76 Glossary: The Digestive System
absorption passage of digested products from the intestinal lumen through mucosal cells and into the bloodstream or lacteals
accessory digestive organ includes teeth, tongue, salivary glands, gallbladder, liver, and pancreas
accessory duct (also, duct of Santorini) duct that runs from the pancreas into the duodenum
acinus cluster of glandular epithelial cells in the pancreas that secretes pancreatic juice in the pancreas
alimentary canal continuous muscular digestive tube that extends from the mouth to the anus
anal canal final segment of the large intestine
anal column long fold of mucosa in the anal canal
anal sinus between anal columns
appendix (vermiform appendix) coiled tube attached to the cecum
ascending colon first region of the colon
bacterial flora bacteria in the large intestine
bile alkaline solution produced by the liver and important for the emulsification of lipids
bile canaliculus small duct between hepatocytes that collects bile
bilirubin main bile pigment, which is responsible for the brown color of feces
body mid-portion of the stomach
bolus mass of chewed food
brush border fuzzy appearance of the small intestinal mucosa created by microvilli
cardia (also, cardiac region) part of the stomach surrounding the cardiac orifice (esophageal hiatus)
cecum pouch forming the beginning of the large intestine
cementum bone-like tissue covering the root of a tooth
central vein vein that receives blood from hepatic sinusoids
cephalic phase (also, reflex phase) initial phase of gastric secretion that occurs before food enters the stomach
chemical digestion enzymatic breakdown of food
chief cell gastric gland cell that secretes pepsinogen
chyme soupy liquid created when food is mixed with digestive juices
circular fold (also, plica circulare) deep fold in the mucosa and submucosa of the small intestine
colon part of the large intestine between the cecum and the rectum
common bile duct structure formed by the union of the common hepatic duct and the gallbladder’s cystic duct
common hepatic duct duct formed by the merger of the two hepatic ducts
crown portion of tooth visible superior to the gum line
cuspid (also, canine) pointed tooth used for tearing and shredding food
cystic duct duct through which bile drains and enters the gallbladder
deciduous tooth one of 20 “baby teeth”
defecation elimination of undigested substances from the body in the form of feces
deglutition three-stage process of swallowing
dens tooth
dentin bone-like tissue immediately deep to the enamel of the crown or cementum of the root of a tooth
dentition set of teeth
descending colon part of the colon between the transverse colon and the sigmoid colon
duodenal gland (also, Brunner’s gland) mucous-secreting gland in the duodenal submucosa
duodenum first part of the small intestine, which starts at the pyloric sphincter and ends at the jejunum
enamel covering of the dentin of the crown of a tooth
enteroendocrine cell gastric gland cell that releases hormones
enterohepatic circulation recycling mechanism that conserves bile salts
enteropeptidase intestinal brush-border enzyme that activates trypsinogen to trypsin
epiploic appendage small sac of fat-filled visceral peritoneum attached to teniae coli
esophagus muscular tube that runs from the pharynx to the stomach
external anal sphincter voluntary skeletal muscle sphincter in the anal canal
fauces opening between the oral cavity and the oropharynx
feces semisolid waste product of digestion
flatus gas in the intestine
fundus dome-shaped region of the stomach above and to the left of the cardia
G cell gastrin-secreting enteroendocrine cell
gallbladder accessory digestive organ that stores and concentrates bile
gastric emptying process by which mixing waves gradually cause the release of chyme into the duodenum
gastric gland gland in the stomach mucosal epithelium that produces gastric juice
gastric phase phase of gastric secretion that begins when food enters the stomach
gastric pit narrow channel formed by the epithelial lining of the stomach mucosa
gastrin peptide hormone that stimulates secretion of hydrochloric acid and gut motility
gastrocolic reflex propulsive movement in the colon activated by the presence of food in the stomach
gastroileal reflex long reflex that increases the strength of segmentation in the ileum
gingiva gum
haustrum small pouch in the colon created by tonic contractions of teniae coli
haustral contraction slow segmentation in the large intestine
hepatic artery artery that supplies oxygenated blood to the liver
hepatic lobule hexagonal-shaped structure composed of hepatocytes that radiate outward from a central vein
hepatic portal vein vein that supplies deoxygenated nutrient-rich blood to the liver
hepatic sinusoid blood capillaries between rows of hepatocytes that receive blood from the hepatic portal vein and the branches of the hepatic artery
hepatic vein vein that drains into the inferior vena cava
hepatocytes major functional cells of the liver
hepatopancreatic ampulla (also, ampulla of Vater) bulb-like point in the wall of the duodenum where the bile duct and main pancreatic duct unite
hepatopancreatic sphincter (also, sphincter of Oddi) sphincter regulating the flow of bile and pancreatic juice into the duodenum
hydrochloric acid (HCl) digestive acid secreted by parietal cells in the stomach
ileocecal sphincter sphincter located where the small intestine joins with the large intestine
ileum end of the small intestine between the jejunum and the large intestine
incisor midline, chisel-shaped tooth used for cutting into food
ingestion taking food into the GI tract through the mouth
internal anal sphincter involuntary smooth muscle sphincter in the anal canal
intestinal gland (also, crypt of Lieberkühn) gland in the small intestinal mucosa that secretes intestinal juice
intestinal juice mixture of water and mucus that helps absorb nutrients from chyme
intrinsic factor glycoprotein required for vitamin B12 absorption in the small intestine
intestinal phase phase of gastric secretion that begins when chyme enters the intestine
jejunum middle part of the small intestine between the duodenum and the ileum
labium lip
labial frenulum midline mucous membrane fold that attaches the inner surface of the lips to the gums
lacteal lymphatic capillary in the villi
large intestine terminal portion of the alimentary canal
