Digestive System Part 2
Gallstones
-Crystallization of cholesterol or calcium and bile salts
Location and Function of Mesenteries
-Double layer folds of peritoneum -support and stabilize the intraperitoneal GI tract organs. -Include: Greater omentum, lesser omentum, Mesentery proper, mesocolon.
Appendicitis
-Fecal matter obstructs the appendix -It will swell and burst if untreated -Causes peritonitis
Hernias
-Hiatal hernia: stomach pushes through esophageal hiatus -Umbilical hernia: intestines push through the rectus abdominis -Inguinal hernia: Intestines push through inguinal canal. More common in males -Femoral hernia: Intestines push through the femoral triangle. More common in females
Large intestine gross anatomy
-Ileocecal valve, cecum, appendix, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon, rectum, anal canal.
Viral hepatitis
-Inflammation of the liver -Flu-like symptoms and jaundice
Cirrhosis of the liver
-Liver cells are destroyed and replaced by connective tissue -Most commonly caused by alcoholism -Results in jaundice (yellowing of the skin) and toxin buildup in the blood -Treatment is a liver transplant
Histology of the small intestine
-Mucosal and submucosal tunics of the small intestine are thrown into macroscopic circular folds. They help increase the surface area through which nutrients can be absorbed. -Villi are microscopic, fingerlike projections of mucosa only that line the surface of circular folds. Villi increase surface area for both absorption and chemical digestion. -Microvilli line the apical surface of the simple columnar cells. They amplify absorptive surface, are called the "brush border" and contain enzymes that complete the final stages of digestion.
Gallbladder
-attached to the inferior surface of the liver. -stores and concentrates bile
Function of bile
-breaks down fats to assist in their chemical digestion.
Embryonic development of digestive system
-endoderm becomes a tube after transverse folding -This primitive gut contains: -foregut: pharynx to duodenum -Midgut: duodenum to transverse colon -Hindgut: transverse colon to anus -accessory organs bud off of the primitive gut tube
Digestive processes that occur in the small intestine
-majority of chemical digestions occur here. -bile fro liver and digestive enzymes from pancreas -Nutrient absorption
Colorectal Cancer
2nd most common cancer most arise from intestinal polyps colonoscopy
Intestinal Obstruction
Any hindrance to movement of chyme of feces through intestine
Liver Functions
Associated with blood: -storage of excess blood nutrients -Detoxification of poisons, metabolites, and drugs -Clean out debris and old RBCs -Production of blood proteins (albumin, globulins, and blood clotting proteins.) Digestive function: produce bile
Flow of bile from liver to duodenum
Biliary apparatus: network of thin ducts that carry bile from the liver and gallbladder to the duodenum. Left and right lobes of liver drain bile into left and right hepatic ducts, which merge to form the common hepatic duct. Cystic duct is attached to the common bile duct and carries bile to and from the gallbladder. Bile travels from the common hepatic duct through the cystic duct to be stored in the gall bladder; stored bile travels back through the cystic duct for conduction to the small intestine. Union of the cystic duct and common hepatic duct forms common bile duct that extends inferiorly to the duodenum.
Regions of the small intestine
Duodenum - 10 inches. Receives pancreatic duct and bile duct Jejunum - 7.5 feet. Ileum - 10.8 feet
Large intestine
Functions: -absorbs water and electrolytes -forces feces toward rectum Special Features: -Teniae Coli: three thin, longitudinal bundles of smooth muscle -Haustra: sacks or bulges -Epiploic appendages: fat filled pouches of visceral peritoneum
Liver histology
Hepatic lobules: functional units of the liver. -made of hepatocyte cells -Blood flow through a hepatic lobule: -Branch of hepatic artery -branch of hepatic portal vein -Hepatic sinusoid -Central vein -Bile flow: -Bile canaliculi -branch of bile duct. SEE BOOK FOR PICTURES
Anal Canal
Internal Anal Sphincter: Smooth muscle, involuntary External anal sphincter: skeletal muscle, voluntary Anal sinuses: Produce mucus to lubricate anal canal
Intraperitoneal vs. Retroperitoneal
Intraperiotoneal: organs within parietal peritoneum. Retroperitoneal: organs that lie directly against the body wall (superficial to parietal peritoneum) -Most of duodenum -pancreas -ascending and descending colon -rectum -kidneys
Anatomy of the small intestine
Lined with simple columnar epithelium Suspended by the mesentery proper Functions: -Majority of Chemical digestions occur here -bile from liver and digestive enzymes from pancreas -Nutrient Absorption
Pancreas
Location: Left upper quadrant of abdominal cavity right next to jejunum. Retroperitoneal. Anatomy: Main pancreatic duct, accessory pancreatic duct Function: Both exocrine and endocrine Exocrine: produces digestive enzymes Endocrine: produces the hormones insulin and glucagon
Liver
Location: Right upper quadrant of abdominal cavity, immediately inferior to diaphragm. Anatomy: Right lobe (biggest), Left lobe, quadrate lobe, caudate lobe. Falciform ligament and round ligament of the liver. Gall bladder. Hepatic artery and Hepatic portal vein enter liver Hepatic vein, then Inferior Vena Cava leave liver
Location and function of peritoneum
Location: abdominal cavity. Parietal lines the inside surface of the body wall. Visceral covers the surface of internal organs. Function: Cover surface of organs, secrete serous fluid, create peritoneal cavity, the space between the two layers of the peritoneum that is filled with serous fluid. Serous fluid lubricates both the body wall and the internal organ surfaces, allowing the abdominal organs to move freely and reducing any friction resulting from this movement.
Inflammatory bowel disease
Periodic inflammation of intestinal wall symptoms include cramping, diarrhea, weight loss, intestinal bleeding
Peritonitis
inflammation of the peritoneum
