10.10 Lecture 11 - The Digestive System

ingestion

the process of taking food, drink, or another substance into the body by swallowing or absorbing it.

define chyme

the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food.

large intestine histology what kind of epithelium? what are large intestinal cells called? large intestine has what other cells? ... why is there a change from columnar epithelium to stratified squamous epithelium near the pectinate line in the anal canal (closer end near anus than rectum)?

- goblet cells for mucin production (probably to lubricate feces traveling via peristalsis along the large intestine) - Columnar epithelium, not as much microvilli, don't need as much absorption ... columnar epithelium changes to stratified squamous (for protection) b/c passing on fecal contents

identify the abdominopelvic regions

-9 region system more commonly used -Know these regions for both systems and what organs are in the 4 quadrants -Chondro ... cartilage ... hypochondriac = below cartilage of ribs

large intestine functions: absorption of what? - other functions? (3) 3 special features - teniae coli? - haustra? - omental (epiploic) appendices?

-Absorption of water -Need to create a solid, compact substance for excretion (feces) -Teniae coli = the lines that we can see ... shortens the large intestines ... muscular structures -Haustra = resulting bulges that we see as a result of teniae coli shortening the large intestine -Omental appendices = feature of large intestines, don't know a lot about these

stomach: blood supply and innervation what are the 3 branches of the celiac trunk? which branches supply the stomach with blood? innervation from the _______ plexus - _________ nerve (sympathetic) - _________ ganglion (sympathetic) also the vagus nerve (parasympathetic)

-Celiac trunk = most superior blood vessel -Stomach gets blood supply from those 3 arteries listed -Innervation via celiac plexus ... travel by the arteries to get to the stomach

defense in the digestive tract defense against what? (3) how might we deal w/ these stresses in the digestive tract?

-Glands from epithelial tissue secrete stuff for chemical stress and mechanical stresses (mucus) -Epithelial tissue (fast regeneration) for mechanical stresses -We have a lot of cushioning in our abdominal cavity (mesentery, fat tissue) ... insulation, protection from external forces

histology of the stomach ***challenging but important slide gastric pit - surface mucous cells vs mucous neck cells? gastric gland (cells here help with what?) - parietal cells? - entero-endocrine cell? - chief cells?

-Harsh environment in the stomach created by the secretion of these cells -Other cells trying to counter this acidity to protect the epithelium Gastric pit = have extension into the underlying tissue ... gland is deep to the gastric pit ... gland is where we create these secretions - Surface mucous cells on the surface ... secrete alkaline fluid (base / basic substance) + mucin = creating a protective barrier to protect epithelium - Foveolar cells or surface mucous cells are mucus-producing cells which cover the inside of the stomach, protecting it from the corrosive nature of gastric acid. - The mucous neck cells = acidic fluid + mucin ... goes to the bolus and lubricates the contents of the bolus so it can pass more easily through the stomach Cells of the gastric glands = helps with digestion - Parietal cells ... HCl helps break down food ... gastric intrinsic factor = absorption of vitamin B12 by the small intestines ... instrinsic factor not actually acting in the stomach, but it is produced and secreted in the stomach ... goes with food to the small intestine ... B12 necessary for creating RBC's - Entero-endocrine cell = secretes gastrin (a hormone) ... secreting in blood vessels around the gland ... gastrin carried to the other cells ... they sense when things are in the stomach ... secrete stuff so they can tell other stuff to secrete stuff for digestion - gastrin = a hormone which stimulates secretion of gastric juice and is secreted into the bloodstream by the stomach wall in response to the presence of food. - Chief cells ... gastric lipase = fat digestion ... pepsinogen = protein digestion ... pepsinogen (in presence of HCl) = converted into pepsin, and this is what actually breaks down proteins stomach stem cells give rise to these cells

large intestine rectum? - ______ valves? function? anal canal? - through opening in the __________ (recall: from pelvic floor muscles) - anal sinuses secrete what? what sphincters?

-Have 3 transverse structures ... rectal valves = prevent sharting -Anal canal ... levator ani

large intestine cecum aka ? - appendix = ? identify the major components of the large intestine structure, including the 'bends'

-Ileum of small intestine meets cecum ("blind pouch") of large intestine ... -Appendix = lymphatic tissue, deals with a lot of bacteria that get in here -Ascending colon ... hepatic flexure ... transverse colon ... splenic flexure ... descending colon ... sigmoid colon (S-shaped) ... rectum ... anus

gallbladder attached to the ______ surface of the _____ lobe of the liver function of the gallbladder? bile functions? what makes bile?

