TITLE: RESPIRATORY AND CIRCULATORY SYSTEM OF THE GRASSHOSPER INTRODUCTION The grasshopper is classified in the order of Orthoptera and in the class of insects. Orthoptera derived from the word "orthos" means straight or rigid while "ptera" means wing. The grasshopper is classified in the class Insecta because it has 3 body segments which include the head, thorax and abdomen. Insects have the characteristic of an articulated exoskeleton with each body segment equipped with a dorsal sclerite, back, sternum and pleura (Chapman, 1998). It is known that animal cells are immersed in an extracellular fluid (ECF) in which most cells exchange solutes with extracellular substances. fluid and not with the external environment which is facilitated by the mass flow (circulatory system) of the ECF and powered by pumps (hearts). Most insects have only one main pump, one dorsal vessel, multiple accessory pumps with circulating portion of ECF known as blood or hemolymph. Four main functions of hemolymph are as a means of transporting hormones and nutrients between tissues and as storage sites for some nutrients and water (Chapman et al., 2013). The gas exchange process occurs via a system of air-filled internal tubes, tracheal system, finer branches that extend to all parts of the body and become functional intracellular muscle fibers in which oxygen can be transported in the gaseous phase directly to the sites of use. It is known that some insects possess hemocyanin, an oxygen-transporting pigment present in the blood, some aquatic insects have gaseous exchanges with water using series of tracheae under the permeable cuticle while in some aquatic and terrestrial insects, the existence of spiracles (tracheae which opens through segmented pores) functions as a filter s...... center of paper ......pic/289001/insect/41290/Circulatory-system.Chapman, RF (1998). The structure and function of insects (4th ed.). Cambridge University Press, Cambridge, UK. Chapman, R. F., Simpson, S. J., & Douglas, A. E. (2013). Insects: Structure and Function (5th ed.). Cambridge University Press, Cambridge, UK. Jamal, J. (n.d.). Bio-network: invertebrate circulatory system. Retrieved May 6 from http://bionetonline.blogdetik.com/invertebrate-circulatory-system/John RM (2005). Insect physiology circulatory system. NC State University, General Entomology ENT 425. Web. May 19, 2014. Giovanni WB (2000). Respiratory physiology: the essential elements. Baltimore: Breathing. 1–10.Lighton, J.R.B. (1996). Discontinuous gas exchange in insects. Entomology Review 41:309–324. Ryan S., Josh A., and Nick SS (2002). Evolution of the respiratory system. System diversity. 2:33.