aboral surface of starfishaudit assistant manager duties and responsibilities
Now flip your starfish over so you can view the oral surface. Use a pair of scissors to carefully remove the integument starting at the dorsal edge of the cut arm and working your way slowly towards the madreporite. (2016), Multiscale alterations in bone matrix quality increased fragility in steroid induced osteoporosis, Kimura S, Omura Y, Ishida M, etal. Structure of Starfish (With Diagram) | Zoology - Biology Discussion The edges of the body wall samples were marked with Xray absorbent lead tape to aid detection of the sample centre when scanning with the Xray beam. 1 For example, the mechanical properties of the body wall influence the flexibility of the rays, limiting and/or enabling specific feeding behaviour (Gale, 2013) and the thickened dermal tissue in the sturdy rays of tropical shallow water valvatids and spinulosids such as L.laevigata and E.spinuslosis has also been attributed to an adaptation against extensive predation (Blake, 1983). (1993), Molecular characterization of fibrillar collagen from the body wall of starfish, Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, Koob TJ, KoobEmunds MM, Trotter JA (1999), Cellderived stiffening and plasticizing factors in sea cucumber (, PILATUS 2M a detector for small angle Xray scattering, Krauss S, Fratzl P, Seto J, etal. 2015; Karunaratne etal. The differences in the observed D and O/D values between aboral body wall and ambulacrum could therefore arise either from differential strain conditions or the molecular structure of the fibrils. 2016). 4 is presented in the associated figure legend and therefore the focus here will be on a few key observations. However, regions of lower Xray absorption are evident and these assist in identifying boundaries between adjacent ossicles. Note, however, that the intensities shown in Fig. 3E. 2016). What the images show most strikingly is the variety of shapes of the different ossicle types and the geometry of their interactions. (2012), Type I collagen Dspacing in fibril bundles of dermis, tendon, and bone: bridging between nano and microlevel tissue hierarchy, Ferrario C, Leggio L, Leone R, etal. The voxel size was set to 15m; 1201 projections were recorded in 19h (the long scan time is required to obtain a high contrast ratio and two complete scans were required to cover the ~20mm length of the rays). This ring of ten plates encircles the anal opening and is always positioned on the aboral surface. Ossicle (echinoderm) - Wikipedia Trichrome staining of sectioned starfish has been employed previously for analysis of the structure and composition of the body wall, revealing that it is a composite of calcite ossicles linked by interossicular muscles and ligaments (O'Neill, 1989; Wilkie etal. 3A,B). The sampledetector distance was 1008.2mm for aboral body wall samples and 847.2mm for ambulacral samples, calculated based on a measurement of a calibration standard consisting of silver behenate. Article Shared by ADVERTISEMENTS: In this article we will discuss about Asterias (Starfish):- 1. Lastly, we gratefully acknowledge two anonymous reviewers for helpful comments on this paper. This can be attributed to thicker ossicles in the ambulacrum and/or proportionally higher amounts of collagen in the aboral body wall. The common starfish is usually orange or brownish in color, and sometimes violet; specimens found in deeper waters are pale. (2003), Purification, characterization and cloning of tensilin, the collagenfibril binding and tissuestiffening factor from, Molecular structure and functional morphology of echinoderm collagen fibrils, Trotter JA, LyonsLevy G, Luna D, etal. 2011; Yang etal. (D1,D2) Vector and circle plots of collagen fibril structure overlapped with a transmission map of the aboral (D1) and ambulacral samples (D2). Likewise, when starfish feed on prey such as mussels they adopt a humped posture, with the rays bent so that tube feet proximal to the mouth are able to attach to the valves of the mussel and tube feet in the distal region of the rays maintain attachment to the substratum (Norberg & Tedengren, 1995). mq5 is the measured FWHM of the sample of interest, and w (2006), Native collagen fibrils from echinoderms are molecularly bipolar, Tipper JP, LyonsLevy G, Atkinson MA, etal. This study also highlights the lack of knowledge of invitro/vivo ultrastructural properties of collagen fibrils from nonmammalian animals. The accelerating voltage was set to 40kV with a tube current of 405A. The colour of this starfish is variable, but may be orange, pink or violet, with the warts being a contrasting colour, usually white, pink, red or