Gastrointestinal Tract

Question 1

Mucosa of esophagus

Answer 1

Stratified squamous non-keratinized epithelium –> muscularis mucosa (smooth muscle) –> esophageal glands in sub-mucosa –> circular smooth muscle –> longitudinal smooth muscle

Question 2

Muscularis externa of esophagus

Answer 2

Circular skeletal muscle (distal) –> skeletal and smooth muscle (middle) –> longitudinal smooth muscle (distal)

Question 3

Esophago-gastric junction

Answer 3

This is where the lining of the mucosa changes from stratified squamous to simple columnar epithelium. Contains some goblet cells

Question 4

Cardiac stomach

Answer 4

Shallow gastric pits and cardiac glands. Lined by mucous columnar cells

Question 5

Fundus and body stomach

Answer 5

Gastric pits and gastric glands. The glands are branched tubular.

Question 6

Rugae

Answer 6

Large mucosa and submucosa folds in the stomach

Question 7

Pyloric stomach

Answer 7

End of the stomach that contains deep gastric pits and short pyloric glands which are coiled tubular branched. Represents the transition from stomach to duodenum. Secretes mostly mucous

Question 8

Surface mucous cells

Answer 8

Stomach. Secretes protective mucous

Question 9

Mucous neck cells

Answer 9

Stomach. Secretes mucous

Question 10

Parietal cells

Answer 10

Stomach. Light stained, eosinophilic, and secrete HCl and intrinsic factor

Question 11

Chief cells

Answer 11

Stomach. Dark stained, basophilic, secrete pepsinogen

Question 12

G cells

Answer 12

Secrete gastrin, hormonal function

Question 13

Enteroendocrine cells (stomach)

Answer 13

Secrete serotonin

Question 14

Active parietal cells

Answer 14

Contain microvilli that have filled up the intracellular canaliculi, and Golgi

Question 15

Resting parietal cells

Answer 15

Contain tubulovesicles and empty intracellular canaliculi

Question 16

Gastro-duodenal junction

Answer 16

Transition from the stomach to the intestine. There is a change in mucosa from gastric pits to intestinal villi. Smooth muscle of the pyloric sphincter can be seen

Question 17

Enterocyte

Answer 17

Mature absorptive cell of the GI tract. Contains a terminal web

Question 18

Goblet cells

Answer 18

Protective cell that secretes mucous for lubrication. Located in the upper gland of small intestine

Question 19

Enteroendocrine cells (small intestine)

Answer 19

Located in the lower gland of crypts

Question 20

Paneth cells

Answer 20

Located in base of glands in the small intestine. Innate immunity. Eosinophilic cells with dark granules.

Question 21

Regions of the small intestine

Answer 21

Duodenum –> jejunem –> ileum

Question 22

Duodenum

Answer 22

Villi on the surface, intestinal glands (short crypts of Lieberkuhn), and Brunner’s glands. Can contain the plicae circularis

Question 23

Jejunem

Answer 23

Contains surface villi and crypts of Lieberkuhn. Also contains the plicae circularis

Question 24

Ileum

Answer 24

Contains surface villi, crypts of Lieberkuhn and Peyer’s patches. Location where most bile salts are reabsorbed back into the portal circulation.

Question 25

Micovillus of small intestine

Answer 25

Increases surface area and stores digestive enzymes

Question 26

Peyer's patches

Answer 26

Located in the ileum. Lymphatic nodules that increase the area where absorption can occur.

Question 27

Structure of large intestine

Answer 27

Cecum -> ascending column -> transverse column -> descending column -> sigmoid column -> rectum

Question 28

Appendix

Answer 28

Location for an accumulation of debris that is cleaned out by the lymphatic system, attached to the cecum. Contains dense lymphatic nodules

Question 29

Teniae coli

Answer 29

3 longitudinal bands of smooth muscle in the muscularis externa of large intestine. Forms the distinct bumps of the colon

Question 30

Recto-anal junction

Answer 30

Change from simple columnar in the rectum to stratified squamous in the anus. There are abundant goblet cells in the rectum.

Question 31

Peristaltic movement

Answer 31

Downward movement of material. More prevalent in the intestines than the esophagus

Question 32

Intestinal villi

Answer 32

Contain blood vessels, lacteal, lamina propria, enterocytes and actin. Absorption

Question 33

Intestinal crypts

Answer 33

Contain paneth cells, enteroendocrine cells, goblet cells, smooth muscle, and lymphocytes. Secretion

Question 34

Absorptive cell

Answer 34

Absorb and process digestion products of small intestine. Microvillus brush border and numerous cytoplasmic organelles.

Question 35

Auerbach's plexus

Answer 35

located in the muscularis externa in the small intestine. Also called the myenteric plexus

Question 36

Myenteric plexus

Answer 36

Major nerve supply to the GI tract. Controls muscle contraction

Question 37

Brunner's glands

Answer 37

Branched tubular glands of the submucosa of duodenum

Question 38

Plicae circularis

Answer 38

Extension of the submucosa that gives characteristic folds. Most prevalent in the jejunum but can be found in the duodenum too.

Question 39

Colon

Answer 39

Responsible for water absorption of feces