42 Questions
What is the function of physiological sphincters in the small intestine?
To isolate one region from the next and provide selective retention of luminal contents
Which of the following is NOT a physiological sphincter in the small intestine?
Internal Anal Sphincter
What is the main function of the pylorus?
To prevent backflow from the small intestine to the stomach
What is the term for the movement of electrical activity from the stomach to the small intestine?
Migrating Myoelectric Complex
What is the abbreviation for the Cystic Fibrosis Transmembrane Conductance Regulator?
CFTR
Which of the following is NOT a part of the Autonomic Nervous System?
Somatic Nervous System
What is the term for the process of releasing enzymes from the pancreas into the small intestine?
Exocrine function
What is the name of the protein that stimulates the release of digestive enzymes from the pancreas?
Cholecystokinin
What is the velocity of peristalsis in the small intestine?
0.5-2 cm/sec
What is the primary initiator of a neural reflex arc that propagates peristalsis?
Stretching of the gut wall by food bolus
What is the direction of the ascending fibers in the enteric neural circuitry of peristalsis?
Towards the mouth
What is the result of peristaltic rush in some cases of infectious diarrhea?
Relieving the small intestine of irritative chyme and excessive distension
What is the time required for the passage of chyme from the pylorus to the ileocecal valve?
3-5 hours
What is the effect of a bolus on the longitudinal muscle in the muscularis externa behind the bolus (orad)?
Relaxation
What is the role of serotonin in the stimulation of sensory neurons in the gut wall?
Indirect activation of sensory neurons in the gut wall
What is the direction of the descending fibers in the enteric neural circuitry of peristalsis?
Away from the mouth
What happens to the area of the colon distal to the constriction when a ring of constriction occurs?
It loses haustration and contracts as a unit pushing fecal matter in towards the rectum
What is the estimated transit time through the colon?
2-3 days
What affects the rate of material moving through the digestive tube?
Composition of the meal and other factors
Where does most of the water absorption take place in the colon?
Proximal half of the colon
What is the consistency of the stool in the ascending and transverse colon?
Mushy
What happens to the feces in the distal colon?
It transforms into semi-solid states
What is the definition of transit time?
The time it takes for food to pass through the digestive tract
How often does the mass movement occur in the colon?
1-3 times a day
What is the approximate percentage of blood flow to the liver from the hepatic artery?
25%
What is the function of the portal vein in the liver?
To deliver nutrient-rich blood to the liver
What is the location of the base of the liver?
Right upper quadrant of the abdomen
What is the shape of the liver?
Prism or wedge
What is the function of the falciform ligament in the liver?
To divide the liver into right and left lobes
What is the direction of blood flow in the classic lobule?
From the portal triads to the central vein
What is the characteristic of the blood in the hepatic arteries?
Nutrient-poor and oxygen-rich
What is the characteristic of the blood in the portal vein?
Nutrient-rich and oxygen-poor
What is the composition of pancreatic juice in the unstimulated state?
Similar to that of plasma
What happens to the concentration of bicarbonate in pancreatic juice upon stimulation?
It increases
What is the primary component of pancreatic juice in the stimulated state?
Sodium, bicarbonate, and water
What is the relationship between the electrolyte composition of pancreatic fluid and its secretory rate?
They are directly related
What is the difference between the fasting state and the fed state in terms of pancreatic secretion?
The fed state has a higher enzyme secretion
What is the pattern of enzyme secretion during the fasting state?
Basal and variable
What is the relationship between small bowel motility and pancreatic enzyme secretion during the fasting state?
They are directly related
What is the main difference between the pancreatic juice in the unstimulated and stimulated states?
The concentration of bicarbonate
What is the role of ductal cells in the stimulated state?
Secretion of isotonic solution
What is the composition of the pancreatic juice in the stimulated state?
Rich in sodium, bicarbonate, and water
This lecture covers the lower gastrointestinal tract and its accessory organs, including the liver, gallbladder, and exocrine pancreas. It discusses their functional anatomy, electrophysiology, and motility.
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