1. Gastro Anatomy Flashcards
Phase of GI response characterized by anticipation and the sight, smell, and taste of food
Cephalic Phase
During the cephalic phase the vagus nerve stimulates the release of_______________.
Gastrin-releasing peptide (GRP) and acetylcholine
Function of gastrin-releasing peptide and acetylcholine
Makes you salivate, gets stomach fluids moving
_______________in the brainstem inhibits breathing during swallowing.
Reticular formation
Amylase digests_________
Carbohydrates
Lipase digests_______
Fats
________L of saliva is secreted each day.
1.5
Food bolus is moved via _______, coordinated by the_______system.
Smooth muscle peristalsis. Enteric nervous system.
The upper esophageal sphincter is controlled by _________
Extrinsic nerves
The lower esophageal sphincter is controlled by _____________
Autonomic nerves
These three products bind to the parietal cell and work synergistically to stimulate gastric acid production.
Gastrin, Histamine, and Acetylcholine
The release of ________will shut off gastric acid production.
Somatostatin
Parietal cells secrete:
Hydrochloric Acid and Instrinsic Factor
Peptic (chief) cells secrete:
Pepsinogen
Endocrine secretions include:
Gastrin, Somatostatin, Histamine
_______may have a role in regulating hunger and satiety.
Gherkin
_________stimulates parietal cells to produce acid
Gastrin
___________deactivates G cell secretion of gastrin.
Somatostatin
What happens when you suppress parietal cells?
Turns off intrinsic factor which can lead to B12 deficiency (and pernicious anemia).
___________protects against the corrosive properties of gastric juice in the stomach.
Mucus-bicarbonate barrier
Gastrin is stimulated by _________ ,________ via the enteric nervous system, and broken down proteins in the stomach.
Stomach stretch. Gastrin-releasing peptide.
What triggers the release of acetylcholine?
Vagal outflow from the brain (initiating secretory function in the salivary glands)
This is released when pH in the stomach is low.
Somatostatin (gastrin antagonist)
When are G cells directly inhibited?
When the pH in the stomach is at or below 3.
During the intestinal phase, feedback inhibition of gastric acid production is caused by the release of ________from the small intestine.
Enterogastrones (Secretin)
Most absorption of nutrients occurs where?
During the intestinal phase
What is the widest and shortest part of the small intestine?
Duodenum
What opens into the second part of the duodenum?
Sphincter of Oddi
Which glands in the mucosa secrete mucous?
Brunner’s glands
Endocrine cells in the duodenal wall produce _______ and _______.
Cholectystokinin. Secretin. (Feedback loop: shut off).
The duodenum is responsible for the absorption of ______ and______.
Iron. Calcium
What is the main digestive function of the pancreas?
Secrete the enzymes that break down the macromolecules in food, producing smaller nutrient molecules for intestinal absorption.
Pancreatic________create the pancreatic enzymes.
Acinar cells.
Pancreatic _________cells secrete bicarbonate.
Duct Cells. (Stimulated by secretin)
What is required to activate zymogens and where is it activated?
Trypsin. Small intestine.
What does bile do?
It facilitates the assimilation of dietary lipid by promoting its emulsification and solubilization. (Emulsifies lipids and binds with a lot of things in the kidneys.)
-provides a pathway to excrete hydrophobic molecules that may not be readily excreted by the kidney.
Bile is an ________solution.
Alkaline
Which cells in the liver are responsible for ingesting foreign bodies entering the blood via the gastrointestinal tract?
Kupffer cells
Where is bile stored?
Gallbladder
Bile composition (4)
Bile acids. Bile salts. Micelles of bile salts. Bile pigments.
What are micelles of bile salts?
Long-chain fatty acids, cholesterol, and other hydrophobic molecules at the center.
What is the main component of bile pigments?
Bilirubin-made from the breakdown of hemoglobin
_______% of bile salts are reabsorbed.
95
Bile acids are secreted by______, delivered to the GI tract via the _______, absorbed by the _______, and then returned to the liver via the _______________.
Hepatocytes. Biliary tract. Small intestines. Portal venous system.
Transverse folds in the mucosa are called:
Plicae circulares
The villus epithelium consists of ______, ________,and________.
Enterocytes. Mucous-secreting goblet cells. Endocrine cells.
Function of jejunum and ileum.
Mixing chyme with digestive secretions and enzyme.
Distribution across mucosa to enhance absorption.
Propulsion of luminal contents away from the mouth via segmentation and peristalsi.
The Jejunum and Ileum absorb:
Carbohydrates, protein, fat, salts, and water.
Bile acids and vitamin B12 absorbed in distal ileum.
Daily fluid load to jejunum is _____/day
7-10L
The longitudinal layer of smooth muscle in the colon:
Teniae coli
Contractions of teniae coli form bulges known as ______.
Haustra
A giant colonic peristaltic contraction triggered by the entry of food into the stomach and duodenum?
Gastrocolic reflex
Functions of the large intestine:
1) absorb fluid
2) Transport electrolytes
3) Store and eliminate fecal waste
Max reabsorption capacity of colon is _____/day.
5L
The rectum absorbs:
Electrolytes and water.
The internal anal sphincter is controlled by:
Smooth muscle-Autonomic nerves.
The external anal sphincter is controlled by:
Skeletal muscles controlled by extrinsic nerves.
Rectal distension initiates the ____________reflex.
Rectosphincteric (when you eat….)
Two major networks of nerve fibers that are intrinsic to the gastrointestinal tract:
1) Myentric plexus (Auerbach plexus)-motility
2) Submucous plexus (Meissen plexus)-secretions
“The little brain”
The enteric nervous system-100 million sensory neurons.
Increases smooth muscle activity.
Parasympathetic cholinergic activity from autonomic nervous system.
Decreases intestinal smooth muscle.
Sympathetic noradrenergic activity.
Another name for gastrointestinal circulation.
Splanchnic circulation
All blood from the intestines and pancreas drain via the ________to the liver.
Portal vein
What controls the splanchnic vascular resistance?
Sympathetic nervous system.
The intestinal mucosa contain a high number of ______ and ________ that rapidly defend the mucosa if epithelial defenses are breached.
Lymphocytes.
Inflammatory cells.
Lymphocytes circulate and populate all of the mucosal tissues of the body as _____________.
IgA-secreting plasma cells.
Kupffer cells have highly active________
Phagocytic properties-they are exposed to virtually all of the portal blood flow and serve as a sentinel for antigens/bacteria arising from the intestine.
