BIOL 111 Lab Exam 2

BIOL 111 Lab Exam 2 - Bio Lab Exam 2 Lab 7 Phylum Cnidaria...

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Bio Lab Exam 2 Lab 7 Phylum Cnidaria (jellyfish, coral) posses cnidocytes, marine, radially symmetrical Cnidocytes: specialized stinging cells, assists in capturing prey and defense Radially Symmetrical: arms/tentacles radiating outward from mouth region Polyp: oral surface upward, aboral surface attached to a substrate, asexual reproduction Medusa: free swimming, mouth downward, sexual reproduction Dimorphic: showing both forms Hydra: small, freshwater polyp (no medusa), carnivore, 2 tissues with cavity Locomotion: gliding along foot, inching with tentacles and foot, somersaulting, floating Feeding: capture prey with tentacles, subdue with toxic stings of the nematocyst, digestion in gastrovascular cavity, absorbed by gastrodermal cells Nematocyst: filament with barb at end, stinging, entangling or adhesive Hypostome: conical elevation with mouth (entrance and exit) opening at tip Tentacles: food catching arms that radiate from the hypostome, contain cnidocytes Gastrovascular Cavity: where digestion and absorption of food occurs, some gas exchange Body Column: mesoglea between 2 tissue layers of cells: Epidermis: outer layer of epithelial cells Gastrodermis: inner layer Mesoglea: thin, gelatinous layer between epidermis and gastrodermis, provides support as a hydrostatic skeleton Basal Disc: posterior end of the body used to attach to a substrate, locomotion Epitheliomuscular Cells: cover/line surfaces, contractile muscle fibers (longitudinal in epidermis, circular in gastrodermis) Cnidocytes: in epidermis, contain nematocyst capsules (triggered by cnidocils) Cnidocils: bristle-like projections on the outer surface of the cnidocyte (like cilia) Neurons: nerve cells, extend along base of epidermis and gastrodermis, form nerve net Sensory Cells: type of receptor neuron in epidermis, sensitive to external stimuli Gland Cells: in epidermis of basal disc, secrete sticky substance for anchoring Interstitial Cells: between epitheliomuscular cells in epidermis, can divide continuously and into other types of cells (like stem cells) Sexual Reproduction: occurs in the fall, sperm from male is released into the water and enters the ovary through a hole in the epidermis, zygote forms hard covering and drops to sediment Asexual Reproduction: budding, 2-4 days Gonionemus: small medusa, shallow marine, some cling to seagrass, some poisonous Bell: dome of epidermis, gastrodermis, mesoglea Tentacles: arms for capturing prey/attaching Tentacular Bulbs: dark swelling at base of tentacles with interstitial cells (develop into cnidocytes) Adhesive Pads: near tips of tentacles, for attachment
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Cnidocytes: stinging cells in spiral swellings (batteries) on tentacles, each contain nematocyst which projects a penetrating/paralyzing tube Velum: shelf under bell, assist in propulsion (jellyfish don’t have) Manubrium: tube inside bell ending in mouth, homologous to hypostome (hydra), base a dark square Stomach: below base of manubrium, lighter in color, extracellular digestion
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BIOL 111 Lab Exam 2 - Bio Lab Exam 2 Lab 7 Phylum Cnidaria...

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