8- Gastrointestinal Physiology Flashcards
What are the 6 primary gastrointestinal functions?
- Absorption
- Digestion
- Excretion
- Motility
- Storage
- Secretion
From an engineering tube viewpoint, which area of the gastrointestinal system functions primarily as hydrolizer & lubricator?
Salivary glands
Parasympathetic nervous system stimulation causes what actions?
Increase secretions
Increase motility
Decrease constriction of sphincters
Increase blood flow
Sympathetic nervous system stimulation causes what actions?
Decrease secretions
Decrease motility
Increase constriction of sphincter
Increase blood flow
Which nerves participate in sympathetic nervous regulation of the gastrointestinal tract?
Lumbar spinal nerve
What are the 4 paracrine signaling molecules?
Histamine
Nitric oxide
Prostaglandins
Somatostatin
What are the GI hormones?
CCK (cholecystokinin) Gastrin GIP (gastric inhibitory peptide) Motilin Secretin
List the neural signaling molecules
Acetylcholine ATP CGRP (calcitonin gene related peptide) Enkephalins GRP (gastrin releasing peptide) Norepinephrine Neuropeptide Y Substance P VIP (vasoactive intestinal peptide)
What is the primary secretion of the parotid glands?
Serous secretions
What do the submandibular & sublingual glands secrete?
A mixture of mucous & serous secretions
As salivary rate increases, which ions concentration in saliva decreases?
Potassium
Which salivary gland is anatomically most inferior in the craniofacial complex?
Submandibular glands
What are the functions of serous and mucous secretions?
Serous secretions: hydrolyzing
Mucous secretions: lubrication
The parasympathetic nervous system increases salivary secretions by which of the following neurotransmitters ?
A. Norepinephrine
B. ATP
C. Vasoactive intestinal peptide
D. Neuropeptide Y
C. Vasoactive intestinal peptide
What is the site of action of norepinephrine, leading to increased salivary secretions?
Beta adrenergic receptors
Which gastric cell type is responsible for pepsinogen secretion?
Chief cells
What is the function of somatostatin?
Decreased acid secretion
Which of the following hormones increases H-K pump activity in the oxyntic gland? A. Somatostatin B. Gastrin C. VIP hormone D. Prostaglandin
B. Gastrin
Which of the following is an effect of acetylcholine?
A. Decreased acid production
B. Decreased gastrin production
C. Increased gastrin production
C. Increased gastrin production
What percentage of control & regulation of hydrogen ions is done in the gastric phase?
50%
Which of the following is a stimulant for gastrin?
A. Carbohydrates
B. Proteins
C. Vitamin A
B. Proteins
Which receptors is the site of action for acetylcholine from the vagus nerve resulting in release of hydrogen ions?
Muscarinic M3 receptors
What is the location for release of exocrine pancreatic secretions?
Small intestine
Which ion is secreted from the pancreas at a concentration that is many fold above what is in the plasma?
Bicarbonate
Which phase of digestion accounts for the majority of the control and regulation of the exocrine pancreas?
Intestinal phase
Which substance that increases secretion in the exocrine pancreas primarily utilizes a cAMP second messenger system?
Secretin
Which substance is the primary mediator of release of bile stored in the gallbladder?
Cholecystokinin
What is the concentration of bile salts in the gallbladder?
5-20%
The Cystic Fibrosis Transmembrane Regulator can be checked by which glands clinically?
Sweat glands
What can be found in the lumen portion of the duct of sweat gland of an individual with defected cystic fibrosis transmembrane regulator?
Sodium and chloride
What is the mechanism of action of pilocarpine?
Cholinergic agonist
What is the function of the stomach?
Blender acid
Amylase works on which carbohydrate bonds?
Alpha 1,4 bonds
Which of the following is a digestible form of carbohydrates in humans?
A. Amylopectin
B. Cellulose
C. Gums
A. Amylopectin
The absorption of fructose across the apical membrane of an enterocyte most likely utilizes which receptor?
GLUT5
What is the co transmitted substance utilized by PEPT1 to move across di and tri peptides?
Hydrogen ions
Which hormone aids in the increase of calcium absorption across the enterocyte?
Vitamin D3
SGLT1 allows the transport of how many sodium ions for each glucose molecule?
2
Which transporter is requires for glucose to exit the basolateral membrane of cells in the small intestine?
GLUT2
The amino acid transporters are divided according to which physical property?
pH
What requires mixed micelles for the purpose of absorption?
Large lipids