-Inferior surface of the right lobe of the liver -Storage of bile -Bile made by liver

small intestine: duodenum ... other 2 components? what region is the primary region for chemical digestion and nutrient absorption? the distal end of the ileum terminates at the ____________ , which is a sphincter that controls the entry of materials into the large intestine?

-Jejunum = chemical digestion and nutrient absorption -Ileocecal valve = ileum meets large intestine

what is the biliary apparatus? - draw it and label its components when are we contracting the gallbladder? what does this do? what happens when we are not active digesting?

-Know this -How we get bile and pancreatic ducts to duodenum -Actively digesting = contraction of gallbladder to release bile -Not actively digesting = storage of bile to the gallbladder

living donor liver transplants is this possible? why?

-Liver can regenerate itself

stomach, located where? maximum capacity? (volume) food remains in the stomach for approximately how long? where wrt to the peritoneum (key term)? what is bolus? this is eventually processed into what? physical digestion? chemical digestion? storage time? limited absorption? the stomach produces what? (this is also mixed in with the partly digested food, these are called the same thing ... gastric juices + bolus)

-Max capacity = 4 L (close to a gallon) -Food stays there for 4 hours -Bolus = when we chew something and swallow it, substance is then called this ... processes in the chyme in the stomach -Stomach churns for physical digestion -Secretes chemicals for chemical digestions -Storage for 4 hours -Certain drugs can be absorbed in the stomach; alcohol

small intestine: histology circular folds are also called? - villi? - what cells are on these? what kind of cells are these? what do they have? function? what are the 4 layers of the small intestine? goblet cells? enteroendocrine cells? intestinal crypts? (have what 2 cells? functions?)

-On these folds we have villi ... projections sticking up from the folds ... villi are lined by absorptive enterocytes (columnar epithelial cells) which have microvilli ... greatly increase surface area for nutrient absorption -Goblet cells = secrete mucin (becomes mucus) for smooth travel in the small intestine -Enteroendocrine cells = secretions travel to the pancreas and liver ... stimulate these structures to secrete their secretions -Intestinal crypts ... Paneth cells counter against pathogens ... small intestine epithelial cells get replaced every 3-6 days -Have a lot of lymphatic tissue countering against dangerous stuff we may come across

small intestine: duodenum receives substances from the ______ and ______ that aid in digestion what is the duodenal papilla? where?

-Pancreas and gallbladder secreting stuff into the duodenum via duodenal papilla -Duodenal papilla = deviates end of foregut and start of midgut -Bile duct and pancreatic duct converge on the hepatopancreatic ampulla into the duodenal papilla

Peritoneum & the Peritoneal Cavity identify the 3 main components

-Peritoneum ... visceral = touching / directly surrounding the organs -Parietal = to the outside (outer layer lining abdominal wall) -Have peritoneum cavity that is holding fluid

liver what quadrant? it is the largest ______ in the body 4 lobes, which are? on the inferior surface, there are what structures? (3)

-Porta hepatis ... where structures are coming/going ... bile ducts -Heptatic portal vein = blood from digestive system to the liver ... pick up all these nutrients through this vein for transport to liver capillaries for processing ... returned to the blood stream for circulation (via inferior vena cava) -Gall bladder = green b/c bile

digestive system explain the 7 important structures (which make up the major subdivisions of the digestive tract vs accessory organs of the digestive system?

-Recall tonsils ... lymphatic tissue -Mucosa-associated lymphatic tissue (MALT) or gut-associated lymphatic tissue -Defense against pathogens

esophagus epithelium type? when is the epithelium replaced? - has what kind of glands? why? muscularis externa, superior vs middle vs inferior? esophageal glands proper function? where? esophageal cardiac glands? where?

-Replaced every 5-7 days -Stratified squamous epithelia (non-keratinized, not exposed to sun) -Mucus for lubrication of the surfaces for smooth transport down -Esophageal glands proper = lubricate surface ... more prominent superiorly -Esophageal cardiac glands = located closer to the stomach ... secreting substances that counteract the acid in the stomach (so secreting a more basic substance in case of throwing stuff up) -Skeletal muscle ... Can control via somatic NS ... smooth muscle controlled via autonomic NS

liver histology hepatic lobule? liver cells are called what? arranged around a ______ portal triads ... where and what makes them up?

