On the epithelial surface of most of the gastrointestinal tract, the billions of single-cell mucous glands are called:

A. Chief cells
B. Paneth cells
C. Goblet cells
D. Parietal cells

C. Goblet cells

In the small intestine, epithelial pits formed by invagination are known as:

A. Gastric rugae
B. Crypts of Lieberkühn
C. Peyer patches
D. Plicae circulares

B. Crypts of Lieberkühn

Large numbers of deep tubular glands are especially found in the:

A. Esophagus and ileum
B. Colon and rectum
C. Jejunum and ileum
D. Stomach and upper duodenum

D. Stomach and upper duodenum

The presence of food in one GI segment usually causes glands of that region and nearby regions to secrete:

A. Minimal acidic fluid
B. Moderate to large juices
C. Only alkaline mucus
D. Highly concentrated enzymes

B. Moderate to large juices

Which local stimulus can activate the enteric nervous system to promote glandular secretion?

A. Tactile stimulation
B. Hypoxemia
C. Systemic fever
D. Portal congestion

A. Tactile stimulation

Which local factor is specifically listed as a trigger of enteric reflex secretion?

A. Hypoglycemia
B. Gut wall distention
C. Hypercapnia
D. Venous stasis

B. Gut wall distention

Which of the following is another listed epithelial stimulus for local glandular activation?

A. Chemical irritation
B. Protein malnutrition
C. Dehydration
D. Bile obstruction

A. Chemical irritation

The nutrient material used to form glandular secretions first enters which part of the secretory cell?

A. Apical membrane
B. Nuclear envelope
C. Cell base
D. Tight junction

C. Cell base

Nutrient material for secretion reaches glandular cells directly from blood in the:

A. Lacteals
B. Capillaries
C. Venules
D. Lymph nodes

B. Capillaries

Many mitochondria are concentrated near the base of glandular cells primarily to generate:

A. NADPH
B. cAMP
C. GTP
D. ATP

D. ATP

The organic secretory substances are synthesized primarily in the:

A. Lysosome
B. Peroxisome
C. Endoplasmic reticulum
D. Plasma membrane

C. Endoplasmic reticulum

ATP and nutrient-derived substrates are used for synthesis in the endoplasmic reticulum and:

A. Golgi complex
B. Nucleolus
C. Centrosome
D. Mitochondrial matrix

A. Golgi complex

In the Golgi complex, secretory materials are modified, concentrated, and packaged into:

A. Ribosomal subunits
B. Secretory vesicles
C. Secondary lysosomes
D. Endocytic vacuoles

B. Secretory vesicles

Before release, secretory vesicles are stored in which region of the cell?

A. Basal cytoplasm
B. Around nucleus
C. Lateral borders
D. Apical end

D. Apical end

Nervous or hormonal signals cause glandular cells to release stored vesicle contents by:

A. Pinocytosis
B. Transcytosis
C. Exocytosis
D. Osmosis

C. Exocytosis

Mucus is composed mainly of water, electrolytes, and:

A. Bile pigments
B. Glycoproteins
C. Phospholipids
D. Steroid hormones

B. Glycoproteins

The ability of mucus to coat surfaces effectively depends in part on its tendency to adhere:

A. Loosely to epithelium
B. Tightly to particles
C. Only to bacteria
D. Only to lipids

B. Tightly to particles

Which physical property of mucus most directly allows luminal particles to slide easily along epithelium?

A. High surface tension
B. Low slippage resistance
C. High osmotic pressure
D. Low bicarbonate content

B. Low slippage resistance

In the colon, mucus most directly helps bowel movements by causing fecal particles to:

A. Dissolve into chyme
B. Repel one another
C. Adhere to one another
D. Undergo fermentation

C. Adhere to one another

A patient with impaired mucus quality develops increased luminal enzyme injury. Which normal mucus property is most protective here?

A. Strong enzyme resistance
B. High protein absorption
C. Acid generation
D. Rapid emulsification

A. Strong enzyme resistance

Mucus commonly contains which ion that helps neutralize acids?

A. Chloride
B. Potassium
C. Bicarbonate
D. Phosphate

C. Bicarbonate

Which set correctly lists the four principal salivary glands named in this material?

