2A Anotomy and physiology of the stomach

Question 1

What are the 4 main regions of the stomach

Answer 1

• Cardia
• Fundus
• body
• Pylorus

Question 2

what are two sphincters associated with the stomach

Answer 2

LES (upper)

Pyloric (lower)

Question 3

whare is the lower esophageal sphincter located

Answer 3

within the cardia of the stomach

Question 4

what are the three layers to the muscularis externa

Answer 4

• outermost longitudinal later
• Middle circular later
• innermost oblique layer

Question 5

which muscular layer is unique to the stomach

Answer 5

Innermost oblique layer

Question 6

__________ play an impertant role in protecting the stomack amucosa from injury by __________ mucus production

Answer 6

prostaglandins, enhancing

Question 7

what plays the largest role in protection of the gastric mucosa

Answer 7

Layer of alkaline mucus or Gastric mucosal barrier

Question 8

what is the normal range pH in the stomach

Answer 8

between pH 1 and 2

Question 9

what type of epithelium lines the stomach

Answer 9

simple culumnar

Question 10

the mucosal sruface of the stomach is a simple solumnar epithelium that is dotted with millions of deep channels called _____ ______ which are lined with columns of specialized cells called _______ ______

Answer 10

gastric pits, gastric glands

Question 11

mucous neck cells secret

Answer 11

alkaline mucus

Question 12

perietel cells secrete

Answer 12

HCl and intrinsic factor

Question 13

chief cells secrete

Answer 13

pepsinogens and gastric lipase

Question 14

endocrine cells secrete

Answer 14

gastrin (G cells) and histamin (ECL cells)

Question 15

the cells of the gastric glands secterv how much gastric juice daily

Answer 15

2500 ml

Question 16

what are some roles of the HCl secreted by Parietal cells

Answer 16

• kills bacteria
• protein digestion
• provides pH needed for pepsin
• stimulates flow of bile and pancreatic juice

Question 17

what are some substances that cause gastric irritation or injury (4)

Answer 17

• ethenol
• bile salts
• NSAIDs
• H. pylori

Question 18

what cells are located in the fundus and upper part of the body of the stomach

Answer 18

Perietal cells

Question 19

what cells are found in the middle body of the stomach

Answer 19

Chief cells

Question 20

what cells are found in the lower body of the stomach

Answer 20

G cells

Question 21

what are the functions of the stomach

Answer 21

• temporarily story ingested liquids and solids
• mechanical digestion
• secretes gastric juice for chemical digestion
• secretes gastrin and histamine

Question 22

what role does the vagus nerve play in food digestion

Answer 22

• weakly stimulates gastric juice secretion when food is being shewed in the mouth or with the sight, smell, or thought of food
• stimulates gastrin secretion from the enteroendoctrine cells of the gastric glands

Question 23

_______ further stimulates secretion of gastric juices

Answer 23

Gastrin

Question 24

what are the three phases of stomach digestions

Answer 24

Cephalic phase (Vegus nerve)
Gastric phase (when food reaches the stomach)
Intestinal phase

Question 25

what are the four points of the Gastric Phase

Answer 25

- begins when food reaches stomach - Distention stimulates gastrin release which stimulates gastric juice release - Vagus nerve continues to stimulate gastrin release - Elevated levels of gastrin stimulates histamin which increases HCl from parietal cells

Question 26

what three hormones are stimulated when acidic chyme enter the duedenum

Answer 26

- Cholecystokinin (CKK) - Secritin - Gastric Inhibiroty peptide (GIP)

Question 27

why is controlling chyme entering the duodenum so critical

Answer 27

- So the duodenum does not become too full (especially with acid) - so the small intestines can adequately process in incoming chyme

Question 28

what is the enterogastric reflex

Answer 28

Inhibits vagus nerve (occurs during the intestinal phase)