welcome back welcome back welcome back to science all right we're going to talk about the small intestine and the different segmentations of the small intestine we're going to look at the cellular composition how it works how it absorb absorbs and the different things that are involved in that absorption so if you take the small intestine and you take it out of your body and line it up from end to end you'll die um anyway it's it's quite a long organ in comparison to your small intestine a large intestine all right so the small intestine is going to start where the pyloric sphincter of the stomach ends so at that moment it's going to be the small intestine three different areas are going to be involved here and if you look at where it is this is where people are going to call their belly or their tummy as they're touching essentially where their belly button is that area so this is going to be most of what your abdominal cavity is so you're going to have um your liver is going to be a big part around the outside you're going to have the large intestine but in the middle that's going to be your small intestine so what does it do it receives chyme from the stomach the liver and the pancreatic secretions are also going to help in this process as digestion even more of it occurs here and more importantly absorption of those things that have been broken down whatever's left over goes to large intestine so three parts of the small intestine the first part is going to be called the duodenum duodenum is going to have it's the honestly it's the region that we've been talking about how we've been identifying how um the paint grow duodenal secretions occur of course in the duodenum this is the shortest and if you look at the movement of the of the others this is the part that's really fixed that doesn't move much moving from the duodenum you get into the jejunum so the jejunum is going to be thicker it's going to move more um and so in comparison of the three it moves the most the ilium is going to be after the jejunum and before he gives the point of being in the large intestine so this is the most disapportion and it's going to have the pyres patches that we talked about when we were discussing the lymphatic system so the jejuna minilium are suspended by a double layer this to me kind of looks like an apron and I've heard it called that anatomically and so this apron is going to be the mesentery and you can see that mesentery a little bit of it here um and from here's a connection of the mesentery the mesenteric and you can see the artery and vein and the lymphatics that's going to be tied to there and take a look here at this greater omentum so this is that apron that's covering this and if you go back there's the greater momentum that's here and you can see the Lesser that's going to be towards the back but it's still going to be there all right so this double folded layer of the peritoneum is going to be called the mesentery and it transport blood and lymphatic vessels and nerves to the wall of the intestine so the double fold the uppermost part that if you open the person up and let's say a cadaver the first thing you would see in the abdominal region after you got underneath the muscle is that greater momentum it's going to be draped over the intestines so just going through here's the stomach here is the pyloric sphincter and now we move into the duodenum and then we're going to get to the jejunum and then we're going to eventually get to the point of the ilium and we're going to terminate into the colon specifically starting with the ascending colon and take a look at that pretty little appendix right there all right this is a cross section and you'll you know you look at this and like what is going on here this is all the tubes that you see here uh at a cross section from the side so that's why you see all those circles not odd looks so yes it kind of looks odd but you can see some of the things that we haven't really discussed yet and so let's see the parietal peritoneal and the visceral peritoneal is going to be actually on the organs and that's no surprise that's a theme that we've seen on every organ we've looked at the visceral being I don't know like Saran Wrap and that balloon nature where you put your fist into the balloon part of it is actually touching your fist that's going to be the visceral on the outer layer will be the parietal and so you see this here in the abdominal cavity as well so this is the peritoneal cavity so you have the parietal peritoneal which is going to be on the the wall moving down and the visceral peroneal is going to be wrapped around every single thing that's on the interior wall of the material all right so let's take a look at the small intestinal wall what's going on here there are tiny little projections and on this projection there's even more projections so these kind of projections of mucosa are going to be the intestinal villi so everything about projections so we're going to take a look here everything about this projection and there's projections on the projections just like all these microvilli and they have those um all of these different villas with microvillus on top of it everything that is going to increase surface area so think of my finger my a mitten hand has this much surface area spread it apart a little bit and you have surface area all the way around this and if you took a measurement from like here to here you get more like 8 to 12 inches if you did this you're going to have essentially way more 24 inches I would guess that you would have the surface area to account for and so there's lots of surface area that's extended because of those extensions so surface area to volume ratio is drastically increased because of these microvilli with all of those different absorption area that's there surface area there it's going to Aid in absorption so in each one of this Villas you're going to see a simple columnar epithelium at the core of the connective tissue and at the center of that you're going to have the blood vessels and the lacteal if you remember this beautiful lacteal the lactils this lymphatic vessel it's the Green in this picture it's the shrekish thing and so you have that lacteal and remember that the lymphatic system is a one-way system moving towards the heart and at this point this is where it's taking up the gastric fats the fats that have been absorbed and so it's