Chapter 21

12 September 2022
4.7 (114 reviews)
25 test answers

Unlock all answers in this set

Unlock answers (21)
question
Chemical digestion of food begins in the ________.
answer
Mouth
question
What is the first area that food contacts as it moves from the stomach to the small intestines?
answer
Duodenum
question
What is the "migrating motor complex"?
answer
A pattern of slow contractions sweeping along the GI tract
question
GI contractions that are sustained for minutes or hours are called ________ contractions.
answer
Tonic
question
Which type of contraction pattern allows the small intestines to churn and mix a food bolus?
answer
Segmental
question
What is the function of the interstitial cells of Cajal?
answer
They are the origin of slow waves
question
What happens to the OH- group that results from the hydrolysis of water to create H+ for HCl secretion by parietal cells?
answer
It is converted to bicarbonate and shuttled out of the parietal cell by a HCO3-/Cl- exchanger.
question
Which hormone stimulates the release of insulin in response to glucose in the intestinal lumen?
answer
Gastric Inhibitory Peptide (GIP)
question
During which phase in the control of the digestive system would bicarbonate and bile be stimulated?
answer
Intestinal Phase. Food in the intestines initiates a reflex that stimulates secretions of bicarbonate, digestive enzymes, and bile.
question
Norepinephrine is the neurotransmitter released by which fibers?
answer
Sympathetic Postganglionic Fibers. Norepinephrine is the neurotransmitter of the sympathetic postganglionic fibers. An increase in the sympathetic system would decrease digestion.
question
Enteric interneurons that are inhibitory to smooth muscle use which of the following neurotransmitters?
answer
VIP (vasoactive intestinal peptide). Both VIP and NO (nitrous oxide) are inhibitory to smooth muscle.
question
Which of the following intestinal hormones stimulates bile from the gall bladder?
answer
CCK (cholecystokinin) CCK causes the gall bladder to contract, releasing bile and an enzyme-rich pancreatic juice to be secreted from the pancreas.
question
Which of the following GI hormones promotes a pancreatic juice rich in bicarbonate ions?
answer
Secretin Secretin (from S cells in the duodenum) causes both the liver and pancreas to secrete bicarbonate into the small intestine.
question
Merely anticipating that one is about to eat can trigger the ________ phase of digestion.
answer
Cephalic
question
In terms of chemical digestion of organic molecules, the stomach primarily digests ________.
answer
Proteins
question
What happens to the OH- group that results from the hydrolysis of water to create H+ for HCl secretion by parietal cells?
answer
It is converted to bicarbonate and shuttled out of the parietal cell by an HCO3-/Cl- exchanger.
question
Which vitamin must be complexed with intrinsic factor in order to be absorbed?
answer
B12
question
What is the role of bile?
answer
Increases the surface area of fats so that they are easier to digest.
question
Which of the following molecules can be found within the membrane or interior of a micelle?
answer
Monoglycerides, diglycerides, phospholipids, cholesterol, bile salts, and free fatty acids.
question
Given the chemical nature of free fatty acids and monoglycerides, how are these absorbed across the epithelial border of the small intestine?
answer
Simple diffusion
question
What is the order of fat digestion?
answer
1. Bile salts from liver coat fat droplets 2. Lipase and colipase break down fats 3. Digested fats are stored in micelles 4. Monoglycerides, free fatty acids, and cholesterol are absorbed along the enterocyte border 5. Chylomicron is formed and transported out of the enterocyte
question
Which of the following structures are found within the chylomicron?
answer
Triglycerides, protein, and cholesterol
question
Where do chylomicrons go after they are transported out of the enterocyte, and why do they go there?
answer
Lymphatic system, because they are too large to enter into the blood
question
Blood draining from the intestines flows directly to the ________.
answer
Liver for filtering
question
Why must the process of lipid digestion be different from proteins and carbohydrates?
answer
Lipids are hydrophobic