0:00 The pancreas is a soft elongated gland consisting of two main functions, ex 0:13 ocrine and endocrine. 0:15 The pancreas comes from the Greek word pan which means all, and creas which 0:20 means flesh, 0:21 fleshy organ. 0:23 The pancreas sits somewhat horizontally and can be divided into a few parts. 0:28 The unsenate, head, neck, body and tail is shown. 0:33 The tail of the pancreas tickles the spleen, behind the pancreas sits the left 0:38 kidney. 0:39 The head and unsenate of the pancreas interacts with the first part of the 0:43 small intestine 0:44 called the duodenum. 0:46 The beginning of the second part of the small intestine, called the jejunum, 0:50 also interacts 0:51 with the inferior surface of the pancreas. 0:54 Using anterior and superior to the pancreas is a stomach, which joins to the du 1:00 odenum. 1:01 The liver lies in the right upper quadrant of the abdomen and is the source of 1:05 bile production. 1:08 Bile is produced and travels from the liver down, the right and left hepatic 1:13 ducts. 1:14 The right and left hepatic ducts merge and form the common hepatic duct. 1:18 The bile can be stored actually in the gall better, the organ just below the 1:23 liver. 1:23 And the bile can be carried out from the gall better into the cystic duct. 1:30 The cystic duct actually joins with the common hepatic duct, we talked about, 1:34 to form the 1:35 common bile duct. 1:36 The common bile duct joins with the main pancreatic duct here, before entering 1:42 into the small intestine, 1:44 the duodenum. 1:45 Let's take a closer look at this area and to understand a bit more about the 1:51 common bile 1:52 duct and the pancreatic duct. 1:57 The flow of bile is controlled by the sphincter coliticus. 2:04 Pancreatic juices during digestion travel through the pancreatic duct and joins 2:08 with the common 2:09 bile duct. 2:10 There is also a sphincter called sphincter pancreaticus. 2:15 The common bile duct and pancreatic duct will join to form the ampular avata. 2:20 The ampular vata is surrounded by the sphincter papillae. 2:24 The sphincter papillae sphincter pancreaticus and sphincter coliticus make up 2:30 what is known 2:31 as the sphincter of odi. 2:34 The major duodenal papillae is the opening into the duodenum. 2:40 So just a reminder, here is the duodenal wall and here is the pancreas. 2:47 So let's take a closer look now at the pancreas and its physiology. 2:51 How it helps in food digestion and in particular what actually stimulates its 2:56 function. 2:57 Here again is the pancreas surrounded by other organs. 3:01 The pancreas is open here as I have drawn. 3:04 Remember when we eat food is in the stomach and the content is actually acidic 3:08 and it's 3:08 because the stomach is where acid is produced and it really helps the first 3:14 phase of digestion. 3:16 Food then will enter the duodenum, the first part of the small intestine. 3:21 When food is in the small intestine the gallbladder is stimulated to secrete 3:25 its stored 3:26 bile into the duodenum. 3:28 Also, the pancreas is stimulated to secrete digestive juices into the main 3:33 pancreatic 3:34 duct and then into the duodenum. 3:37 The juices are produced from the asinac cells which again produce the enzymes 3:41 to help in 3:42 the digestion of food, the juices. 3:44 The common bile duct and main pancreatic duct converge at the ampula vata 3:50 before entering 3:51 the duodenum through the major duodenal papilla. 3:54 It's important to know there is an accessory pancreatic duct which also has its 4:00 own opening 4:00 in the duodenum. 4:02 Now it's also important to remember that 98% of cells in the pancreas are ex 4:08 ocrine cells 4:10 which means cells that produce enzymes, the digestive juices. 4:16 And the other 2% are the endocrine cells which are responsible for the hormones 4:22 such as insulin. 4:24 These hormone cells of the pancreas are found in clusters and these clusters 4:29 are called 4:29 the islet of langehan and their role in the human body is so important. 4:35 Let's take a closer look at how everything works now. 4:45 So here you have the asinac cells which make up the exocrine function of the 4:50 pancreas. 4:50 They secrete enzymes such as amylase, lipase and peptidase into the main 4:56 pancreatic duct 4:57 and then eventually the pancreatic duct will carry this into the duodenum to 5:02 help with the 5:03 digestion of food. 5:05 The islet of langehan sits around the asinac cells and are part of the end 5:09 ocrine function 5:10 of the pancreas, the hormones. 