Exercise No. 3: Excretory System: Malpighian Tubules PDF

Exercise No. 3: Excretory System: Malpighian Tubules Introduction The insect excretory system is consisting of two important organ system: the Malpighian tubules (MTs) and the hindgut (Nation et al., 2008). Malpighian tubules are the main osmoregulatory and excretory organs of ins...

Exercise No. 3: Excretory System: Malpighian Tubules Introduction The insect excretory system is consisting of two important organ system: the Malpighian tubules (MTs) and the hindgut (Nation et al., 2008). Malpighian tubules are the main osmoregulatory and excretory organs of insects. They are finger-like projections of the intestinal tract. The tubules at the proximal ends are attached to the intestine at the junction of the midgut and hindgut while the tubules at the distal ends floats freely in the hemolymph of the insect (Silverthorn, 1995). They are responsible for the insect homeostasis, intestinal pH, regulation and secretion of calcium, immunological defense, and clearance of toxic substances (Nocelli et al., 2016). The main compounds that are finally excreted are ammonia, urea and uric acid. Learning Outcomes 1. Determine how insects use Malpighian tubules to excrete wastes. Materials 70% ethyl alcohol Ice box Specimen: cockroach Dissecting kit: forceps, dissecting needle, dissecting pin Scalpel/razor blade Plastic Petri dish, gloves, mask, laboratory gown, magnifying glass Dye (Venus)/Red Ink Procedure 1. Anesthetize two cockroaches by putting them in an ice box for 3 min prior to dissection. 2. Fill the syringe with a red dye.  8 CrsCode101: Course Title 3. Insert the needle ventrally, through the intersegmental membrane, to the left or right of the midline. 4. Run the needle anteriorly against the integument, to prevent the injury to intestinal tract. Inject the solution and withdraw the needle. 5. Immediately after injecting the red dye, dissect one cockroach and observe the Malpighian tubules. 6. After one hour, dissect the other cockroach and observe the areas of dye concentration in the Malpighian tubules using the magnifying glass. 7. Take pictures on the result of you experiment. Attach these pictures on your research paper. Guide questions and instructions on how to prepare and submit the laboratory Make a research paper about the result of your experiment. Follow the format: introduction, materials and method, results with photos, discussion, conclusion and references. Send your outputs to [email protected] (Mannylen C. Alde) or [email protected] (Jay Darryl L. Ermio). Additional Resources Nation, J. L.2008. Insect Physiology and Biochemistry, Second Edition. CRC Press. 69 p. References BELL, W.J., 2012. The Laboratory Cockroach: Experiments in cockroach anatomy, physiology and behavior. Springer Science & Business Media. p47 NOCELLI, R.C., P. CINTRA-SOCOLOWSKI, T.C. ROAT, E.C. SILVA-ZACARIN, and O. MALASPINA. 2016. Comparative physiology of Malpighian tubules: form and function. Open Access Insect Physiology, 6, pp.13-23. SILVERTHORN, D. U. 1995. Active Transport in Insect Malpighian Tubules. Pages 141-154, in Tested studies for laboratory teaching, Volume 16 (C. A. Goldman, Editor). Proceedings of the 16th Workshop/Conference of the Association for Biology Laboratory Education (ABLE), 273 pages. Page 8 of 34 Vision: A globally competitive university for science, technology, and environmental conservation. Mission: Development of a highly competitive human resource, cutting-edge scientific knowledge TP-IMD-04 V0 07-15-2020 and innovative technologies for sustainable communities and environment. No.