Large Intestine

Large Intestine

The colon, or large intestine, is where absorption is complete, leaving waste products (fecesSolid waste material formed in the large intestine and expelled through the anus.). The colon compacts feces, reclaims waterThe universal solvent essential for life., and harvests vitamins produced by beneficial bacteria. These bacteria also produce gases.

Large Intestine Macroanatomy

The flow of chymeA semi-fluid mixture of partially digested food and digestive juices that moves from the stomach int, the liquid slurry of digested foods, moves from this right, lower side of the abdomen. It travels up through the ascending colon and over the top of the transverse colon. Then it moves down the descending colon. It goes through the sigmoid colon. Finally, it reaches the rectumThe final section of the large intestine, where feces are stored before elimination., which is like the waiting room for the anusThe terminal opening of the digestive tract through which feces are expelled.. 

Appendix

Off the large intestine where it comes in to contact with the small intestine. The ileocecal valve separates the small and large intestines at the cecum. The cecum is the specific word for the entrance to the large intestine. This cross section A cut or slice of the body or an organ for study. of the appendixA small, finger-like pouch attached to the cecum, thought to play a role in immune function. resembles Peyer’s patches. They were in the submucosa of the small intestine. Even if you can’t see that just trust me. This makes the appendix part of the MALT system or the mucosaThe innermost lining of the digestive tract that contains mucus-secreting cells for protection and a associated lymphoid tissue. The appendix is basically just a little lymph node. Much like any other lymph node this structure can become overrun with bacterial, viral or any other type of pathogen. As lymphocytes in the appendix try to battle the pathogen they lose the fight and can ultimately lead to a burst appendix leaking toxic substances into your peritoneal cavity

Large Intestine Serosa

The large intestine has these little pockets that are called haustra. Haustra is the plural word. Haustrum is the singular word. Each of these pockets can expand independently from the adjacent pockets. This allows for the gases created by the bacteria harvesting vitamins. The large intestine has a thick serosa. It is continuous with the omenta or mesenteries. These structures hold all of your abdominal organs in place. Epiploic appendages, little pieces of fat, kind of hang off the large intestine.  They are part of the serosa of the large intestine

Large Intestine Muscularis Externa

As we move deeper into the wall of the large intestine deepAway from the surface of the body. to the serosa is the muscularis externaA smooth muscle layer of the digestive tract responsible for peristalsis and segmentation.. This has the characteristic 2 layers of circular and longitudinal muscle that used mostly for peristalsis Rhythmic contractions of smooth muscle that move food through the digestive tract.. In the large intestine these muscle layers are quite thick compared to the other organs.  There is also this stripe of smooth muscle that runs down all the haustra called the tena coli.  This extra strip of smooth muscle provides additional power. It helps move very compacted and dry feces along.

Large Intestine Mucosa

The large intestine’s lining differs from that of the small intestine. The small intestine has plicae circulares and villiFinger-like projections in the small intestine that increase surface area for absorption. for absorption. However, the large intestine lacks these structures. It instead has deep crypts and abundant mucus cellsThe basic structural and functional units of life. for lubrication. The large intestine, stomach, and rectum are all lined with simple columnar epithelial cells, but their functions differ.

Constipation and Diarrhea

I always like to ask my classes if you’d rather be afflicted with constipation or diarrhea. It’s a tough question These two conditions are opposites of each other.  Constipation results usually from a lack of water or too much water reclamation by the large intestine. This compacts the feces making them more difficult to move through the large intestine. On the opposite end of the spectrum is diarrhea. In this condition, the large intestine is secreting too much water. It may also not be reclaiming enough. This is commonly associated with bacterial or viral infections. The increased water in your feces is your body’s way to flush out the pathogen. It tries to remove the foreign invader from your digestive system. I dare you to mention the Bristol scale the next time you go to your gastroenterologist. This is the Bristol scale. I’m sure I have to explain it. I do have to ask why you would want this named after you.

Large Intestine Flora

I do not like kimchi. I don’t even let my husband purchase it. It makes the entire refrigerator smell like the fart of someone who ate cabbage earlier in the day. However, kimchi contains live active beneficial bacteria. It is similar to kombucha, real sauerkraut, and real root beer. It is comparable to sour cream and yogurt. It is also similar to any product the FDA requires us to label as containing live and active cultures. This is generally what we refer to as good bacteria or probiotics. The benefit of these bacteria living in your colon is that they are excellent at harvesting vitamins. They take them from whatever is leftover in your feces. Whatever it was that your small intestine couldn’t extract your large intestine will. If you have ever taken a course of keflex or biaxin, you have cleared your good bacteria from your large intestine. All of it is removed. The same happens with any other incredibly wide-range antibiotic. This is why taking measures to keep or repopulate your large intestine flora is very important when taking antibiotics.

Colonoscopy & Biopsy

Many years ago, I suffered from a digestive condition. It went undiagnosed and seemed to resolve itself, knock on wood. I was teaching an A&P class in Geneva at night. I announced that I would have to take a day off. My students immediately asked me if I was going to have a colonoscopy. Since it was an A&P class, I admitted that yes, I would be having a colonoscopy. This made many of my students raise their hands. They all had pieces of advice to offer for preparing for colonoscopy. Their advice ranged from purchasing baby wipes. Others suggested setting up a desk in front of my toilet. This way, I could do work from there. There were other suggestions that were both ridiculous and wonderful. This picture is the colonoscopy. This tube has a light in the camera at its end. It sometimes has a little punching mechanism that can help us take a biopsy if needed. No, normal colonoscopies do not go all the way around the bend to the ascending:. Most are limited to either your sigmoid and maybe a little bit of your descending.