between the colon, appendix, vermiformis, ileum and duodenum?

23 Slide 44: Muscle fibers motor end plates Gold This is a slide of separated skeletal muscle fibers illustrating the motor end plates of the peripheral nervous system. Identify microscopically: 1. (i) Separated skeletal muscle fibers 2. (ii) Nerve fibers 3. (iii) Motor end plates A motor end plate. 1. What is the difference between an end plate and a motor end plate? 2. What is a motor unit?

24 Slide 59: Peripheral nerve: myelinated fibers This is a cross-section through a peripheral nerve that has been stained for myelin. Identify microscopically: 1. Myelin sheath 2. Axon A number of myelin sheaths in detail. 1. Are all the axons and myelin sheaths sectioned the same? 2. Why can't the structure of the axons be seen? Osmium

25 Slide 60: Cerebellum This slide is a sagittal section through the cerebellum. Silver Identify: A Macroscopic The grey and white matter B Microscopic The different layers of the cerebellar cortex White matter The neurons of the different layers of the cerebellar cortex. 1. What type of neurons are seen in the grey matter?

26 Slide 61: Cerebrum astrocytes Silver This is a section through the cerebrum illustrating neuroglia of the central nervous system. Identify microscopically: 1. Astrocytes 2. Blood vessels An astrocyte in detail. 1. What type of astrocyte is visible in this slide, and with which structure are they in contact? 2. Where are these astrocytes found? 3. What is distinctive of astrocytes? 4. Describe the perivascular feet?

27 Slide 61: Cerebrum This slide is a section through the cerebrum. Silver Identify: A Macroscopic The white and grey matter B Microscopic The different layers of the cerebral cortex. White matter The different types of neurons found in the different layers of the cerebrum. 1. What types of neuron are seen here? 2. What other structures are also visible in this slide?

28 Slide 69: Muscular artery and medium vein This slide is a cross-section through a medium artery and vein. H/E Identify microscopically: 1. The three layers of the vessels, and their subdivisions A diagram of the artery and vein showing a portion of detail of each layer. 1. What is the relative thickness of the three layers of the artery and vein with respect to each other? 2. What is characteristic of each layer seen in the artery and the vein? 3. What are the identifying features of the artery and the vein. Tabulate the differences and similarities of these arteries and veins.

29 Slide 77: Heart muscle This is a specimen of a cross section of heart muscle. H/E Identify microscopically: 1. Muscle fibers 2. Nuclei of the heart muscle fibers 3. Connective tissue A few cross sectioned heart muscle fibers. 1. What is characteristic of heart muscle in cross section? 2. How does heart and skeletal muscle differ in cross section? 3. Which connective tissue/s found in skeletal muscle is/are also found in heart muscle?

30 Slide 82: Multipolar neurons Silver This is a cross section through the spinal cord and spinal ganglion. The spinal cord is used as an example of multipolar neuron cell bodies. Identify microscopically: 1. Cell bodies 2. Nuclei 3. Neurofibrils 4. Meshwork 5. Nuclei of neuroglia A multipolar neuron. Questions 1. Is the neuron nuclei visible? 2. How do the neurofibrils appear and what are they in reality? 3. What is the meshwork surrounding the cell bodies in reality?

31 Slide 82: Spinal cord: synapse Silver This is a cross-section through the spinal cord showing the nerve ends (synapses) of the central nervous system, which are situated on the neuron cell bodies of the large anterior horn of the spinal cord. Identify microscopically: 1. Neuron bodies 2. End plates A neuron cell body with end plates included. 1. How are the end plates presented under the light microscope?

32 Slide 86: Heart muscle This is a longitudinal section through heart muscle, stained to show the cross striations clearly. Identify microscopically: 1. Muscle fibers 2. Nuclei of the heart muscle fibers 3. Intercalary discs and cross striations 4. Connective tissue A few heart muscle fibers. Indicate the different components in detail. 1. Which bands are visible with the light microscope? 2. How do the intercalary discs appear? 3. What are the regions at the poles of the nucleus called and how are they formed? Y/H

33 Slide 98: Ependyma This is a section through the choroid plexus illustrating neuroglia of the central nervous system. Identify microscopically: 1. Ependyma 2. Connective tissue and blood vessels A few ependymal cells, including the underlying blood vessels and connective tissue. 1. Where is the choroid plexus located? 2. What is the difference between ependyma and simple cuboidal epithelium? H/E

34 Slide 100: Umbilical cord This specimen is a cross section through the umbilical cord. It consists mainly of gelatinous connective tissue. The three large blood vessels present inside the umbilical cord are used as examples of smooth muscle. 1. View the slide at low magnification. You should be able to see three dark stained areas within the confines of the umbilical cord. Name the blood vessels found in the umbilical cord. What is the main component of the wall of blood vessels in general? What epithelium lines blood vessels? 2. Identify: 1. The three large blood vessels of the umbilical cord. 2. The lumens of each of the blood vessels. 3. The lighter stained areas around the blood vessels. What are the three components of connective tissue? Which area of a cell is stained with haematoxillin? What colour is haematoxillin generally? 3. View the slide at higher magnification. 4. In the lighter area, using appropriate magnification, identify the following: 1. Nuclei stained purple. 2. Fibroblasts. 3. Collagen fibers. 4. Amorphous ground substance. What are the function/s of fibroblasts? What are the function/s of collagen fibers? What are the function/s of amorphous ground substance? What are the relative proportions of each as seen in the umbilical cord? 5. In the blood vessels, identify the following: 1. Nuclei stained purple. 2. Longitudinally sectioned smooth muscle fibers. 3. Cross sectioned smooth muscle fibers. Imagine a balloon. What happens if the balloon is compressed from all sides? How is a balloon analogous to a muscle fibre and the nucleus within a muscle fibre? 6. Make annotated drawings of the following: 1. A line diagram, showing the orientation of the blood vessels in the umbilical cord. 2. The three components of gelatinous connective tissue in the correct ratio. Draw an additional fibroblast showing its microscopic detail (at higher magnification). 3. A few longitudinal and cross sectioned smooth muscle fibers. Note the shape and different diameters of the smooth muscle fibers. What is the shape of the fibroblasts and their nuclei? What is the shape of the smooth muscle fibre and their nuclei? Compare fibroblasts with smooth muscle fibres. How is the collagen arranged? How do the collagen fibers appear? How does the amorphous substance appear and how does it stain? H/E

35 What is characteristic of the cellular and nuclear shapes? How does the nucleus appear in a contracted smooth muscle fibre? What is found between the muscle fibres?