mauve. Belonging to the family Asteriidae, it has five arms and usually grows to between 1030cm across, although larger specimens (up to 52cm across) are known. UK, 2 and M.R.E. 2000; Aizenberg etal. [6], The common starfish is dioecious, which means that each individual is either male or female. London, Contraction of supraambulacral and outer lateral abductor muscles flatten the shape of the starfish ray, increasing the angle between antimeric ambulacral ossicles forming the ambulacral arch. The calcareous struts of the ossicles appear as voids, due to decalcification of the tissue, and the cellular stroma appears red. A lower O/D ratio is observed for the aboral body wall relative to the ambulacrum. This loose arrangement of ossicles is of functional significance for gas exchange because the voids are overlaid by clusters of papulae (Figs (Figs11 and and2),2), fingerlike extendable and retractable exvaginations of the coelomic lining of body wall. (2001), Calcitic microlenses as part of the photoreceptor system in brittlestars, Barbaglio A, Tricarico S, Ribeiro AR, etal. 2009; Yang etal. This anatomy can be inferred from detailed analysis of serial sections of starfish rays (Fig. The starfish is usually orange or brick red on the aboral surface and paler on the oral surface but can also be purple or pale brown. It is the slide of T.S. In the ambulacrum, the overall level of Xray absorption is much higher than in the aboral body wall, consistent with the presence of the regular and densely packed rows of pairs of long ladleshaped ambulacral ossicles (Fig. 5A1). The madreporite is located on the aboral (top) surface in sea stars, sand dollars, and sea urchins, but in brittle stars, the madreporite is on the oral (bottom) surface. The starfish is usually orange or brick red on the aboral surface and paler on the oral surface but can also be purple or pale brown. Areas lacking detectable amounts of collagen correspond to voids in the body wall skeleton that underlie clusters of papulae on the body wall surface (Figs (Figs11 and and2).2). External Features 4. (2005), Developing macroporous bicontinuous materials as scaffolds for tissue engineering, On the use of magnesium in stupefying marine animals, Mo J, Prvost SF, Blowes LM, etal. Azimuthally wide diffraction peaks (large 0>10) indicate high variation in the angular orientation of fibres. Starfish are mostly carnivorous and have a mouth, oesophagus, two-part pyloric stomach with a pyloric duct leading to the intestine and rectum, with the anus located in the center of the aboral body surface. What these images also show is that muscle fibres of the interossicular muscles appear to be wrapped around voids that would be filled by calcite struts near the ossicle surface invivo. m(aboral)=0.012nm1, w The red speckling within the ossicle voids are stained cells, which are located in pores between the calcite struts of the ossicle stereom invivo. Animals were fedperiodically with the mussel Mytilus edulis Linnaeus, 1758 (Mytiloida). To obtain new insights into relationships between body wall structure and function in starfish, here we have used histology, microCT and SAXD to perform a detailed analysis of the structural properties of the body wall in the common European starfish Asterias rubens Linnaeus, 1758 (Forcipulatida). Examples of the small muscles that link ossicles in the aboral body wall are shown in Fig. (2010), Opportunities and challenges for digital morphology, Ziegler A, Faber C, Mueller S, etal. Furthermore, the microCT data complement histological data in providing 3D representations of ossicle shapes and the gaps between adjacent ossicles. 28.5A: Phylum Echinodermata - Biology LibreTexts (2010), A novel stiffening factor inducing the stiffest state of holothurian catch connective tissue, Yang W, Sherman VR, Gludovatz B, etal. the contents by NLM or the National Institutes of Health. 5D1,D2 show vector plots overlaid on grayscale Xray transmission maps, with the orientation of vectors representing mean collagen fibril orientation at each scan point. The body wall of starfish is composed of magnesium calcite ossicles connected by collagenous tissue and muscles and it exhibits remarkable variability in stiffness, which is attributed to the mechanical mutability of the collagenous component. Furthermore, it was use of SAXD that recently enabled interfibrillar stiffening of echinoderm MCT to be demonstrated at the nanoscale, using sea cucumber dermis as an experimental system (Mo etal. The prominent Vshaped radial nerve cord (RNC) can be seen between the two rows of tube feet podia (TF), which are connected to the intracoelomic bulbshaped ampullae (AMP) by tubular connections