Topics and aims. Introduction. Metabolism and Excretion

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1 Topics and aims Introduction This section contains instructions that are applicable to all material, irrespective of your specific course. Please take note and make sure to comply. Failure to comply could lead to difficulty in mastering the knowledge areas. IMPORTANT: Course specific instructions will be supplied. Each course will complete different areas in different sequences. This will be communicated before and during each practical session. 1. Describe the six levels of organisation of the human body. 2. Name eleven organ systems of the human body. 3. Define histology. 4. Identify the four main tissue types. 5. Discuss the function of each tissue type in the human body. 6. Correlate structure, location and function for all. You should bring your notes, a handbook, stationary and additional paper to the practical sessions. Coloured pencils are useful but not mandatory. You will be required to use the computers in the laboratory. Keep your login information current and working. There are three components to each topic. The first component consists of Aims relating to the topic. Make sure you are able to fulfil these by the end of the session. Next is a set of slides which have to be studied for that topic. Slides have to be finished before the end of each session. The third component is the review section. You can use this to assist in assessing your knowledge for each topic and can be completed at your leisure. Each slide consists of a description, instructions, drawing instructions and a set of reflection questions. You have to complete the slides before the conclusion of each practical session. Read the description and instructions for each slide carefully. The description and instructions will assist you in orienting the slide and identifying the tissues and structures. About drawings. Drawing is an important part of the learning process. We do not require textbook sketches, but drawings should be complete and should be annotated. Use all keywords from the aims and description as annotations. Create a glossary by adding a concise definition or description next to each annotated term. Always add your name and a date to material you are working on. In the case of the workbook, your name should be in front of the book. Add the date as you work on topics and slides. This will assist in building a mental image of progression on the content. Metabolism and Excretion The hepatobiliary system, kidneys, skin and lungs are important for metabolism and excretion. After absorption of any substance (nutrients, drugs or toxins); be it through the digestive tract, skin, lungs, the eye, mammary gland or uterus, it is distributed via the bloodstream to reactive sites. By metabolism, the body process absorbed substances. In some cases, detoxification can produce substances more toxic than the initial compound. The liver receives the portal circulation, and is most commonly involved in detoxification. The kidneys are responsible for excreting metabolites not used by the body. Knowledge of these processes and the ways it can vary is important to evaluate treatment of patients. The liver, kidney, skin and lungs are dealt with in their respective sections.

2 Digestive system The purpose of this topic is to practically illustrate the structures, organs and glands of the gastrointestinal tract. The secretory units which were covered in the session on glandular epithelia, should be reviewed for the salivary glands. The digestive system can be divided into three parts: 1. Upper Digestive Tract (oral cavity, oesophagus and stomach). Histology of the structures found in and around the mouth, the oesophagus and stomach. 2. Lower Digestive Tract (duodenum to anus). Most digestion and absorption takes place from the duodenum to the ileum. The colon and lower is involved with water balance and excretion. 3. Accessory organs. Those organs whose primary function related to the digestive system. These include the liver, gall bladder and pancreas. Digestive system in general 1. Describe the generic components, organisation and functions common to most of the digestive tract. 2. Describe how the basic organisation of the digestive tract is modified along its course. 3. Relate the structure to the function of each section of the digestive tract. 4. Describe the morphology and histology of each component of the digestive tract. 5. Describe functional variations related to differing functions. 6. Relate the morphology with the function of each component of the digestive tract. 7. Describe the appearance, organisation and functions of the epithelial cells throughout the digestive system. 8. Discuss the distribution of lymphoid tissue in the digestive system. 9. Identify and describe the cells found in the various areas of the digestive tract. 10. Describe the specialised functions of cells found in the various areas of the digestive tract. 11. Identify and describe the intrinsic glands of the digestive tract. 12. Describe the surface topology of the mucosa of the digestive tract. 13. Identify the layers of the digestive tract and compare cross and longitudinal appearance. 14. Define the cellular composition of the mucosal layers and their function. 15. Describe changes in layers in the transitional areas of the digestive tract. Upper digestive tract 1. Describe the characteristics of the lip. 2. Name and identify the papillae on the tongue. 3. Name, identify and compare the salivary glands. 4. Identify and describe the structure and function of the salivary glands. 5. Describe and identify the histological structures of teeth. 6. Identify and describe the oesophagus. 7. Identify the regions of the stomach. 8. Identify the different types of secreting cells in gastric glands., and the function of each. Lower digestive tract 1. Identify the neural tissue in the intestines and the coats in which they are found. 2. Distinguish between the various sections of the small and large intestine.

