BSC2086L E.11 Digestive System

Developed for the Broward College course BSC2086/L Anatomy and Physiology II.

mucosa

• The deepest layer of the gastrointestinal tract.

• Superficial to the submucosa.

• Composed of a lining epithelium, the lamina propria, and the muscularis mucosae.

lining epithelium

• The deepest layer of the mucosa of the gastrointestinal tract.

• Kept moist by the secretion of mucus.

lamina propria

• The middle layer of the mucosa of the gastrointestinal tract.

• The connective tissue layer of the mucosa.

muscularis mucosae

• The most superficial layer of the mucosa of the gastrointestinal tract.

• The thin layer of smooth muscle.

submucosa

• The second deepest layer of the gastrointestinal tract.

• Composed of loose connective tissue.

• Superficial to the mucosa.

• Deep to the muscularis externa.

muscularis externa

• The secondmost superficial layer of the gastrointestinal tract.

• Composed of oblique (stomach only), circular, and longitudinal layers of smooth muscle.

• Superficial to the submucosa.

• Deep to the serosa.

oblique layer of muscularis

The deepest layer of the muscularis externa of the stomach.

circular layer of muscularis

• The deepest layer of the muscularis externa of the gastrointestinal tract.

• The middle layer of the muscularis externa of the stomach.

longitudinal layer of muscularis

The most superficial layer of the muscularis externa of the gastrointestinal tract.

serosa

• The most superficial layer of the gastrointestinal tract.

• Composed of a layer of epithelium and a layer of connective tissue.

• Also known as the visceral peritoneum.

lip

One of the anterior borders of the opening of the mouth.

hard palate

Forms the anterior part of the roof of the mouth.

soft palate

Forms the posterior part of the roof of the mouth.

uvula

• An extension of the soft palate hanging downwards.

• Visible at the back of the mouth.

fauces

The opening of the mouth into the oropharynx.

nasopharynx

• The superior segment of the pharynx.

• Above the level of the soft palate.

• Receives air from the nose by the internal nares.

oropharynx

• The middle segment of the pharynx.

• Below the level of the soft palate and above the level of the hyoid bone.

• Receives food from the oral cavity.

laryngopharynx

• The inferior segment of the pharynx.

• Below the level of the hyoid bone.

• Extends downward to meet the larynx.

esophagus

• A muscular and slippery tube that stretches open to accommodate swallowed food.

• Propels food by peristalsis.

lower esophageal sphincter

• A sphincter that opens to allow food into the stomach.

• Abbreviated LES.

esophagus

• Slide of the gastroesophageal junction.

• Composed of stratified squamous epithelium.

stomach

• Slide of the gastroesophageal junction.

• Composed of simple columnar epithelium.

stomach

• A J-shaped open immediately inferior to the diaphragm on the left side of the abdominal cavity.

• Divided into four regions: the cardia, fundus, body, and pylorus.

• Mixes and churns food.

cardia

• A region of the stomach.

• Receives food from the esophagus in the superior part of the stomach.

fundus

• A region of the stomach.

• An area that holds food and forms the superior part of the stomach.

body

• A region of the stomach.

• The large, central portion of the stomach.

pylorus

• A region of the stomach.

• The small distal area of the stomach.

lesser curvature

The medial, concave curvature of the stomach.

greater curvature

The lateral, convex curvature of the stomach.

rugae

• Ridges of the mucosa on the internal surface of the stomach.

• Stretches to accommodate a larger volume of food.

• Contains microscopic gastric pits that contain gastric glands.

gastric pit

• Slide histology of the stomach.

• A microscopic invagination of the rugae of the stomach.

gastric glands

• Slide histology of the stomach.

• Located within gastric pits.

• Secretes gastric juice.

pyloric antrum

• Part of the pylorus of the stomach.

• The region of the pylorus adjacent to the body of the stomach.

pyloric sphincter

• Part of the pylorus of the stomach.

