BIOL110 Lecture Notes - Lecture 9: Contractile Vacuole, Germ Layer, Reproduction
23 Nov 2017
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Remove across membrane or use contractile vacuoles: contractile vacuole. Colloblasts (sticky boys): adhesive cells used in prey capture. Contain muscle fibres fill w/ water from cytoplasm release outside cell: prevent protozoa from taking in too much water(by osmosis) lysis, essential to osmoregulation, concern for freshwater. No true tissues (no specialized tissues or layers or organs) Instead has mesohyle(jelly matrix full of collagen protein fibrils and spicules) Both germ layers involved in respiration, excretion, movement, reproduction. Dimorphic: polyp(hydroid,mostly sessile) and medusa (jellyfish form,free- swimming) Epitheliomuscular cells: communicate w/ each other coordinate movement. Nerve net: diffuse nervous system, rhopalia(rhopalium) sense organs (scyphozoa and cubozoa) Osmotic pressure: large conc. gradient in cnidocyte open operculum(cover) water rush in high water volume causes nematocyte to shoot out. Scyphozoa, aurelia: dioecious, strobilation(sac like buds break loose turn into medusa) Spicules=make sponges rigid make good fossils (spicules made by clerocytes) Choanocytes(flagellated cells create water flow) trap food (suspension feeding)
