Diagram of the Digestive System
Thank you for your input. Tractus digestorius mouth to anus , canalis alimentarius esophagus to large intestine , canalis gastrointestinales stomach to large intestine. The characteristic long mesentery allows loops of the jejunum to rest on the contents of the ventral portion of the abdomen. In the large intestine the remaining semi-solid substance is referred to as faeces. Energy systems resources Online quizzes: Open the links to digestive system structures and move the mouse on the black-yellow-red-green marks on the diagram to learn the parts.
Organs of the Body & Organs Systems of the Body
Once your food has traveled through your small intestine, it makes its way through the large intestine! The large intestine is only 5 feet in length, but has a diameter of about 2. Your large intestine will also absorb most of the water from the slop, leaving behind a semi-solid mass of waste material.
From here, it will be stored in the rectum until it can be eliminated from your body as fecal waste poop! Set this aside for later use.
Take your peanut butter sandwich and break it up into tiny pieces. Put the pieces into the sandwich bag and add your water. This will act as the saliva, further breaking down your food. Add the acid into your bag, simulating the hydrochloric stomach acids that work to break down your food. Continue mashing your food, pretending that your hands are acting as stomach muscles! Take your nylon tube and hold it over your shallow pan.
Pour your chyme into the nylon. Start squeezing the chyme through the nylon. This would be the nutrient rich material that is absorbed through the small intestine! If you want to get really detailed, you can roll it into a nice shape, and examine your handiwork.
You should have a nice round pile of…. Now, there is a much more palatable way of appreciating our digestive system. One of our favorite projects of all time, was when I surprised my daughter and niece with making our very own digestive system anatomy cake!
It was really easy, and really fun! Cake Mix and the supplies for baking! Take your kids to the dollar store and pick out a bunch of candy! Have them make a list before you go, detailing what kind of candy they might use for each organ. We ended up using the following candies: We used a simple box cake. I let the kids bake the cake themselves, which gave an added bonus lesson of math and measurements in the kitchen! Tape that down as well.
Fill your bag with icing and trace the organ onto the plastic wrap! Once you have it all drawn out and filled in, carefully move the plastic wrap onto a plate. Put this plate in the freezer for approximately 15 minutes. Repeat the process for any other organs you need to draw on. Alternatively, you could draw on the organs with toothpicks or wooden skewers. This will put the foundation of icing on your cake so you can then lay the details of your digestive system.
Now let the kids make their model of the digestive system! What are they going to use for teeth? How should they place the esophagus? Where should they put everything so that it fits in its proper place? Take your organs out of the freezer and lay them icing side down on your cake.
Have the kids make their own labels and tape them to toothpicks. Then have them stick the labels where they go. Stand back and admire your kitchen anatomy skills, and take a lot of pictures! Here is an adorable skeletal model made with veggies!
Use this as inspiration and carve your organs out of vegetables! We had a fantastic time learning about the digestive system! The science projects we did really added a lot to our learning experience and made it so that the kids were able to recall each function of the various organs, long after we were finished learning about them!
Below are some of the resources that we found to be useful along our learning explorations. Web Sites and Resources Kids Health: Get a great run down on the digestive system and how it works, in a kid friendly format.
This is a fantastic anatomy site with fully detailed diagrams, and extensive information on what each part of the body does. Other Body Systems Finally, if you want to learn about the heart and cardiovascular system , check out our heart unit! If you want to learn about the sense of smell and the olfactory system, then follow your nose and see where it goes! Sometimes even birthday presents can lead to homeschool adventures For my birthday this year, my….
After examining hair, puddles, and red blood cells, I was left wondering what else I could look at. My daughter had a brilliant suggestion — why not look at some of my makeup under the microscope? I could combine two of my favorite things — makeup and science, and check out what my new microscope could do! Percussion helps identify a grossly distended segment of intestine cecum on right, colon on left that may need to be trocarized.
The respiratory rate may be increased due to fever, pain, acidosis, or an underlying respiratory problem. Diaphragmatic hernia is also a possible cause of colic. The most definitive part of the examination is the rectal examination. The veterinarian should develop a consistent method of palpating for the following: The intestine should be palpated for size, consistency of contents gas, fluid, or impacted ingesta , distention, edematous walls, and pain on palpation.
In healthy horses, the small intestine cannot be palpated; with small-intestinal obstruction, strangulating obstruction, or enteritis, the distended duodenum can be palpated dorsal to the base of the cecum on the right side of the abdomen, and distended loops of jejunum can be identified in the middle of the abdomen. A sample of peritoneal fluid obtained via paracentesis performed aseptically on midline often reflects the degree of intestinal damage.
The color, cell count and differential, and total protein concentration should be evaluated. Normal peritoneal fluid is clear to yellow, contains The age of the horse is important, because a number of age-related conditions cause colic. The more common of these include the following: Ultrasonographic evaluation of the abdomen may help differentiate between diseases that can be treated medically and those that require surgery.