• Opens to allow stomach contents into the duodenum.

• Also known as the pyloric valve.

pyloric canal

• Part of the pylorus of the stomach.

• The opening between the stomach and the duodenum.

small intestine

• A long tube-shaped organ.

• Divided into the duodenum, jejunum, and ileum.

• Site of most digestion and nutrient absorption.

villi

• Located in the small intestine.

• Finger-like projections that increases the absorptive surface of the small intestine.

lacteal

• Located in the villi of the small intestine.

• A part of a lymphatic vessel that absorbs digested fats into the circulatory system.

duodenum

• Slide histology.

• The proximal region of the small intestine.

villi

• Slide histology of the duodenum.

• Located in the mucosa layer of the duodenum.

• Increases the absorptive surface of the lining epithelium.

intestinal glands

• Slide histology of the duodenum.

• Located in the mucosa layer of the duodenum.

• Produces hormones that participate in digestion.

duodenal glands

• Slide histology of the duodenum.

• Located in the submucosa layer of the duodenum.

• Produces mucus to protect the intestinal lining from stomach acid.

muscularis

• Slide histology of the duodenum.

• The layer of the duodenum deep to the submucosa.

ileum

• Slide histology.

• The distal region of the small intestine.

villi

• Slide histology of the ileum.

• Located in the mucosa layer of the ileum.

• Increases the absorptive surface of the lining epithelium.

Peyer’s patch

• Slide histology of the ileum.

• Located in the submucosa layer of the ileum.

• A round cluster of dark-staining lymphocytes and macrophages.

ileocecal valve

• The termination of the ileum.

• Allows small intestine contents into the large intestine.

large intestine

• A tube-shaped organ.

• Divided into the cecum, colon, and rectum.

• Site of feces formation.

taenia coli

• The three longitudinal bands of smooth muscle separating parts of the colon into haustra.

• Found only on the ascending, transverse, descending, and sigmoid colon.

haustra

• Pouches of the colon formed by the taenia coli.

• Present on the ascending, transverse, descending, and sigmoid colon.

cecum

• A region of the large intestine.

• A blind pouch arising from the ileocecal valve.

appendix

• Part of the cecum.

• A slender appendage extending from the medial wall of the cecum.

ascending colon

• The first part of the colon of the large intestine.

• The part of the colon moving upwards toward the liver on the right side of the abdominopelvic cavity.

right colic flexure

• The 90° turn of the ascending colon into the transverse colon.

• Occurs just beneath the liver.

• Also known as the hepatic flexure.

transverse colon

• The second part of the colon of the large intestine.

• The part of the colon moving leftwards across the abdominopelvic cavity.

left colic flexure

• The 90° turn of the transverse colon into the descending colon.

• Occurs near the spleen.

• Also known as the splenic flexure.

descending colon

• The third part of the colon of the large intestine.

• The part of the colon moving downwards on the left side of the abdominopelvic cavity.

sigmoid colon

• The fourth part of the colon of the large intestine.

• The S-shaped segment at the level of the iliac crest.

rectum

• A region of the large intestine.

• An area for holding feces until defecation.

anal canal

• The final two inches of the rectum.

• Contains anal columns along the inner wall.

anal column

A fold of the anal canal along the inner wall.

anus

• The opening of the rectum into the exterior.

• Bordered by internal and external sphincters of smooth and skeletal muscle.

goblet cell

• Slide histology of the large intestine.

• Secretes mucus.

mucosa

• Slide histology of the large intestine.

• The deepest layer of the large intestine.

• Deep to the submucosa.

submucosa

• Slide histology of the large intestine.

• The second-deepest layer of the large intestine.

• Superficial to the mucosa.

• Deep to the muscularis.

gingiva

• Anchors the teeth.

• Also known as a gum.

tooth

• Provides mechanical digestion by breaking up food particles in the mouth.

• Composed of a crown and the root.

crown

• A region of the tooth.