that run between adjacent ambulacral ossicles (as seen here on the right side). It is used by the starfish to take in water to fill its water-vascular system. Starfish - Wikipedia Common starfish - Wikipedia The length of the Dperiod and O/D ratio can be used as a measure to characterize collagen fibrils. Inset (A) shows a closeup of the transverse crosssection of the ray with . You Say Starfish, I Say Sea Star - Coastwatch Currents A moderate sized starfish is estimated to be able to produce 2.5 million eggs. Phylum Echinodermata | manoa.hawaii.edu/ExploringOurFluidEarth The collagenous tissue surrounding the ossicle network contains collagen fibres that form loopshaped straps that wrap around calcite struts near to the surface of ossicles. 2016). In contrast, the ambulacral groove fibrils had a uniformly low degree of orientation (the mean vector length; degree of orientation for ambulacral samples was half of the mean length in the aboral body wall; note the different scales in Fig. The combined length of one overlap and gap region equals a Dperiod (D). 2015). Occupying the coelomic space internal to the body wall can be seen the prominent pair of digestive glands (pyloric caeca, PC), which are connected via mesenteries (*) to the aboral coelomic lining (ACL) of the body wall. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Slides were then transferred into aniline blue solution for 510min, followed by washes (31min) in distilled water and then a 15min differentiation step in 1% acetic acid. Barts and The London School of Medicine and Dentistry, [5] It is also known from the western Atlantic where it occurs between Labrador and Florida and the Gulf of Mexico. An official website of the United States government. You should completely expose the dorsal surface of the arm and central disc of the starfish. The orientations of the vectors are parallel to the orientation of the collagen fibrils. This study provides a detailed description of body wall structure in the starfish A.rubens, illustrating the value of a multitechnique approach when characterizing tissue composites. The voids formed by decalcification of the body wall ossicles show the positions and shapes of the different ossicle types: the ambulacral ossicles (AMO), the adambulacral ossicles (ADO), the marginal ossicles (MO), the reticular ossicles (RO) and the carinal ossicle (CO). Biology 1030 - Biological Diversity, Function & Interactions The aboral (upper) surface is usually orange to brick red in colour and the oral (lower) surface is of paler shades. Next, identify the madreporite, ampullae, ring canal, radial canal, and stone canal and label which feature corresponds to each number on the illustration below. Cut along lines a, b, and c (Figure 3) and then remove this flap of skin. functions of starfish structures Flashcards | Quizlet The presence of a thickened inner dermal collagenous layer in E.spinulosus and L.laevigata accounts for the increased stiffness and rigidity of the body wall in these species in comparison with Asterias (Eylers, 1976; Marrs etal. The marginal ossicles that form the lateral body wall region are more varied in shape and size but are quite tightly packed. 2012a). Maurice R. Elphick, Email: ku.ca.lumq@kcihple.r.m. Note also the numerous spines located external to the ossicle network; three spines located above the carinal ossicles are labelled with arrowheads. The bumpy-skinned aboral side is covered with loads of tiny pinchers called pedicellariae that help clean the rough surface. Echinaster callosus - Wikipedia 2003; Tamori etal. (D') Scanning electron micrograph showing the calcite struts and pores of ambulacral ossicle stereom at high magnification. The collagenous tissue occupies the bulk of the space between ossicles and surrounding ossicles, with fibres forming a dense latticework (Fig. Asteroids normally have five rays, or arms, (1) arranged around a central disc (2). Changes in posture of the starfish ray are mediated by the interossicular muscles (Heddle, 1967), whereas changes in the stiffness of the body wall are thought to be mediated by interossicular catchtype collagenous tissue or mutable collagenous tissue (MCT; Motokawa, 1984; Wilkie, 2005). 3C). This was done to reduce the tissue damage caused during fixation and tissue processing that was observed in untreated specimens. This study focuses on two different locations with no external strain applied. The larvae are planktonic and drift for about 87 days before settling on the seabed and undergoing metamorphosis into juveniles. Starfish Dissection Lab The mechanisms of echinoderm MCT are not fully understood. 