-Smallest active portion of liver = hepatic lobule -Hepatocytes = liver cell -On each corner of the 6 sided plates of cells = portal triad (has a duct with bile, branch of portal vein, and a hepatic artery)

defecation reflex defecation process also involves the voluntary contraction of what? (3) what causes the internal anal sphincter to stay contracted? function? what causes the internal anal sphincter to be relaxed, and the walls of the rectum to contract to cause mass peristalsis movements? what controls the external anal sphincter?

-Sympathetics = prevent defecation ... cause internal anal sphincter to stay contracted (ANS) -Parasympathetics = relax internal sphincter, contract walls of rectum to cause mass peristalsis movement = defecation (ANS) -External anal sphincter = voluntary control (must be skeletal muscle)

the serosa

Along regions of the digestive tract within the peritoneal cavity the muscular layer is covered by a serous membrane known as the serosa (Figure 25.2). There is no serosa, however, surrounding the muscular layer of the pharynx, esophagus, and rectum. Instead, the muscular layer is wrapped by a dense network of collagen fibers that firmly attaches the digestive tract to adjacent structures. This fibrous sheath is the adventitia (ad-ven-TISH-a).

right and left hepatic ducts converge to form the common hepatic duct ... function?

Common hepatic duct: The duct formed by the junction of the right hepatic duct (which drains bile from the right half of the liver) and the left hepatic duct (which drains bile from the left half of the liver). The common hepatic duct then joins the cystic duct coming from the gallbladder to form the common bile duct. The connection between the left and right hepatic ducts forms the common hepatic duct, whose function is to drain bile from the liver. This duct is an important part of the biliary duct system, which transports waste from the liver and aids in digestion by releasing bile.

what is cystic fibrosis?

Cystic fibrosis is a hereditary disease that affects the lungs and digestive system. The body produces thick and sticky mucus that can clog the lungs and obstruct the pancreas. Cystic fibrosis (CF) can be life-threatening, and people with the condition tend to have a shorter-than-normal life span. An inherited life-threatening disorder that damages the lungs and digestive system. -Cystic fibrosis = CFTR gene mutation ... major digestive problems ... intestinal obstructions ... thickened pancreatic solutions ... affects glands throughout the body

liver lobule (textbook)

In a liver lobule, the liver cells, or hepatocytes (HEP-a-tō-sīts), form a series of irregular plates arranged like the spokes of a wheel (Figure 25.20). Up to the age of 7, the plates are no more than two cells thick. After age 7 the plates are only one cell thick. The exposed apical and basal surfaces of the hepatocytes are covered with short microvilli. Blood entering the liver by the hepatic artery proper and the hepatic portal system drain into highly fenestrated capillaries termed hepatic sinusoids that surround the plates of hepatocytes. These hepatic sinusoids empty into the central vein (Figure 25.20a-c). The fenestrated walls of the sinusoids contain large openings that allow substances to pass out of the circulation and into the spaces surrounding the hepatocytes. The sinusoidal lining includes a large number of stellate macrophages, or Kupffer (KOOP-fer) cells. These phagocytic cells are part of the monocyte-macrophage system. They engulf pathogens, cell debris, and damaged blood cells. Stellate macrophages also store iron, some lipids, and heavy metals, such as tin or mercury, that are absorbed by the digestive tract. Blood enters the liver sinusoids from small branches of the portal vein and hepatic artery proper. A typical lobule is hexagonal (six-sided) in cross section. There are six portal triads, one at each corner of the lobule. A portal triad contains three structures: (1) an interlobular vein, (2) an interlobular artery, and (3) an interlobular bile duct (Figure 25.20). Branches from the arteries and veins deliver blood to the sinusoids of adjacent liver lobules (Figure 25.20a,b). As blood flows through the sinusoids, hepatocytes absorb solutes from the plasma and secrete materials such as plasma proteins. Blood then leaves the sinusoids and enters the central vein of the lobule. The central veins ultimately merge to form the hepatic veins, which then empty into the inferior vena cava.

esophagus _________ sphincter = junction of the pharynx and the esophagus _______ sphincter (aka the ______ sphincter) = junction of the esophagus and the stomach diaphragm can also help with protection via the _________ , which is the opening in the diaphragm it passes through what is the Z-line?

