Swallowing and Stomach Histology

Question 1

Define peristalsis.

Answer 1

Wave-like contractions promoting motility in GIT

Question 2

What muscles are involved in peristalsis in the esophagus?

Answer 2

Inner circular muscle and outer longitudinal muscle

Question 3

How is primary peristalsis in the esophagus initiated?

Answer 3

By swallow

Question 4

How is secondary peristalsis in the esophagus initiated?

Answer 4

Distension of esophagus

Question 5

Can peristalsis in the esophagus still occur after vagotomy?

Answer 5

Yes. Normal swallowing involves both ANS and ENS

Question 6

How is peristalsis controlled?

Answer 6

Sequential activation of motor neurons
Role of enteric nervous system to co-ordinate contractions

Question 7

What neurotransmitter drives contraction behind the bolus?

Answer 7

ACh

Question 8

What neurotransmitter drives relaxation infront of the the bolus?

Answer 8

NO

Question 9

What type of inhibition occurs in the esophagus during multiple rapid swallow?

Answer 9

Deglutitive inhibition

Question 10

What is Esophageal Achalasia?

Answer 10

Motility disorder
Impaired or absent peristalsis
Distended esophagus and ‘bird beak’ appearance

Question 11

What is Corkscrew Esophagus?

Answer 11

Impaired motility
Un-coordinated contractions
Diffuse spasms

Question 12

What allows the stomach to churn food in another way?

Answer 12

Oblique muscle layer

Question 13

What are the 4 regions of the stomach?

Answer 13

Cardia, fundus, body/corpus, pylorus

Question 14

What hormones are produced in the stomach?

Answer 14

Gastrin and Ghrelin

Question 15

What is the cardia’s function?

Answer 15

Relaxation
Mainly mucous

Question 16

What is the fundus/body’s function?

Answer 16

Mixing
Mainly gastric acid

Question 17

What is the pylorus’ function?

Answer 17

Muscular - aids physical digestion
Mainly mucous

Question 18

Describe the surface mucous cell?

Answer 18

Produces thick mucous
HIgh in bicarbonate
Protects stomach from itself

Question 19

Describe the mucous neck cell?

Answer 19

Present in neck or isthmus
Less columnar - rounded nuclei
Less alkaline secretion - containing mucin

Question 20

Describe the parietal cell?

Answer 20

Present in neck and deeper parts of the gland
Strong eosinophilic staining (pink)
Intracellular canaliculus - many folds for proton pump expression
Secretes HCL and intrinsic factor

Question 21

Describe the chief cell?

Answer 21

Lower region of gastric gland
Produces pepsinogen and gastric lipase

Question 22

Describe the enteroendocrine cell?

Answer 22

Gastrin producing cells in pylous
5HT producing cell

Question 23

Describe the stem cell?

Answer 23

Undiiferentiated cells

Question 24

What is the role of gastric mucous?

Answer 24

Mechanical and viscosity protection
Protects from auto-digestion

Question 25

What is mucous secretion stimulated by?

Answer 25

Prostaglandins

Question 26

What inhibits prostaglandins?

Answer 26

NSAIDS

Question 27

What does gastric acid do?

Answer 27

Denatures proteins - exposes peptide bonds Converts pepsinogen into pepsin Protective role - low pH not permissive for bacterial growth (bar H.pylori)

Question 28

What produces H+ and HCO3- in the parietal cell?

Answer 28

Carbonic anhydrase

Question 29

How does H+ move in the parietal cell?

Answer 29

Moves apically by active transport

Question 30

What maintains the pH of the parietal cell?

Answer 30

HCO3- moving out of the cell across the basolateral membrane

Question 31

Where is H+/K+ATPase mainly found in the parietal cell?

Answer 31

Apical surface

Question 32

What reabsorbs K+

Answer 32

Na+/K+ATPase using active transport

Question 33

What intrinsic factor is produced by parietal cells?

Answer 33

Glycoprotein produced in fundus and corpus

Question 34

What is the glycoproteins optimum pH?

Answer 34

7 - required for uptake of vitamin B12

Question 35

What does vitamin B12 bind to before the glycoprotein?

Answer 35

Haptocorrin

Question 36

Where is B12 absorbed?

Answer 36

Endocytosed by cells in the terminal ileum

Question 37

How is B12 released?

Answer 37

In complexes with transcobalamin II in the cells

Question 38

What is a clinical condition of loss of parietal cells?

Answer 38

Pernicious Anaemia

Question 39

What do G-cells produce?

Answer 39

Gastrin hormone into the blood Promotes gastric acid secretion

Question 40

What do D-cells produce?

Answer 40

Somatostatin Inhibits G cells

Question 41

What do EC cells produce?

Answer 41

Serotonin and substance P Promotes gut motility