GI tract I

Question 1

list the 4 principal layers of the GI tract

Answer 1

• mucosa
• submucosa
• muscularis externa
• serosa or adventitia

Question 2

what are the functions of the mucosa layer?

Answer 2

protection, absorption and secretion

Question 3

what layer does the following describe

“dense irregular CT with vessels has meissner’s plexus”

Answer 3

submucosal layer

Question 4

what layer does the following describe

“lining epithelium, lamina propria and muscularis mucosae”

Answer 4

muscosa layer

Question 5

what layer does auerbach’s plexus lay

Answer 5

muscularis externa

Question 6

describe the components of teh muscularis externa layer

Answer 6

inner circular and outer longitudinal smooth muscle with auebrbach’s plexus

Question 7

what type of epithelium is in the mucosa of the esphagus

Answer 7

stratified squamous epithelium

Question 8

what type of glands does the submucosa of the esphagus have?

Answer 8

esophageal glands proper

Question 9

describe the muscularis externa in the esphagus as the following levels:
upper third
middle third
lower third

Answer 9

upper third- skeletal muscle
middle third- mixed skeletal and smooth muscle
lower third- smooth muscle

Question 10

what part of the esophagus has adventitia? serosa?

Answer 10

adventitia above diaphragm and serosa below

Question 11

what type of circular muscle surrounds the upper esophageal sphincter?

Answer 11

skeletal muscle under voluntary & reflexive control

Question 12

what type of muscle in the lower esophageal sphincter

Answer 12

thickened circular smooth muscle

Question 13

what are the 4 regions at the gross level of the stomach?

Answer 13

cardia, fundus, body and pylorus

Question 14

what are rugae?

Answer 14

temporay longitudinal folds of mucosa and submucosa

Question 15

what are the 3 histological regions of the stomach?

Answer 15

cardia, fundus/body and pylorus

Question 16

describe the cardiac glands

Answer 16

short pits
short coiled glands
most produce mucus
few produce lysozyme and HCl

Question 17

describe gastric/fundus glands

Answer 17

• medium pits

- long straight glands

Question 18

what are the 4 major cell types in the gastric/fundus glands?

Answer 18

mucous neck cells
parietal (oxyntic) cells
chief cells
enteroendocrine cells

Question 19

what type of gland does the following describe

“very long pits, short slightly coiled glands, mostly mucous cells with few parietal cells, has enteroendocrine cells”

Answer 19

pyloric glands

Question 20

what do the surface mucous cells secrete?

Answer 20

an alkaline, viscous mucus with a high bicarb content that protects the stomach’s surface

Question 21

what do the mucous neck cells secrete?

Answer 21

a soluble or mobile mucus

Question 22

where are mucous neck cells?

Answer 22

occur in small groups or singly between parietal cells in the neck of gastric glands

Question 23

what do parietal (oxynitic) cells secrete?

Answer 23

HCl and intrinsic factor

Question 24

what type of cells are parietal cells? where are they found?

Answer 24

large eosinophilic cells found in the middle & upper part of gastric gland

Question 25

what type of receptors are needed to stimulate acid secretion?

Answer 25

acetylcholine, gastrin and histamine

Question 26

what are the functions of zantac and tagament

Answer 26

they are histamine H2 receptor antagonists that suppress both HCl and intrinsic factor secretion

Question 27

what can long term use of zantac or tagament lead to?

Answer 27

can cause vit B12 deficiency and then pernicious anemia

Question 28

what do chief cells synthesize & secrete

Answer 28

pepsinbogens and lipases

Question 29

where are chief cells found?

Answer 29

in the basal half of gastric glands

Question 30

what do enteroendocrine cells produce?

Answer 30

gastrin, somatostatin and ghrelin

Question 31

where are enteroendocrine cells?

Answer 31

occur singly or in groups of diff varieties at the base of gastric glands

Question 32

what type of signaling does enteroendocrine cells do?

Answer 32

endocrine and paracrine signaling

Question 33

describe the lamina propria

Answer 33

it is loose CT resembling the stroma of lyph organs that contains blood and lymphatic vessles as well as lymph tissue and wandering plasma cells and eosinophils

Question 34

what layer of the mucosa is the following describing?
“thin layer of smooth muscle that produces movement of the mucosa creating ridges and valleys that facilitate absorption and secretion:

Answer 34

muscularis mucosae

Question 35

what is the difference bween serosa or adventitia

Answer 35

serosa- simple squamous epithelium (mesothelium)

adventitia-when part the digestive tract is fixed directly to the abdominal or pelvic wall

Question 36

what are the elevations in the tongue called?

Answer 36

lingual papillae

Question 37

what are the 4 types of papillae?

Answer 37

filiform
funbgiform
foliate
circumvallate

Question 38

which papillae lacks tastes buds? what type of epithelium does it have?

Answer 38

filiform papillae

have stratified squamous keratinized epithelium

Question 39

besdies the filiform papillae, what type of epithelium does the papillae have?

Answer 39

stratified sqaumous

Question 40

what are gastric puts?

Answer 40

permanent invaginations into the lamina propria that serve as ducts for the mucosal glands

Question 41

what are the 3 sections of mucosal glands?

Answer 41

the isthmus, the neck and the body

Question 42

what is special about the muscle in the muscularis externa layer of the stomach?

Answer 42

it has an extra inner layer of oblique smooth muscle in addition to the circular and longitudinal layers

Question 43

what parts of the mucosal glands are the stem cells found in?

Answer 43

they are found in the isthmus and the neck

Question 44

how often do the surface mucous cells turn over?

Answer 44

every week

Question 45

how often do the granular cells of the mucosal glands need to be replaced?

Answer 45

every 1-2 months