10 Digestive System II--Esophagus to Stomach

Question 1

Does the early embryo undergo median folding (head and tail) or horizontal folding (lateral body fold)?

Answer 1

BOTH- and in doing so the digestive tract is formed [along with thoracic and abdominal cavities, heart, pleura, peritoneal membrane etc.]

Question 2

What is included in the foregut?

Answer 2

esophagus to proximal duodenum

Question 3

What is included in the midgut?

Answer 3

distal duodenum to proximal colon [also includes accessory organs of digestion]

Question 4

What is included in the hind gut?

Answer 4

distal colon to the anal canal [I think generally the hind gut includes the last 1/3 of the transverse colon on down]

Question 5

What is the epithelial layer in the esophagus?

Answer 5

non-keratinized stratified squamous

Question 6

What is found in the lamina propria of the esophagus?

Answer 6

• esophageal cardiac glands [mucous-only in most distal region near stomach]
• lymphoid aggregates

Question 7

What is found in the esophagus submucosa?

Answer 7

esophageal glands [mucous secreting for bolus passage]

Question 8

What 2 types of muscle are generally found throughout the muscular is extern of the esophagus?

Answer 8

inner circular and outer longitudinal

Question 9

Is the upper 1/3 of the esophagus muscle smooth muscle?

Answer 9

NO–skeletal muscle [last 1/3 is smooth and the middle is mixed]

Question 10

What type of tissue makes up the esophageal adventitia/ serosa?

Answer 10

loose irregular connective tissue adventitia and then gets covered by peritoneum near hiatus and becomes serosa

Question 11

Is the stomach only a chemical digester?

Answer 11

No mechanical as well

Question 12

What are the 4 distinct regions of the stomach?

Answer 12

cardia, fundus, body, pylorus

Question 13

What type of epithelium is in the stomach? what do they produce?

Answer 13

simple columnar- cells produce neutral mucous

Question 14

Besides epithelial cells, what else exists in the epithelial layer of the stomach?

Answer 14

gastric pits and gastric glands-

Question 15

T-F– the gastric pits and glands do not extend to the lamina propria?

Answer 15

false

Question 16

What is different about the muscular is extern in the stomach?

Answer 16

It has an innermost oblique layer

Question 17

What muscle layer forms the pyloric sphincter?

Answer 17

middle circular layer [think of the direction of the fibers for the job]

Question 18

T-F– the outer layer of the stomach is covered by mesothelium?

Answer 18

True- peritonized within the abdomen

Question 19

What gland is most common in the stomach?

Answer 19

principal gastric gland

Question 20

What cell type makes up the gastric pit?

Answer 20

surface mucous cell [same as columnar epithelial and secrete a neutral mucous]

Question 21

What gastric gland cell secretes mucous to protect stomach from self digestion?

Answer 21

neck mucous cell

Question 22

What gastric gland cell is mainly located in the upper portion of the gland, are largely rounded with a central nucleus?

Answer 22

parietal (oxyntic) cell

Question 23

What gastric gland cell stains very eosinophilic?

Answer 23

parietal cell

Question 24

What does the parietal cell secrete?

Answer 24

HCl and intrinsic factor

Question 25

Why are many mitochondria needed in parietal cells?

Answer 25

ATP needed to drive process of H and Cl locations for HCl production

Question 26

Is the proton pump in the parietal cell an anti porter or symporter? with what molecule?

Answer 26

anti----K+

Question 27

Where does the HCl formation actually take place?

Answer 27

in the canaliculus

Question 28

What is a glycoprotein required for uptake of vitamin B12 in the gut?

Answer 28

intrinsic factor

Question 29

What is found in the stomach of many people with gastric ulcers?

Answer 29

H. pylori- helical shape and flagellum allow it to burrow into mucous and stay protected--

Question 30

What can impairment of intrinsic factor lead to?

Answer 30

pernicious anemia---B12 uptake is down which is needed during the process of hematopoiesis

Question 31

What gastric gland cell is located in the lower portion and stains basophilic? what do they secrete?

Answer 31

chief cell- pepsinogen and rennin/chymosin

Question 32

What activated pepsinogen?

Answer 32

HCl in the stomach lumen clips off those extra 44 amino acids that blocked the active site

Question 33

What does chymosin do?

Answer 33

curdle and coagulate milk to maximize time in stomach

Question 34

T-F--rennin is the preferred method to make cheese?

Answer 34

True

Question 35

What gastric gland cells are part of the diffuse neuroendocrine system?

Answer 35

enteroendocrine cell-release a variety of hormones into blood vessels

Question 36

Where are the G cells located in the stomach? what hormone? causes what?

Answer 36

- body and pylorus - gastrin - increase parietal cell/chief cell secretion & contraction of m. externa

Question 37

Where are the D cells located in the stomach? what hormone? causes what?

Answer 37

- pylorus - somatostatin [triggered by increased acid] - targets G cells to inhibit their release

Question 38

Where is the ghrelin cell located in the stomach? what hormone? causes what?

Answer 38

- body - ghrelin [low glucose response] - targets hypothalamus to increase appetite

Question 39

Are there goblet cells in the stomach?

Answer 39

No

Question 40

What are the key features of the cardiac glands?

Answer 40

- in cardia - short gastric pits - long coiled gastric glands - primarily mucous cells

Question 41

What are key features of principal glands?

Answer 41

- in fundus and body - the gastric pits are short - long and branched gastric glands - full complements of stomach cells

Question 42

What do neuroendocrine cells secrete in the fundus and body of the stomach?

Answer 42

ghrelin and gastrin

Question 43

What are the key characteristics of pyloric glands?

Answer 43

- in the pylorus - the gastric pits are long - glands are short and coiled - primarily mucous secreting cells

Question 44

What do neuroendocrine cells secrete in the pylorus of the stomach?

Answer 44

gastrin and somatostatin

Question 45

What glands have short gastric pits?

Answer 45

principal and cardiac

Question 46

What happens in Barrett's esophagus?

Answer 46

metaplasia--> normal stratified squamous of esophagus changes to columnar epithelium [chronic exposure to stomach acids and enzymes during reflux esophagitis]