A. Parotid, buccal, pyloric, Brunner
B. Sublingual, gastric, buccal, cecal
C. Parotid, submandibular, sublingual, buccal
D. Parotid, hepatic, buccal, pancreatic

C. Parotid, submandibular, sublingual, buccal

Saliva contains a serous secretion with which starch-digesting enzyme?

A. Pepsin
B. Ptyalin
C. Trypsin
D. Maltase

B. Ptyalin

Ptyalin is best classified as a:

A. Lipase
B. Protease
C. α-amylase
D. Nuclease

C. α-amylase

The mucus component of saliva contains which substance primarily responsible for lubrication and protection?

A. Elastin
B. Mucin
C. Actin
D. Keratin

B. Mucin

Which salivary gland secretes almost entirely a serous product?

A. Sublingual
B. Buccal
C. Submandibular
D. Parotid

D. Parotid

remember serous is enzyme-rich, watery. mucus is protein-rich, thick

Which glands secrete both serous secretion and mucus?

A. Parotid and buccal
B. Submandibular and sublingual
C. Parotid and sublingual
D. Buccal and parotid

B. Submandibular and sublingual

A biopsy from a GI secretory cell shows intense protein synthesis followed by packaging and concentration of product before release. Which organelle pair is most responsible?

A. Nucleus and lysosome
B. ER and Golgi
C. Mitochondria and peroxisome
D. Cytosol and centrosome

B. ER and Golgi

A local meal-induced reflex increases secretion in a GI segment and nearby regions. This response is most directly attributed to activation of the:

A. Sympathetic chain
B. Enteric nervous system
C. Vagus nerve
D. Adrenal medulla

B. Enteric nervous system

A protective surface secretion forms a thin film over food and mucosa while resisting enzymatic digestion. Which secretion is being described?

A. Bile
B. Saliva
C. Mucus
D. Pancreatic juice

C. Mucus

Which salivary glands secrete only mucus?

A. Parotid glands
B. Buccal glands
C. Submandibular glands
D. Sublingual glands

B. Buccal glands

The salivary secretion process is best described as a two-stage operation involving:

A. Acini, then salivary ducts
B. Ducts, then acini
C. Acini, then crypts
D. Ducts, then alveoli

A. Acini, then salivary ducts

Salivary flow helps protect the oral cavity primarily by washing away pathogenic:

A. Fungi
B. Protozoa
C. Viruses
D. Bacteria

D. Bacteria

Besides microorganisms, saliva also helps remove which material that supports bacterial metabolism?

A. Bile salts
B. Food particles
C. Desquamated enamel
D. Pancreatic enzymes

B. Food particles

Saliva often contains significant amounts of which protective factor that can destroy oral bacteria?

A. Histamine
B. Pepsin
C. Antibodies
D. Gastrin

C. Antibodies

In the absence of salivation, oral tissues most commonly become:

A. Hyperkeratotic and painless
B. Ulcerated and infected
C. Calcified and pale
D. Hemorrhagic and fibrotic

B. Ulcerated and infected

Salivary glands are controlled mainly by which division of the autonomic nervous system?

A. Sympathetic
B. Parasympathetic
C. Enteric
D. Somatic

B. Parasympathetic

The main central origins of salivary parasympathetic output are the superior and inferior salivatory nuclei in the:

A. Midbrain
B. Cerebral cortex
C. Brain stem
D. Hypothalamus

C. Brain stem

The salivatory nuclei are located near the junction of the:

A. Midbrain and thalamus
B. Medulla and pons
C. Pons and midbrain
D. Medulla and spinal cord

B. Medulla and pons

Which stimulus can excite the salivatory nuclei?

A. Taste from tongue
B. Retinal light input
C. Auditory input
D. Muscle stretch reflexes

A. Taste from tongue

Which additional stimulus can excite the salivatory nuclei?

A. Tactile oral stimulation
B. Elevated serum calcium
C. Cold skin exposure
D. Visual food cues only

A. Tactile oral stimulation

Tactile stimuli reaching the salivatory nuclei arise from the tongue and other areas of the mouth and:

A. Esophagus
B. Larynx
C. Pharynx
D. Trachea

C. Pharynx

Salivation directly causes what vascular response in salivary glands?

