lecture 27: digestive system Flashcards
why do we have accessory organs
- secrete substances required for chemical digestion
- food does NOT actually pass through these organs
quadrants
RUQ
RLQ
LUQ
LLQ
regions
epigastric (L&R hypochondriac)
umbilical (L&R lumbar)
pubic (L&R inguinal)
organs
liver
gallbladder
pancreas
stomach
spleen
duodenum
diaphragm
gallbladder
pancreas
- LUQ/left hypochondriac and epigastric regions
- closely associated w spleen and stomach
structure:
- head, body, uncinate process, tail
- pancreatic duct, accessory pancreatic duct
secretory structures
- minor duodenal papilla: the opening for the accessory pancreatic duct
- hepatopancreatic
- major duodenal papilla: rounded projection in the duodenum into which the common bile duct and pancreatic duct drain
- accessory pancreatic duct
- pancreatic duct:
secretes digestive enzymes, ions, and water
blood supply
- celiac trunk: short, arises from aorta, passes below the median arcuate ligament
- superior mesenteric artery (blood to head and uncinate process)
- splenic artery
venous drainage
- portal vein
- superior mesenteric vein
- splenic vein: runs along the posterior border of the pancreas up to the neck, where it joins the superior mesenteric vein
role in digestion (exocrine and endocrine)
exocrine functions: pancreatic juice secretion into duodenum
endocrine functions: hormone secretion into bloodstream
*key for blood glucose/sugar regulation
Pancreatic Acini
Exocrine
- 99% of glandular epithelial cells
- secrete pancreatic juice: water, some salts, sodium bicarbonate (pH balance), pancreatic enzymes (digest macromolecules)
Pancreatic Islets (of Langerhans)
Endocrine
- 1% of glandular epithelial cells
- secrete hormones: insulin (beta cells) lowers blood glucose, glucagon (alpha cells) high blood glucose), somatostatin, pancreatic polypeptide
is the pancreas a endo or exocrine gland
both
what’s in the RUQ
diaphragm, liver
lobes of liver
- caudate lobe
- right lobe
- left lobe
- IVC
- quadrate lobe
liver ligaments
- coronary ligament: liver to diaphragm
- falciform ligament: liver to anterior abdominal wall
- ligamentum teres: “round ligament”
porta hepatis
- hepatic portal vein: receives blood from stomach, intestines, pancreas, and spleen, and carries it into liver through the porta hepatis
- proper hepatic artery: continuation of the common hepatic artery, a branch of the celiac trunk
- common hepatic duct: tube that carries bile from liver
liver blood supply
blood supply:
- portal vein: deoxygenated blood containing nutrients (GI tract), deoxygenated blood containing nutrients (so it can filter toxins by going back to your heart). blood vessel that carries blood from GI, gallbladder, pancreas, and spleen to liver
- proper hepatic artery: oxygenated blood from the heart. continuation of the common hepatic artery, a branch of the celiac trunk
venous drainage:
- hepatic veins: drains low o2 blood into the IVC
hepatic blood flow summary
hepatic blood flow is the blood flow to and from the liver, responsible for delivering oxygen and nutrients to the liver cells and removing waste products from the liver
- oxygenated blood from hepatic artery or nutrient-rich deoxygenated blood from portal vein go into…
- hepatic sinusoids
- central vein
- hepatic veins
- IVC
liver roles in digestion
- metabolic reg
- bile production
- detoxification
- storage
the liver receives blood from the…
hepatic artery and portal vein
RUQ
inferior surface of liver
gallbladder fossa
gallbladder
function: stores and concentrates bile before release into the duodenum
- cystic duct
- neck
- body
- fundus
biliary tree
series of ducts that transport bile from liver to small intestine, aids in digestion and absorption of fats
- L and R hepatic ducts
- common hepatic duct
- cystic duct: bidirectional flow
- bile duct
- accessory pancreatic duct
- pancreatic duct
- hepatopancreatic ampulla
what does bile do
- emulsifies fat breaks down fat into smaller molecules that can be absorbed during digestion
- bile is produced by the liver and stored in the gallbladder and released into the duodenum
- 3 organs associated with bile
bile: for liver to duodenum
hepatocytes produce bile -> bile canaliculi -> small bile ducts
-> right or left hepatic duct ->common hepatic duct -> cystic duct or bile duct -> if bile duct then to the -> hepatopancreatic ampulla -> duodenum
the cystic duct and the ______ join to form the bile duct
common hepatic duct
peritoneum
double-layered serous membrane:
- parietal peritoneum: lines walls of the abdominopelvic cavity
- visceral peritoneum: lines organs in the abdominopelvic cavity
- space between parietal and visceral layers = peritoneal cavity
organ classification
- intraperitoneal organs: completely covered by visceral peritoneum (JIGS CLS - jejunum, ileum, gallbladder, stomach, colon, liver, spleen)
- retroperitoneal organs: covered anteriorly by parietal peritoneum (PAR DUCK - pancreas, rectum/anus, adrenal glands, duodenum, ureters, colon, kidneys)
intraperitoneal organs are mobile, retroperitoneal organs are fixed to the posterior abdominal wall
intraperitoneal organs
- colon (transverse, sigmoid)
- spleen
- stomach
- jejunum
- ileum
- liver
- gallbladder
covered by visceral peritoneum
retroperitoneal organs
- duodenum
- pancreas
- colon (ascending, descending)
- rectum and anal canal
- kidneys and adrenal glands
- ureters
covered by parietal peritoneum
peritoneal folds
- greater omentum: attaches stomach to small intestine and transverse colon
- lesser omentum: attaches stomach and duodenum to the liver
- falciform ligament: attaches liver to anterior abdominal wall and diaphragm
- mesentery: anchors jejunum and ileum to posterior abdominal wall
- mesocolon: anchors transverse and sigmoid colon to posterior abdominal wall
(double-fold of visceral peritoneum)
which organs are retroperitoneal?
a) spleen, rectum, kidney
b) pancreas, rectum, kidney
c) pancreas, spleen, kidney
b) pancreas, rectum, kidney
structures
- mouth: saliva is secreted by the major salivary glands, which lubricates food. through mastication, food is mixed with saliva and shaped into a soft, flexible mass called a bolus
- esophagus: is a collapsible, muscular tube that connects the pharynx to the stomach. it passes a bolus into the stomach by peristalsis.
- stomach: connects the esophagus to the duodenum
accessory organs
small intestine: extends from the pyloric sphincter to the ileocecal junction. it is divided into three parts; duodenum, jejunum, and ileum.
large intestine: extends from the ileocecal junction to the anus. its regions include the cecum, ascending, transverse, descending, sigmoid colon, rectum, and anal
Function review
- ingestion: involves taking foods and liquids into the mouth (eating)
- secretion: cells within the walls of digestive canal and accessory digestive organs secrete water, acid, buffers, and enzymes into the lumen of the digestive canal
- motility: alternating contraction and relaxation of smooth muscle in the walls of the digestive canal mix food and secretions and move them toward the anus
- digestion: the breakdown down of ingested food by the teeth, stomach, and small intestine into small molecules for use by body cells
- absorption: entrance of ingested and secreted fluids, and the products of digestion into the cells lining the lumen of the digestive canal. absorbed substances circulate throughout the body
- defecation: wastes, indigestible substances, bacteria, cells sloughed from the lining of the digestive canal, and digested materials that were not absorbed leave the body through the anus as feces
which major artery supplies blood to the head of the pancreas?
superior mesenteric artery
what does the mesentery bind too
binds the jejunum and ileum to the posterior abdominal wall
the portal vein carries…
deoxygenated, nutrient-rich blood from the GI tract
