Anatomy and Physiology of the Large Intestine - Video & Lesson Transcript | fabula-fantasia.info
The lower part of the GI tract includes the small and large intestines. . as far as the terminal ileum (where the small and large intestine meet), which is .. As you will see from the accompanying diagrams, the human anatomy. The large intestine includes the appendix, cecum, colon, and rectum. MyPlate offers ideas and tips to help you meet your individual health needs. The muscles of the small intestine mix food with digestive juices from the pancreas, liver. Small intestine cancer starts in cells of the small intestine. Learn about symptoms, diagnosis, The ileum absorbs nutrients and passes what is left to the large intestine. Cells in the small of the small intestine. Diagram of the digestive system.
The lining has thousands of tiny folds and projections called villi. There are tinier projects on each villus called microvilli. These folds make a huge area for absorbing food. Amino acids, sugars, vitamin C, the B vitamins, iron, calcium and magnesium are carried through the blood stream to your liver where they are processed and sent to the rest of the body. Fatty acid, cholesterol, and vitamins A, D, E, and K go into the lymph system and then into the blood.
These also go to the liver, get processed and sent out to other cells in the body. Duodenum It is a inch long C-shaped tube found around the head of the pancreas which forms the first part of the small intestine right after the stomach. The food, now chyme, enters from the stomach into the duodenum where it is mixed together with the bile and other digestive juices produced by the accessory digestive organs and drained into the duodenum.
Absorption of food also begins here with the absorption of vitamins, minerals and other nutrients. In particular, before the food passes into the next part of the small intestine iron, calcium and magnesium are absorbed here. The rest of the food is passed into the jejunum. Jejunum Function The second middle section of the small intestine is a coiled tube which is thicker and more vascular than the ileum. It lies in the belly button area of the abdomen. There are small fingerlike projections in the wall of the jejunum called villi.
These villi are covered with smaller projections called microvilli.
The villi increase the surface area of the jejunum and allows much more absorption of nutrients in this part of the small intestine—most of the food absorption is done in this part of the digestive tract. Simple sugars, water soluble vitamins except vitamin C and some Bs and amino acids made from the food is passed from the villi into the blood stream while the fat is passed into the lymph capillaries.
The rest of the food passes into the ileum. Ileum The last part of the small intestine is mainly the pelvic region. It looks very similar to the jejunum. However, the nature of the small intestine gradually changes. It is thinner and has fewer blood vessels as compared to the jejunum.
The last absorption of nutrients from the food takes place here—amino acids the end products of protein digestionfat-soluble vitamins A, D, E, and Kfatty acids the end products of fat digestioncholesterol, sodium, potassium alcohol, and B The terminal ileum is an important part as this is where vitamin B12 is absorbed into the blood capillaries.
The unabsorbed and undigested food then passes from the ileum into the cecum, the beginning of the large intestine. This food residue is full of bacteria. Large Intestine Large Intestine — Click for larger image The large intestine forms the last part of the digestive tract, which is about 5 feet long and wider than the small intestine.
The surface area on the inside of the large intestine is smaller than the small intestine. The large intestine can be divided into the cecum, colon and rectum.
The undigestible food waste passes from the small intestine into the cecum which then passes into the colon further divided into ascending colon, transverse colon, descending colon and sigmoid colon where the fluids and salts are absorbed.
The undigested food moves up the ascending colon, across the transverse colon, down the descending colon and into the rectum. The colon soaks up to 50 fluid ounces of water every day. After absorption, the remaining undigested matter is squeezed into a bundle called feces. Feces is made of fiber, undigested food, cells that slough off the lining of the intestines and bacteria. They make vitamin K and B12 which is absorbed by the colon wall, break down amino acids and make nitrogen, live off of fiber which makes gas.
When the bacteria finish with the feces, it is passed into the rectum, where it is stored until it is passed out through the anus as a bowel movement. The anus has voluntary and involuntary sphincter muscles which can tell the difference between gas and solid contents.
A vestigial organ an organ that had a purpose in the past but is now useless or close to itthe appendix, is attached to the large intestine at the cecum. Though this organ is potentially of no use, it can cause pains and complications once it gets inflamed, a disorder called appendicitis.
Accessory Digestive Organs and Glands Though not directly part of the digestive tract, the accessory digestive organs play a major role in digestion. The accessory digestive organs include the salivary glands, pancreas, liver and gallbladder. Glands are organs that secrete hormones. Salivary Glands There are three pairs of salivary glands: It also helps break down starches in the food. Pancreas A carrot-shaped gland located behind and under the stomach, the pancreas acts both as an endocrine gland and an exocrine gland.