1 shows the anatomy of a dissected specimen of A.rubens. m(ambulacrum) =0.015nm1, w 1996; Takemae & Motokawa, 2005; Ribeiro etal. Starfish Anatomy - Biology Wise School of Engineering & Materials Science, 4 are the shapes and sizes of what appear as unfilled gaps where the Xray attenuation is below the threshold set for the hard tissue image rendering, and which is indistinguishable from the surrounding medium but would be filled with tissue invivo. [9][10], The common starfish produces a saponin-like substance designed to repel predators, which causes a reaction in the common whelk (Buccinum undatum), a common prey species. 5D,D2. the fissure along the midline of the oral surface of each arm of a sea star, where most of . Animals were transported in seawater to Queen Mary University of London where they were then maintained in an aquarium with circulating artificial seawater at ~11C, corresponding to the natural temperature of sea water for this species. 4D) accommodate the fluidfilled tubes that connect each tube foot podium with its associated bulbshaped ampulla (Fig. The present study provides detailed insights into ossicle shape and organization, the structural characteristics of collagenous tissue and the positions of muscles in the body wall of A.rubens. 3D). 2009; Yang etal. The degree of fibril orientation increases 1p with the vector length. The reticular ossicles that form the aboral skeleton have a similar variety of ossicle shapes and sizes but these form a more open skeletal meshwork than that of the marginal ossicles (Fig. Larger irregularshaped marginal ossicles form longitudinal overlapping rows of ossicles, which are connected radially by overlapping smaller, lozengeshaped ossicles (Fig. UK, 4 This anatomical arrangement provides multiple sites of interaction between the soft (muscle and collagen) and hard (ossicle) tissue of the starfish body wall and may enable stiffened collagenous ligaments to bear loads when starfish are static and inbetween changes in posture initiated by muscle contraction. Accessibility Crimping of collagen fibres in the interambulacral ligament located above the adductor infraambulacral muscle can be seen in Fig. sharing sensitive information, make sure youre on a federal Furthermore, there is variability between starfish species in the proportions of the calcite ossicles, muscle and collagenous tissue in the body wall (Heddle, 1967; Motokawa, 2011). The first detailed investigation of the structure and mechanical properties of the starfish body wall was a study by Eylers (1976) on Asterias forbesi Desor, 1848 (Forcipulatida). Only two of these pairs can be observed in A.rubens the transverse supra and infraambulacral muscles and inner and outer lateral muscles (Fig. Queen Mary University of London, The diffraction peak intensity is from collagen (Iq5col) and the background scattering is contributed by the mineral (Iq5min) components of the tissue. (2015), Regrowth, morphogenesis, and differentiation during starfish arm regeneration, Contractile connective tissue in crinoids, Birenheide R, Tsuchi A, Motokawa T (1996), To be stiff or to be soft The dilemma of the echinoid tooth ligament. Lateral to the adambulacral ossicles are the densely packed marginal ossicles (MO). The common starfish, common sea star or sugar starfish (Asterias rubens) is the most common and familiar starfish in the north-east Atlantic. By way of comparison, in A.rubens the aboral body wall ossicles are evenly surrounded by collagenous tissue without thickening of the inner dermis (Figs (Figs22 and and3;3; Wilkie, 2001). Inset (C) shows a closeup of a pedicellaria, a pincershaped defensive organ. The sample holder was clamped on a 2axis motorized stage and a synchrotron Xray beam with a wavelength of 0.8857 and beam diameter 15m was used to acquire the SAXD spectra. It was said that people could not "walk around them because the whole shore was full of starfish". The madreporite is the opening to the water vascular system. q5 is the corrected FWHM, w The degree of variation at different scan points is illustrated by the lengths of the vectors in Fig. a, A. planci (215 mm diameter); b, A . Queen Mary University of London, (2011), Agerelated changes in the plasticity and toughness of human cortical bone at multiple length scales. (B) High magnification image of adjacent reticular ossicles showing how muscle fibres of an interossicular muscle (IOM) insert between and around strut voids near the surface of each ossicle (white arrows). Hitherto, the techniques used to study the soft tissue phase (collagenous and muscle components) of the starfish body wall have been predominantly histological (e.g. Sections were rehydrated and then placed in Weigert's haematoxylin solution for 10min and then washed in running tap water for 10min at room temperature. 