Gastric Secretions

Question 1

What is the main role of the fundus of the stomach ?

Answer 1

Storage

Question 2

What is produced in the body of the stomach ?

Answer 2

HCL, pepsinogen and intrinsic factor

Question 3

Where does mixing and grading occur ?

Answer 3

In the antrum

Question 4

What is secreted in the antrum ?

Answer 4

Gastrin

Question 5

What cells produce pepsinogen ?

Answer 5

Chief cells

Question 6

What is the pH of blood ?

Answer 6

7.4

Question 7

What do parietal cells have receptors for ?

Answer 7

Gastrin

Question 8

What 3 substances activate protein kinases and cause more HCL to form ?

Answer 8

Histamine
Ach
intracellular Calcium levels

Question 9

What substance prevents protein kinase activation and stops HCL production ?

Answer 9

Prostaglandins

Question 10

What 3 mechanism control gastric acid secretion ?

Answer 10

Endocrine - Gastrin
Neurocrine - Ach via vagus nerve
Paracrine - Histamine

Question 11

Describe the cephalic phase of eating

Answer 11

Thinking, seeing or smelling food triggers this phase. Act levels increase and this causes the parietal cells to make more HCL. G cells are also activated producing gastrin. Gastrin and Act cause histamine to be released from the ECL cells. More acid is produced.

Question 12

Describe the gastric phase of eating

Answer 12

Distention of the stomach wall causes vagal/enteric responses to be triggered. Ach and Gastrin produced again this triggers ECL cells to produce histamine and these all increase HCL production in parietal cells.

Question 13

Describe the intestinal phase of eating

Answer 13

Acid moves into the duodenum from the stomach and the enterogastric reflex is triggered. Gastrin secretion is reduced. If CHO and fats detected in duodenum then GIP is released which also reduces gastrin and HCL production in the stomach.

Question 14

Which 3 hormones are secreted by gland cells in the duodenal mucosa ?

Answer 14

• GIP
• CCK
• Secretin

Question 15

What is the combined affect of the hormones secreted by the duodenum ?

Answer 15

Reduces gastric emptying and gastric acid secretion

Question 16

What activates pepsinogen ?

Answer 16

HCL

Question 17

Which two hormones increase gastric emptying ?

Answer 17

Motilin and somatostatin

Question 18

Define paracrine

Answer 18

The hormone secreted only has an affect on the gland secreting it or organs close by

Question 19

Where are pacemaker cells found in the stomach ?

Answer 19

In the longitudinal muscle layer

Question 20

What sets the rhythm of the pacemaker cells ?

Answer 20

The basic electrical rhythm (BER)

Question 21

What control is motility under ?

Answer 21

Neural and hormonal control

Question 22

Where is bicarbonate secreted from in the duodenum ?

Answer 22

Brunner’s glands

Question 23

What causes secretin release and which cells release it ?

Answer 23

Acid in the duodenum triggers the release of secretin and S cells release it.

Question 24

Where is HCO3 released from ?

Answer 24

• Liver duct cells
• Pancreas
• Duodenum

Question 25

What do alpha cells secrete ?

Answer 25

Glucagon

Question 26

What do beta cells secrete ?

Answer 26

Insulin

Question 27

What is the endocrine part of the pancreas known as ?

Answer 27

Islets of Langerhans

Question 28

What is the exocrine part of the pancreas known as ?

Answer 28

Acinar cells

Question 29

What does somatostatin do ?

Answer 29

Controls release of insulin and glucagon

Question 30

What are enzymes released as in the pancreas ?

Answer 30

Inactive zymogen granules

Question 31

Which enzyme converts chymotrypsin into trypsin and where is it found ?

Answer 31

Enterokinase found on the brush border enterocytes

Question 32

What converts all other zymogens into there active forms ?

Answer 32

Trypsin

Question 33

What do lipase break down ?

Answer 33

Triglycerides

Question 34

What do phospholipases break down ?

Answer 34

Phospholipids into fatty acids

Question 35

Which hormone controls zymogen release ?

Answer 35

CCK