The technique also can be applied transrectally to clarify findings noted on rectal palpation. In foals, echoes from the large colon and small intestine are commonly identified from the ventral abdominal wall, whereas only large-colon echoes are usually seen in adult horses.
The large colon can be identified by its sacculated appearance. The duodenum can be identified in the tenth intercostal space and traced around the caudal aspect of the right kidney. The jejunum is rarely identified during transabdominal ultrasonographic examination of normal adult horses, whereas the thick-walled ileum can be identified by transrectal examination.
The most common abnormalities identified by ultrasonography include inguinal hernia, renosplenic entrapment of the large colon, sand colic, intussusception, enterocolitis, right dorsal colitis, and peritonitis. Stallions with inguinal hernia have incarcerated intestine on the affected side; it is possible to identify the intestine and to obtain information concerning the thickness of its wall as well as the presence or lack of peristalsis.
In horses with renosplenic entrapment of the large colon, the tail of the spleen or the left kidney cannot be imaged, or the gas-filled large colon is present in the caudodorsal aspect of the abdomen in the region of the renosplenic space. Horses with sand colic have granular hyperechoic echoes originating from the affected portion of the colon.
Very often the intestine proximal to the intussusception is distended, and the strangulated portion is thickened. Horses with enterocolitis frequently have evidence of hyperperistalsis, thickened areas of the bowel wall, and fluid distention of the intestine.
In contrast, horses with right dorsal colitis commonly have marked thickening of the wall of the right dorsal colon. In horses with peritonitis, the peritoneal fluid may be anechoic, or there may be evidence of flocculent material and fibrin between serosal surfaces of the viscera. Horses with colic may need either medical or surgical treatments.
Almost all require some form of medical treatment, but only those with certain mechanical obstructions of the intestine need surgery. The type of medical treatment is determined by the cause of colic and the severity of the disease. In some instances, the horse may be treated medically first and the response evaluated; this is particularly appropriate if the horse is mildly painful and the cardiovascular system is functioning normally.
Ultrasonography can be used to evaluate the effectiveness of nonsurgical treatment. If necessary, surgery can be used for diagnosis as well as treatment. If evidence of intestinal obstruction with dry ingesta is found on rectal examination, a primary aim of treatment is to rehydrate and evacuate the intestinal contents.
If the horse is severely painful and has clinical signs indicating loss of fluid from the bloodstream high heart rate, prolonged capillary refill time, and discoloration of the mucous membranes , the initial aims of treatment are to relieve pain, restore tissue perfusion, and correct any abnormalities in the composition of the blood and body fluids see Table: If damage to the intestinal wall as a result of either severe inflammation or a displacement or strangulating obstruction is suspected, steps should be taken to prevent or counteract the ill effects of bacterial endotoxins that cross the damaged intestinal wall and enter the bloodstream.
Finally, if there is evidence the colic episode is caused by parasites, one aim of treatment is to eliminate the parasites. Adapted, with permission, from Zimmel DN, Management of pain and dehydration in horses with colic. In most cases of colic, pain is mild, and analgesia is all that is needed. In these instances, the cause of colic is presumed to be spasm of intestinal muscle or excessive gas in a portion of the intestine.
If, however, the pain is due to an intestinal twist or displacement, some of the stronger analgesics may mask the clinical signs that would be useful in making a diagnosis. For these reasons, a thorough physical examination should be completed before any medications are given.
However, because horses with severe colic or pain may hurt themselves and become dangerous to people nearby, analgesics often must be given first. Additionally, many horses with less severe problems may need pain relief until the other treatments have time to be effective.
Medications used commonly for abdominal pain are NSAIDs that reduce the production of prostaglandins. When these drugs are used as recommended, their toxic effects on the kidneys and GI tract occur infrequently. Clinical experience suggests that flunixin meglumine may mask the early signs of conditions that require surgery and, therefore, must be used carefully in horses with colic.
Within a few minutes after administration, the horse stands quietly and is less responsive to pain. Unfortunately, the effects of xylazine are short-lived, and it inhibits intestinal muscular activity; it also decreases cardiac output and thus reduces blood flow to the tissues.
Of the narcotic analgesics, butorphanol is used most often in horses with colic. Butorphanol has few adverse effects on the GI tract or heart.
However, when given in large doses, narcotics can cause excitement, and the horse may become unstable. Although pain relief usually is provided by analgesics, there are other important ways to reduce the degree of pain. For example, passing a nasogastric tube also an important part of the diagnostic evaluation may remove any fluid that has accumulated in the stomach because of an obstruction of the small intestine.
