Nervous System in Gastropoda
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CHAPTER 10 MOLLUSCS 10.1 a Significant Space A
PART file:///C:/DOCUME~1/ROBERT~1/Desktop/Z1010F~1/FINALS~1.HTM CHAPTER 10 MOLLUSCS 10.1 A Significant Space A. Evolved a fluid-filled space within the mesoderm, the coelom B. Efficient hydrostatic skeleton; room for networks of blood vessels, the alimentary canal, and associated organs. 10.2 Characteristics A. Phylum Mollusca 1. Contains nearly 75,000 living species and 35,000 fossil species. 2. They have a soft body. 3. They include chitons, tooth shells, snails, slugs, nudibranchs, sea butterflies, clams, mussels, oysters, squids, octopuses and nautiluses (Figure 10.1A-E). 4. Some may weigh 450 kg and some grow to 18 m long, but 80% are under 5 centimeters in size. 5. Shell collecting is a popular pastime. 6. Classes: Gastropoda (snails…), Bivalvia (clams, oysters…), Polyplacophora (chitons), Cephalopoda (squids, nautiluses, octopuses), Monoplacophora, Scaphopoda, Caudofoveata, and Solenogastres. B. Ecological Relationships 1. Molluscs are found from the tropics to the polar seas. 2. Most live in the sea as bottom feeders, burrowers, borers, grazers, carnivores, predators and filter feeders. 1. Fossil evidence indicates molluscs evolved in the sea; most have remained marine. 2. Some bivalves and gastropods moved to brackish and fresh water. 3. Only snails (gastropods) have successfully invaded the land; they are limited to moist, sheltered habitats with calcium in the soil. C. Economic Importance 1. Culturing of pearls and pearl buttons is an important industry. 2. Burrowing shipworms destroy wooden ships and wharves. 3. Snails and slugs are garden pests; some snails are intermediate hosts for parasites. D. Position in Animal Kingdom (see Inset, page 172) E. -
Mollusca, Archaeogastropoda) from the Northeastern Pacific
Zoologica Scripta, Vol. 25, No. 1, pp. 35-49, 1996 Pergamon Elsevier Science Ltd © 1996 The Norwegian Academy of Science and Letters Printed in Great Britain. All rights reserved 0300-3256(95)00015-1 0300-3256/96 $ 15.00 + 0.00 Anatomy and systematics of bathyphytophilid limpets (Mollusca, Archaeogastropoda) from the northeastern Pacific GERHARD HASZPRUNAR and JAMES H. McLEAN Accepted 28 September 1995 Haszprunar, G. & McLean, J. H. 1995. Anatomy and systematics of bathyphytophilid limpets (Mollusca, Archaeogastropoda) from the northeastern Pacific.—Zool. Scr. 25: 35^9. Bathyphytophilus diegensis sp. n. is described on basis of shell and radula characters. The radula of another species of Bathyphytophilus is illustrated, but the species is not described since the shell is unknown. Both species feed on detached blades of the surfgrass Phyllospadix carried by turbidity currents into continental slope depths in the San Diego Trough. The anatomy of B. diegensis was investigated by means of semithin serial sectioning and graphic reconstruction. The shell is limpet like; the protoconch resembles that of pseudococculinids and other lepetelloids. The radula is a distinctive, highly modified rhipidoglossate type with close similarities to the lepetellid radula. The anatomy falls well into the lepetelloid bauplan and is in general similar to that of Pseudococculini- dae and Pyropeltidae. Apomorphic features are the presence of gill-leaflets at both sides of the pallial roof (shared with certain pseudococculinids), the lack of jaws, and in particular many enigmatic pouches (bacterial chambers?) which open into the posterior oesophagus. Autapomor- phic characters of shell, radula and anatomy confirm the placement of Bathyphytophilus (with Aenigmabonus) in a distinct family, Bathyphytophilidae Moskalev, 1978. -
Structure and Function of the Digestive System in Molluscs
Cell and Tissue Research (2019) 377:475–503 https://doi.org/10.1007/s00441-019-03085-9 REVIEW Structure and function of the digestive system in molluscs Alexandre Lobo-da-Cunha1,2 Received: 21 February 2019 /Accepted: 26 July 2019 /Published online: 2 September 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The phylum Mollusca is one of the largest and more diversified among metazoan phyla, comprising many thousand species living in ocean, freshwater and terrestrial ecosystems. Mollusc-feeding biology is highly diverse, including omnivorous grazers, herbivores, carnivorous scavengers and predators, and even some parasitic species. Consequently, their digestive system presents many adaptive