In human anatomy, the esophageal hiatus is an opening in the diaphragm through which the esophagus and the vagus nerve pass. A demarcation line, the squamocolumnar (SC) junction or "Z-line", represents the normal esophagogastric junction where the squamous mucosa of the esophagus and columnar mucosa of the stomach meet -Trying to prevent regurgitation from stomach to esophagus (cardiac / inferior esophageal sphincter) -Diaphragm ... has a hole (hiatus) -Recall that metaplasia can occur (epithelia changes) depending on environmental / mechanical / chemical stresses

intraperitoneal = ?

Intraperitoneal = within or administered through the peritoneum. - intra = surrounded forever by peritoneum

explain histological organization/structure of the digestive tract

Most organs of the digestive tract have four histological layers: the (1) mucosa, (2) submucosa, (3) muscular layer, and (4) serosa. Just as the functions of the different organs of the digestive tract vary, these layers differ histologically from one organ to another. Variations in the structure of these four layers from organ to organ are related to the specific functions of each organ

secondary retroperitoneal?

Secondary retroperitoneal structures originally lied intraperitoneally, but have been pushed aside and adhered to the body wall. ... Some organs originally lied intraperitoneally, but have been pushed to the side during the embryological development. These organs and their mesenteries adhered to the abdominal wall -Secondary retro = starts inside the peritoneum initially during development ... as development progresses, the organ then gets pushed back against the interior wall of the peritoneum

· Duodenojejunal fissure

The duodenojejunal flexure or duodenojejunal junction is the border between the duodenum and the jejunum.

hepatic portal system hepatic portal vein the blood supply to the liver (textbook)

The hepatic portal system is a series of veins that carry blood from the capillaries of the stomach, intestine, spleen, and pancreas to capillaries in the liver. It is part of the body's filtration system (processing, of digested components) The portal vein or hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Two blood vessels deliver blood to the liver, the hepatic artery proper and the hepatic portal vein (Figures 25.16a and 25.19d). Roughly one-third of the normal hepatic blood flow arrives through the hepatic artery; the rest arrives through the hepatic portal vein. Blood returns to the systemic circuit through the hepatic veins, which empty into the inferior vena cava. The arterial supply provides oxygen-rich blood to the liver, and the hepatic portal vein supplies nutrients and other chemicals absorbed from the intestine.

stomach anatomy: identify the layers of the stomach what are gastric ulcers?

The lamina propria is a thin layer of loose (areolar) connective tissue, which lies beneath the epithelium, and together with the epithelium and basement membrane constitutes the mucosa. - inner to outer ... [epithelium, lamina propria, basement membrane] = mucosa -HCl very acidic -Must replace epithelium of stomach every 3-5 days -Failure to regenerate epithelium = onset of gastric ulcers -Can even break down the entire wall and can perforate the stomach

stomach anatomy: identify the layers of the stomach lamina propria what is the mucosa? what kind of cells in the stomach?

The lamina propria is a thin layer of loose (areolar) connective tissue, which lies beneath the epithelium, and together with the epithelium and basement membrane constitutes the mucosa. - inner to outer ... [epithelium, lamina propria, basement membrane] = mucosa note (simple) mucous columnar epithelium cells

liver functions (textbook)

The liver (1) regulates metabolism, (2) regulates the composition of blood by removing old and damaged red blood cells and synthesizing plasma proteins, and (3) produces and secretes bile.

the mucosa (textbook) - circular folds function? muscularis mucosae?

The mucosa, the inner lining of the digestive tract, is a mucous membrane, which is a layer of loose connective tissue covered by an epithelium moistened by glandular secretions. p. 71 The mucosal epithelium is either a stratified or a simple epithelium, depending on the location and the stresses involved. For example, the oral cavity and esophagus are lined by a nonkeratinized stratified squamous epithelium that resists stress and abrasion. In contrast, the stomach, small intestine, and almost the entire large intestine encounter considerably less stress and abrasion than the oral cavity and esophagus. As a result, these structures have a simple columnar epithelium specialized for secretion and absorption. Many segments of the digestive tract have circular folds or plicae (PLĪ-se; singular, plica [PLĪ-kā]) circulares. (Figure 25.2). These transverse or longitudinal folds of the mucosa increase the surface area available for absorption and secretion. In some regions of the digestive tract, circular folds are permanent features involving both the mucosa and submucosa. In other regions, circular folds are temporary features that disappear as the lumen fills, enabling the lumen to expand after a large meal. Ducts opening onto the epithelial surfaces carry the secretions of gland cells located either in the mucosa and submucosa or within accessory organs. A layer of areolar connective tissue is found deep to the epithelium of the mucosa. This layer, the lamina propria, contains blood vessels, sensory nerve endings, lymphatic vessels, smooth muscle fibers, and scattered areas of lymphatic tissue. In most regions of the digestive tract the border of the mucosa is a narrow band of smooth muscle and elastic fibers. This band of smooth muscle is called the muscularis (mus-kū-LA-ris) mucosae. The smooth muscle fibers in the muscularis mucosae are arranged in two thin concentric layers—an internal circular layer and an external longitudinal layer (Figure 25.2). Contraction of these layers alters the shape of the lumen and moves the epithelial pleats and folds.

