30 Questions
What initiates peristalsis in the GI tract?
Stretch of the gut wall
During peristalsis, what occurs behind the stimulus?
Circular contraction
At what speed can peristalsis propel the contents of the GI tract forward?
10-20 cm/s
How does peristaltic activity respond to autonomic input?
Increases peristalsis
What type of motility in the gastrointestinal tract is aimed at retarding the movement of intestinal contents?
Segmentation
How does removal and resuturing of a segment of intestine affect peristaltic progression?
Has no effect
What structure restricts reflux of colonic contents into the ileum?
Ileocecal valve
What happens to the ileocecal valve under increases in conic pressure?
It is squeezed shut
What type of muscle controls the internal (involuntary) anal sphincter in humans?
Smooth muscle
Which nerve supplies the external anal sphincter?
Pudendal nerve
What initiates the reflex contractions of the rectum musculature?
Distention of the rectum with feces
At what rectal pressure does the urge to defecate typically first occur?
18 mmHg
What is the function of the intrinsic smooth muscle at the esophagogastric junction?
To surround the esophagus and apply pinchcock-like action
What is the key feature of achalasia?
Increased resting LES tone
Which condition is associated with reflux of gastric contents into the esophagus?
Gastroesophageal reflux disease
What can severe cases of LES incompetence lead to?
Formation of ulceration and stricture in the esophagus
What contributes to the prevention of regurgitation at the esophagogastric junction?
Flap valve formation
What are the main symptoms associated with gastroesophageal reflux disease?
Heartburn and esophagitis
What is the function of migrating motor complexes (MMCs) in the intestine?
Coordinate muscle contractions for movement
How often does the entire cycle of migrating motor complexes (MMCs) under fasting conditions?
Every 90-100 minutes
What happens to migrating motor complexes (MMCs) when a meal is ingested?
They are abolished temporarily
Which part of the digestive system is responsible for breaking up large food particles and mixing the food with saliva?
Mouth
Where are the cells located that are responsible for the pacemaker activity in the stomach and small intestine?
Outer circular muscle layer
How do peristaltic waves in the esophagus function?
Move food into the stomach
What triggers the reflex response of swallowing (deglutition)?
Afferent impulses in the trigeminal, glossopharyngeal, and vagus nerves
Why do large food particles cause strong and often painful contractions of the esophageal musculature?
They don’t form a bolus
What initiates the involuntary contraction in the pharyngeal muscles during swallowing?
Collection of oral contents on the tongue
Why are edentulous patients generally restricted to soft diets?
They have difficulty eating dry food
What nerves carry efferent fibers to the pharyngeal musculature and the tongue during swallowing?
Trigeminal, facial, and hypoglossal nerves
Why do small food particles make swallowing difficult?
They disperse in the absence of saliva
Learn about the general patterns of motility in the gastrointestinal tract, focusing on the reflex response of peristalsis which helps in propelling contents from the esophagus to the rectum. Understand how the gut wall stretching initiates circular contractions and relaxation areas to facilitate movement.
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