really great this is doing its job it's going to be taking this we know pyrus patches that's going to be involved so it's picking up the fat that's where it's at so the free surface of the episode epithelial cells contained in microvilli so not only Villi but the microvilli as well that also increases surface area so we're talking about surface area on surface area literally uh and the intestinal glands like the Crips uh lubricun they are located at the base of the Villi so you can see the intestinal glands the lubricant that's there the plique circularis there these are going to be the muscular folds that are going to be found in the mucosa of small intestine so the plique circularis you can see on maybe some different slides here we go so if you looked at this it's ridged along the inside these are circular rings and if you look at what they are just I want you to focus on the surface area it's such a beautiful thing it is increasing the likelihood absorption of nutrients I mean this is this is great this is key for survival if we were just a slick pipe in there it would take so much intestines to do what our small amount of intestines do I think it's 27 feet of small intestine anyway we have these plique circularis are these circular motions circular structures and you can also see there's a circular muscle that's the name of a muscle you can see a longitudinal muscle and you can see the serosa that's going to be on that side once again serosa a common name for just an outside layer so these ring-like regions are going to help especially when it gets to the talking about the point of peristaltic movements all right so we have the Villas we can see the different simple on columnar epithelial that's going to be there mucosal cells the intestinal gland that's going to be fair and even further going from a lacteal to a lymph vessel moving up the highway system and here is the microvilli that's going to be on one of those cells so these are additional levels of um surface area all right so mucus mucus is going to be released by goblet cells no surprise there these are the columnar epithelial cells that's kind of what they do those goblet cells they also have secretion also secreted by the specialized Bruner glands the intracinase is where you may have remembered the word Bruner gland and so the intracinases are going to be releasing intracinase and intracinase is going to cause the common obsription trypsin to be become trypsin and now the trypsin is going to have many different Pathways that can be activated as the result of it doing its job so this is going to be a thick alkaline secretion and remember that alkaline because the chyme is going to have that hydrochloric acid that's digested in the stomach so now once it's there we're going to have the stimulation like we need to have that bicarbonate to bring down that acidity so we're not digesting digesting our small intestine we also have the relation release of a watery a watery fluids man so this picks up digestive products and promotes them into the Villi no digestive enzymes in that watery fluid is just going to help the movement of things it's going to keep things flowing literally so the enzymes that are going in the membranes of the microvilli we have peptidasis these break down peptides into smaller amino acids like okay we have so many protein right we have so many protein protein things it's a difficult compound and we've had our proteases that have broken them down to these peptides these polypeptides and this is breaking it down into amino acids now that you have the amino acids you can actually absorb those into your bloodstream and use them maybe store them in your liver to go through a deionization or the production or urea or whatever it may be but we have the pepsodases that are breaking down those spinal polypeptides into even amino acids other things doing their final digestive process you have to think of it that there's been a giant products consumed that make nasty that you ate from the the restaurant you started digesting that when you saw that um you're releasing these fluids in your mouth and then you started mixing that the mechanical as well as mixing in the chemicals then you push that down to swallowing soft palate up epiglottis Down You're Now swallowing moving down through peristaltic waves through your esophagus through the cardiac sphincter and to the stomach into the fundus and then the body then you have the pylorus you're moving it back and forth and churning it moving it with a different muscular directions now that you have this chyme made you're going to have a little bit leaking out into the duodenum and you have the pancreatic juices as well as the the bile from the comma bile duct that's going to be released and you're also going to have the releasing of bicarbonates to neutralize this the alkaline mucus that's going to be there the Bruner's glands that are going to be triggering the intracinases to cause the trypsin to be activated so then we can have the different products that trips and triggers to start you've deconstructed things from something elaborate to now into sub categorical pieces now we have the final Precision chopping and so we have sucrase which is breaking down sucrose and to glucose you have maltase breaking down maltose and to glucose and fructose um long short of it is we are breaking down disaccharides into monosaccharides that we can actually use light bases gonna break down fats it's going to actually have emulsification and it's going to break down the fatty acids all and the glycerol so they're broken off so we have all these things that are happening able enabling your body to actually absorb here in the small intestine so regulation of the small intestine secretion occurs by these methods so these four muco secretion occurs in response to Mechanical stimulation in the presence of irritants such as gastric juice so that's moving into your intestinal tract so you deal with it you it's going to stimulate and cause like okay since this is here we need to do this so the contact with the chyme it's going to stimulate goblet cells to secrete mucus and the intestinal glands just create the watery fluid once again no enzymes there the distention of the intestinal wall activates nerve plexuses in the wall of the small intestine and distension also stimulates the parasympathetic remember the rest and digest to trigger the release