A. Venous constriction
B. Arteriolar dilation
C. Capillary collapse
D. Lymphatic spasm

B. Arteriolar dilation

The vascular effect of salivation primarily serves to increase gland:

A. Fibrosis
B. Innervation
C. Nutrition
D. Drainage

C. Nutrition

The stomach mucosa contains two important types of tubular glands called:

A. Brunner and Lieberkühn
B. Oxyntic and pyloric
C. Parotid and pyloric
D. Mucous and acinar

B. Oxyntic and pyloric

Oxyntic glands are also known as:

A. Salivary glands
B. Gastric glands
C. Brunner glands
D. Duodenal glands

B. Gastric glands

Which secretion is produced by oxyntic glands?

A. Bile
B. Trypsin
C. Hydrochloric acid
D. Secretin

C. Hydrochloric acid

Oxyntic glands also secrete which zymogen?

A. Pepsin
B. Pepsinogen
C. Trypsinogen
D. Proelastase

B. Pepsinogen

Which additional product is secreted by oxyntic glands?

A. Intrinsic factor
B. Cholecystokinin
C. Bicarbonate only
D. Enteropeptidase

A. Intrinsic factor

Oxyntic glands also secrete:

A. Mucus
B. Bile salts
C. Lipase
D. Gastrin

A. Mucus

Pyloric glands secrete mainly which substance?

A. Acid
B. Mucus
C. Pepsinogen
D. Histamine

B. Mucus

The hormone secreted by pyloric glands is:

A. Secretin
B. Somatostatin
C. Gastrin
D. Histamine

C. Gastrin

The mucus from pyloric glands mainly protects the pyloric mucosa from:

A. Bile reflux
B. Stomach acid
C. Pancreatic enzymes
D. Bacterial toxins

B. Stomach acid

Oxyntic glands are located primarily in the:

A. Cardia and pylorus
B. Body and fundus
C. Antrum and pylorus
D. Jejunum and ileum

B. Body and fundus

Pyloric glands are located mainly in the:

A. Fundus
B. Body
C. Antral region
D. Cardia

C. Antral region

Which cell type in oxyntic glands secretes mainly mucus?

A. Parietal cells
B. Mucous neck cells
C. Chief cells
D. ECL cells

B. Mucous neck cells

Peptic cells are also called:

A. Enterochromaffin cells
B. Chief cells
C. Mucous cells
D. Oxyntic cells

B. Chief cells

Peptic cells secrete large quantities of:

A. Pepsin
B. Pepsinogen
C. Gastrin
D. Histamine

B. Pepsinogen

Parietal cells are also called:

A. Chief cells
B. Mucous cells
C. Oxyntic cells
D. Enteric cells

C. Oxyntic cells

Parietal cells secrete hydrochloric acid and:

A. Gastrin
B. Histamine
C. Mucin
D. Intrinsic factor

B. Histamine

The main driving force for hydrochloric acid secretion by parietal cells is the:

A. Sodium-calcium exchanger
B. Hydrogen-potassium pump
C. Chloride-bicarbonate exchanger
D. Sodium-potassium pump

B. Hydrogen-potassium pump

A major component of the gastric barrier that limits acid backleak is:

A. Acidic mucus
B. Alkaline mucus
C. Histamine film
D. Pepsin layer

B. Alkaline mucus

Another key component preventing gastric acid backleak is:

A. Gap junctions
B. Desmosomes
C. Tight junctions
D. Hemidesmosomes

C. Tight junctions

Parasympathetic acetylcholine stimulates peptic cells to secrete:

A. Histamine
B. Pepsinogen
C. Gastrin
D. Bicarbonate

B. Pepsinogen

Parasympathetic acetylcholine stimulates parietal cells to secrete:

A. Hydrochloric acid
B. Pepsinogen
C. Gastrin
D. Mucin

A. Hydrochloric acid

Parasympathetic acetylcholine stimulates mucous cells to secrete:

A. Histamine
B. Intrinsic factor
C. Mucus
D. Gastrin

C. Mucus

Which two mediators strongly stimulate parietal cell acid secretion?

