Nematocysts

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" height=115 BGCOLOR="#66CCCC" TEXT="#080000" bgproperties="fixed" background="03500730ezvthe.gif"> <div> <FONT SIZE="4" COLOR="#CCFFFF" FACE="Arial" ><B>The wonders of the weeverfish ( T.vipera )</B></FONT><B>|   </B><A HREF="index.htm" TARGET="_top" TITLE="Wonders of the Weeverfish (Trachinus vip"><U><B>home</B></U></A></div> <div> <A HREF="id74.htm" TARGET="_top" TITLE="Abnormal Cells"><U>Abnormal Cells</U></A>   |   <A HREF="id75.htm" TARGET="_top" TITLE="Individual Venom Gland Cells"><U>Individual Venom Gland Cells</U></A>   |   <A HREF="id76.htm" TARGET="_top" TITLE="Venom gland Membrane 1"><U>Venom gland Membrane 1</U></A>   |   <A HREF="id77.htm" TARGET="_top" TITLE="Venom gland cells"><U>Venom gland cells</U></A>   |   <A HREF="id78.htm" TARGET="_top" TITLE="Outer membrane and Spine"><U>Outer membrane and Spine</U></A>   |   <A HREF="id79.htm" TARGET="_top" TITLE="Outer Membrane 2"><U>Outer Membrane 2</U></A>   |   <A HREF="id80.htm" TARGET="_top" TITLE="Basal groove and Venom gland"><U>Basal groove and Venom gland</U></A>   |   <A HREF="id81.htm" TARGET="_top" TITLE="Venom gland cells"><U>Venom gland cells</U></A>   |   <A HREF="id82.htm" TARGET="_top" TITLE="Venom gland 2"><U>Venom gland 2</U></A>   |   <A HREF="id83.htm" TARGET="_top" TITLE="All structures"><U>All structures</U></A>   |   <B>Nematocysts</B></div> <div> <A HREF="id72.htm" TARGET="_top" TITLE="Marine photographs"><U>Marine photographs</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id87.htm" TARGET="_top" TITLE="Marine Environments"><U>Marine Environments</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id131.htm" TARGET="_top" TITLE="Rockpools"><U>Rockpools</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id94.htm" TARGET="_top" TITLE="SANDY SHORE"><U>SANDY SHORE</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id143.htm" TARGET="_top" TITLE="Movies"><U>Movies</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id97.htm" TARGET="_top" TITLE="MUD SHORE"><U>MUD SHORE</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id134.htm" TARGET="_top" TITLE="Man Made"><U>Man Made</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id150.htm" TARGET="_top" TITLE="Marine Colonisation"><U>Marine Colonisation</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id117.htm" TARGET="_top" TITLE="ZONATION"><U>ZONATION</U></A><FONT SIZE="2" COLOR="#FFFFFF" FACE="Symbol" >   ·   </FONT><A HREF="id140.htm" TARGET="_top" TITLE="Q A"><U>Q & A</U></A></div> </td> </tr><tr> <td valign="top" height=365 BGCOLOR="#66CCCC" TEXT="#080000"> <div> <B>Nematocysts</B></div> <DIV ALIGN="LEFT"></DIV> <div> <B>What is a Nematocyst?</B></div> <bR> <div> Nematocysts are unique to the phylum; Cnidaria ( = Coelenterata)</div> <bR> <div> Nematocysts are individual cells usually on the outer surface of the organism which have a variety of functions, most usually in defence or capture of prey species. These cells are known as stinging cells sometimes used to inject toxins which in some cases are toxic to man.</div> <bR> <div> Nematocysts can be specialised to carry out a number of functions within the organism these include; Sticking to surfaces and wrapping around objects, Penetrating surfaces or secreting proteinaceous toxins. These functions are used in food collection,defense and to some extent, locomotion. </div> <bR> <div> Nematocysts are usually most abundant on the feeding tentacles of all species, and within the digestive cavity of some species. The individual nematocyst rarely exceed 50 um (microns) in size, but is the great number that make them effective in providing protection or as a method to capture and stun prey species.</div> <div> These cells are also important to the biologist in individual species recognition.</div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="24f07aa0.gif" border=0 width="519" height="426" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <div> A diagram showing the stages of a Nematocyst discharge</div> <div> (Picture taken from BIOLOGY of the invertebrates, Jan A.Pechenik p79)</div> <bR> <div> Nematocyst discharge is triggered by direct contact or other external stimulus. Once the cell is discharged a new nematocyst is formed as the mechanism in each cell can only be triggered once.</div> <DIV ALIGN="LEFT"></DIV> <div> <A HREF="id67.htm" TARGET="_top" TITLE="SITE INDEX"><U><B><IMG SRC="27194e10.jpg" border=0 width="148" height="225" ALT="Index Page To Site Link" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></U></A></div> </td> </tr></table></body>