From the exocrine part it secretes pancreatic enzymes amylase and lipase which pass through the pancreatic duct into the small intestine the duodenum.
The pancreatic duct joins the bile duct. These enzymes aid in the further breakdown of food, mainly the carbohydrate, protein and lipid part of the food. From the endocrine part it secretes insulin and glucagon. Insulin enables you to digest and metabolize carbohydrates.
The pancreas also secretes an antacid to help settle an upset stomach.
Your Digestive System & How it Works | NIDDK
It is the largest organ of the human body and is below the diaphragm in the upper epigastric region of the abdomen. It has many functions including production of chemicals necessary for digestion, synthesis of protein and detoxification.
The major function of the liver is to produce bile yellowish-green fluid which aids in the digestion and absorption of fats. It also stores glucose, iron and vitamins A, B12, D etc. The liver also sends out the nutrients and substances digested from the food to the cells of the body.
Gallbladder The gallbladder is a small organ located just below the liver. It is about 3 inches long and shaped like a hollow balloon. Its main function is to store bile produced by the liver and release it into the duodenum when food that contains fat needs to be broken down and absorbed.
The bile in the gallbladder becomes more concentrated and more effective in breaking down the fat. Gallstones are a common disorder of the gallbladder. Gallstones are formed when there is too much cholesterol in the bile and often need removing the gallbladder.
Gallstones can get as big as a golf ball. The teeth and tongue also aid in digestion and are very much a part of the digestive system.
Diarrhea The condition of watery stools during a short period is called diarrhea. It is a very common problem and most often gets better on its own. Dehydration is a major side effect of this problem and thus the fluid lost should be replaced with constant intake of saline water.
Meet the gastrointestinal tract!
Diverticular Disease In some people, especially the elderly, the colon begins to have sac like protrusions called diverticula singular diverticulum. This condition is known as diverticular disease. It is generally caused due to constipation where there is increased pressure to pass stool that is too hard. The pressure causes weak parts of the colon to bulge causing diverticula. In cases where the diverticula get infected, a condition called diverticulitis; it needs thorough treatment by a doctor.
The abdominal pains caused by diverticulitis can be very severe and require hospitalization. Rare cases may require surgery to correct the problem. Gastroenteritis Also called stomach flu is a temporary illness caused by a virus which mainly affects the stomach and intestines with diarrhea, nausea and vomiting. Gastroenteritis can be treated by your regular doctor. We just pass it on down to the next guy.
We don't even really do anything to it. But the next guy is a little more exciting. Now we get to the stomach.
Jejunum's Function in the Small Intestine and Digestive System:
A lot of action going on in the stomach, one of my favorite parts of the GI tract. The stomach is responsible for multiple things, including churning, which is a lot like chewing, except that there are sort of more dimensions of contraction affecting the food and breaking it down. We also have hydrolysis going on here, the enzyme-assisted breakdown of food.
In addition to that, you can store food in your stomach if it's not time to pass it on to the next component of your GI tract.
Anatomy and Function of the Digestive System
The overall goal here is to make what's called chyme. So we take our bolus, and we sort of melt it down, per se, into this more fluid type of substance that we can pass on to our intestines.
So we're moving on now to our intestines. Starting now from about this point right here, we get our duodenum, and then this kind of circulates around here, and then we end up at this point. Everything in between, I'll draw it way out here, I'm just going to group together for right now as the small intestine. There are three parts to this, and we'll talk about that in a subsequent video, but the main functions that we achieve here are hydrolysis, and also the absorption of nutrients.
Notice this is kind of the first part of your GI tract that you're finally taking in some of the break down food products, and using them for nutrition to make other products in your body. Now that we have gone through the small intestine, what do you think shows up next?
Starting from after the small intestine ended, all the way through this lined structure right here, we are going to be passing through the large intestine. Do you guys remember the other name for the large intestine?
It starts with a C. If you said "colon," absolutely right. The colon is also one of the more boring parts of the GI tract, because really all we have going on here is absorption, but not of nutrients per se, more like things like water, or ions, or vitamin K, just things like that are absorbed in the large intestine, so not a very high yield place for acquiring nutrients. Then after that, we're going to pass food on to this structure here.
This is called the rectum.