3 Accessory organs 1. Describe the organisation of liver tissue. 2. Recognise and describe the histological structure and function of liver lobules. 3. Explain how blood and bile pass through the liver lobules and relate this to liver function and pathologies. 4. Identify and describe the structure of the gall bladder and bile duct. 5. Identify and describe the structure and function of the exocrine and endocrine pancreas.

4 Revision Introduction What are the three types of barriers responsible for protection of the human body against pathogenic factors? Give an example of each. (physical, chemical, cellular) Cardiovascular system Tabulate the differences between elastic and muscular arteries and arterioles. Name the 3 types of capillaries. Tabulate the differences between small, medium and large veins. Name the 3 layers of the heart wall. Explain the conducting system of the heart. How does some common diseases affect the structures of the cardiovascular system? Digestive system Name and discuss the three types of papillae. What cells are responsible for the secretion of dentine? Name the 3 main salivary glands and their secretions. Tabulate the differences in the layers of the oesophagus, stomach, small intestine and colon. Name 7 functions of the liver. Name and discuss the functional structures of the liver. What classifies liver cirrhosis? What layer is absent in the mucosal layer of the gall bladder? What is the capsule of the pancreas composed of? How is ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation controlled? Name the six fundamental activities of the digestive system, giving an example of each. Why does the stomach not digest itself? Describe the mechanical and chemical digestion of food entering the stomach. What are the adaptations of the small intestine wall that increase its absorptive capacity What features are unique to the wall of the large intestine? Describe the contributions of the unique features of the large intestine to its function. What roles does bacterial flora play in functioning of the digestive system? Identify three main features of liver histology that are critical to its function.

5 Liver This slide is a section through the liver. Various 1. Slide 46: A section through the human liver (H/E). 2. Slide 48: A section through the liver to demonstrate reticular fibers and the space of Disse (Silver). 3. Slide 68: A section through pig liver. In the pig, liver lobules are well defined, in contrast to those of humans (H/E). 4. Slide 110: A section through liver which has been injected with Berlin blue, to show the blood vessels (H/E). These slides should be viewed in conjunction with each other, and supplemented with suitable additional resources. 1. View the slides at low magnification. At this magnification, the mass of liver tissue should be visible. In some cases, the capsule could still be present. Small structures like blood vessels can be seen, but may not be specifically identified. 1. How does human liver differ from pig liver? 2. Name the three types of fibres found in connective tissue. 3. What are characteristic of each of the three types of fibres of connective tissue? 4. What characteristic is used to identify reticular fibres? 5. What are the three ways used to describe the arrangement of liver tissue? 6. Give the structures and their components used to demarcate the borders used to describe the arrangement of liver tissue. 7. What cells are found in liver lobules? 2. Identify the following: 1. The mass of liver tissue. 2. A capsule (if present). 3. Blood vessels and ducts within the mass of liver tissue. 1. Where are reticular fibres specifically found? 2. How are reticular fibres arranged three dimensionally? 3. What is a portal area and where are they found? 4. From which anatomical structures does the liver receive blood? 5. Where do portal areas drain into? 6. What drains into the portal area? 7. What drains from the liver? 8. How are sinusoids arranged? 3. View the slide at higher magnifications. Structural detail should be discernible and at the highest magnification, you should be able to see cell borders. 4. Compare slide 46 (H/E) and slide 48 (silver stained for reticular fibres) at high magnification. 1. Identify the nuclei of the liver parenchyme in each. 2. Identify the cell borders in each. 1. Where are the cell borders located relative to the reticular fibres? 5. Identify microscopically: 1. Liver lobules.

6 2. Liver parenchyma. 3. The fibrous capsule of the liver (capsule of Glisson). 4. Vena centralis. 5. Portal areas. 6. Sinusoids and their position. 7. Networks of reticular fibers. 8. Outlines or ghost image of liver cells. 9. Position of the space of Disse 1. How does reticular fibres differ from collagen and elastic fibres? 2. Where do sinusoids drain into? Make annotated drawings and line diagrams to illustrate the following: 1. A cross-section through a liver lobule, showing the components of the three types of arrangements. 2. The reticular fibers, cords of liver cells and sinusoids. Indicate the general outline of the liver cells. 3. The blood supply and drainage of the liver lobule. Also indicate the drainage of gall.