the muscular layer = muscularis externa - mechanical processing - myenteric nerve (neural) plexus sphincter = ?

The muscular layer is a double layer of smooth muscle fibers deep to the submucosa. These smooth muscle fibers are arranged in internal circular and external longitudinal layers (Figure 25.2). These layers of smooth muscle mechanically process and propel materials along the digestive tract. These movements are coordinated by neurons of the myenteric (mī-en-TER-ik; mys, muscle, + enteron, intestine) neural plexus. This plexus, located between the two muscular layers, is composed of parasympathetic ganglia and sympathetic postganglionic fibers. Parasympathetic stimulation increases muscular tone and stimulates contractions, while sympathetic stimulation decreases muscular tone and promotes relaxation. At specific locations along the digestive tract there are thickened areas of the muscular circular layer. These localized thickenings form sphincters, or valves. The sphincters constrict to restrict movement or to ensure one-way passage of materials along the lumen.

pancreas pancreatic acini pancreatic juices

The secretory units of the exocrine pancreas are the pancreatic acini (AS-i-nī). Each pancreatic acinus is composed of a simple cuboidal epithelium. The pancreatic acini are the beginning of the duct system of the pancreas. These ducts drain into progressively larger ducts, which drain into the main pancreatic duct, which runs the length of the pancreas. The pancreatic acini produce pancreatic juice, a mixture of water, ions, and pancreatic digestive enzymes. These enzymes are released into the duodenum, where they break down ingested materials into small molecules suitable for absorption. The pancreatic ducts also secrete buffers (primarily sodium bicarbonate). These buffers neutralize the acid in chyme and stabilize the pH of the intestinal contents.

Muscular Layers and the Movement of Digestive Materials what causes peristalsis and segmentation? difference between the two?

The smooth muscle of the digestive tract contracts spontaneously, producing the rhythmic contractions of peristalsis and segmentation. Contractions within the muscularis mucosae that move a bolus (a small oval mass of food) along the digestive tract are called peristalsis (per-i-STAL-sis). During a peristaltic wave, the circular muscles contract behind the digestive contents. Longitudinal muscles contract next, shortening adjacent segments. A wave of contraction in the circular muscles then forces the materials in the desired direction (Figure 25.3a). Most areas of the small intestine and some regions of the large intestine undergo segmentation (Figure 25.3b). These movements churn and fragment the digestive materials, mixing the contents with intestinal secretions. They do not move the bolus in any particular direction.

the submucosa

The submucosa (sub-mū-KŌ-sa) is a layer of areolar connective tissue deep to the muscularis mucosae. Large blood and lymphatic vessels are found in this layer. In some regions of the digestive tract the submucosa also contains exocrine glands that secrete buffers and enzymes into the lumen. The submucosa contains a network of nerve fibers and scattered neuron cell bodies. These submucous neural plexuses innervate the mucosa. They contain sensory neurons, parasympathetic ganglia, and sympathetic postganglionic fibers (Figure 25.2).

Mesentery ... the peritoneum - The peritoneum is a serous membrane with two parts: the visceral peritoneum and parietal peritoneum. Mesenteries connect the visceral and parietal peritoneal membranes. what is mesentery? lesser omentum? greater omentum? mesentery proper? mesocolon?