laryngopharynx part of the pharynx that functions in respiration and digestion
left colic flexure (also, splenic flexure) point where the transverse colon curves below the inferior end of the spleen
lingual frenulum mucous membrane fold that attaches the bottom of the tongue to the floor of the mouth
lingual lipase digestive enzyme from glands in the tongue that acts on triglycerides
liver largest gland in the body whose main digestive function is the production of bile
lower esophageal sphincter smooth muscle sphincter that regulates food movement from the esophagus to the stomach
major duodenal papilla point at which the hepatopancreatic ampulla opens into the duodenum
mass movement long, slow, peristaltic wave in the large intestine
mastication chewing
mechanical digestion chewing, mixing, and segmentation that prepares food for chemical digestion
mesoappendix mesentery of the appendix
microvillus small projection of the plasma membrane of the absorptive cells of the small intestinal mucosa
migrating motility complex form of peristalsis in the small intestine
mixing wave unique type of peristalsis that occurs in the stomach
molar tooth used for crushing and grinding food
motilin hormone that initiates migrating motility complexes
motility movement of food through the GI tract
mucosa innermost lining of the alimentary canal
mucosal barrier protective barrier that prevents gastric juice from destroying the stomach itself
mucous neck cell gastric gland cell that secretes a uniquely acidic mucus
muscularis muscle (skeletal or smooth) layer of the alimentary canal wall
myenteric plexus (plexus of Auerbach) major nerve supply to alimentary canal wall; controls motility
oral cavity (also, buccal cavity) mouth
oral vestibule part of the mouth bounded externally by the cheeks and lips, and internally by the gums and teeth
oropharynx part of the pharynx continuous with the oral cavity that functions in respiration and digestion
palatoglossal arch muscular fold that extends from the lateral side of the soft palate to the base of the tongue
palatopharyngeal arch muscular fold that extends from the lateral side of the soft palate to the side of the pharynx
pancreas accessory digestive organ that secretes pancreatic juice
pancreatic juice secretion of the pancreas containing digestive enzymes and bicarbonate
parietal cell gastric gland cell that secretes hydrochloric acid and intrinsic factor
parotid gland one of a pair of major salivary glands located inferior and anterior to the ears
pectinate line horizontal line that runs like a ring, perpendicular to the inferior margins of the anal sinuses
pepsinogen inactive form of pepsin
peristalsis muscular contractions and relaxations that propel food through the GI tract
permanent tooth one of 32 adult teeth
pharynx throat
porta hepatis “gateway to the liver” where the hepatic artery and hepatic portal vein enter the liver
portal triad bile duct, hepatic artery branch, and hepatic portal vein branch
premolar (also, bicuspid) transitional tooth used for mastication, crushing, and grinding food
propulsion voluntary process of swallowing and the involuntary process of peristalsis that moves food through the digestive tract
pulp cavity deepest portion of a tooth, containing nerve endings and blood vessels
pyloric antrum wider, more superior part of the pylorus
pyloric canal narrow, more inferior part of the pylorus
pyloric sphincter sphincter that controls stomach emptying
pylorus lower, funnel-shaped part of the stomach that is continuous with the duodenum
rectal valve one of three transverse folds in the rectum where feces is separated from flatus
rectum part of the large intestine between the sigmoid colon and anal canal
reticuloendothelial cell (also, Kupffer cell) phagocyte in hepatic sinusoids that filters out material from venous blood from the alimentary canal
retroperitoneal located posterior to the peritoneum
right colic flexure (also, hepatic flexure) point, at the inferior surface of the liver, where the ascending colon turns abruptly to the left
root portion of a tooth embedded in the alveolar processes beneath the gum line
ruga fold of alimentary canal mucosa and submucosa in the empty stomach and other organs
saccharolytic fermentation anaerobic decomposition of carbohydrates
saliva aqueous solution of proteins and ions secreted into the mouth by the salivary glands
salivary amylase digestive enzyme in saliva that acts on starch
salivary gland an exocrine gland that secretes a digestive fluid called saliva
salivation secretion of saliva
segmentation alternating contractions and relaxations of non-adjacent segments of the intestine that move food forward and backward, breaking it apart and mixing it with digestive juices
serosa outermost layer of the alimentary canal wall present in regions within the abdominal cavity
sigmoid colon end portion of the colon, which terminates at the rectum
small intestine section of the alimentary canal where most digestion and absorption occurs
soft palate posterior region of the bottom portion of the nasal cavity that consists of skeletal muscle
stomach alimentary canal organ that contributes to chemical and mechanical digestion of food from the esophagus before releasing it, as chyme, to the small intestine
sublingual gland one of a pair of major salivary glands located beneath the tongue
submandibular gland one of a pair of major salivary glands located in the floor of the mouth
submucosa layer of dense connective tissue in the alimentary canal wall that binds the overlying mucosa to the underlying muscularis
submucosal plexus (plexus of Meissner) nerve supply that regulates activity of glands and smooth muscle
tenia coli one of three smooth muscle bands that make up the longitudinal muscle layer of the muscularis in all of the large intestine except the terminal end
tongue accessory digestive organ of the mouth, the bulk of which is composed of skeletal muscle
transverse colon part of the colon between the ascending colon and the descending colon
upper esophageal sphincter skeletal muscle sphincter that regulates food movement from the pharynx to the esophagus
Valsalva’s maneuver voluntary contraction of the diaphragm and abdominal wall muscles and closing of the glottis, which increases intra-abdominal pressure and facilitates defecation
villus projection of the mucosa of the small intestine