of the intestinal enzymes to cause the breakdown of this to actually cause true um chemical breakdown so we can actually absorb this billi they increase the absorption area small intestine is the most important absorbing organ in the alimentary canal so that is the tube going from mouth all the way through because we're a tube in a tube a stuff you can swallow marble and defecate the marble out so it's going through this tube in our body absorption is so effective that very little absorbable material reaches the organs distillant so very little things that you can actually absorb is defecated out most of it we go through we strip every single part of a nutrient we can from it using all of these different kinds of chemical enzyme cocktails to break it down so carbohydrate digestion and secretion saliva and the pancreatic amylases both are starch breaker downers are going to break down starch and glycogen into disaccharides and the intestinal enzymes break down disaccharides into monosaccharides the monosaccharides are going to be absorbed by facilitated diffusion active transport into the blood vessels in the Villi then we know we're going to utilize its insulin to cause that to go into our cells all right so protein digestion pepsin in the stomach breaks down the proteins into polypeptides and it takes the acidity of both the chief and the parietal cells doing their job making the acidic environment making the Como pepsin becoming actually usable form a pepsin if it's in the right pH the pancreatic proteases like trypsin and comatrypsin are going to break down proteins and polypeptides in the smaller peptides so once again this is duodenal so now after this we're going to have the intestinal pepsodases that are going to break down the peptides into amino acids that's absorbable so we're going to absorb that put it in our blood vessels and it's going to be absorbed through the villain so this is the breakdown of maltose and in the end you have glucose glucose that's what maltose is the disaccharide of um glucose and you can see at the bottom a dipeptide broken down into the different amino acids that are there and they're just using generic versions to show in our group um just to show that dipepsodase breaking it down all right so fat absorption so we went through carbohydrates we've went through protein now we get to fat fat digestion and absorption we're going to have the emulsification because of bile salts that's why if you're missing your gallbladder you can't have that digestion and you're going to have to use a low fatty diet and also take medication to help fix that digest it mainly by enzymes from the pancreas and the small intestine digested into glycerol and fatty acids we've broken it down and now that the fatty acids and glycerol are absorbed by a process involving several steps absorbed into the blood or lymphatic capillaries the lactils that we looked at all right so myosin what is a Maya cell a mild cell is going to have a nonpolar structure and you're going to have nonpolar Tails pointing towards it and you're going to have polar heads wrapping around it so you make a sphere of polar outside with a nonpolar Center think of to me it's like a dandelion where the white fuzzy part let's say a dandelion is now a sphere instead of just part of that flower um the outer wider part would represent polar things the stem coming off to the seed that connects to that core would be nonpolar and that core would be nonpolar all right so my cells are going to be loose complexes of fatty acids and bile salts which uh form which from which fatty acids migrate to the microvilli and then can be absorbed so the fatty acids plus the glycerol are re-synthesized in the triglycerides in the smooth ER we know that this is where we're going to make phosphipids and different things like that like to make our cell membrane new triglycerides cluster clusters are encased in protein forming chylomicrons that's a great name for a cat if you're trying to think of a good name for a cat chylomicron is a good starting point so chylomicrons can be absorbed by lacteals and this is going to go into the lymphatic system and we know ultimately that these chylomicrons the fatty material will eventually be dumped into your right or left subclavian and then dumped into the superior vena cava so this is showing the fat absorption how it's going through smooth endoplasmic reticulum it's going to alter it it's going to make the chylomicrons chylomicron is going to go out they're going to be absorbed by that lactil now it's going to be the lymph system that's going to then be moved later on all right movement of the small intestine small intestines going to carry um and move things in two ways one is peristalsis we know the balloon moving the marble down is peristalsis then segmentation is something we haven't talked about segmentation is going to have those rings where it's going to be essentially moving it back and forth which is going to form a mixture as it breaks apart and has more surfaces that are now exposed you have more areas that can be broken down so that's going to increase increase the effectiveness of the enzymes that's working on it the parasympathetic impulse will stimulate both mixing and peristaltic movements no surprise because the parasympathetic is the rest and digest the sympathetic is going to inhibit them if small intestine becomes over distended or irritated a strong peristaltic Rush is going to sweep contents in the large intestines like we're not dealing with this just get it out of here get this crap out of here and it it does it's called diarrhea and please make sure you learn how to spell diarrhea d-i-a-r-r-h-e-a not a good animal not a good name for a cat it's a hard one to spell it is the most misspelled word in the medical world diaphragm is the second most d-i-a-p-h-r-a-g-m and thirdly oddly enough is alcohol all right so ileocecal ileocecal sphincter ilio is referring to your Ilium and SQL as in it's moving to your cecum it's going to move to your large intestine a sphincter is going to be a circular muscle so if you had to use a little bit of deductive logic here you would probably be right that this is a way that we regulate and how we're moving that material that final breakdown stuff into your large intestine so this helps regulate the flow of chyme all right guys next is the great big bad large intestine all right I'll see