The Digestive System and the Urinary System
Man loves food and loves to eat. His appetite is always good and in some cases, he will eat food even if he is not hungry especially if the food is tasty. Of course, food has to get into the blood to be carried to the body’s cells.
Only soluble food or food which has already been dissolved can do this. Most of the food we eat, however, is insoluble. Even if you grind it down finely, it still won’t dissolve. And so, to make use of it, our body has to break it down into chemicals which can dissolve.
This breakdown is called digestion, and it takes place in the digestive system. After our body completely utilizes the food and its nutrients or minerals, it becomes waste and this waste should be removed. It is now the part or role of the urinary system to control the discharge of certain waste materials filtered from the blood by the kidneys. Understanding these two systems, working hand in hand, would further improve one’s appreciation of how our body functions. Our digestive system is a tube with two openings and many specialized organs.
It extends from the mouth of the anus and is also called the gastrointestinal tract. An interesting fact about the gastrointestinal tract is that while food or food residues are in it, technically the material is still outside the body. Nutrients don’t “officially” enter the body until they move from the space inside the digestive tube, its lumen, into the bloodstream. From beginning to end, mucus-coated epithelium lines surfaces facing the lumen. The thick, moist mucus protects the wall of the tube and enhances diffusion across its inner lining.
When we eat, the food advances in one direction, following the major components of the human digestive system, from the mouth or oral cavity, pharynx, esophagus, stomach, small intestine and the large intestine or colon. The large intestine ends in the rectum, anal canal and anus. . If the complete digestive system of an adult human were fully stretched out, it would extend 6. 5 to 9 meters or 21 to 30 feet; definitely one big tube. The mouth or the oral cavity is the entrance to the digestive system where the food is moistened and chewed. It can be said that the polysaccharide digestion starts in the mouth.
The pharynx is the entrance to the tubular part of the system and to the respiratory system as well. It moves the food toward by contracting sequentially. On the other hand, the esophagus is the muscular, saliva-moistened tube that moves food from pharynx to stomach. The stomach is the muscular sac which stretches to store the food we take, faster than can be processed. Gastric fluid mixes with food and kills many pathogens. If the mouth is the place for polysaccharide digestion, the stomach is the place where protein digestion starts. It secretes grhelin.
Grhelin is the appetite hormone which is responsible for those individuals who always want to eat. The small intestine on the other hand, has three parts. The first part of the small intestine, namely the duodenum which is C-shaped and almost 10 inches long, receives secretions from the pancreas, gallbladder and liver. The second part, the jejunum which is almost three feet long, is the part of the small intestine where most nutrients are digested and absorbed. The third part is the ileum which is six to seven feet long and absorbs some nutrients and delivers unabsorbed material to large intestine.
The large intestine concentrates and stores undigested matter by absorbing mineral ions and water. The large intestine of the adult human is about five feet long and it is divided into ascending transverse and descending portions. The last two major components of the digestive system are the rectum and the anus. The rectum is the distension which stimulates expulsion of the feces while the anus is the end of the digestive system and has a terminal opening through which feces are expelled. (Smith and Morton, 2001). The other system, urinary system, consists only of the two kidneys, two ureters, urinary bladder and the urethra.
The two kidneys are shaped like beans, with the indentation or hilum, which faces medially. The kidney contains both excretory and collecting elements in the form of epithelial tubes and cavities, which are separated and supported by connective tissue laced with blood vessels. The two ureters, urinary bladder and urethra are all collecting elements. The ureters carry the urine from each kidney to the urinary bladder. A single urethra then carries the urine to the outside. We should be aware that the urethra is one component of the urinary system whose final development and location differ in the male and female.
The ureters and urinary bladder are also lined with transitional epithelium. Surrounding this lining are thick walls formed by multiple layers of smooth muscle held together by connective tissue, particularly prominent in the urinary bladder. The urethra is lined by a combination of epithelial types, ranging from transitional to stratified squamous. The stratified squamous is the epithelium characteristic of structure close to or on the outside of the body (Premkumar, 2004). To sum the components and functions of the urinary system, the two kidneys produce urine while the ureters convey the urine to the urinary bladder.
