Section 7: Exam Study Flashcards
What receptor can turn on the CFTR channel?
M3
What nucleus does the psyche stimulate that leads to a high volume of salivary secretion?
salivary nucleus in the medulla
What neurotransmitter acts on what receptors when the SNS is activated?
norepinephrine to alpha or beta receptors
Immunological injury to what (in Sjorgen Syndrome) reduces secretion?
acini
Main components of gastric juices:
water and H+
True or False? Pepsinogen is essential for protein digestion.
F. proteases from pancreas digest protein
Vitamin B12 deficiency leads to:
pernicious anemia
True or False? We can live without a stomach.
T. as long as we can get intrinsic factor
Secreted volume of acid per day:
2-3L
True or False? Acid is essential to our digestion.
F. Not essential and less important because food is less dirty
3 stimuli of oxyntic cells:
gastrin, acetylcholine, histamine
In which portion of the stomach are G cells found?
antrum
2 names for the cells that release pepsinogen:
peptic and chief cells
What do surface cells produce all the time?
NaCl/NaHCO3 and water
True or False? Gastrin is released into the blood stream
T
What and how much can parietal/ oxyntic cells produce when stimulated?
3ml/min of isotonic HCl, KC, and IF
True or False? Gastrin is released via the exocrine system.
F. Endocrine
Mucus goes out through:
gastric pits
Gastric juice composition with stimulation:
As rate increases, H+ concentration increases dramatically, Cl- increases, Na drops, and K doesn’t change much.
Origin of basal secretions:
surface cells; NaCl, NaHCO3, KCl, isotonic H2O
Origin of stimulated secretion:
partietal cells; HCL, NaCl, KCl, isotonic H2O
What is at the center of the mechanism for H+ secretion?
HK-ATPase, splits water, pumps H+ out against gradient while moving K into the cell
Is the blood bathing the stomach acidic or alkalinic?
alkalinic
When to take atropine:
for ulcer, blocks all muscarinic receptors
What does atropine block?
all muscarinic receptors, decreases acid secretion, not 100% block
True or False? Cimetidine stops secretion completely.
F. reduces
This is the only drug that 100% blocks the pump so there is no H+ secretion.
Omeprazole
Gastrin, acetylcholine, and histamine exhibit:
potentiation, secretory respons fo 2 is greater than the individual responses summed
True or False? The 3 phases of acid secretion cannot happen concurrently.
F. can happen all at once
Cephalic phase of acid secretion is via:
the vagus, extrinsic nerve, leads to acetylcholine release
Is there (direct, indirect, or both) secretion of H+ in cephalic phase?
both
Food inhibits this so that G cells will be stimulated, thereby secreting H+.
somatostatin
a pH under __ will inhibit gastrin release.
3
What stops the release of gastrin?
increase in pH due to food entering stomach
True or False? The vaso-vagal reflex leads to decreased G-cells and parietal cell secretion.
F. increased
This neurotransmitter is involved in the local response:
acetylcholine, stimulate G cells or parietal cells to secrete
Substances that stimulate parietal cells or G cells in the lumen of the intestines:
amino acids, proteins, caffeine, calcium, ethanol
Food in the stomach act on these cell types:
G cells and parietal cells
3 ways proteins can cause acid release:
g cells in the duodenum release gastrin that will signal increase acid secretion in stomach, protein stimulate endocrine cells, amino acids in the blood can circulate back and stimulate parietal cells
Stimulation of the vagus because of chewing, swallowing, smell, or taste can lead to the release of:
GRP or acetylcholine
Distention that triggers local reflexes uses this neurotransmitter:
acetylcholine
Both __ and __ G cells can lead to the release of gastrin.
gastric and intestinal
4 stimuli of parietal cells:
acetylcholine, gastrin, circulating amino acids, histamine
What does the decrease in pH of the stomach after all the food is gone stimulate?
somatostatin release which inhibits gastrin release
List 3 enterogastrones:
Secretin, CCK, and GIP
What effect do enterogastrones have?
inhibit parietal and G cells
True or False? GERD is life threatening.
T
How long does it take for food to go down the esophagus?
8 sec
Does pressure increase or decrease at the LES?
decrease
True or False? The esophageal peristaltic wave is due to spontaneous muscle activity.
F. Vagal nuclei in brainstem
What activates the second wave contraction in the esophagus?
stretch receptors in the esophagus activate a reflex stimulation via the vagus
LES opening and closing:
LES is normally closed. Before the pressure wave, the vagus signals the LES to relax and makes sure to send extra ACh after the opening to make sure it closes.
3 neurotransmitters of the myenteric and submucosal plexus:
Relaxation: VIP and NO, contraction: Acetylcholine
Neurotransmitters of the myenteric and submucosal plexus that are neurotransmitter sympathetic or parasympathetic:
purinergic
When are VIP/ NO released?
Inhibitory motor neurons are signaled by the vagus and have receptors for acetylcholine which then release VIP or NO
True or False? CCK causes contraction of the stomach.
F. relaxation, leading to food storage
True or False? If a meal is present in the stomach there is more calcium and more contractions.
T
How is slow wave electrical information being passed from cell to cell?
gap junctions
2 ways to control gastric peristalsis:
Vagal stimulaiton via acetylcholine OR gastrin
How does gastrin affect calcium?
raises levels in the smooth muscle cells
True or False? Vagal stimulation via acetylcholine and gastrin release can both occur just by thinking about food.
T
Fats inhibit gastric emptying via:
CCK
Acids inhibit gastric emptying via:
purinergic stimulation
How can vagal stimulation affect gastric emptying?
deviation from isotonicity lowers vagal stimulation and inhibits gastric emptying
What type of stimulation does H+ in the duodenum lead to?
purinergic stimulation leading to the relaxation of the sphincter
True or False? Osmoreceptors causing the vagus not to release as much acetylcholine is a purinergic response.
F
Fats in the duodenum cause the stomach to:
relax
True or False? Vomiting is activated by the stimulation of smooth muscle.
F. skeletal muscle
Where is the vomiting center?
at the pons-medulla junction
True or False? Control of vomiting is via both the CNs and the spinal cord.
T. proximal GI organs, diaphragm and abdominal muscles
What happens in the stomach during vomiting?
stomach doesn’t contract much more and becomes looser, strong contraction of abdominal muscles propels the food
