Stomach and Duodenum Flashcards
L and R Gastric Veins
Lesser curve.
-both drain into the portal vein that drains into liver before returning to the systemic circulation
Splenic Vein
drains from spleen and superior/posterior pancreas
Inferior mesenteric vein
Drains the hindgut (inferior colon) into the splenic vein
Superior mesenteric vein
Drains the midgut (small intestine) and joints splenic vein
Hepatic portal vein
formed from gastric veins, splenic vein (IMV) and superior mesenteric vein
Mechanical Digestion in Stomach
Gentle mixing waves
- every 15-25 s, mixes bolus w 2 quarts/day of gastric juice to turn it into chyme
More vigorous waves
- travel from body of stomach to pyloric region
Intense waves near pylorus
- open and squirt out 1-2 teaspoons full w each wave
Chemical Digestion in Stomach
Protein digestion begins
- HCL denatures protein molecules
- HCL transforms pepsinogen into pepsin that breaks peptide bonds between certain amino acids
Fat digestion continues
- Gastric lipase splits the triglycerides in milk fat (most effect at pH 5-6 aka infant stomach)
HCL kills microbes in food (protective)
Mucous cells project stomach walls from being digested with 1-3mm thick layer of mucous
Celiac Phase
“Stomach getting ready”
Cerebral Cortex: sight, smell, taste, thought
- stimulates parasympathetic nervous system
Vagus Nerve: parasympathetic
- increases stomach muscle and glandular activity
Sympathetics
DESCENDING. T5/T10 (preganglionic) via greater thoracic splanchnic nerve. Synapses in celiac ganglia via splanchnic nerve. Postganglionic through celiac plexus to organ
Parasympathetics
Vagus N (preganglionic) passes through the celiac ganglia but doesn’t synapse there, instead synapses in the ganglia of target organ (postganglionic)
- travels with alimentary canal and sends off branches to serve organs regionally, also sends branches through specific ganglia to travel with sympathetics
Absorption of nutrients by the stomach
- water (especially cold)
- electrolytes
- Some drugs (aspirin) and alcohol
Absorption of alcohol in stomach
Fat content in the stomach slows the passage of alcohol to the intestine where absorption is more rapid.
Gastric mucosal cells contain Alcohol Dehydrogenase that converts some alcohol to acetaldehyde
- more acetaldehyde in males than females, because females have less total body fluid and do not degrade alcohol as quickly
Vomiting (emesis)
Forceful expulsion of contents of stomach and duodenum through mouth.
CAUSE: irritation or digestion of stomach, unpleasant sights, general anesthesia, dizziness, drugs
-Sensory input from medulla causes stomach contraction and complete sphincter relaxation
-contents of stomach squeezed by abdominal muscles and diaphragm and forced through open mouth
-can cause loss of acidic gastric juice and can lead to alkalosis
Duodenum
First part of small intestine (10 in long)
3 accessory organs associated
- pancreas (pancreatic duct), gallbladder(cystic D.), liver (hepatic D.)
Brunner’s Glands- make alkaline mucous to neutralize chyme
Small intestine
Convoluted tube (length varies in muscular tone, shorter in live person)
Longest part of GI tract
Extends from pyloric sphincter to ileocaval valve
3 regions
- duodenum
-jejunum
- ileum
Parts of the duodenum
Superior part: ampulla/duodenal cap, has no circular folds
Descending part: receives contents from accessory digestive organs via major and minor duodenal papilla
Horizontal part
Ascending part
Where do the pancreas, gallbladder, and liver empty their contents
second part of duodenum aka descending part
Falciform ligament
specialized mesentery on anterior body wall from the umbilical vein in development
- supplies oxygenated blood to baby
-inferior aspect contains round ligament of liver
Which lobe of the liver is greater
Right lobe is larger than left
Ligamentum Venosum
Where falciform and round ligaments carry destroyed umbilical vein thru fissure
Liver
Largest internal organ
2 major lobes: right and left anchored by falciform ligament
- quadrate and caudate associated with underside of left
Digestion:
- bile production (alkaline yellow-green fluid) breakdown production of heme
-bile salts (cholesterol derivative) emulsify large fat globules for enzyme attack
Other functions:
- destroys or stores toxins
- removes antibodies, foreign debris, or old RBC’s, hormones in circulation
-plasma protein synthesis
Portal Triad
Hepatic portal vein, hepatic artery proper, and common hepatic duct
- where things enter and exit the liver
Gallbladder
- Muscular greenish sac attached to liver (ventral side)
- Stores and concentrates bile (released thru cystic duct)
- Common bile duct + pancreatis duct= hepatopancreatic ampulla -> duodenal papilla. Opening is controlled by hepatopancreatic sphincter (sphincter of oddi)
- Cholecystokinin (CCK)= contraction of bladder and relaxes sphincter of oddi
-Gallstones
What does the sphincter of oddi do
releases bile and pancreatic juices to duodenum when relaxes
