Physiopatho - gastro Flashcards
Which statement is true with regard to the parasympathetic fibers that innervate the cells of the ENS?
a. The fibers exit the central nervous system from lumbar
segments of the spinal cord.
b. The fibers have vasoactive intestinal peptide as a
neurotransmitter.
c. The fibers are inhibitory.
d. The fibers are preganglionic.
e. There are no parasympathetic fibers that innervate cells of
the ENS.
D - pre-ganglionic for the parasymp
post-ganglionic for the symp
Which statement is true with regard to the GI endocrine cells?
a. Secretory activity is influenced by the luminal contents of
the gut.
b. Hormones are secreted directly into the gut lumen and
affect the activity of glands “downstream” from the point
of secretion.
c. The secretory products of the GI endocrine cells are
steroid hormones.
d. Each GI endocrine cell can produce many different types
of hormones, depending on the stimulus applied to it.
a - luminal content influences release (i.e.: gastrin released when detecting perp tons (partially digested proteins) and low pH, secretin with low pH, CCK with proteins and fatty acids, GIP with glucose and fat….)
Which of the following conditions in the gut would NOT provide direct sensory input to the ENS?
a. Changes in luminal pressure resulting in changes in
tension of gut wall musculature.
b. Changes in luminal pH.
c. Changes in luminal osmotic pressure.
d. Changes in the rate of ingesta flow.
D - rate does not change
Which of the following neurocrine transmitter molecules is most consistently excitatory relative to gut functions?
a. Somatostatin
b. Acetylcholine
c. Vasoactive intestinal peptide (VIP)
d. ATP
B - ACH major excitatory transmit of parasympathetic system
All neurocrine transmitter molecules are peptides.
a. True
b. False
False
The conscious sensation of pain due to excessive distention of a segment of the gut arises from afferent impulses traveling to the brain through:
a. The myenteric plexus
b. The submucosal plexus c. The vagus nerve
d. The splanchnic nerves
D - splanchnic nerves afferent nociceptive
The influence of the GI mucosal immune system on gut functions is mediated by:
a. The CNS.
b. The direct action of cytokines on gut smooth muscle and
glands.
c. The interaction of cytokines with the ENS and GI
endocrine/paracrine cells.
d. The direct action of T cells on gut smooth muscle and
glands.
C - IMminteracts via cytokines with enteric nervous system and endo-/para-crine cells
A unique feature of gastrointestinal (GI) smooth muscle cells is that:
a. Their resting transcellular electrical potential has the posi- tive pole on the outside surface of the cell membrane.
b. Action potentials, or spikes of membrane depolarization,
are not associated with muscle contractions.
c. Muscle contractions are stimulated by partial depolariza-
tion of the membrane.
d. There are spontaneous, rhythmical undulations in the
electrical potential across the cell membrane.
e. Contraction of the muscles is never influenced by nervous
activity.
D - slow waves - intrinsic electrical properties of the smooth muscle mass consist of spontaneously undulating waves of partial depolarization that sweep over the gut smooth muscle. From specialized smooth muscle cells called interstitial cells of Cajal (ICC). The ICC form an interconnecting lattice of cells that surrounds the circular and longitudinal layers of muscle over the entire length of the gut. ICC exhibit rhythmical and spontaneous oscillation in their transmembrane electrical potentials. Slow waves are constantly passing over GI smooth muscle, whether it is actively contracting or not. GI smooth muscle cells, as with other muscle cells, contract in association with action, or spike, potentials. These potentials are characterized by complete depolarization of the membrane for a short time, in contrast to the slow waves, which are characterized by incomplete depolarization. Action potentials in the GI smooth muscle occur ONLY in association with slow waves.
The interstitial cells of Cajal are:
a. Modified neurons capable of generating contraction.
b. Modified neurons capable of generating only action
potentials.
c. Modified neurons capable of generating only slow waves.
d. Modified smooth muscle cells capable of generating only
slow waves.
e. Modified smooth muscle cells capable of generating only
action potentials.
D - they generate only smooth waves. Slow waves are constantly passing over GI smooth muscle, whether it is actively contracting or not. GI smooth muscle cells, as with other muscle cells, contract in association with action, or spike, potentials. These potentials are characterized by complete depolarization of the membrane for a short time, in contrast to the slow waves, which are characterized by incomplete depolarization. Action potentials in the GI smooth muscle occur ONLY in association with slow waves.
The term slow waves as applied to the gut refers to:
a. Slowly moving fronts of electrical activity that are propagated down the enteric nervous system.
b. Slowly moving fronts of electrical activity that result from
coordinated changes in cell membrane potential occurring
throughout the smooth muscle of the intestinal wall.
c. Slowly moving fronts of ingesta that proceed down the
intestine in response to peristaltic movement.
d. Slowly moving fronts of action potentials that are con-
stantly passing over the gut smooth muscle.
e. Slowly moving fronts of peristaltic contractions that pass uniformly over the entire small intestine during the diges-
tive period
B
An animal is presented to you with aspiration pneumonia (the result of food material entering the lower respiratory tract). Which of the following lesions would be a likely cause?
a. Loss of myenteric plexus function in the pharynx and
upper esophagus
b. Loss of slow-wave activity in the pharynx and upper
esophagus
c. A lesion in the brainstem
d. A lesion in the trachea
e. None of the above
C - brain stem
chemoreceptor trigger zone: important structure outside the GI tract that supplies afferent input in the vomit center. This is an area of the brainstem that lies in contact with the third ventricle. The chemoreceptor trigger zone is sensitive to the presence of some drugs and toxins in the blood. When stimulated, this zone sends signals to the vomit center and induces vomiting
The term cephalic phase is used in reference to a number of activities occurring in the GI tract. In general, the term means:
a. The early phases of digestion, when food is nearest the
head.
b. Any actions stimulated directly by the presence of food in
the stomach.
c. Any actions stimulated directly by the presence of food in
the mouth.
d. Digestive events stimulated by the presence of food in the
GI tract but requiring reflexes integrated in the central
nervous system.
e. Digestive events that occur before the ingestion of food
and in response to central nervous system stimulation brought on by the anticipation of eating.
