01:146:328 Lecture Notes - Lecture 15: Hydrostatic Skeleton, Cuticle, Hemolymph
1 Dec 2016
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Introduction - about 25,000 species: found in every environment on earth i. ii. Some are parasitic: of plants: 10% of crop losses is caused by this. 2: vertebrates are also parasitized (cause of major medical issues) Invertebrates like cockroaches have their own parasites: about 3 billion humans are dealing with this infection, kingdom: animalia (found in ecdysozoa) i. 2 most abundant phyla in this group are: arthropoda and nematoda: arthropods have a hard exoskeleton, nematoda have a soft cuticle ii. Outside is body wall and then a digestive tract inside: body wall has three parts, outer layer is cuticle. Covers entire body surface and all of the opening i: cuticle is metabolically active but not as active as the tegument in platyhelminthes, hypodermis. Functions: i. ii: transport function: solutes to tissue, structural function, psudocoel hydrostatic skeleton. This means there is a mouth gut anus: foregut (the opening into the worm) is lined with cuticle i.