Within the peritoneal cavity, most regions of the digestive tract are suspended by sheets of serous membrane connecting the parietal peritoneum with the visceral peritoneum. These mesenteries (MES-en-ter-ēz) are fused double sheets of peritoneal membrane (Figure 25.2a). The areolar connective tissue between the two surfaces provides a route for the passage of blood vessels, nerves, and lymphatic vessels to and from the digestive tract. Mesenteries also stabilize the positions of the attached organs and prevent their entanglement during digestive movements or sudden changes in body position. During development, dorsal and ventral mesenteries suspend the digestive tract and accessory organs within the peritoneal cavity (Figure 25.4a). - The ventral mesentery later disappears along most of the digestive tract, remaining only in two locations. - One is on the ventral surface of the stomach, between the stomach and liver, forming the lesser omentum (Ō-MEN-tum; omentum, fat skin). - The second is between the liver and the anterior abdominal wall and diaphragm, forming the falciform ligament (Figure 25.4b-d). (Although this peritoneal sheet is called a "ligament," it is not comparable to the ligaments interconnecting bones.) (For additional information concerning the development of the digestive system, see the Embryology Summary in Chapter 28.) - lesser omentum = A small pocket in the mesentery that connects the lesser curvature of the stomach to the liver. As the digestive tract elongates, it twists and turns within the crowded peritoneal cavity. The dorsal mesentery of the stomach enlarges, forming a pouch extending inferiorly between the body wall and the anterior surface of the small intestine. This pouch is the greater omentum (Figure 25.4b and Spotlight Figure 25.10). The loose connective tissue within the mesentery of the greater omentum contains a thick layer of adipose tissue. The lipids in the adipose tissue are thought to have two possible functions: (1) serving as an important energy reserve and (2) providing insulation that minimizes heat loss across the anterior abdominal wall. The greater omentum also contains numerous lymph nodes. These protect the body from foreign proteins, toxins, or pathogens that evade the defenses of the digestive tract. A thick mesentery, the mesentery proper, suspends all but the first 25 cm of the small intestine. This provides stability while permitting a certain amount of independent movement. The mesocolon is a mesentery attached to the large intestine. The middle portion of the large intestine (the transverse colon) is suspended by the transverse mesocolon. The sigmoid colon, which leads to the rectum and anus, is suspended by the sigmoid mesocolon. During embryonic development, the dorsal mesentery of the ascending colon, descending colon, and rectum fuses to the posterior body wall. This fused mesentery fixes them in position. These organs are now secondarily retroperitoneal, and the visceral peritoneum covers only their anterior surfaces and portions of their lateral surfaces

secretion

a process by which substances are produced and discharged from a cell, gland, or organ for a particular function in the organism or for excretion.

digestion vs absorption

digestion = the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body. - digestion is when the ingested food is now broken down into smaller building blocks. ... Absorption is when the digested building blocks are now absorbed into the bloodstream or lymphatic system through the intestines and then transported to various cells, tissues, organs in the body

what is a hernia? what is a hiatal hernia? what is GERD?

hernia = a condition in which part of an organ is displaced and protrudes through the wall of the cavity containing it (often involving the intestine at a weak point in the abdominal wall). -Diaphragm no longer supporting inferior esophageal (cardiac) sphincter ... more acid reflux Gastroesophageal reflux disease (GERD) happens when a muscle at the end of your esophagus does not close properly. This allows stomach contents to leak back, or reflux, into the esophagus and irritate it. You may feel a burning in the chest or throat called heartburn

compaction - defecation

large intestine ... reabsorption of water ... compacting of waste and fecal content ... defecation = discharge of feces from body aka pooping

pancreas exocrine function? - goes where via what?

note that the pancreas endocrine function is control of blood sugar via insulin and glucagon release into the bloodstream -Pancreas -Controls blood sugar via insulin and glucagon -Pancreatic duct meets the bile duct ... pancreatic duct carrying pancreatic juices (bicarbonate, others) (substances that are required for digestion and absorption of foods)

digestive system development begins forming into its adult shape in week _____ lumen is open by what week? starts as what, then undergoes what? does it continue developing after birth? foregut vs midgut vs hindgut?

note that the superior mesenteric artery supplies blood to the midgut, while the inferior mesenteric artery supplies blood to the hindgut

stomach: anatomical features - identify the regions of the stomach (4) - identify the musculature of the stomach (3) gastric folds, aka ? function?

note: the inferior esophageal sphincter = cardiac sphincter -Greater curvature laterally ... lesser curvature towards the midline -Gastric folds = rugae ... as stomach fills, the rugae flattens out and allows the stomach to expand ... also helps guide the food through the stomach to the small intestines

retroperitoneal = ?

retroperitoneal = situated or occurring behind the peritoneum. -Retro = behind the peritoneum