E
Conditions in the duodenum, such as low pH or high fat concentration, can reflexively inhibit gastric emptying. Which reflex arc is involved in this inhibition?
a. Parasympathetic nervous system
b. GI enteric nervous system c. GI endocrine system
d. All the above
D
Which of the following best describes the motility of the proximal region of the monogastric stomach?
a. Rhythmic segmentation
b. Peristalsis
c. Retropulsion
d. Adaptive relaxation
C
The rectosphincteric reflex is integrated in the: a. Brainstem
b. ENS
c. Lumbar spinal cord d. Sacral spinal cord
D
Colonic “pacemakers”:
a. Are anatomically distinct structures composed of special-
ized smooth muscle cells.
b. Shift in their sites under the influence of the ENS.
c. Are involved in segmentation but not peristalsis.
d. Control defecation.
B
Inhibition of the enzyme carbonic anhydrase is likely to have what effect on gastric pH?
a. Decrease gastric pH
b. Increase gastric pH
c. Have no effect on gastric pH
B
Which of the following is not a natural ligand for receptors in the pancreas?
a. Cholecystokinin
b. Acetylcholine
c. Gastrin
d. Secretin
C - gastrin
Which of the following is not a potential stimulus for gastric acid secretion?
a. Norepinephrine secretion resulting from stimulation of
sympathetic nerves.
b. Vagal nerve activity resulting from the sight of food.
c. The presence of undigested protein in the pyloric antrum.
d. Acetylcholine release stimulated by gastric stretch receptors
acting on nerves of the ENS.
e. Histamine release from cells in the gastric mucosa.
A - sympathy note not stimulatory but only inhibitory of GI tract
During sodium absorption by glucose cotransport:
a. Chloride is absorbed by the paracellular route.
b. Chloride absorption is not affected.
c. Chloride is absorbed in exchange for bicarbonate.
d. Chloride absorption is coupled with potassium absorption. e. Chloride is absorbed in exchange for hydrogen ion.
A
Which statement about the tight junctions is false?
a. Tight junctions encircle the enterocyte near its apical end.
b. Tight junctions form the dividing line between the apical
membrane and the basolateral membrane.
c. Tight junctions are impermeable to water.
d. Tight junctions separate the lateral space from the intestinal
lumen.
e. Tight junctions are the only points that attach enterocytes
together.
C - they allow passage of small ions and water in the intestine
A drug that blocks the activity of the Na+,K+-ATPase pump could be expected to have what effect on sodium-glucose cotransport?
a. Increased sodium-glucose cotransport
b. Decreased sodium-glucose cotransport
c. No effect on sodium-glucose cotransport
B - gradient of sodium out of cell generated by Na/K/ATPase is essential for making the cotransporter Na/glucose (from out- to in-side the cell) working
During sodium absorption by glucose cotransport:
a. Chloride is absorbed by the paracellular route.
b. Chloride absorption is not affected.
c. Chloride is absorbed in exchange for bicarbonate.
d. Chloride absorption is coupled with potassium absorption. e. Chloride is absorbed in exchange for hydrogen ion.
A
Before entering the intestinal capillaries, all nutrients pass through the:
a. Apical membrane
b. Tight junction
c. Lateral space
d. Basolateral membrane e. Enterocyte cytoplasm
C - either directly, or first via the membrane (transcellular transport) and then to the lateral space
Which of the following amino acids is not extensively catabolized by the liver?
a. Valine
b. Alanine
c. Glutamine
d. Asparagine
e. Glycine
A
Which of the following reactions in the liver could be expected to occur during both the digestive phase and a prolonged fast?
a. Glycogen synthesis
b. Fatty acid synthesis
c. Ketone body synthesis
d. Ketone body oxidation
e. Triglyceride synthesis from fatty acids
E
Which of the following statements is true of both ketone bodies and nonesterified fatty acids?
a. They are water soluble.
b. They provide energy for muscle metabolism.
c. They circulate in blood bound to albumin.
d. They can provide energy to the brain.
e. They are formed exclusively in the liver.
B
All the following are metabolites that can be oxidized for fuel in the animal body. Which one is not important in the transport of energy between organs and organ systems?
a. Triglyceride
b. Ketone bodies
c. Oxaloacetic acid
d. Nonesterified fatty acids
e. Amino acids
C - it is just a product
Which of the following reactions is not characteristic of the absorptive phase of digestion?
a. Hepatic synthesis of glycogen
b. Hepatic uptake of glucose
c. Destruction of dietary amino acid
d. Utilization of muscle-derived amino acid for gluconeogenesis
e. Hepatic synthesis of triglyceride from glucose
D - typical of fasting phase