A. Gastrin and histamine
B. Secretin and CCK
C. Acetylcholine and somatostatin
D. Pepsin and gastrin

A. Gastrin and histamine

Pepsinogen is converted to active pepsin after contact with:

A. Gastrin
B. Histamine
C. Hydrochloric acid
D. Intrinsic factor

C. Hydrochloric acid

Parietal cells closely associate with which neighboring cell type?

A. Goblet cells
B. Enterochromaffin-like cells
C. Paneth cells
D. Chief cells

B. ECL cells

The primary function of Enterochromaffin-like cells is secretion of:

A. Gastrin
B. Pepsinogen
C. Histamine
D. Somatostatin

C. Histamine

A patient has impaired pepsinogen release from peptic cells despite normal gastric acidity. Loss of which signal would most directly explain this finding?

A. Secretin
B. Acetylcholine
C. Histamine
D. Gastrin

B. Acetylcholine

Pepsinogen secretion by peptic cells is stimulated by acetylcholine and by:

A. Acid in stomach
B. Fat in duodenum
C. Alkaline mucus
D. Bile in jejunum

A. Acid in stomach

Which sequence correctly lists the phases of gastric secretion?

A. Gastric, cephalic, intestinal
B. Cephalic, gastric, intestinal
C. Intestinal, cephalic, gastric
D. Cephalic, intestinal, gastric

B. Cephalic, gastric, intestinal

A diner begins salivating and secreting gastric juice while chewing, before any swallowed food arrives. This is the:

A. Intestinal phase
B. Gastric phase
C. Cephalic phase
D. Interdigestive phase

C. Cephalic phase

The cephalic phase occurs before food enters the:

A. Duodenum
B. Stomach
C. Jejunum
D. Colon

B. Stomach

A physiology lab infuses a meal directly into the stomach. Which phase of gastric secretion is now dominant?

A. Intestinal
B. Cephalic
C. Basal
D. Gastric

D. Gastric

The gastric phase is initiated when what enters the stomach?

A. Bile
B. Acid
C. Food
D. Enzymes

C. Food

Food entering the upper small intestine, especially the duodenum, triggers which phase of gastric secretion?

A. Gastric
B. Cephalic
C. Intestinal
D. Fasting

C. Intestinal

The intestinal phase is associated especially with food in the:

A. Ileum
B. Duodenum
C. Cecum
D. Esophagus

B. Duodenum

Trypsin and chymotrypsin digest proteins mainly into:

A. Monosaccharides
B. Free fatty acids
C. Individual amino acids
D. Peptides

D. Peptides

Which statement best describes the action of trypsin and chymotrypsin?

A. Release all free amino acids
B. Form peptides of varying sizes
C. Hydrolyze only dipeptides
D. Split triglycerides completely

B. Form peptides of varying sizes

Which enzyme can split some peptides into individual amino acids?

A. Elastase
B. Enterokinase
C. Carboxypolypeptidase
D. Pepsin

C. Carboxypolypeptidase

A patient lacks the enzyme that activates trypsinogen at the intestinal surface after chyme contacts mucosa. Which enzyme is deficient?

A. Carboxypolypeptidase
B. Enterokinase
C. Chymotrypsin
D. Secretin

B. Enterokinase

Enterokinase is secreted by the:

A. Intestinal mucosa
B. Gastric mucosa
C. Pancreatic acini
D. Hepatic canaliculi

A. Intestinal mucosa

Enterokinase release occurs when chyme comes into contact with the:

A. Hepatic duct
B. Pancreatic duct
C. Intestinal mucosa
D. Gastric antrum

C. Intestinal mucosa

Which set contains the three major stimuli for pancreatic secretion?

A. Histamine, gastrin, pepsin
B. Acetylcholine, CCK, secretin
C. Motilin, gastrin, bile
D. Somatostatin, CCK, pepsin

B. Acetylcholine, CCK, secretin

Which pancreatic stimulus is released from parasympathetic vagal endings?

