GI system

Question 1

Chemical digestion of food begins in the ________.

small intestine
mouth
stomach
large intestine

Answer 1

mouth

Question 2

What is the outer layer of the gut wall called?

serosa
muscularis externa
the myenteric plexus
submucosa

Answer 2

serosa

Question 3

What is the first area that food contacts as it moves from the stomach to the small intestines?

ileum
antrum
jejunum
duodenum

Answer 3

duodenum

Question 4

Which of the following is NOT considered to be one of the four basic functions of the digestive system?

matching fluid input with output
acid-base balance
repelling foreign invaders
decreasing the size of food molecules

Answer 4

acid-base balance

Question 5

GI contractions that are sustained for minutes or hours are called ________ contractions.

tonic
segmental
phasic
peristaltic

Answer 5

tonic

Question 6

Crypt cells in the small intestine and colon secrete ________ into the lumen.

a bicarbonate solution
an isotonic sodium chloride solution
digestive enzymes
mucus

Answer 6

an isotonic sodium chloride solution

Question 7

What happens to the OH- group that results from the hydrolysis of water to create H+ for HCl secretion by parietal cells?

It follows H+ into the stomach lumen because of the electrochemical gradient created by the H+/ K+ exchanger.

It remains in the parietal cell to maintain a high pH and keep pepsin inactivated. This protects the parietal cells from degradation by pepsin.

It is converted to bicarbonate and shuttled out of the parietal cell by a HCO3-/Cl- exchanger.

It is combined with another hydroxyl group to form molecular oxygen and two more H+ that can be shuttled into the lumen.

Answer 7

It is converted to bicarbonate and shuttled out of the parietal cell by a HCO3-/Cl- exchanger.

Question 8

What is the “migrating motor complex”?

a shift of smooth muscle cells from the circular to the oblique layer in the stomach

movement, or migration, of food from the mouth into the stomach

alternating patterns of electrical activity that stimulate the longitudinal and then the circular layer of smooth muscle throughout the GI tract

a pattern of slow contractions sweeping along the GI tract

Answer 8

a pattern of slow contractions sweeping along the GI tract

Question 9

Which type of contraction pattern allows the small intestines to churn and mix a food bolus?

migrating
mesenteric
segmental
peristalsis

Answer 9

segmental

Question 10

During which phase in the control of the digestive system would bicarbonate and bile be stimulated?

gastric phase
intestinal phase
cephalic phase

Answer 10

intestinal phase

Question 11

Norepinephrine is the neurotransmitter released by which fibers?

interneurons of the enteric nervous system
both sympathetic and parasympathetic preganglionic fibers
sympathetic postganglionic fibers
parasympathetic postganglionic fibers

Answer 11

sympathetic postganglionic fibers

Question 12

Enteric interneurons that are inhibitory to smooth muscle use which of the following neurotransmitters?

VIP (vasoactive intestinal peptide)
norepinephrine
ACh (acetylcholine)
substance P

Answer 12

VIP (vasoactive intestinal peptide)

Question 13

Which of the following intestinal hormones stimulates the release of bile from the gall bladder?

CCK (cholecystokinin)
GIP (gastric inhibitory peptide)
motilin
gastrin

Answer 13

CCK (cholecystokinin)

Question 14

Which of the following GI hormones promotes a pancreatic juice rich in bicarbonate ions?

GIP (gastric inhibitory peptide)
secretin
motilin
gastrin

Answer 14

secretin

Question 15

Which is NOT classified as a member of the secretin family of GI hormones?

vasoactive intestinal peptide (VIP)
glucagon-like peptide 1 (GLP-1)
gastric inhibitory peptide (GIP)
cholecystokinin (CCK)

Answer 15

cholecystokinin (CCK)

Question 16

Which hormone stimulates the release of insulin in response to glucose in the intestinal lumen?

gastric inhibitory peptide (GIP)
gastrin
cholecystokinin
motilin

Answer 16

gastric inhibitory peptide (GIP)

Question 17

Merely anticipating that one is about to eat can trigger the ________ phase of digestion.

intestinal
cephalic
deglutition
emesis

Answer 17

cephalic

Question 18

What is the role of bile?

provides the chemical digestion needed in order to break down triglycerides
enhances the effects of colipase and lipase
increases the surface area of fats so that they are easier to digest
allows fat droplets to reassemble as they enter from the stomach into the duodenum

Answer 18

increases the surface area of fats so that they are easier to digest

Question 19

Which of the following molecules can be found within the membrane or interior of a micelle?
Check all that apply.

bile salts
diglycerides
lipase
phospholipids
cholesterol
triglycerides
colipase
monoglycerides
free fatty acids
small fat droplets

Answer 19

bile salts
diglycerides
phospholipids
cholesterol
monoglycerides
free fatty acids