variations. The digestive tract starting in the mouth consists of the buccal cavity, oesophagus, stomach and intestine ending in the anus. Several types of glands are associated, namely, oral and salivary glands, oesophageal glands, digestive gland and, in some cases, anal glands. The digestive gland is the largest and more important for digestion and nutrient absorption. The digestive system of each of the eight extant molluscan classes is reviewed, highlighting the most recent data available on histological, ultrastructural and functional aspects of tissues and cells involved in nutrient absorption, intracellular and extracellular digestion, with emphasis on glandular tissues. Keywords Digestive tract . Digestive gland . Salivary glands . Mollusca . Ultrastructure Introduction and visceral mass. The visceral mass is dorsally covered by the mantle tissues that frequently extend outwards to create a The phylum Mollusca is considered the second largest among flap around the body forming a space in between known as metazoans, surpassed only by the arthropods in a number of pallial or mantle cavity. -
Torsion & Detorsion in Gastropoda
BYJU'S INSTALL Torsion & Detorsion In Gastropoda Home (https://www.iaszoology.com) / Torsion & Detorsion In Gastropoda BYJU'S BYJU'S Live | Learn From Home INSTALL In freshwater and terrestrial molluscs, there is no free swimming larval stage. Both trochophore and veliger stages are passed inside the egg and a tiny snail hatches out of the egg. Early larva is symmetrical with anterior mouth and posterior anus and gills lie on the posterior side. As the larva develops shell its visceral mass starts twisting in anticlockwise direction to rearrange the visceral organs so that they are accommodated inside the coils of the shell and openings of organs are shifted to the anterior side where the shell opening lies. During torsion visceral and pallial organs change their position by twisting through 180°. Posterior mantle cavity is brought to the front position. Gills and kidney move from left to right side and in front which helps in breathing. In nervous system the two pleurovisceral connectives cross themselves into a figure of 8, one passing above the intestine and the other below it. Alimentary canal twists in the visceral mass and opens by anus on the side of the head on the anterior side. After torsion the foot can be withdrawn after the head. ^ Top During torsion head and foot remain fixed and rotation takes place in the visceral mass only behind the neck so that the visceral organs of the right side come to occupy the left side and vice versa. BYJU'S INSTALL Before torsion the visceral mass points forward and the mantle cavity is posterior in position. -
The Essential Bronchoscopist© Learning Bronchoscopy-Related Theory in the World Today
The Essential Bronchoscopist© Learning bronchoscopy-related theory in the world today Henri Colt MD, FCCP University of California, Irvine Irvine, California [email protected] http://www.bronchoscopy.org/education This page intentionally left blank. The Essential Bronchoscopist© Learning bronchoscopy-related theory in the world today Contents Module I ……………………………………………………………………………… Page 3 Module II ……………………………………………………………………………..Page 41 Module III …………………………………………………………………………….Page 77 Module IV …………………………………………………………………………….Page 113 Module V ……………………………………………………………………………..Page 149 Module VI …………………………………………………………………………….Page 187 Conclusion with Post-Tests .………………………………………………….Page 233 1 This page intentionally left blank. 2 The Essential Bronchoscopist© Learning bronchoscopy-related theory in the world today MODULE 1 http://www.bronchoscopy.org/education 3 This page intentionally left blank. 4 ESSENTIAL BRONCHOSCOPIST MODULE I LEARNING OBJECTIVES TO MODULE I Welcome to Module I of The Essential Bronchoscopist©, a core reading element of the Introduction to Flexible Bronchoscopy Curriculum of the Bronchoscopy Education Project. Readers of the EB should not consider this module a test. In order to most benefit from the information contained in this module, every response should be read regardless of your answer to the question. You may find that not every question has only one “correct” answer. This should not be viewed as a trick, but rather, as a way to help readers think about a certain problem. Expect to devote approximately 2 hours of continuous study completing the 30 question-answer sets contained in this module. Do not hesitate to discuss elements of the EB with your colleagues and instructors, as they may have different perspectives regarding techniques and opinions expressed in the EB. While the EB was designed with input from numerous international experts, it is written in such a way as to promote debate and discussion. -