The removal of this fluid not only relieves pain from gastric distention but also prevents rupture of the stomach. Horses with displacement of the colon over the renosplenic ligament ie, left dorsal displacement of the colon may benefit from administration of phenylephrine. This drug is given to contract the spleen and often is followed by light exercise on a lunge line in an effort to dislodge the entrapped colon.
Many horses with colic benefit from fluid therapy to prevent dehydration and maintain blood supply to the kidneys and other vital organs. The fluids may be given either through the nasogastric tube or IV, depending on the particular intestinal problem see General Concepts Regarding Fluid Needs in Dehydrated Horses. Horses with strangulating obstruction or enteritis must be given fluids IV, because absorption of fluids from the diseased intestine is impaired and fluid may be secreted into the lumen of the intestine.
The latter mechanism causes a buildup of fluid in the intestine, which must be removed from the stomach through a nasogastric tube. This abnormal movement of body fluids into the intestine contributes to the development of circulatory shock, which is often the ultimate cause of death.
In healthy horses, most of the fluid in the intestinal tract is reabsorbed in the cecum and colons. Therefore, horses with intestinal obstructions near the pelvic flexure usually require relatively small amounts of IV fluids, whereas horses with small-intestinal obstructions need extremely large amounts. The volume and type of fluid to be given are determined by the severity and cause of the problem.
Laboratory tests to determine the degree of hemoconcentration and whether concentrations of electrolytes are abnormal are critical for accurate treatment of horses with severe colic. The balance of body fluids can be reestablished by administering IV fluids formulated to replenish the deficient electrolyte s. In most instances, however, fluid therapy must be started before laboratory results are available, particularly when the horse is showing clinical signs of circulatory shock.
When IV fluids are needed but the clinical signs are mild to moderate, the horse is usually given 8—10 L of a sterile replacement fluid that contains electrolytes in concentrations similar to those that normally exist in the blood. This volume is administered throughout 1—2 hr, and the horse is reevaluated to determine whether additional fluids are needed. Horses in circulatory shock require much larger volumes of IV fluids, given as rapidly as possible; as much as 20 L in 1 hr may be needed to reestablish tissue perfusion.
Depending on the cause of colic, IV fluids may be needed for several days until intestinal function has returned, electrolyte concentrations are balanced, and the horse can maintain its fluid needs by drinking. Under such circumstances, the daily IV fluid requirements may range from 30 to L.
Fluids are sometimes given through the nasogastric tube as part of the treatment of impactions of the colon. Many clinicians believe the same result can be accomplished by giving large volumes of fluids IV. If the horse will not drink voluntarily and there is no obstruction in the small intestine, hydration may be maintained by administering fluids through the tube.
Fluids or medications should not be given through the nasogastric tube if fluid reflux is being removed from the stomach, because this indicates either the stomach or the small intestine is not emptying properly.
In healthy horses, the mucosal lining of the GI tract restricts enteric bacteria and their structural components eg, endotoxins, lipoproteins, nucleic acids, flagellin to the intestinal lumen. These bacterial components exist in high concentrations in the intestinal lumen, because they are released when the bacteria die or, in some cases, when bacteria multiply rapidly.
However, when this mucosal barrier is disrupted, as occurs with intestinal ischemia or inflammation, the bacterial components can move into the peritoneal cavity and then be absorbed into the systemic circulation. Based on recent research studies, equine leukocytes are most sensitive to endotoxins but also respond strongly to other components, most notably flagellin. Most studies performed to date have focused on endotoxins, because they are assumed to be the primary triggers for the systemic inflammatory responses that occur in many horses with GI disease.
These responses can include fever, depression, hypotension, reduced tissue perfusion, and coagulation abnormalities. Flunixin meglumine reduces the cellular production of prostaglandins and can help prevent some of their effects. Because flunixin can help prevent some of the early effects of endotoxemia at dosages less than the recommended dosage 1. There is considerable controversy regarding the efficacy of plasma or serum that contains antibodies designed to neutralize endotoxin.
These antibodies are directed against the components of endotoxins that are consistent among different gram-negative bacteria. The results of clinical studies using such antibodies have been conflicting, with evidence of protection being seen in some studies and no positive effects identified in others.
This apparent lack of efficacy of anti-endotoxin antibodies also may indicate that some of the systemic inflammatory responses encountered are triggered by other bacterial components. Because endotoxin itself stimulates the generation of a wide array of inflammatory substances that ultimately produce the pathophysiologic effects, neutralizing antibodies should be used as early as possible in the course of the disease. Polymyxin B has well-documented nephrotoxicity; however, concentrations of polymyxin B that bind endotoxin are far less than those that cause toxic effects.
This form of therapy should be started as early as possible in the clinical course of the disease. In addition, fluid replacement therapy should be maintained in hypovolemic horses, and serum creatinine concentration should be closely monitored. This latter concern is especially relevant for azotemic neonatal foals, because they appear to be more susceptible to the nephrotoxic adverse effects of polymyxin B.
