Indicates resources that are free. Lab 7: Respiratory Systems. This is precisely how the glands develop. The structure and function of the lung. Time: ~45-60 minutes. Method External examination 1. Lung adenocarcinoma is one of the most deadly human diseases. Interstitial restrictive lung diseases are characterized by inflammation or scarring of the lung tissueor filling of the air spaces with exudate and debris. To understand the microscopic and gross anatomy of the respiratory tract. g Fix a dead adult locust to the stage of a monocular microscope and examine the abdominal and thoracic spiracles more closely. Investigation: stage 2. g Fix a dead adult locust to the stage of a monocular microscope and examine the abdominal and thoracic spiracles more closely. 4.3 9 reviews. Alveolar ducts do not have walls of their own but are created by several openings of alveoli. Even though the lungs are primarily for respiration,studies indicate that they have many non-respiratory functions. The epithelium is devoid of goblet cells. Insert a length of rubber tubing into the trachea and attach it to a bellows or foot pump to inflate the lungs and then watch them deflate. Another adaptation to the task of efficient gaseous exchange is that the capillaries surrounding the alveoli are so thin that only one red blood cell may pass through at a time. Silicated macrophages stay for a long time and convert silica into silicic acid, which stimulates the proliferation of fibroblasts and collagen, leading to fibrosis of lung and node. q Cut the portion of gut longitudinally, open it out flat, wash away all trace of the gut contents and mount the specimen in water on a slide beneath a coverslip. There is also a brief view of a fully dissected set of lungs that shows the trachea, bronchioles, and individual lobes. cartilaginous hoops in the trachea these are horseshoe-shaped and keep the trachea open for the passage of air, but allow the tube to bend and flex easily. Rich matrix of elastic and reticular fibers provides the only support for duct and alveoli. The movement of spiracles may be hard to see because they are opened only at intervals when the locust is at rest. Fix it by means of pins through the legs and thorax. The presence of fluid in the tracheae obscures the fine terminations of the system. Alternatively you can use old enamel pie dishes or heavy-gauge aluminium dishes with sloping sides and fill these with molten black wax (eg, from Philip Harris; A72291 or A72308). The thin cytoplasm shows numerous pinocytotic vesicles. This could be shown to a class or used as an instructional guide for a teacher. Some of the listed structures may not be present in your sample depending on your order. AT k . Observe its movements and record carefully what you see. Thus anything that you can obtain through normal channels should not be SRM and could therefore be used. The main sections of lung tissue are also cut into at the abattoir (as part of the inspection process). During expiration, the diaphragm relaxes and is pushed up by the displaced digestive organs. The lungs are a pair of primary organs of respiration, present in the thoracic cavity beside the mediastinum. Hope that helps. 4.3 Something went wrong, please try again later. Performing a lung dissection Note: To be undertaken only by trained personnel in conjunction with a current Safety Data Sheet (SDS) and site-specific risk assessment. Rekhtman N, Ang DC, Sima CS, Travis WD, Moreira AL. The pathologies associated with the lung are diverse, with significant variations in disease presentation. 5 If students receive cuts or scratches during dissection, wash the wound in cold running water, allow minor wounds to bleed freely, and refer to a first aider. During each respiratory cycle (inspiration and expiration), the aeration of the lungs does not exceed 10% of its capacity. Word Document File. If particles make it down to the acinus, the macrophages are the last defense and janitors of the respiratory epithelium. Smooth muscle bundles are present at all levels of the airway to allow forregulation of airflow. Extrapulmonary restrictive diseases show thickening of alveolar septa and epithelium and are associated with an endothelial injury. Surfaces of the lung are specialised for exchanging materials. The surfactant is necessary to maintain an open airway. It is possible to learn about the function of lungs from diagrams, models and animations. Type II pneumocytes are also mitotically active and can replace the easily damaged type I pneumocytes. Khan YS, Lynch DT. In the conducting zone, the air is moistened, warmed, and filtered before it reaches the start of the respiratory region at the respiratory bronchioles. There are ten bronchopulmonary segments in each lung with their apex directed towards the hilum, and each is aeriated by a tertiary (segmental) bronchus[2]. IBO was not involved in the production of, and does not endorse, the resources created by Save My Exams. Granchi C, Bertini S, Macchia M, Minutolo F. Inhibitors of lactate dehydrogenase isoforms and their therapeutic potentials. It is essential to include the sections of related lymph nodes for histological evaluation, which will help in turn to understand the extent of metastasis of the lung tumors[16]. Some alveolar macrophages also go via lymphatics to hilar lymph nodes. Type I Pneumocytes (Alveolar lining cells). This allows air to flow from one alveolus to another, which may be beneficial if there is any blockage preventing air from entering alveoli through a direct route. The thickened mucus disrupts the mucociliary escalator filtration function of the lungs resulting in obstruction. These alveoli are lined by flattened epithelial cells called pneumocytes with a single opening. Explore the Beetle Dissection The outside of beetles can be shiny, dull, or extremely colorful. In addition to the animals mutilated in dissection, millions of live mice, rabbits, rats, turtles, and other animals are tormented and killed in crude university-level biology and psychology demonstrations. As you cut, let the lower blade of your scissors pull the locust up slightly. The collapse of the alveoli results in a significant loss of surface area for gas exchange. Alveolar epithelium is composed of type I pneumocytes, type II pneumocytes, and the occasional brush cells. 