89 Questions
What effect does increased acid secretion have on further gastrin secretion?
Inhibits further gastrin secretion
What is the primary route for the body to dispose of cholesterol?
Through bile
Besides I cells in the mucosa of the upper small intestine, where else is Cholecystokinin (CCK) found?
In nerves in the distal ileum and colon
Which component is responsible for the golden yellow color of bile?
Biliverdin
What is NOT an action of Cholecystokinin (CCK) as described in the text?
Promoting relaxation of the esophageal sphincter
What is the primary difference in secretion between the three glands mentioned in the text?
Proportion of serous and mucous acinar cells
What is the primary function of bile acids in digestion?
Aiding in fat digestion
How does saliva help neutralize any gastric secretions that reflux into the esophagus?
By being alkaline
What triggers increased secretion of Cholecystokinin (CCK) according to the text?
Contact with peptides and amino acids
Which modality is NOT involved in gastrointestinal regulation discussed in the text?
Exocrine regulation
Which branch of the autonomic nervous system plays the most significant role in controlling salivary secretion?
Parasympathetic
Which part of the body, besides the intestinal mucosa, secretes Cholecystokinin (CCK)?
Nerves in the brain
How much bile is secreted per day on average?
500 mL
What is the primary function of saliva mentioned in the text?
Facilitating movements of lips and tongue
What happens to some components of bile after being reabsorbed in the intestine?
They are excreted by the liver again
When does the gastric phase of secretion occur?
During food storage in the stomach
What influences the cephalic phase of gastric secretion according to the text?
Food preferences
What stimulates the secretion of gastric inhibitory peptide (GIP)?
Glucose and fat in the duodenum
What is the main effect of GIP when administered at blood levels similar to those produced by oral glucose?
Stimulates insulin secretion
Where is somatostatin primarily secreted from?
Pancreatic islets
What is the main function of somatostatin in inhibiting hormone secretion?
Inhibits the secretion of gastrin, VIP, GIP, secretin, and motilin
What does motilin act on in the gastrointestinal system?
G-protein-coupled receptors on enteric neurons in the duodenum and colon
What is the main effect of motilin in the gastrointestinal system between meals?
Stimulation of smooth muscle contraction in the stomach and intestines
What is the role of ghrelin in the gastrointestinal system?
Stimulates growth hormone secretion
Where is Substance P found and what is its effect in the gastrointestinal tract?
Found in the gastrointestinal tract; increases small intestine motility
Which nervous system is sometimes referred to as the 'little brain' due to its role in regulating gastrointestinal function?
Enteric Nervous System
What is the unique characteristic of the myenteric plexus concerning motor control?
Innervates longitudinal and circular smooth muscle layers
Which statement accurately describes the relationship of the Enteric Nervous System with the CNS?
Can function autonomously without CNS connections
What is the primary role of ghrelin in relation to growth hormone secretion?
Stimulates growth hormone secretion
What is the primary function of saliva as mentioned in the text?
Neutralizing acidic gastric secretions
Which nervous system branch plays the most prominent role in controlling salivary secretion?
Parasympathetic
What is the primary effect of the cephalic phase on gastric secretion?
Prepares the stomach to receive food
Which gland contributes a significant volume of digestive juices to a meal?
Stomach
What is the main role of salivary acinar cells in determining saliva composition?
Controlling the proportion of proteinaceous and mucinous components in saliva
What is the main function of saliva in relation to taste buds?
Acts as a solvent for taste molecules
What is the primary purpose of mucus secretion in the stomach according to the text?
To protect the stomach lining from self-digestion
Which cells in the stomach are responsible for secreting hydrochloric acid?
Parietal cells
What is the main function of intrinsic factor in the digestion process?
Aids in vitamin B12 absorption
Which hormone is released by G cells in response to a specific neurotransmitter from enteric nerve endings?
Gastrin
What is the precursor of pepsin, the enzyme that initiates protein digestion?
Pepsinogen
Which component is important for beginning the digestion of dietary fats in the stomach?
Gastric lipase
What is the principal physiologic action of Gastrin as described in the text?
Stimulation of the growth of the mucosa of the stomach and intestines
What directly inhibits Gastrin secretion by acting partly on G cells as per the text?
Acid in the antrum
What is the basis of the negative feedback loop regulating Gastrin secretion according to the text?
Release of somatostatin
What is the effect of acid in the antrum on Gastrin secretion?