5:12 There are few types of cells which make up the islet of langehan and these 5:17 include the 5:17 alpha cells which secrete glucagon, the beta cells which produce insulin, the 5:23 gamma cells 5:23 which produce polypeptides and the delta cells which produce somatostatin. 5:29 Humans are secrete from these cells into the bloodstream and obviously after 5:36 you eat insulin 5:37 is the hormone that is produced by the beta cells to help store all this energy 5:44 that we 5:44 have just eaten. 5:46 Now let's go back and see how everything is regulated, specifically the enzymes 5:50 in digestion. 5:52 So imagine you ate a meal and you have food coming down into the duodenum from 5:56 the stomach. 6:00 Here is the duodenol lumen, cells of the small intestine and in the basement 6:04 membrane below 6:06 and then below that is the circulation, the blood. 6:10 You have two important cells in the small intestine, the S cells and the I 6:14 cells. 6:14 When acidic food from the stomach arrives in the duodenum it will stimulate the 6:19 S cells 6:19 to produce secreten. 6:22 Proteins and fats in the small intestine will stimulate the I cells to secrete 6:22 polycystokinin, 6:28 CCK, another important hormone. 6:31 Let's look at the function of secretein first. 6:35 Secretein has several functions. 6:37 One is to reduce bile production and secretion from the liver and gallbladder. 6:43 The second function of secretein is that it reduces stomach motility and 6:48 activity to get 6:49 the small intestine prepared and to stop acidic food content from coming into 6:55 the duodenum. 7:00 Secretein is also responsible for telling the ductile cells on the pancreas to 7:04 produce 7:05 bicarbonate and this is in order to neutralize the acidity which is now in the 7:11 small intestine. 7:12 Polycystokinin is a hormone which main function is to stimulate the digestive 7:17 process essentially. 7:19 It stimulates the acidity cells to secrete its pancreatic juices so it can 7:23 digest the 7:24 proteins and the fats which are right now in the duodenum. 7:28 Also it will tell the gallbladder and liver to produce and to secrete bile to 7:33 help in 7:34 the digestion of fat. 7:36 Also important to remember that when we absorb glucose it will stimulate the 7:41 pancreas to 7:41 produce the hormone insulin. 7:44 Some clinical anatomy now is acute pancreatitis which is acute inflammation of 7:48 the pancreas. 7:49 Due to many causes, the two main ones are gallstones and alcohol. 7:54 The pathophysiology is basically oto digestion. 7:58 The enzymes which are meant to go into the pancreatic duct essentially go 8:02 everywhere else. 8:03 The enzymes particularly are the proteases and lipases which eat up everything 8:09 around 8:09 causing inflammation and severe epicastric pain. 8:19 Let us now focus more on the arteries and veins of the pancreas. 8:25 The pancreas sits in front of the inferior vena cava and the descending aorta. 8:30 The tail of the pancreas tickles the spleen and the head of the pancreas is 8:34 next to the 8:35 duodenum. 8:37 The descending aorta runs here and the celiac trunk branches at about T12 to L1 8:42 vertebral 8:43 level. 8:44 The celiac trunk has three main branches which supply the organs around it. 8:50 At about L2, another important artery called the superior mesenteric artery 8:55 comes off the 8:56 descending aorta and runs behind the pancreas and over the duodenum. 9:02 Jason to the superior mesenteric artery is the superior mesenteric mane which 9:08 comes also 9:09 behind the pancreas but it does not drain into the inferior vena cava. 9:16 Let us focus more on the arteries. 9:19 So here is a pancreas. 9:21 Remember the celiac trunk branches at T12 L1. 9:26 It has three main branches, the left gastric artery will supply the stomach. 9:33 The spleenic artery, the second branch is a very tortuous artery and has some 9:39 branches 9:39 supplying the superior part of the pancreas as well as the greater curvature of 9:45 the stomach. 9:46 The spleenic artery ends at the spleen. 9:51 The common hepatic artery is the last branch of the celiac trunk. 9:56 And it will branch off to the right and has many branches. 10:01 It becomes the common hepatic proper which will supply the liver with oxygen 10:06 but also 10:06 the gallbladder nearby. 10:08 The other branch is the gastric duodenal artery. 10:12 The gastric duodenal artery branches again into the superior pancreatic dooden 10:17 al artery. 