3F) connecting antimeric ambulacral ossicles probably explains the uniform mean orientation with low degree of orientation in the ambulacrum. Therefore, when using the abovementioned equationto solve O/D it was assumed that electron densities within overlap and gap regions were constant and that the starfish collagen O/D ratio would be 0.40.5, i.e. It normally lives on the outer surface of the starfish feeding on sloughed-off epidermal tissue. Language links are at the top of the page across from the title. 3DF). (1994) (65.70.5nm), but they are higher and less variable than those reported by Ferrario etal. In this way, SAXD has been used successfully to analyse the structural and mechanical properties of, for example, mammalian tendons, bone and antlers (Gupta etal. Other abbreviations as in Fig. 1 Aboral views of starfish. As long as exposure times to Xrays are not too long (from seconds down to milliseconds depending on the brilliance of the Xray source), the tissue can be examined in its native state (Jeffries etal. These make enzymes to digest food in the stomach. Changes in fibril strain and orientation during invitro micromechanical testing can be tracked via changes in the SAXD patterns reflective of four different mechanisms for collagenous tissue elongation: (i) straightening of the fibrillar crimps; (ii) fibril reorientation; (iii) interfibrillar displacement (changes in the interfibrillar cohesion) and (iv) stretching of the fibrils themselves (Sasaki & Odajima, 1996a; Gupta, 2008). in having very short and numerous spines on the aboral disk surface, Madsen and Caso' were dubious of its status . 4B). (2002), Viscoelastic properties of collagen: synchrotron radiation investigations and structural model, Rahman IA, Belastegui Z, Zamora S, etal. Spectra were collected using a silicon hybrid pixel PILATUS 2M detector system (Kraft, 2010). In inhomogeneous ossicletissue networks such as the starfish body wall, changes in MCT properties could mechanically affect the links to and between the ossicle network, leading to flexion, torsion, etc. The males shed their sperm and fertilisation takes place in the water column. Therefore to calculate Iq5col, the background scattering (Iq5min) was approximated as a linear falloff over the small qrange around the peak and subtracted from Iq5 to get Iq5col. Thus, the contractile state of small interossicular muscles that link the aboral body wall ossicles (Fig. Differences in body wall structure in the Asteroidea have been discussed in detail previously with respect to phylogeny, evolutionary success, ecology and habitat, defence strategies, mode of feeding and reproductive behaviour (Blake, 1990; Gale, 2011; Mah & Blake, 2012; Feuda & Smith, 2015). Based on data obtained using microCT to analyse the ray skeleton of A.rubens, here we present images that show for the first time the 3D architecture of the starfish skeleton in unprecedented detail (Fig. Red corresponds to the highest amount of collagen. of the catch mechanism in the sea urchin spine ligament, Autotomy as a prelude to regeneration in echinoderms. The scaled (from 0 to 1, normalized using a standard minimum and maximum for all the samples) mean degree of orientation for aboral body wall samples (0.13, SD 0.20) was twice that of ambulacrum samples (0.06, SD 0.03). Furthermore, flexion of rays is aided by contraction of the apical muscle, a midline thickening of the longitudinally orientated muscle beneath the coelomic epithelium (Figs (Figs22 and and33C). the amount of collagen linking the ossicles or the orientation of the fibrils). The https:// ensures that you are connecting to the spines, * in Fig. To enable analysis of the histological composition of the body wall in A.rubens, Masson's trichrome staining was used; this differentiates collagenous (blue) from noncollagenous (red) tissues. It can clearly be seen that the collagen fibres form loopshaped straps that wrap around the voids that would be filled by calcite struts near the ossicle surface invivo (black arrow heads, Fig. The aboral surface of the starfish is an arrangement of calcareous plates or ossicles of endoskeleton (internal skeleton) that allow both lateral and up and down movement (see detail Figure 1) Numerous spines protrude from the surface of the endoskeleton and give the body a warty or spiny appearance, hence the name echinoderm--spiny skin. The apical disc is composed of five genital and five ocular plates which surround a flexible plated membrane that contains the anus. The Ins and Outs of the Madreporite - ThoughtCo Cut a circular flap of skin from the central disc.
