30 Questions
What happens to the ionization of polar molecules in the gastric lumen?
It alters
What is not dissolved by acid in the stomach?
Fat
What is the purpose of hydrochloric acid in the stomach?
To kill bacteria
What is the result of the digestive actions of the stomach?
A solution known as chyme
What is the diameter of the small intestine?
1.5 inches
Where do the final stages of digestion and most absorption occur?
Small intestine
What is the main function of micelles in the small intestine?
To provide a means of keeping most of the insoluble fat digestion products in small soluble aggregates
Which of the following is NOT a component of micelles?
Proteins
What happens to the contents of micelles when they break down?
They are released into the solution and become available to diffuse across the intestinal lining
What is the purpose of the polar ends of each molecule in micelles?
To orient towards the micelle's surface
What is the result of the continuous breakdown and reformation of micelles?
A constant supply of lipids available to diffuse into the intestinal epithelium
What is included in the core of the micelle, in addition to fatty acids and monoglycerides?
Small amounts of fat-soluble vitamins and cholesterol
What is the effect of secretin on pancreatic bicarbonate secretion?
It strongly stimulates pancreatic bicarbonate secretion
What is the result of the interaction between secretin and CCK?
CCK potentiates the effect of secretin on pancreatic bicarbonate secretion
What is the consequence of potentiation on the actions of gastrointestinal hormones?
Small changes in the plasma concentration of one hormone have a large effect on other hormones
What type of effects do gastrointestinal hormones have on various tissues?
Tropic (growth-promoting) effects
How many phases of gastrointestinal control are mentioned in the text?
Three phases
What is the location of the stimulus that determines the phase of gastrointestinal control?
The location of the stimulus
What stimulates the secretion of the salt solution by the bile ducts?
Secretin in response to the presence of acid in the duodenum
What controls the secretion of bile salts?
The concentration of bile salts in the blood
What happens to bile secretion during and just after a meal?
It increases
What is the function of the sphincter of Oddi?
To block bile from flowing into the duodenum
What happens to bile in the gallbladder?
It becomes more concentrated
What is the signal for gallbladder contraction and sphincter relaxation?
The intestinal hormone CCK
What is the process of inserting H,K-ATPases into the plasma membrane regulated by?
Four chemical messengers: gastrin, acetylcholine, histamine, and somatostatin
What is the effect of somatostatin on acid secretion?
It inhibits acid secretion
What is the role of histamine in stimulating acid secretion?
It markedly potentiates the response to other stimuli
What is the effect of the cephalic phase on acid secretion?
It increases acid secretion
What is released from the plexus neurons during the cephalic phase?
Acetylcholine
What is the result of blocking histamine receptors in the stomach?
Decreased acid secretion
Learn about the acid environment in the stomach, its effects on proteins and polysaccharides, and the role of enzymes like pepsin and amylase in digestion. Understand how the stomach breaks down food components.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
