GI Hormones and Neurotransmitters

Play an AI-generated podcast conversation about this lesson

What is the main purpose of segmentation contractions in the small intestine?

To propel chyme through the small intestine

To regulate the frequency of migrating motility complexes

To prevent the return of fecal content into the small intestine

To mix chyme with intestinal secretions and bring it into repeated contact with the intestinal absorptive epithelium (correct)

What regulates the intensity of segmentation contractions?

Motilin and gastrin

Sympathetic activity and slow waves

Long and short reflexes only

Parasympathetic activity and hormones (correct)

Where is the frequency of segmentation contractions highest?

In the ileum

In the jejunum

In the duodenum (correct)

In the stomach

What type of movements are responsible for propelling chyme through the small intestine?

Peristaltic waves Signup and view all the answers

What prevents the return of fecal content into the small intestine?

The ileocecal valve Signup and view all the answers

What type of contractions occur during the inter-digestive period?

Migrating motility complexes Signup and view all the answers

What is the approximate frequency of migrating motility complexes?

One every 90 minutes Signup and view all the answers

What is the function of migrating motility complexes?

To sweep undigested material toward the terminal ileum Signup and view all the answers

What is the main dietary source of carbohydrates?

Starch and disaccharides Signup and view all the answers

What is the process by which carbohydrates are broken down into their component monosaccharides?

Digestion Signup and view all the answers

Where does the digestion of carbohydrates begin?

Mouth Signup and view all the answers

What is the enzyme responsible for breaking down starch into maltose, maltotriose, and limit dextrin?

Amylase Signup and view all the answers

What is the pH at which pepsin is optimal?

pH 2 Signup and view all the answers

What is the form in which most dietary fat is found?

Triglycerides Signup and view all the answers

Where does protein digestion begin?

Stomach Signup and view all the answers

What is the result of pepsin breaking peptide bonds?

Peptide fragments and individual amino acids Signup and view all the answers

What is the main function of the peritoneal cavity?

To lubricate the mobile digestive organs Signup and view all the answers

What is the primary function of gastrin and other GI hormones?

To regulate the digestive system Signup and view all the answers

What is the effect of norepinephrine on the smooth muscle of the digestive tract?

It inhibits the smooth muscle Signup and view all the answers

What is the primary function of the mesentery?

To provide routes for blood vessels, lymphatic vessels, and nerves Signup and view all the answers

Which organs are considered retroperitoneal organs?

Most of the pancreas and parts of the large intestine Signup and view all the answers

What is the result of a wound, perforating ulcer, or burst appendix in the peritoneum?

Inflammation of the peritoneum Signup and view all the answers

What is the percentage of cardiac output received by the splanchnic circulation?

One-quarter Signup and view all the answers

What is the function of the hepatic portal circulation?

To collect nutrient-rich venous blood draining from digestive viscera Signup and view all the answers

Which structural modification in the small intestine forces chyme to spiral slowly through the lumen?

Circular folds Signup and view all the answers

Which enzyme is responsible for breaking down lactose in the small intestine?

Lactase Signup and view all the answers

What type of cells are primarily responsible for mucus secretion in the villi of the small intestine?

Goblet cells Signup and view all the answers

How are glucose and galactose primarily transported across the small intestine's epithelial cells?

Secondary active transport with Na+ Signup and view all the answers

What is the main form in which carbohydrates are absorbed in the small intestine?

Monosaccharides Signup and view all the answers

Which structural modification contains brush border enzymes that complete the digestion of carbohydrates and proteins?

Microvilli Signup and view all the answers

Which enzyme is involved in the breakdown of sucrose in the small intestine?

Sucrase Signup and view all the answers

Which enzyme continues the digestion of carbohydrates in the small intestine and has an optimal pH of ~7?

Pancreatic amylase Signup and view all the answers

Which neurons send messages to the myenteric plexus?

Cholinergic sensory neurons Signup and view all the answers

What is the result of impulses being sent distally in the enteric nervous system?

Distension of the intestine and contraction of the longitudinal muscle layer Signup and view all the answers

Which of the following is NOT a function of the colon?

Digestion of proteins Signup and view all the answers

What types of contractions allow absorption through the large intestine’s epithelium?

Slow, segmenting contractions Signup and view all the answers

What facilitates mass movements in the colon?

Gastrocolic and duodenocolic reflexes Signup and view all the answers

Which contraction type forms haustrations in the colon?

Combined contractions of the longitudinal and circular muscles Signup and view all the answers

Which reflex initiates the defecation process?

Spinal cord-mediated defecation reflex Signup and view all the answers

What is the only secretion of the esophagus?

Mucus Signup and view all the answers