A common cause of colic in horses is simple obstruction of the large colon by dehydrated ingesta, sometimes mixed with sand. These impactions generally develop near the pelvic flexure or in the right dorsal colon but may involve any portion of the large colon, descending colon, or cecum. In most instances, lubricants or fecal-softening agents given through a nasogastric tube soften the impacted ingesta, allowing it to be passed.
This form of therapy can be aided by the simultaneous administration of IV fluids. Keeping the horse muzzled is advised to prevent further impaction of feed material while the obstruction is softening.
Mineral oil is the most commonly used medication in the treatment of a large-colon impaction. It coats the inside of the intestine and aids the normal movement of ingesta along the GI tract. It is administered through a nasogastric tube, as much as 4 L, once or twice daily, until the impaction is resolved. Although mineral oil is safe, it is not highly effective in treating severe impactions or sand impactions, because it may simply pass by the obstruction without softening it.
Dioctyl sodium sulfosuccinate DSS is a soap-like compound that acts by drawing water into the dry ingesta. It is more effective than mineral oil in softening impactions; however, it may interfere with the normal fluid absorptive functions of the colon and can be toxic.
Thus, DSS can be given safely only in small quantities two times 48 hr apart. A safe and useful compound to treat impactions, especially those containing sand, is psyllium hydrophilic mucilloid.
When mixed with water, it forms a gelatinous mass that carries ingesta along the GI tract. Although usually given through a nasogastric tube to horses with impactions, psyllium also may be used as a preventive by mixing the dry powder into the feed.
This treatment is repeated 2—3 times each year in an effort to prevent development of sand impactions. Strong laxatives that stimulate intestinal contractions are not commonly used to treat impactions and, in fact, may worsen the problem. Occasionally, horses with extremely hard impactions are treated with magnesium sulfate , which draws body fluids into the GI tract. Adverse effects include dehydration and an increased risk of diarrhea.
Fluid therapy, whether the fluids are administered through a nasogastric tube or IV, is an important and effective part of treating horses with colonic or cecal impactions. If an impaction does not start to break down within 3—5 days, surgery may be necessary to evacuate the intestine and help restore normal motility.
The normal migratory routes of the larvae of large bloodworms, particularly Strongylus vulgaris , have been implicated in many cases of colic. In response to the migratory and maturation processes of the larvae in the cranial mesenteric artery, the wall of the artery becomes thickened and forms loose plaques of inflammatory tissue. It has been hypothesized that these plaques activate coagulation, resulting in thromboembolism. The blood supply to the intestine may be reduced, resulting in altered intestinal motility, a change in the absorption of nutrients from the intestine, or death of the intestine.
Thus, thromboembolism has been presumed to be a cause of recurrent episodes of colic and weight loss. Modern deworming medications, such as ivermectin and moxidectin, have activity against migrating S vulgaris larvae. Fenbendazole kills migrating strongyles if given at twice the recommended dosage daily for 5 days or at 10 times the recommended dosage daily for 3 days.
As a result of common use of these anthelmintics, chronic intermittent colic once thought to be caused by thromboembolism or parasite larval migration has largely been eliminated from equine practice.
There is considerable evidence that damage caused by cyathostomins causes colic, diarrhea, and loss of condition, particularly in young horses. These signs are seen on a seasonal basis and are synchronous with the emergence of large numbers of encysted larvae into the lumen of the large colon. In temperate areas of the Northern hemisphere, the larvae encyst during the winter months and emerge in the late winter and spring, causing ulceration, edema, and inflammation of the mucosa of the large colon.
This may result in diarrhea, protein loss, weight loss, and mild intermittent colic and fever. Horses with cyathostomosis require treatment with larvacidal dosages of anthelmintics such as ivermectin , moxidectin, and fenbendazole. Some horses require analgesics, supportive care, and proper nutritional support. Also see Gastrointestinal Parasites of Horses for a detailed discussion of treatment for large and small strongyles.
Surgery usually is necessary if there is a mechanical obstruction to the normal flow of ingesta that cannot be corrected medically or if the obstruction also interferes with the intestinal blood supply. The latter conditions result in death of the horse unless surgery is performed quickly.
Occasionally, surgery is indicated as an exploratory diagnostic procedure for horses with chronic colic that have not responded to routine medical therapy. Under most circumstances, horses exhibiting signs of severe abdominal pain nonresponsive to analgesic therapy require emergency abdominal surgery.
Generally, the lumen of the intestine is completely obstructed, such as occurs with a strangulating obstruction, enterolithiasis, or severe displacement. Similarly, horses with an abnormally distended intestine on rectal examination and peritoneal fluid with an increased total protein concentration and number of erythrocytes probably have a strangulating lesion that requires surgical correction.