Dirona Albolineata Bobby Coalter OIMB
The Development ofa Northeast Pacific Opisthobranch: Dirona Albolineata Bobby Coalter OIMB - Comparative Embryology Spring 2008 INTRODUCTION Although the aesthetics and behaviors are well described in many field guides, little information is available in the literature concerning the early development ofnudibranch molluscs from the northeast Pacific. Hurst (1967) compared morphological traits ofthe egg masses and veliger larvae of nudibranchs from the San Juan archipelago. However, she described characters for identification in the field, and gave no indication ofembryonic duration. M. F. Strathmann (1987) provided a summary of the available data on several nudibranchs ofthis region, but did not include a developmental time table for D. albolineata. Goddard (1992) characterized the mode ofdevelopment and variability in mode of development in nudibranch molluscs from the coastal waters ofthe northeast Pacific Ocean. His work included D. albolineata and will be ofuse for making comparisons with my data presented here. During the Comparative Embryology course at OIMB, Spring term 2008, I reared cultures ofthe arminid nudibranch Dirona albolineata. I also observed the early development ofthis opistibranch species which is characterized by spiral cleavage, gastrulation by invagination and epiboly, and offspring that hatch as planktotrophic veligers after having passed through a trochophore stage. After metamorphosis, D. albolineata juveniles are capable ofusing their jaws and narrow radula to crack shells ofsmall snails. This carnivorous species has also been observed to feed on ascidians, such as Bugula, and bryozoans. The body ofmature D. albolineata is translucent to purplish with a wide, undulating frontal veil and compressed, sharp-tipped cerata. The anterior edge ofthe veil, the tail and the lateral edge ofeach cerata are all lined with an opaque white line. -
Historical and Biomechanical Analysis of Integration and Dissociation in Molluscan Feeding, with Special Emphasis on the True Limpets (Patellogastropoda: Gastropoda)
Historical and biomechanical analysis of integration and dissociation in molluscan feeding, with special emphasis on the true limpets (Patellogastropoda: Gastropoda) by Robert Guralnick 1 and Krister Smith2 1 Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, CA 94720-3140 USA email: [email protected] 2 Department of Geology and Geophysics, University of California, Berkeley, CA 94720 USA ABSTRACT Modifications of the molluscan feeding apparatus have long been recognized as a crucial feature in molluscan diversification, related to the important process of gathering energy from the envirornment. An ecologically and evolutionarily significant dichotomy in molluscan feeding kinematics is whether radular teeth flex laterally (flexoglossate) or do not (stereoglossate). In this study, we use a combination of phylogenetic inference and biomechanical modeling to understand the transformational and causal basis for flexure or lack thereof. We also determine whether structural subsystems making up the feeding system are structurally, functionally, and evolutionary integrated or dissociated. Regarding evolutionary dissociation, statistical analysis of state changes revealed by the phylogenetic analysis shows that radular and cartilage subsystems evolved independently. Regarding kinematics, the phylogenetic analysis shows that flexure arose at the base of the Mollusca and lack of flexure is a derived condition in one gastropod clade, the Patellogastropoda. Significantly, radular morphology shows no change at the node where kinematics become stereoglossate. However, acquisition of stereoglossy in the Patellogastropoda is correlated with the structural dissociation of the subradular membrane and underlying cartilages. Correlation is not causality, so we present a biomechanical model explaining the structural conditions necessary for the plesiomorphic kinematic state (flexoglossy). -
Streptoneury Is Independent from Ontogenetic Torsion in the Caenogastropod Snail Marisa Cornuarietis
