Cnidarians are a phylum of aquatic organisms that include jellyfish, corals, hydroids, and anemones. They are an ancient group of animals that are thought to have emerged more that 500 million years ago. They are characterized by their radial symmetry, their diploblastic bodies, and specialized cells called cnidocytes. Cnidarians are represented as either polyps or medusae. Sea anemones and corals are consistently found as polyps, and jellyfish have a polyp stage early in their development. These polyps are mostly sessile, but some have the ability to relocate themselves if necessary. When jellyfish mature they are medusae with a fully formed bell. When in the medusae stage jellyfish are completely mobile. Both of these forms are radially symmetrical. Both are also diploblastic, which means they only have two cell layers. The outer layer is called the ectoderm, and the inner layer is called the endoderm. They are connected by a non-cellular mass called the mesoglea, which is a jelly like substance made of water and various proteins. This mesoglea is what give structural support to the cnidarian body. The trait that most cnidarians are known for are their stinging cells, which are found in all cnidarians.
Cnidocytes, or cnidae, are cellular organelles that are enclosed by the membrane of the ectoderm. They consist of a capsule with a eversible tubule inside.They come in many forms, but the main three types nematocyst, spirocyst, and ptychocysts. Nematocysts are the most common cnidae, and are characterized by their ability to peirce other tissue. They do this with a combination of a stylus and a tubule, which then will inject some sort of venom. All nematocysts are described by their structure and function, instead of phylogeneti...
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...rane configurations, and release mediators of inflammation. Most venoms affect the muscle or nervous system, but most human reactions to jellyfish stings are consistent and the severity varies more. (Bailey, 2003) Sponges and Hydroids usually have the mildest venom among cnidarian, with the exception of some species. They usually only result in slight inflammation. Some species of jellyfish will also give a slight sting that causes inflammation. The most severe stings are caused by the Physalia species, scyphozoans, and cubozoans. (Bailey, 2003) These can give stings that cause loss of consciousness, edemas, muscle spasm, heart failure, coma, or death. (Bailey, 2003) This is just a very short list of the symptoms from cnidarian stings. This quick, and effective, firing system combined with potent venom makes many cnidarians the most venomous organisms known to man.
This research focuses on Gambierdiscus toxicus which is an armored, marine, benthic species in the phylum Dinoflagellata. It has an epitheca and a hypotheca, that is very similar in size, compressed anterio-posteriorly. The theca is covered with numerous deep and dense pores which are very thick. This species is autotrophic creating energy via several golden-brown chloroplasts (Hackett et al 2004), but is also heterotrophic and hence is referred to as mixotrophic. It has a ventrally – oriented crescent shaped nucleus. (Adachi & Fukuyo 1979). It usually inhabits warmer waters such as bay, mediterranian, tropical/sub – tropical in North/Central America (Shiumuzu et al 1982; Loeblich & Indelicato 1986), Asia/Pacific (Holmes & Tao 2002; Lu & Hodgkiss 2004) and has recently been identified in the Mediterranean (Aligizaki & Nikolaidis 2008). These authors identified the organisms to genus level, at best of their effort, so may have been one of the less common members of its genus although it is unlikely.
The crustacean moult cycle is initiated when the Y-organ in the head secretes the hormone Ecdysone (E) into the circulatory system[3,4,5]; the Y-organ is the primary source of E[5]. Upon contact with the haemolymph (a combination of blood and tissue fluid) within the circulatory system E is converted to its active form, 20-hydroxyecdysone (20E), by a P450 enzyme[4]. This causes the epidermal cells to secrete moulting fluid, which contains a mixture of enzymes such as proteases and chitinases. The moulting fluid degrades the exo- and endocuticle, and the digested cuticle is reabsorbed to create new cuticle; moult fluid also has a role in initiating the moult. The degraded cuticle is replaced by water or air so that the animal can swell in order to lose the shell. During the passive phase of the moult cycle, the shell splits along the break point caused by the decalcification of the shell, in the crab this is along the epimeral lines. Once the shell has split, the animal wiggles side-to-side to free itself from i...
A defining feature of the lionfish which everyone sees are the “18 venomous spines on its dorsal fin and its pelvic and anal fins, which are used for defense” as described in FACE OFF WITH THE ENEMY: LIONFISH by Special To The Citizen. Which is a neurotoxin that results in intense pain and swelling of one’s body. Fernando Simal, a marine hunter at STINAPA National Marine Park, found out the potency of their venom after his first hunt when being stung by the lionfish he caug...