• The area of the tooth visible above the gum line.

root

• A region of the tooth.

• The area of the tooth below the gum line.

periodontal ligament

• Lines the alveolar socket of the tooth.

• Anchors the root of the tooth to the gingiva.

enamel

• A very hard substance.

• Covers the crown of the tooth.

dentin

• Calcified connective tissue.

• Composes most of the internal tooth.

cementum

• An adhesive connective tissue.

• Adheres the dentin to the periodontal ligament.

pulp cavity

• Located in the center of the crown of the tooth.

• Filled with pulp containing blood vessels, nerves, and lymphatics.

root canal

• A slender channel in the root of the tooth.

• The continuation of the pulp cavity and pulp into the root of the tooth.

incisor

• A type of tooth.

• Has narrow edges for cutting food.

canine

• A type of tooth.

• Has a pointed edge for tearing food.

premolar

• A type of tooth.

• Has two flat cusps for grinding food.

molar

• A type of tooth.

• Has broad or rounded cusps for grinding food.

pancreas

• An organ located within the abdominal cavity posterior to the stomach and proximal end of the duodenum.

• Composed of a head, body, and tail.

• Secretes digestive enzymes and hormones.

head

• A region of the pancreas.

• The expanded portion of the pancreas located posterior to the duodenum.

body

• A region of the pancreas.

• The central portion of the pancreas behind the pylorus of the stomach.

tail

• A region of the pancreas.

• The narrow portion of the pancreas behind the body of the stomach.

main pancreatic duct

• A central duct extending from the tail to the head of the pancreas.

• Secretions from acinar cells travel by this duct.

• Joins the common bile duct to form the hepatopancreatic ampulla.

• Opens into the duodenum at the major duodenal papilla.

accessory pancreatic duct

• A division of the main pancreatic duct.

• Secretions from acinar cells travel by this duct.

• Opens into the duodenum at the minor duodenal papilla.

acinar cells

• Slide histology of the pancreas.

• Dark-staining cells that produce digestive enzymes.

pancreatic islets

• Slide histology of the pancreas.

• Light-staining cells that produce hormones.

• Also known as islets of Langerhans.

liver

• A large, soft organ located on the right side of the abdominal cavity pressing against the diaphragm.

• Consists of right, left, caudate, and quadrate lobes.

• Detoxifies blood, processes nutrients, and produces bile.

falciform ligament

• Suspends the liver from the diaphragm and the anterior abdominal wall.

• Separates the right and left lobes of the liver.

right lobe

• A lobe of the liver.

• The larger lobe on the anterior of the liver.

left lobe

• A lobe of the liver.

• The smaller lobe on the anterior of the liver.

caudate lobe

• A lobe of the liver.

• The superior lobe on the posterior of the liver, next to the inferior vena cava.

quadrate lobe

• A lobe of the liver.

• The inferior lobe on the posterior of the liver, next to the gallbladder.

hepatic portal vein

Carries blood from the digestive tract to the liver for nutrient processing and detoxification.

right hepatic duct

• A bile duct.

• The R. duct transports bile directly from the liver.

• Converges with the L. hepatic duct to form the common hepatic duct.

left hepatic duct

• A bile duct.

• The L. duct transports bile directly from the liver.

• Converges with the R. hepatic duct to form the common hepatic duct.

common hepatic duct

• A bile duct.

• The convergence of the R. and L. hepatic ducts.

• Converges with the cystic duct to form the common bile duct.

gallbladder

• A hollow organ located between the right and quadrate lobes of the liver.

• Receives and stores bile from the liver until digestion occurs.

cystic duct

• A bile duct.

• Transports bile to and from the gallbladder.

• Converges with the common hepatic duct to form the common bile duct.

common bile duct

• A bile duct.

• The convergence of the common hepatic and cystic ducts.

• Converges with the major duodenal papilla of the pancreas to form the hepatopancreatic ampulla.