Lecture 13 - GI

Question 1

Mesentery

Answer 1

wall surrounding the tract and separating it from other tissues. Binds to the abdominal wall.

Question 2

Serosa and its two layers

Answer 2

visceral inner layer and parietal outer layer. secretion between the two and aids in protection.

Question 3

Muscularis externa

Answer 3

3 layers. outer longitudinal and inner circular muscle.

Question 4

Mucosal layers

Answer 4

submucosa - may contain some lymphoid nodules

Mucosa - inner alyer of epithelium with microvilli

Question 5

Small intestine unique features

Answer 5

interstinal villi and plica circularis

Question 6

Interstinal villi

Answer 6

multiple juts into the lumen space

Question 7

plica circularis

Answer 7

larger structure that juts into the lumen to increase surface area.

Question 8

Colon unique features

Answer 8

invaginations of the wall (crypts of Lieberkuhn)

Question 9

Auerbach’s plexus

Answer 9

connection to the nervous system that helps control the tract. In the muscluaris externa

Question 10

Meissner’s plexus

Answer 10

also helps with nervous system control. In the submucosa

Question 11

Mucosa

Answer 11

stratified squamous non-keratinized. muscularis mucosa (smooth muscle

Question 12

esophagus’s muscularis externa

Answer 12

3 layers. upper skeletal, middle skeletal and smooth, lower smooth

Question 13

esophagus’ mucosa

Answer 13

non-keratinized. esophageal glands in submucosa secrete mucous

Question 14

esophago-gastric junction

Answer 14

change from stratified squamous to simple columnar with gastric pits

Question 15

cardiac stomach

Answer 15

will have cardiac glands which are straight, tubular lined by mucous columnar cells. few parietal and chief cells.

Question 16

Glands of body and fundus of stomach

Answer 16

glands are branched tubular which have a isthmus, neck, and base.

Question 17

Isthmus cells of the glands of body and fundus of stomach

Answer 17

mucous cells and a few parietal cells

Question 18

Neck cells of the glands of body and fundus of stomach

Answer 18

mucous cells and parietal cells

Question 19

Base cells of the glands of body and fundus of stomach

Answer 19

parietal cells and chief cells

Question 20

Rugae

Answer 20

large mucosa and submucosa folds

Question 21

Pyloric stomach

Answer 21

deeper gastric pits and short pyloric glands which are coiled tubular branched. mucous.

Question 22

Parietal cells secretion

Answer 22

HCl and intrinsic factor (light staining)

Question 23

Chief or zymogenic cell secretion

Answer 23

gastric lipase (lipids) and precursor pepsinogen (proenzyme). dark staining - basophilic since RER.

Question 24

G cell secretion and location

Answer 24

gastrin. located at the bottom of the pit.

Question 25

Enteroendocrine (argentaffin) cells

Answer 25

stain silver. secrete serotonin. important for endrocrine function

Question 26

Where do lymph nodes occur?

Answer 26

above the submucosa region

Question 27

Where do veins and arteries occur?

Answer 27

in the submucosa region

Question 28

Active parietal cells and how it changes from a resting cell

Answer 28

secrete HCl. induced by beginning of digestion. microvilli will increase as tubulovesicles fuse together and fill the intracellular canaliculi. More mitochondria

Question 29

HCl production in parietal cells

Answer 29

requires ATP and thus lots of mitochondria. carbonic anhydrase creates bicarbonate and protons from water and CO2. Protons and chloride go out of cell.

Question 30

Transition to duodenum

Answer 30

mucosa from gastric pits to intestinal villi. Thickened smooth muscle of the pyloric sphincter

Question 31

Structure of small intestine and cell types

Answer 31

glands and villi. In pits - see goblet cells, mitoses (dividing cells), smooth muscle, paneth’s cells, and lymphocytes.

Question 32

Goblet cells

Answer 32

mucus secreting cells. thus light staining. can be found in the villi.

Question 33

Paneth cells

Answer 33

serous secreting cells. can be found in the pits, usually at the bottom.

Question 34

Structural components of a microvillus

Answer 34

filled by actin and fibrin (bridges between actin filaments). capped by villin.

Question 35

Other components of a microvillus

Answer 35

blood circulation, lymphatic circulation (central lacteal) with lymphoid nodule, and innervation and muscle

Question 36

Duodenum’s glands

Answer 36

Brunner’s glands - branched tubular. extend through submucosa. short crypts of Lieberkuhn

Question 37

Jejunum

Answer 37

only surface villi and crypts of Lieberkuhn

Question 38

Ileum

Answer 38

surface villi with crypts of Lieberkuhn. Lymphatic nodules form Peyer’s patches under mucosa

Question 39

Colon sequence

Answer 39

ascending colon, right colic flexure (liver), transverse, left colic flexure (spleen), descending, sigmoid colon, rectum, anus

Question 40

Difference between small intestine and large intestine?

Answer 40

no villi in the large intestine

Question 41

Taeniae coli

Answer 41

3 longitudinal muscle accumulations in the large intestine

Question 42

Recto-anal junction

Answer 42

rectum lined by simple columnar epithelium and tubular glands to stratified squamous epithelium of anus.

Question 43

Stem cell location in stomach, small intestine, and colon

Answer 43

stomach - high in the pits.
small intestine - bottom of the crypt
colon - mid to low in the crypt.

Question 44

Muscularis mucosa

Answer 44

defines the border of the mucosa and the submucosa.

Question 45

Brunner’s glands

Answer 45

in the duodenum. Secrete a basic solution that helps to neutralize the chyme being released by the stomach.

Question 46

submucosal plexus

Answer 46

connection to the nervous system beneath the villi.