The neurons or brain cells are shaped like trees. Young brain cells, called soma, resemble an acorn or small seed of a tree. The seed sprouts limbs when stimulated, called dendrites. Further on in development, the cell will grow a trunk like structure called an axon. The axon has an outer shell, like the bark of a tree, called the myelin sheath. Finally, at the base of the cell, there are root-like structures called axon terminal bulbs. Through these bulbs and the dendrite of another cell, cells communicate with each other through electrochemical impulses. These impulses cause the dendrites to
The outer layer of a reef consists of living animals, or polyps, of coral. Single-celled algae called zooxanthellae live within the coral polyps, and a skeleton containing filamentous green algae surrounds them. The photosynthetic zooxanthellae and green algae transfer food energy directly to the coral polyps, while acquiring scarce nutrients from the coral. The numerous micro habitats of coral reefs and the high biological productivity support a great diversity of other life.
Malignant melanoma is a type of cancer arising from the melanocyte cells of the skin. The melanocytes are cells in the skin that produce the pigment melanin. Malignant melanoma develops when the melanocytes no longer respond to normal control mechanisms of cellular growth and are capable of invasion locally or spread to other organs in the body (metastasis), where again they invade and compromise the function of that organ.
Phylon 49.3/4 (2001): 173. Academic Search Premier -. Web. The Web. The Web. 20 Mar. 2014.
Hypothalamic Lesion from the Perspective of Neurologist and Neurosurgeon The hypothalamus is a substructure of the diencephalon and acts as one of the most significant control centers of the brain. It is located inferior to the thalamus, encapsulates the ventral portion of the third ventricle, and lies just superior to the pituitary gland, which it has direct regulatory control over (Gunderson, 1996). Neurosecretory neurons in the hypothalamus secrete releasing and inhibiting hormones which are carried to the anterior pituitary where they exert their effects via hypothalamic-hypophyseal portal veins. Included in the many functions of the hypothalamus are regulation of food and water intake, autonomic function, emotions, body temperature, motor functions, and circadian sleep-wake cycles (Kalat, 2004).
The word melanoma comes from the Greek words, melas (black) and -oma (tumour). It is a very serious cancer that most often occurs in the skin and less frequently in the eye or in the lining of the nose, mouth, or genitals. Melanoma begins in melanocytes, cells that make a pigment called melanin. Both light- and dark-skinned people have melanin, which gives colour to the skin, hair, and parts of the eye.
The coral polyps are tiny tubular shaped animals that are sometime referred to as hexacorals. The coral look like small sea anemone. Hundreds of them together make up the reef colony. The polyps reproduce by budding or splitting ...
The body of a coral animal consists of a polyp, which is the living portion of the coral. A polyp is a hollow, cylindrical structure attached at one end to a surface, the other end is a mouth surrounded by tentacles, which gather food and can sting prey to paralyze it. Polyps live in colonies, which grow from 1 to 7 inches, depending on the species. Coral polyps are classified as animals. Microscopic algae live within the animal tissues in a symbiotic relationship. The algae turn sunlight into carbon and sugars, which are then available to the polyp. In turn the polyp filters particles out of the water and excretes waste (nitrogen and phosphorus) that becomes available to the symbiotic algae. It's this very tight nutrient recycling within the coral itself that allows these corals to live in very low nutrient waters.
Corals are a type of animal called a polyp, the simplest of predators that eat meat in the form of drifting zooplankton…all corals have boarders, zillions of microscopic, one-celled plants called zooxanthellae that live inside the polyps and transform sunlight into oxygen, keeping the corals alive. As you will see, the corals need these algae in order to live, but too much is deadly.
Because cells are the ‘basic unit of life’, the study of cells, cytology, can be considered one of the most important areas of biological research. Almost every day on the evening news, we are told about new discoveries in cell biology, such as cancer research, cloning, and embryology. (https://highered.mheducation.com/sites/0073031216/student_view0/exercise3/the_importance_of_cell_biology.html) This report provides an insight into the differences in the structure of cells and the way that they carry out their internal mechanisms. Cells form the basis of all living things and they are the smallest single unit of life.
They are invertebrates (spineless animals) and are cousins of anemones and jellyfish. When thousands of these animals are grouped together, they are referred to as coral colonies. Each coral "tree" or "mound" is one colony of coral polyps. A polyp has a sac-like body and an opening or mouth encircled by stinging tentacles called cnidae.