10:19 And this has an anterior and posterior part to it. 10:24 So where does the inferior pancreatic doodenal artery come from? 10:29 Well, it comes from the superior mesenteric vein which, if you remember, comes 10:35 off the 10:36 descending aorta here at about L1 to L2 level. 10:40 The inferior pancreatic doodenal artery also has the anterior and posterior 10:49 portions. 10:51 From clinical anatomy, there's a thing called superior mesenteric artery 10:55 syndrome. 10:56 It is a rare condition in which the duodenum is compressed against the superior 11:01 mesenteric 11:02 artery and the abdominal aorta or the descending aorta. 11:06 Let's take a look at the descending aorta and the superior mesenteric artery 11:10 from the 11:11 side. 11:13 Remember, the superior mesenteric artery is a branch of the descending aorta 11:17 and goes 11:17 over the duodenum. 11:20 Right under the superior mesenteric artery here is actually the left renal vein 11:25 as well. 11:26 And then below this is the duodenum. 11:30 Surrounding all these structures is mesenteric fat, which is really important 11:34 in maintaining 11:35 everything where it is. 11:37 You can say it protects the superior mesenteric artery and the duodenum. 11:43 So you can imagine if you become malnourished resulting in catexia, it can be 11:47 due to anorexia 11:49 or malabsorption. 11:50 You lose all this mesenteric fat. 11:54 This causes duodenal compression, which will essentially give symptoms of bowel 11:59 obstruction. 12:01 But when you think about it, superior mesenteric artery syndrome, the angle is 12:06 very acute and 12:07 it can also cause left renal vein obstruction, which can cause kidney injury 12:13 and also left-sided 12:15 varicoseal. 12:19 So those are the important arteries to remember about the pancreas. 12:22 Let's look at the veins now. 12:24 Here is the pancreas again and behind it is the inferior vena cava and the 12:28 descending aorta. 12:31 Draining from the spleen is a splenic vein and this travels posterior behind 12:37 the pancreas. 12:38 The inferior mesenteric vein, which carries blood from the hind gut, drains 12:43 into the 12:44 splenic vein, then there is the superior mesenteric vein, which carries blood 12:49 from the mid gut 12:50 and also joins to the splenic vein. 12:54 And together, the superior mesenteric vein and the splenic vein will form what 12:57 's called 12:58 the portal vein. 13:00 You have to realize that the blood draining from these GIT veins carry a lot of 13:07 nutrition. 13:08 All this glucose protein will travel via the portal vein into the liver where 13:15 further biochemical 13:16 reactions will take place. 13:19 So these veins from the GIT don't drain into the inferior vena cava, but will 13:25 drain into 13:26 the liver via the portal vein, which is very important to understand. 13:31 Now let's look at the embryology of the pancreas. 13:42 You have the duodenum here. 13:44 Here is your dorsal pancreatic bud and then you have your ventral pancreatic 13:49 bud on the 13:49 other side. 13:51 The biliary system here is a common bile duct will drain into the main pancreat 13:57 ic duct, 13:57 which is actually where the ventral pancreatic duct will be. 14:02 During embryological development, the gut normally rotates and so does the vent 14:08 ral pancreatic 14:08 bud. 14:10 It will go around and carry the bile duct with it. 14:20 The ventral pancreatic bud will fuse with a dorsal pancreatic bud. 14:27 The ventral pancreatic bud will then become the unsanade process. 14:33 The ventral and dorsal pancreatic buds ducts will anastomose and this again 14:39 will become 14:40 the main pancreatic duct and this will become the accessory duct we spoke about 14:48 . 14:48 And of course the common bile duct here will join with the main pancreatic duct 14:54 and drain 14:55 into the duodenum. 14:57 The ventral bud again becomes the unsanade process of the pancreas. 15:04 Some clinical anatomy, annula pancreas. 15:08 It is a developmental anomaly in which a ring of the pancreas tissue completely 15:13 encircles 15:14 the duodenum. 15:15 What happens here is the ventral pancreatic bud may consist of two lobes which 15:20 will maybe 15:21 rotate to either end of the dorsal pancreatic bud, encircling the duodenum 15:28 really. 15:29 Annular pancreas is a cause of pancreatitis and also symptoms of partial bowel 15:33 obstruction. 15:34 Surgical correction is often required. 15:45 The ventral pancreatic bud is also required to have a very advanced muscle.
