MARB 435 1st Edition Lecture 6Outline of Current Lecture Notes taken on CtenophoraCurrent LectureCtenophora represents the animals known as comb jellies. Ctene means comb, and the jellies are lined with many of the cilia ctenes down their body in order to swim. That is why they are called comb jellies.Facts about comb jellies: Mostly planktonic Exclusively marine Approximately 80 species Size range: few mm to 30 cm or more (one grows to over 1.5 m in length) Use cilia for locomotion Transparent and gelatinous Voracious predators They have Biradial symmetry Synapomorphies: ctenes, organized in comb rows Collocytes (on tentacles)Tissue Layers BilayeredEpidermisThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Outer layer: multiciliated cells, mucus-secreting cells, collocytesand sensory cells Inner layer: myoepithelial cells and nerve net Gastrodermis Nutritive cells Photocytes (bioluminescence) (this is what shines on the comb jelly that we saw in the lab) Mesoglea Extracellular matrix with collagen Ameboid cells Nerve cells MyocytesComb jellies have muscles!The comb jelly musculature consists of actin and myosin filaments. They have two types of musculature, Epithelial and non-epithelial.They use their muscles to contract and control their tentacles. However, unlike jellyfish, they do not contract their bodies to move, they use cilia. Muscles contractions are typically only used in benthic forms.Terms to know:1. Epidermal nerve net- nervous system that is concentrated near the comb rows, pharynx, tentacles and aboral organ.2. Mesogleal nerve cells- innervate mesogleal musculature3. Apical organ- serves as rudimentary brain for the comb jelly4. Spin capture- a typical feeding technique where a comb jelly will grasp food with its tentacle and spin with it until the prey reaches its mouth where it licks the food off of its tentacle5. Ctenes- tiny rows of combs that a ctenophore possesses for locomotion6. Haeckeliarubra- a ctenophore that does not have collocytes but has cnidocysts that it steals from its prey and uses for defence.7. Collocytes- cells that are similar to cnidocysts but do not sting. They are sticky instead and produce a sticky mucous to capture prey.Other facts:Some ctenophores can be invasive, such as the MnemiopsisleidyiMake sure you know the 3 germ layers of the ctenophore!Remember to think about the way it moved and functioned from the
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