A. Cholecystokinin
B. Secretin
C. Acetylcholine
D. Gastrin

C. Acetylcholine

Cholecystokinin is secreted by the mucosa of the:

A. Colon and rectum
B. Duodenum and upper jejunum
C. Stomach and pylorus
D. Ileum and cecum

B. Duodenum and upper jejunum

Secretin is secreted by the mucosa of the:

A. Duodenum and jejunum
B. Esophagus and stomach
C. Ileum and colon
D. Fundus and antrum

A. Duodenum and jejunum

Highly acidic food entering the small intestine most directly stimulates release of:

A. Gastrin
B. Histamine
C. Secretin
D. Motilin

C. Secretin

Acetylcholine and CCK act primarily on which pancreatic cells?

A. Acinar cells
B. Kupffer cells
C. Ductal cells
D. Stellate cells

A. Acinar cells

Stimulation of pancreatic acinar cells by acetylcholine and CCK leads to secretion of large quantities of:

A. Bicarbonate-rich water
B. Digestive enzymes
C. Intrinsic factor
D. Acidic mucus

B. Digestive enzymes

Secretin primarily stimulates which pancreatic tissue?

A. Islet tissue
B. Acinar epithelium
C. Ductal epithelium
D. Stromal tissue

C. Ductal epithelium

Secretin causes secretion of a pancreatic fluid with high bicarbonate and low:

A. Potassium
B. Sodium
C. Calcium
D. Chloride

D. Chloride

Secretin is released from which cells?

A. I cells
B. S cells
C. G cells
D. D cells

B. S cells

Release of CCK from I cells is promoted by proteoses, peptones, and:

A. Short-chain acids
B. Medium-chain acids
C. Long-chain fatty acids
D. Branched-chain amino acids

C. Long-chain fatty acids

Bile serves as an excretory route for bilirubin and:

A. Glucose
B. Cholesterol
C. Urea
D. Lactate

B. Cholesterol

The initial portion of bile is secreted by the:

A. Cholangiocytes
B. Hepatocytes
C. Kupffer cells
D. Stellate cells

B. Hepatocytes

After secretion from hepatocytes, bile first flows in the:

A. Canaliculi
B. Central veins
C. Lacteals
D. Sinusoids

A. Canaliculi

Bile in canaliculi flows toward the:

A. Portal vein
B. Interlobular septa
C. Central lobule
D. Gallbladder fundus

B. Interlobular septa

Canaliculi empty into terminal bile ducts, which then drain into the hepatic duct and:

A. Pancreatic duct
B. Cystic duct
C. Common bile duct
D. Thoracic duct

C. Common bile duct

Most gallbladder absorption is driven primarily by active transport of:

A. Chloride
B. Bicarbonate
C. Potassium
D. Sodium

D. Sodium

A patient undergoes vagotomy. Which pancreatic stimulus is most directly reduced?

A. Secretin
B. Acetylcholine
C. Cholecystokinin
D. Enterokinase

B. Acetylcholine

A meal rich in partially digested protein and long-chain fatty acids enters the small intestine. Which hormone rises most directly?

A. CCK
B. Motilin
C. Secretin
D. Gastrin

A. CCK

The most abundant solutes secreted in bile are:

A. Bile salts
B. Cholesterol esters
C. Phospholipids
D. Bilirubin conjugates

A. Bile salts

Effective gallbladder emptying requires gallbladder contraction plus simultaneous relaxation of the:

A. Ileocecal valve
B. Pyloric sphincter
C. Lower esophageal sphincter
D. Sphincter of Oddi

D. Sphincter of Oddi

The most potent stimulus for gallbladder contraction is:

A. Secretin
B. Gastrin
C. Acetylcholine
D. CCK

D. CCK

Small quantities of bile salts lost in feces are replaced continuously by the liver in a process referred to here as:

A. Biliary diversion
B. Enterohepatic circulation
C. Cholestatic recycling
D. Portal recirculation

B. Enterohepatic circulation

Brunner’s glands are best described as:

A. Compound mucous glands
B. Serous acinar glands
C. Endocrine gastric glands
D. Pancreatic duct glands

A. Compound mucous glands

Brunner’s glands are located primarily in the wall of the:

