Physiology Lecture: Lower GIT with Accessory Organs

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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 (correct)

To mix luminal contents

To decrease absorption

To increase motility

Which of the following is NOT a physiological sphincter in the small intestine?

Gastroesophageal junction

Pylorus

Ileocecal junction

Internal Anal Sphincter (correct)

What is the main function of the pylorus?

To mix food with enzymes

To increase peristalsis

To prevent backflow from the small intestine to the stomach (correct)

To decrease absorption

What is the term for the movement of electrical activity from the stomach to the small intestine?

Migrating Myoelectric Complex Signup and view all the answers

What is the abbreviation for the Cystic Fibrosis Transmembrane Conductance Regulator?

CFTR Signup and view all the answers

Which of the following is NOT a part of the Autonomic Nervous System?

Somatic Nervous System Signup and view all the answers

What is the term for the process of releasing enzymes from the pancreas into the small intestine?

Exocrine function Signup and view all the answers

What is the name of the protein that stimulates the release of digestive enzymes from the pancreas?

Cholecystokinin Signup and view all the answers

What is the velocity of peristalsis in the small intestine?

0.5-2 cm/sec Signup and view all the answers

What is the primary initiator of a neural reflex arc that propagates peristalsis?

Stretching of the gut wall by food bolus Signup and view all the answers

What is the direction of the ascending fibers in the enteric neural circuitry of peristalsis?

Towards the mouth Signup and view all the answers

What is the result of peristaltic rush in some cases of infectious diarrhea?

Relieving the small intestine of irritative chyme and excessive distension Signup and view all the answers

What is the time required for the passage of chyme from the pylorus to the ileocecal valve?

3-5 hours Signup and view all the answers

What is the effect of a bolus on the longitudinal muscle in the muscularis externa behind the bolus (orad)?

Relaxation Signup and view all the answers

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 Signup and view all the answers

What is the direction of the descending fibers in the enteric neural circuitry of peristalsis?

Away from the mouth Signup and view all the answers

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 Signup and view all the answers

What is the estimated transit time through the colon?

2-3 days Signup and view all the answers

What affects the rate of material moving through the digestive tube?

Composition of the meal and other factors Signup and view all the answers

Where does most of the water absorption take place in the colon?

Proximal half of the colon Signup and view all the answers

What is the consistency of the stool in the ascending and transverse colon?

Mushy Signup and view all the answers

What happens to the feces in the distal colon?

It transforms into semi-solid states Signup and view all the answers

What is the definition of transit time?

The time it takes for food to pass through the digestive tract Signup and view all the answers

How often does the mass movement occur in the colon?

1-3 times a day Signup and view all the answers

What is the approximate percentage of blood flow to the liver from the hepatic artery?

25% Signup and view all the answers

What is the function of the portal vein in the liver?

To deliver nutrient-rich blood to the liver Signup and view all the answers

What is the location of the base of the liver?

Right upper quadrant of the abdomen Signup and view all the answers

What is the shape of the liver?

Prism or wedge Signup and view all the answers

What is the function of the falciform ligament in the liver?

To divide the liver into right and left lobes Signup and view all the answers

What is the direction of blood flow in the classic lobule?

From the portal triads to the central vein Signup and view all the answers

What is the characteristic of the blood in the hepatic arteries?

Nutrient-poor and oxygen-rich Signup and view all the answers

What is the characteristic of the blood in the portal vein?

Nutrient-rich and oxygen-poor Signup and view all the answers

What is the composition of pancreatic juice in the unstimulated state?

Similar to that of plasma Signup and view all the answers

What happens to the concentration of bicarbonate in pancreatic juice upon stimulation?

It increases Signup and view all the answers

What is the primary component of pancreatic juice in the stimulated state?

Sodium, bicarbonate, and water Signup and view all the answers

What is the relationship between the electrolyte composition of pancreatic fluid and its secretory rate?

They are directly related Signup and view all the answers

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 Signup and view all the answers

What is the pattern of enzyme secretion during the fasting state?

Basal and variable Signup and view all the answers

What is the relationship between small bowel motility and pancreatic enzyme secretion during the fasting state?