Inhibition
What affects Gastrin secretion by acting directly on G cells?
Protein digestion products in the stomach
What is the primary function of bile acids in digestion?
To aid in the breakdown and absorption of fats
Where are G cells, responsible for producing Gastrin, primarily located?
Antral portion of the gastric mucosa
In bile, what component is responsible for the golden yellow color?
Glucuronides of bile pigments
What triggers endocrine regulation in gastrointestinal function?
The release of hormones by meal-associated triggers
What is the main route through which the body disposes of cholesterol?
Conversion to bile acids
What happens to some components of bile after being reabsorbed in the intestine?
They are excreted by the liver
Which component of bile represents the most important aspect when considering it as a digestive secretion?
Bile acids
What effect does ghrelin have on growth hormone secretion?
Stimulates growth hormone secretion by the pituitary gland
How is the Enteric Nervous System connected to the central nervous system?
Through sympathetic and parasympathetic fibers
What is the primary function of Substance P in the gastrointestinal tract?
Increases the motility of the small intestine
Which component does somatostatin primarily inhibit the secretion of?
Insulin
In what part of the gastrointestinal tract does Ghrelin play a crucial role?
Stomach
What is the main function of the myenteric plexus in the gastrointestinal tract?
Control of smooth muscle layers
What is the primary role of intrinsic factor mentioned in the text?
Aids in the absorption of vitamin B12
What is the main function of gastrin as discussed in the text?
Stimulates G cells in the stomach
Which of the following is a primary stimulus of gastric secretion based on the text?
Histamine
What is the primary function of pepsinogen in the digestive process as per the text?
Precursor of pepsin for protein digestion
'Intrinsic factor' is secreted by which type of cells in the stomach according to the text?
Parietal cells
What is the volume of gastric secretion added to intestinal contents per day as mentioned in the text?
~2.5 L/day
What is the primary function of bile acids in digestion according to the text?
Emulsify fats to aid in their digestion and absorption
Where are the three pairs of salivary glands located that produce saliva for food digestion?
Draining into the oral cavity
Which gastrointestinal hormone is responsible for stimulating acid secretion in the stomach?
Gastrin
What is the significant function of the myenteric plexus within the gastrointestinal tract?
Regulating movement of food through the GI tract
True or False: Saliva mainly serves as a protective barrier against stomach acid.
False
Which structure in the gastrointestinal system has a substantial surface area important for absorption?
Ileum
What is the main function of somatostatin in the gastrointestinal tract, as described in the text?
Inhibiting the release of gastrin
What is the primary role of intrinsic factor in the digestion process, according to the text?
Aiding in the absorption of vitamin B12
What triggers increased secretion of cholecystokinin (CCK) based on the text?
Presence of meal constituents
What is NOT an action of ghrelin as described in the text?
Stimulates pancreatic enzyme release
Which cells in the stomach are responsible for secreting hydrochloric acid, as mentioned in the text?
Parietal cells
What represents a key mechanism whereby gastric secretion is terminated after a meal moves from the stomach into the small intestine?
Release of somatostatin
What is the primary function of saliva mentioned in the text?
Keeps the mouth and teeth clean
Where does the cephalic phase of gastric secretion occur?
In the mouth before food enters the stomach
Which nervous system branch slightly modifies the composition of saliva?
Sympathetic branch
What is the primary role of the gastric phase of secretion?
Adding digestive juices to the meal
What is the most significant influencer of salivary secretion?
Parasympathetic branch of the autonomic nervous system
What does saliva do to facilitate speech?
Facilitates movements of lips and tongue
How are the digestive enzymes in pancreatic juice primarily activated?
Following proteolytic cleavage by trypsin
What is the main risk associated with the release of a small amount of trypsin into the pancreas?
Potential digestion of the pancreas by active enzymes
Why does the pancreas secrete a trypsin inhibitor?
To prevent self-digestion by trypsin
What is the primary control mechanism for the secretion of pancreatic juice?
Hormonal control
What is a critical function of bile in digestion?
To assist in the digestion and absorption of fats
How are zymogen granules containing digestive enzymes discharged into the lumens of pancreatic ducts?
By exocytosis from the apexes of the cells
Test your knowledge on the composition and functions of bile in the human body, including bile acids, pigments, and its role in disposing of cholesterol. Explore the process of bile secretion, reabsorption, and the enterohepatic circulation.
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