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Digestion
Digestion, as one of the main life processes, is necessary in all organisms to break down food, allowing for the absorption of nutrients and the creation of energy. Most organisms perform two different kinds of digestion: mechanical and chemical digestion. Mechanical digestion accounts for the physical break down of food into smaller chunks, increasing their surface area. In humans, mechanical digestion well known to occur in the mouth (as teeth chop, mash, and grind), the esophagus (during peristalsis), and the stomach (through churning), as well as a few other places. Chemical digestion accounts for the chemical break down of food with powerful acids and enzymes. In humans, chemical digestion begins in the mouth where amylase (an enzyme in the saliva) breaks down starch into smaller compounds (like dextrose and maltose). It continues in the stomach where strong HCl acid and pepsin (an enzyme that breaks down proteins into amino acids) dissolve most foods to form a thick, unattractive liquid-like substance called chyme. And it concludes in the intestines, where enzymes, bile (a substance created by the liver to dissolve fats), and other pancreatic fluids play the last roles in chemical digestion. By the end of the digestion process in humans, formerly food-like substances can be absorbed though villi projections in the intestinal wall, sent into the blood stream and distributed as required among cells. In the cells, however, but another process begins in the mitochondria to release energy stored in chemical bonds. Cellular respiration is the process by which cells use oxygen to release energy from molecules (like glucose) in the form of ATP in their mitochondrion, creating waste products of water and carbon dioxide [the equation being C6H12O6 + 6 O2 --------> 6 CO2 + 6 H2O + Energy (ATP)]. Then, ATP (Adenosine Tri-Phosphate, composed of three phosphate groups) is converted into ADP (Adenosine Di-Phosphate, composed of two phosphate groups), the bonds are broken and the stored energy is released. The energy released can and will be used to conduct other necessary life processes.
Digestion, as one of the main life processes, is necessary in all organisms to break down food, allowing for the absorption of nutrients and the creation of energy. Most organisms perform two different kinds of digestion: mechanical and chemical digestion. Mechanical digestion accounts for the physical break down of food into smaller chunks, increasing their surface area. In humans, mechanical digestion well known to occur in the mouth (as teeth chop, mash, and grind), the esophagus (during peristalsis), and the stomach (through churning), as well as a few other places. Chemical digestion accounts for the chemical break down of food with powerful acids and enzymes. In humans, chemical digestion begins in the mouth where amylase (an enzyme in the saliva) breaks down starch into smaller compounds (like dextrose and maltose). It continues in the stomach where strong HCl acid and pepsin (an enzyme that breaks down proteins into amino acids) dissolve most foods to form a thick, unattractive liquid-like substance called chyme. And it concludes in the intestines, where enzymes, bile (a substance created by the liver to dissolve fats), and other pancreatic fluids play the last roles in chemical digestion. By the end of the digestion process in humans, formerly food-like substances can be absorbed though villi projections in the intestinal wall, sent into the blood stream and distributed as required among cells. In the cells, however, but another process begins in the mitochondria to release energy stored in chemical bonds. Cellular respiration is the process by which cells use oxygen to release energy from molecules (like glucose) in the form of ATP in their mitochondrion, creating waste products of water and carbon dioxide [the equation being C6H12O6 + 6 O2 --------> 6 CO2 + 6 H2O + Energy (ATP)]. Then, ATP (Adenosine Tri-Phosphate, composed of three phosphate groups) is converted into ADP (Adenosine Di-Phosphate, composed of two phosphate groups), the bonds are broken and the stored energy is released. The energy released can and will be used to conduct other necessary life processes.
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Morning Sun Star Diet
The Solaster dawsoni, or the Morning Sun Star, is often called the "Death Star" as it survives on a diet of green urchins, sea cucumbers and other sea stars. It is predator to various species, including the Solaster stimpsoni, Leptasterias hexactis, Evasterias troschelii, Dermasterias imbricata, Henricia leviuscula, Croassaster papposus, Pycnopodia helianthoides, Mediaster aequalis, and other Solaster dawsoni.[1] It takes on opponents of assorted size, moving with its leading rays raised and lunging quickly when coming into contact with its prey.[2] Its prey, however, have ways of dodging the cannibalistic creatures; most sea stars swim away quickly when touched by the Solaster dawsoni, however, others release mucous and prick their attackers with rays covered in pincers, and some like the Solaster stimpsoni raise their rays above their disk in attempts to hold off the Death Star. [3]
The Solaster dawsoni, or the Morning Sun Star, is often called the "Death Star" as it survives on a diet of green urchins, sea cucumbers and other sea stars. It is predator to various species, including the Solaster stimpsoni, Leptasterias hexactis, Evasterias troschelii, Dermasterias imbricata, Henricia leviuscula, Croassaster papposus, Pycnopodia helianthoides, Mediaster aequalis, and other Solaster dawsoni.[1] It takes on opponents of assorted size, moving with its leading rays raised and lunging quickly when coming into contact with its prey.[2] Its prey, however, have ways of dodging the cannibalistic creatures; most sea stars swim away quickly when touched by the Solaster dawsoni, however, others release mucous and prick their attackers with rays covered in pincers, and some like the Solaster stimpsoni raise their rays above their disk in attempts to hold off the Death Star. [3]
Anatomy: Body Structures Aiding in Digestion
There are many structures working in and aiding the digestive system of sea stars. In the digestive system, the mouth (face down, and usually surrounded by tooth-like spines) splits into two stomachs, which join with the pyloric caeca (labeled in the above diagram as "Digestive gland"). The pyloric caeca, stretching and expanding into each ray, releases digestive fluids and stores dissolved food. Wastes are excreted through the anus, and undigestible materials are regurgitated. [4]
Other structures, however, also play a large role in aiding the digestive system, and in aiding the sea star find its next meal. A simple nerve ring, and radial nerves allow the Solaster dawsoni to move and swim, even without a brain. Sensory organs, like an eyespot at the tip of a ray, allow the Solaster dawsoni to adjust its positioning. Skin cells may allow the Solaster dawsoni to detect chemicals given off by its prey. The water vascular system transports nutrients and oxygen. And several other structures from other systems interact, aiding and helping perform each and every life process. [5]
Other structures, however, also play a large role in aiding the digestive system, and in aiding the sea star find its next meal. A simple nerve ring, and radial nerves allow the Solaster dawsoni to move and swim, even without a brain. Sensory organs, like an eyespot at the tip of a ray, allow the Solaster dawsoni to adjust its positioning. Skin cells may allow the Solaster dawsoni to detect chemicals given off by its prey. The water vascular system transports nutrients and oxygen. And several other structures from other systems interact, aiding and helping perform each and every life process. [5]