Question 20

Given the chemical nature of free fatty acids and monoglycerides, how are these absorbed across the epithelial border of the small intestine?

facilitated diffusion
simple diffusion
secondary active transport
endocytosis
primary active transport

Answer 20

simple diffusion

Question 21

Which of the following structures are found within the chylomicron?
Check all that apply.

monoglycerides
diglycerides
triglycerides
protein
cholesterol
free fatty acids

Answer 21

triglycerides
protein
cholesterol

Question 22

Where do chylomicrons go after they are transported out of the enterocyte, and why do they go there?

blood, because they must be used by the body for energy
adipocytes, because they need to be stored
lymphatic system, because they are too large to enter into the blood
liver, because they must be metabolized and packaged before entering into general circulation

Answer 22

lymphatic system, because they are too large to enter into the blood

Question 23

In terms of chemical digestion of organic molecules, the stomach primarily digests ________ .

nucleic acids
carbohydrates
proteins
fats

Answer 23

proteins

Question 24

What must be present in the intestinal lumen to activate pancreatic zymogens?

trypsin
secretin
fats and proteins
acidic pH

Answer 24

trypsin

Question 25

What happens to the OH– group that results from the hydrolysis of water to create H+ for HCl secretion by parietal cells? It is combined with another hydroxyl group to form molecular oxygen and two more H+ that can be shuttled into the lumen. It follows H+ into the stomach lumen because of the electrochemical gradient created by the H+/ K+ exchanger. It remains in the parietal cell to maintain a high pH and keep pepsin inactivated. This protects the parietal cells from degradation by pepsin. It is converted to bicarbonate and shuttled out of the parietal cell by an HCO3–/Cl– exchanger.

Answer 25

It is converted to bicarbonate and shuttled out of the parietal cell by an HCO3–/Cl– exchanger.

Question 26

Which vitamin must be complexed with intrinsic factor in order to be absorbed? B6 B12 C D

Answer 26

B12

Question 27

Salivation is controlled almost entirely by the nervous system. Which of the following stimuli would inhibit salivation? fear a lemon the thought of food nausea

Answer 27

fear

Question 28

HCl secretions convert pepsinogen to the active hormone pepsin. What cells in the gastric pits produce pepsinogen? paracrine (also known as enteroendocrine cells) chief G cells parietal

Answer 28

chief

Question 29

In response to a steak dinner, certain secretions are needed to aid digestion. What cells in the pancreas would provide these secretions? acinar cells islet of Langerhans cells duct cells

Answer 29

acinar cells

Question 30

An increase in HCl (hydrochloric acid) arriving in the duodenum would stimulate which hormone that would help to counteract the effects of HCl? gastrin secretin GIP (gastric inhibitory peptide) CCK (cholecystokinin)

Answer 30

secretin

Question 31

The secretion in the large intestine consists of which of the following? bile bicarbonate- and potassium-rich mucus intrinsic factor digestive enzymes such as CCK and secretin

Answer 31

bicarbonate- and potassium-rich mucus

Question 32

Blood draining from the intestines flows directly to the ________. heart chambers for rapid systemic re-circulation liver for filtering kidneys for filtering venous circulation for return to the heart

Answer 32

liver for filtering

Question 33

Why must the process of lipid digestion be different from proteins and carbohydrates? The lipids include the largest molecules in the body. Many hormones are lipids and require special handling to avoid side effects. Lipids are hydrophobic. Lipid molecules contain charges that repel most enzymes.

Answer 33

Lipids are hydrophobic.

Question 34

Which is the best example of a short reflex? cephalic phase insulin release (CPIR), which occurs when the taste of sweet foods initiates the release of insulin from beta cells in the pancreas ghrelin, released by the stomach, causing feelings of hunger cholecystokinin, released by the duodenum, stimulates the contraction of the gall bladder and feelings of satiety the gastrocolic reflex, which occurs when stretch in the stomach causes increased motility in the large intestine

Answer 34

the gastrocolic reflex, which occurs when stretch in the stomach causes increased motility in the large intestine

Question 35

Which enzyme is responsible for producing bicarbonate in pancreatic acini and in duodenal cells? Hint: It is the same enzyme that is active in erythrocytes. carbonic anhydrase angiotensin converting enzyme (ACE) amylase Na+/K+-ATPase

Answer 35

carbonic anhydrase

Question 36

The process of carbohydrate digestion begins when the complex carbohydrate starch is broken down into maltose. Which enzyme breaks these down into monomers and where are they found? pancreatic amylase released by the pancreas carbohydrases located throughout the intestines GLUT2 located on the basolateral surface disaccharidases located at the intestinal brush border

Answer 36

disaccharidases located at the intestinal brush border

Question 37

Which of the following structures do triglycerides, cholesterol, and proteins form inside enterocytes that allow them to be carried in lacteals? chylomicrons emulsions bolus micelles

Answer 37

chylomicrons