The urinary bladder in return stores the urine while the urethra transports the urine out of the body. The digestive system maintains the homeostasis in the human body through mechanical processing and motility, secretion, digestion, absorption and elimination. In mechanical processing and motility, movements of the various parts, such as teeth, tongue and muscle layers, break up, mix and propel the food material that we eat. In secretion, the digestive enzymes and other substances are released into the digestive tube.
Digestion occurs when the food that we eat is chemically broken down into nutrient molecules until they become small enough to be absorbed. Following digestion, of course, is absorption, where the digested nutrients and fluid pass across the tube wall and into blood or the lymph. Finally, elimination takes place when the undigested and unabsorbed residues are eliminated form the end of the digestive system or gastrointestinal tract. While the urinary system maintains homeostasis in the body by excreting and reabsorbing important electrolytes, compounds and water.
Depending on the changes in the blood’s acid-base balance, the kidneys can either excrete bicarbonate or form new bicarbonate and add it to the blood. The necessary chemical reactions go on in the cells of the so called nephron tubule walls. For example, when the blood is too acid such as when we drink softdrinks or soda, water and carbon dioxide combine with the help of an enzyme. They form a compound called the carbonic acid that then can be broken into bicarbonate and H+. Then, the bicarbonate produced in the reactions moves into the interstitial fluid, and form there into peritubular capillaries.
It ends up in the general circulation, where it buffers excess H+. H+ formed in the tubule cells is removed from the body. It is secreted into the nephron’s lumen, where it may combine with bicarbonate ions in the filtrate. Sadly for them, those ions can’t cross the tubule wall. But when bicarbonate is not available, the excess H+ combines with phosphate ions or ammonia and is excreted in the urine. This is how kidneys rid the body of hydrogen ions. On the other hand, when the blood is too alkaline, chemical adjustments in the kidneys normally ensure that less bicarbonate is reabsorbed into the bloodstream.
Based on how the structure and function of two organ systems collaborate to maintain the body’s homeostasis, I think that a robot having a digestive system and urinary system exactly alike that of the humans is impossible. Robots can be used to cure or treat digestive or urinary system problems but robots having these systems seem impossible. More generally, robots are used to treat humans and help doctors in surgeries. This is evident in the use of robots in surgery or the so-called “Surgical Robotics” which is considered to be the “state of the art and future trend, especially towards autonomy” (Finlay, 2007).
The examples of medical robot taxonomy are medical robots, surgical robotics, non-surgical robotics, image guided robots and multi-arm telemanipulators. They are also used in neurosurgery and there are new developments such as the developing strategic surgical robots and tactical surgical robots. On the contrary, robots may have a “digestive system or urinary system” that is similar or functions the same way as the digestive system or urinary system of humans, but not totally or exactly the same.
If humans were to create robots with digestive systems of urinary systems, then that would be really difficult and the resulting project would be really complex. In addition to this, it would require us to develop sophisticated nanotechnology or use a lot of nanotechnology just to create one digestive system or one urinary system. After all, it is the body which secretes the enzymes or chemicals which conducts the bodily processes needed in the human body. A robot cannot simply produce the chemicals which are exactly the same as what our body creates or secretes.
A hypothetical digestive and urinary system for a robot would look similar to the parts and processes that occur inside the automobiles. The gasoline is the robot’s food and the carburetor or the pistons are the teeth of the robot. An engine will serve as the stomach and in the case of a spark ignition engine, the spark will be similar to the chemicals or enzyme which the digestive system releases in order to digest or ignite the food. The gasoline which was not properly utilized or if incomplete combustion occurs, carbon dioxide or other gas emissions (similar to feces in the human body) will be released in the exhaust.