24 Questions
What is the primary function of the gastric phase of control?
To prepare the arrival of the meal
Which phase of control occurs simultaneously with the others after the meal begins?
Gastric phase
Where do inhibitory reflexes originate to slow gastric emptying?
Small intestine
What is released into the lumen of the GI tract during the intestinal phase of control?
Digestive enzymes and bicarbonate
What is the primary function of the cephalic phase of control?
To prepare the stomach for food arrival
During which phase of control is the meal in the small intestine?
Intestinal phase
What is the primary site of fat digestion and absorption?
Small intestine
What is released into the small intestine during the intestinal phase of control?
Pancreatic juice and bicarbonate
Which structural modification of the small intestine forces chyme to spiral slowly, allowing more time for nutrient absorption?
Circular folds
Which type of cells line the villi in the small intestine and are responsible for absorption?
Enterocytes
What enzymes are found in the microvilli that complete the digestion of carbohydrates?
Brush border enzymes
What is the primary form in which carbohydrates are absorbed in the small intestine?
Monosaccharides
Which enzyme breaks down lactose into its monosaccharide components?
Lactase
How are glucose and galactose primarily transported across the epithelial cells in the small intestine?
Secondary active transport
Which enzyme continues the digestion of carbohydrates in the duodenum of the small intestine?
Pancreatic amylase
By what mechanism are most nutrients absorbed in the small intestine?
Transepithelial transport
What is the primary breakdown product of triglyceride molecules during digestion?
One monoglyceride and two free fatty acids
Where does most digestion and absorption occur in the gastrointestinal tract?
Small intestine
Which enzyme is essential for the bulk of fat digestion?
Pancreatic lipase
What is the primary mechanism of water absorption in the small intestine?
Passive transport through osmosis
Why is the stomach a poor absorptive area of the GI tract?
It lacks villi and has tight junctions between epithelial cells
What type of substances can be absorbed in small quantities in the stomach?
Lipid-soluble substances
What is the primary function of pancreatic lipase in fat digestion?
Breaking down fats into fatty acids and glycerol
What is the primary mechanism of sodium transport in the small intestine?
Active transport through sodium-potassium pumps
This quiz covers the structural modifications that increase the absorptive surface in the small intestine, including circular folds and villi, and their role in nutrient absorption.
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