27 Questions
What is the main purpose of the alimentary tract?
Absorption of water, electrolytes, vitamins, and digestive products
What are the characteristics of gastrointestinal smooth muscle fibers?
Arranged in bundles of 1000 parallel fibers
What is one of the objectives regarding the GI tract organization and functioning?
Knowing the basic physiology behind the GI tract
How does the alimentary tract provide the body with a continual supply of nutrients?
By circulation of blood flow through the gastrointestinal organs
What is the role of the Nervous system in the organization and functioning of the GI tract?
To regulate digestion and absorption in the GI tract
What is required for the purpose of secretion of digestive juices and digestion of the food?
Movement of food through the alimentary tract
Which of the following is NOT a stimulus for the secretion of cholecystokinin?
Carbohydrate
In the GI tract, which hormone stimulates gastric emptying?
Motilin
Which site secretes gastric inhibitory peptide?
K cells of the jejunum
What is the role of secretin in the GI tract?
Stimulates pancreatic enzyme secretion (bicarb into lumen of duodenum)
Which statement about smooth muscle contraction in the GI tract is false?
Muscle layers in the GI tract wall do not share electrical connections
What type of stimuli are needed for the secretion of motilin?
Fat, acid, nerve
Which hormone inhibits gastric acid secretion?
Gastric Inhibitory Peptide
Where are the S cells located that secrete cholecystokinin?
I cells of the duodenum, jejunum, and ileum.
What is inhibited by secretin?
Gastric acid secretion
What are the stimuli for the secretion of gastric inhibitory peptide?
Protein, fat, carbohydrate
What is the main reason for the low resistance movement of ions from one muscle cell to the next?
Existence of gap junctions
Which type of electrical waves are slow, undulating changes in the resting membrane potential?
Slow waves
What causes smooth muscle contraction in response to entry of calcium ions into the muscle fiber?
Activation of myosin filaments
How many plexus are present in the enteric nervous system, and what are their respective functions?
Two plexus: One for controlling gastrointestinal movements and another for gastrointestinal secretion and local blood flow
Which stimuli can activate afferent sensory nerve fibers?
Irritation of the gut mucosa
What is the main effect of parasympathetic stimulation on the enteric nervous system?
General increase in activity of the entire enteric nervous system
What is the function of slow waves in intestinal smooth muscle?
Rhythmically determine the frequency and intensity of contraction
Which factor causes hyperpolarization of the membrane, making it more difficult to depolarize?
Stimulation by norepinephrine or epinephrine in the fiber membrane
What is a characteristic feature of tonic contraction in intestinal smooth muscle?
Continuous partial depolarization causing tonic contraction
Which type of reflexes are controlled entirely within the gut wall, integrating gastrointestinal secretion, peristalsis, mixing, contractions, and local inhibitory effects?
Short distance reflexes
Which stimuli can cause increased secretion of gastrin?..
Protein, distension, and nerve stimulation
This quiz covers the histology and general arrangement of the GI tract, basic physiology, characteristics and electrical activity of GI smooth muscle, the role of the nervous system, and its association with the GI tract. Test your understanding of the organization and regulation of the gastrointestinal tract.
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