ENTO 210 Lecture Notes - Lecture 3: Arthropod Cuticle, Hox Gene, Hemolymph
10 Sep 2016
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Document Summary
After molting the body of the insect is very vulnerable and soft. Open circulatory system, haemolymph ows freely through body cavity compound eyes. Hard layer made of largely chitin (the exoskeleton) The exoskeleton is made up of a structure called the cuticle. split into: epicuticle, exocuticle, endocuticle, and the epidermis. Epicuticle: wax and cement layer that provides waterproo ng, and color. Exocuticle is hardened by sclerotization in which chitin proteins become crossed-link with each other. Endocuticle is soft and pliable and proves exibility. Epidermis consists of a layer of life cells that secrete the material that makes up the rest of the cuticle. Molting steps: very stepwise processes endoskeleton is reabsorbed. Arthropod expands in size by in ating air bags inside body. Tagmosis- segments frequently fused to form new function units. Anthropod appendages have taken on multiple different shapes and sizes due to the many function/tasks they need them for. Hox gene responsibility in determining where body structures form.