Streptoneury Is Independent From Ontogenetic Torsion in the Caenogastropod Snail Marisa Cornuarietis J. Anton Morath University of Tübingen Stefan Fischer University of Tübingen Leonie Hannig University of Tübingen Simon Schwarz University of Tübingen Rita Triebskorn University of Tübingen Oliver Betz University of Tübingen Heinz-R. Köhler ( [email protected] ) Animal Physiological Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 5, D-72076 Tübingen, Germany Research Article Keywords: snails’ anatomy, conspicuous crossing, streptoneury, developmental biology and evolution Posted Date: February 2nd, 2021 DOI: https://doi.org/10.21203/rs.3.rs-156111/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Streptoneury is independent from ontogenetic torsion in the caenogastropod snail Marisa cornuarietis J. Anton Morath1#, Stefan Fischer2,3#, Leonie Hannig1, Simon Schwarz1,4, Rita Triebskorn1,5, Oliver Betz2, Heinz-R. Köhler1* 1 Animal Physiological Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 5, D-72076 Tübingen, Germany 2 Evolutionary Biology of Invertebrates, Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany 3 Present address: Tübingen Structural Microscopy Core Facility, Applied Geosciences, University of Tübingen, Schnarrenbergstrasse 94-96, D-72076 Tübingen, Germany 4 Present address: German Environment Agency, Wörlitzer Platz 1, D-06844 Dessau-Roßlau, Germany 5 Steinbeis-Transfer Center Ecotoxicology and Ecophysiology, Blumenstrasse 13, D-72108 Rottenburg, Germany # joint first authorship * Corresponding author: [email protected] A hallmark in snails’ anatomy is the conspicuous crossing of the pleurovisceral nerve cords present in all but the most derived gastropod clades. -
HSVMA Guide to Congenital and Heritable Disorders in Dogs
GUIDE TO CONGENITAL AND HERITABLE DISORDERS IN DOGS Includes Genetic Predisposition to Diseases Special thanks to W. Jean Dodds, D.V.M. for researching and compiling the information contained in this guide. Dr. Dodds is a world-renowned vaccine research scientist with expertise in hematology, immunology, endocrinology and nutrition. Published by The Humane Society Veterinary Medical Association P.O. Box 208, Davis, CA 95617, Phone: 530-759-8106; Fax: 530-759-8116 First printing: August 1994, revised August 1997, November 2000, January 2004, March 2006, and May 2011. Introduction: Purebred dogs of many breeds and even mixed breed dogs are prone to specific abnormalities which may be familial or genetic in nature. Often, these health problems are unapparent to the average person and can only be detected with veterinary medical screening. This booklet is intended to provide information about the potential health problems associated with various purebred dogs. Directory Section I A list of 182 more commonly known purebred dog breeds, each of which is accompanied by a number or series of numbers that correspond to the congenital and heritable diseases identified and described in Section II. Section II An alphabetical listing of congenital and genetically transmitted diseases that occur in purebred dogs. Each disease is assigned an identification number, and some diseases are followed by the names of the breeds known to be subject to those diseases. How to use this book: Refer to Section I to find the congenital and genetically transmitted diseases associated with a breed or breeds in which you are interested. Refer to Section II to find the names and definitions of those diseases. -
Zooacoro3t: Unit O5 Mollusca- Torsion in Gastropods
Zooacoro3t: unit o5 Mollusca- torsion in gastropods What’s a torsion? Torsion may be defined as a pleisiomorphic character trait of evolutionary process present in larval grastropods of phylum mollusca, where the visceropallium of the body is rotated anti clockwise through 180◦ from its original position on head-foot complex arising the asymmetry in visceral organs formation and position. RituparnaMaity HMMCW [email protected] Body plan of a mollusca Torsion a phenomenon occur during formation of embryo of a gastropod • Visceropallium rotated anti-clockwise through 180◦ from its initial position on head-foot complex • Probably the contraction of larval retractor muscles account for 90◦ of the rotation • Differential growth of the body tissue accounts for the rest 90 • Site : behind the head-foot complex • Time and duration: Complete very rapidly, but may last from 2-3mins to few hours or days RituparnaMaity HMMCW [email protected] Ways- 5 ways • 180◦ rotation by muscle contraction alone • 180◦ rotation achieved in 2 stages • 180◦ rotation achieved by differential growth process alone • Torsion achieved by differential growth process • Torsion recognisable as a movement of visceropallium RituparnaMaity HMMCW [email protected] Mechanism of torsion The process of torsion commences as soon as the larval retractor muscles develop contractile power. • Accomplishes in 2 stages. • Stage 1 : accounts for invovlement of 90◦ rotation due to muscle contraction and mantle cavity shift it’s position from posterior to anterior -