4 Insect saline is 0.9 g sodium chloride in 100 cm3 of distilled water. Comprehensive A Level Biology revision and teaching materials for use with UK and international exam boards. They may be thought of as the stem cells of the respiratory epithelium as they maintain the ability to potentiate ciliated cells and goblet cells[9]. It may be prudent to avoid dissecting locusts if students have taken an active role in caring for them. 4 Cleaning equipment and work surfaces: dissecting instruments are best autoclaved after use because most disinfectants attack metal instruments. . Since the elastic layer is difficult to visualize with routine stains, a special elastin stain may be used to demonstrate this finding. Contributed by Wikimedia Commons (CC by 2.5) https://creativecommons.org/licenses/by/2.5/deed.en, Histology, Section of Lung, Pneumonic. Alveolar macrophages (or dust cells) may be free within the alveolar space or sometimes connected to the alveolar wall. Any general stain will do in place of methylene blue. Histology, Lung. It is important that the locusts are treated with respect and not unduly stressed by handling students (and teachers) should handle them calmly and with care. Why do we dissect frogs? Oxygen diffuses directly from the tracheoles and oxidative phosphorylation occurs in the mitochondria, ensuring an efficient supply of ATP to the muscle fibres to provide energy for contraction. Since Cahan (1960) reported the first 48 cases that successfully underwent lobectomy with regional lymph node dissection, which was called radical lobectomy, this procedure has been a standard surgery for lung cancer. 3. The Control of Gene Expression (A Level only), 8.2 Regulation of Gene Expression (A Level only), 8.2.4 Producing Tissue Cultures of Explants, 8.2.6 Evaluating Data about Genetic Expression, 8.4.3 Investigating the Specificity of Restriction Enzymes, 8.4.9 Genetic Counselling & Personalised Medicine, Dissections are a vital part of scientific research, They allow for the internal structures of organs to be examined so that theories can be made about how they function, There are ethical concerns surrounding dissections, People worry about how the animals for dissections are raised and killed, It goes against the religious beliefs of some individuals, The biological specimen used for dissection should be from a reputable source and should be disposed of in the correct manner, If multiple specimens are being dissected then they should be taken from individual organisms of the same species and roughly the same age, A lab coat, gloves and eye protection should be worn, To avoid contamination with biological material (which could cause an allergic reaction), Place the specimen on the dissecting board, Use the tools to access the desired structure, When using the scalpel cut away from your body and keep your fingers far from the blade to reduce the chance of cutting yourself, Scissors can be used for cutting large sections of tissue (cuts do not need to be precise), Scalpel enables finer, more precise cutting and needs to be sharp to ensure this, Use pins to move the other sections of the specimen aside to leave the desired structure exposed, It can be hard to see some of the smaller, finer structures within organs, The specimens do not reflect how the tissue would look in a living organism, If only a single specimen is dissected then anomalies found within that specimen may be ignored or glossed over, The main structures of the gas exchange systems in mammals and fish can be revealed in dissections, The much smaller gas exchange systems of organisms such as insects can be more difficult to examine by dissection, The key structures that can be seen from a dissection of mammalian lungs are shown in the image below, The smaller structures such as the alveoli can be hard to distinguish in a dissected lung, The key structures that can be seen from a dissection of fish gills are shown in the image below, The smaller structures such as the lamellae can be hard to distinguish in a dissected fish, Microscopes are also needed to observe the structures. The Lungs, Schematic longitudinal section of a primary lobule of the lung, respiratory bronchiole, alveolar duct, atria, alveolar sac, alveolus or air cell, pulmonary artery, pulmonary vein, lymphatic, lymph node. Identify the most prominent organ the brown alimentary canal (or gut). At the end of expiration, some air is always left in the lungs to warm the new air coming into the lungs . Arthritis is the inflammation of a joint (s). In The Golgi Complex: Methods and Protocols, . Tes classic free licence. The type II Pneumocytes are the cuboidal cells grouped in 2-3, large, a central, and plump nucleus with dispersed chromatin and prominent nucleoli. Beyond that with the beginning of respiratory bronchiole is the respiratory part of the respiratory system. Set of lungs from diagrams, models and animations lung tissueor filling of the respiratory system of,! Of type I pneumocytes scissors pull the locust is at rest % of its capacity equipment work. 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