A. Distal ileum
B. Gastric antrum
C. First duodenal centimeters
D. Ascending colon

C. First duodenal centimeters

Brunner’s glands are inhibited by:

A. Parasympathetic activity
B. Sympathetic stimulation
C. CCK release
D. Vagal efferents

B. Sympathetic stimulation

In a highly anxious patient, persistent inhibition of Brunner’s glands would most directly predispose to:

A. Jejunal volvulus
B. Duodenal bulb ulcers
C. Ileal strictures
D. Colonic polyps

B. Duodenal bulb ulcers

Crypts of Lieberkühn in the small intestine are:

A. Deep gastric tubules
B. Mucosal venous lakes
C. Small epithelial pits
D. Lymphoid nodules

C. Small epithelial pits

In the small intestine, crypts of Lieberkühn are located over:

A. Only proximal duodenum
B. Only terminal ileum
C. Peyer patch surfaces
D. Entire small-intestinal surface

D. Entire small-intestinal surface

The surfaces of both crypts and villi are covered by epithelium containing goblet cells and:

A. Paneth cells
B. Chief cells
C. Enterocytes
D. Parietal cells

C. Enterocytes

Intestinal goblet cells primarily secrete:

A. Pepsinogen
B. Mucus
C. Bicarbonate
D. Histamine

B. Mucus

The main function of goblet-cell secretion in the small intestine is to:

A. Acidify luminal contents
B. Activate pancreatic enzymes
C. Lubricate and protect
D. Absorb amino acids

C. Lubricate and protect

Enterocytes in the small intestine secrete large quantities of:

A. Water
B. Mucin
C. Pepsin
D. Bile salts

A. Water

Enterocytes also reabsorb water, electrolytes, and:

A. Bacterial toxins
B. Gastric acid
C. Intrinsic factor
D. Digestive end products

D. Digestive end products

Cells deep in the crypts of Lieberkühn continually undergo:

A. Meiosis
B. Apoptosis
C. Mitosis
D. Endocytosis

C. Mitosis

The ongoing cell division in deep crypt cells helps replace the:

A. Muscularis externa
B. Villus epithelium
C. Submucosal plexus
D. Serosal mesothelium

B. Villus epithelium

Deep crypt epithelial cells also contribute to formation of new:

A. Bile acids
B. Tight junctions
C. Hormones
D. Digestive enzymes

D. Digestive enzymes

The large-intestinal mucosa contains many crypts of Lieberkühn but lacks:

A. Goblet cells
B. Muscularis mucosae
C. Villi
D. Mucus glands

C. Villi

Colonic mucus protects the intestinal wall from intense:

A. Acid secretion
B. Bacterial activity
C. Enzyme release
D. Bile precipitation

B. Bacterial activity

The barrier protecting the colonic wall from fecal acids is formed by mucus plus the:

A. Osmolarity of chyme
B. Viscosity of bile
C. Motility of haustra
D. Alkalinity of secretion

D. Alkalinity of secretion

Mucus and alkaline secretion in the colon prevent fecal acids from:

A. Entering the portal vein
B. Activating pancreatic juice
C. Attacking the intestinal wall
D. Digesting dietary starch

C. Attacking the intestinal wall

During bacterial enteritis, an irritated colonic segment secretes extra:

A. Water and electrolytes
B. Mucus and bile salts
C. Pepsin and acid
D. Protein and glucose

A. Water and electrolytes

In enteritis, the diarrhea described is beneficial mainly because it:

A. Increases bile recycling
B. Washes away irritants
C. Suppresses villus mitosis
D. Concentrates fecal bicarbonate

B. Washes away irritants

Which finding best identifies large intestine?

A. Many villi, no crypts
B. Brunner glands present
C. Crypts without villi
D. Goblet cells absent

C. Crypts without villi

A pharmacologist gives a strong CCK antagonist before a fatty meal. Which response is most likely reduced?

A. Gallbladder contraction
B. Brunner inhibition
C. Crypt cell mitosis
D. Colonic mucus release

A. Gallbladder contraction