Hickman, Roberts, Larson
hic09617_ch16.qxd 5/30/00 12:43 PM Page 325 CHAPTER 16 Molluscs Phylum Mollusca Fluted giant clam, Tridacna squamosa. A Significant Space space within the mesoderm, the coelom. This meant that the Long ago in the Precambrian era, the most complex animals space was lined with mesoderm and the organs were sus- populating the seas were acoelomate. They must have been pended by mesodermal membranes, the mesenteries. Not inefficient burrowers, and they were unable to exploit the only could the coelom serve as an efficient hydrostatic rich subsurface ooze. Any that developed fluid-filled spaces skeleton, with circular and longitudinal body-wall muscles within the body would have had a substantial selective acting as antagonists, but a more stable arrangement of advantage because these spaces could serve as a hydro- organs with less crowding resulted. Mesenteries provided an static skeleton and improve burrowing efficiency. ideal location for networks of blood vessels, and the ali- The simplest, and probably the first, mode of achieving mentary canal could become more muscular, more highly a fluid-filled space within the body was retention of the specialized, and more diversified without interfering with embryonic blastocoel, as in pseudocoelomates. This was not other organs. the best evolutionary solution because, for example, the Development of a coelom was a major step in the evo- organs lay loose in the body cavity. lution of larger and more complex forms. All the major Some descendants of Precambrian acoelomate organ- groups in chapters to follow are coelomates. I isms evolved a more elegant arrangement: a fluid-filled 325 hic09617_ch16.qxd 5/30/00 12:45 PM Page 326 326 PART 3 The Diversity of Animal Life Position in Animal common ancestor with annelids 3. -
Aeolidiella Stephanieae Valdéz, 2005 (Mollusca, Gastropoda, Nudibranchia) Alen Kristof1*, Annette Klussmann-Kolb2
Kristof and Klussmann-Kolb Frontiers in Zoology 2010, 7:5 http://www.frontiersinzoology.com/content/7/1/5 RESEARCH Open Access Neuromuscular development of Aeolidiella stephanieae Valdéz, 2005 (Mollusca, Gastropoda, Nudibranchia) Alen Kristof1*, Annette Klussmann-Kolb2 Abstract Background: Studies on the development of the nervous system and the musculature of invertebrates have become more sophisticated and numerous within the last decade and have proven to provide new insights into the evolutionary history of organisms. In order to provide new morphogenetic data on opisthobranch gastropods we investigated the neuromuscular development in the nudibranch Aeolidiella stephanieae Valdéz, 2005 using immunocytochemistry as well as F-actin labelling in conjunction with confocal laser scanning microscopy (cLSM). Results: The ontogenetic development of Aeolidiella stephanieae can be subdivided into 8 stages, each recognisable by characteristic morphological and behavioural features as well as specific characters of the nervous system and the muscular system, respectively. The larval nervous system of A. stephanieae includes an apical organ, developing central ganglia, and peripheral neurons associated with the velum, foot and posterior, visceral part of the larva. The first serotonergic and FMRFamidergic neural structures appear in the apical organ that exhibits an array of three sensory, flask-shaped and two non-sensory, round neurons, which altogether disappear prior to metamorphosis. The postmetamorphic central nervous system (CNS) becomes concentrated, and the rhinophoral ganglia develop together with the anlage of the future rhinophores whereas oral tentacle ganglia are not found. The myogenesis in A. stephanieae begins with the larval retractor muscle followed by the accessory larval retractor muscle, the velar or prototroch muscles and the pedal retractors that all together degenerate during metamorphosis, and the adult muscle complex forms de novo.