Gastrointestinal: accessory glands

Question 1

What are the 2 major parts of the GI system?

Answer 1

GI tract

Accessory gland

Question 2

What is the GI tract?

Answer 2

Several organs joined in series to process food and digestion products

Question 3

What are the accessory glands?

Answer 3

Secrete various fluids and enzymes to aid the digestive process

Question 4

What are the 4 types of GI gland types and give an example of them?

Answer 4

Surface glands - goblet cells
Deep, tubular glands - gastric glands
Mucosal/sub mucosal glands - crypts of Liberkuhn
Specialised glands - salivary glands

Question 5

What is the role of an accessory gland and give 3 examples:

Answer 5

Secrete products via ducts into lumen of the GI tract:

• Salivary glands, saliva
• Pancreas, pancreatic juice
• Liver, bile

Question 6

What are the 2 characteristics of saliva and what are the 2 enzymes in it?

Answer 6

Rich in bicarbonate ions
Contains mucus
enzymes: salivary amylase, lysozyme

Question 7

What are the 2 types of secretions in saliva?

Answer 7

Serous secretion (salivary amylase)
Mucous secretion (mucins)

Question 8

What are the glands that secrete into gastric juice and what do they secrete? (3)

Answer 8

Cardiac glands: mucous
Oxyntic/gastric glands: HCl, pepsinogen, mucous
Pyloric glands: pepsinogen, mucous

Question 9

What are the 3 main cells that secrete from the glands?

Answer 9

Chief cells - pepsinogen
Parietal cells - HCl
Neck cells - mucous

Question 10

What is the pH of the stomach?

Answer 10

1.0 - 3.5

Question 11

What causes peptic ulcers? (5)

Answer 11

Excess acidity - lining the stomach
Excess pepsin
Poor mucous secretion - no bicarbonate layer
Irritation of mucosa
Infection of mucosa

Question 12

What are the symptoms of peptic ulcer disease? (3)

Answer 12

• Chronic, rhythmic and periodic burning pain in the stomach
• Relieved by drinking milk or antacids
• bleeding due to acid and pepsin attacks on blood vessels

Question 13

How is the stomach protected from acid? (3)

Answer 13

1. Luminal membrane of gastric mucosal cells are impermeable to H+ - HCl can’t pentrate
2. Cells are joined by tight junctions that prevent HCl penetrating between them
3. A mucus coating over the gastric mucosa offers further protection

Question 14

What is a helicobacter pylori? (3)

Answer 14

• Gram negative bacteria found in the mucus lining in stomach
• Triggers ulcer by activating immune response that destroys tissue - makes lining vulnerable
• Secretes urease enzyme - neutralises HCl

Question 15

What does the pancreas release exocrinely into the GI system?

Answer 15

Pancreatic juice: bicarbonate, enzymes (pancreatic amylase, lipases, proteases, nucleases)

Question 16

What is a zymogen? (3)

Answer 16

• Inactive form of digestive enzymes
• Stored in zymogen granules of acinar cells in cytoplasm
• Activated by proteolytic enzymes in lumen of intestinal tract

Question 17

What is the endocrine role of the pancreas? (3)

Answer 17

• Consists of isolated islands of there endocrine tissue (islets of Langerhans)
• Produce hormones - insulin and glucagon
• Exocrine and endocrine derived from different tissues

Question 18

What are the functions of the liver? (7)

Answer 18

Secreting bile
Processing of nutrients
Storing glycogen
Removal of old RBC
Elimination of wastes and toxins
Synthesis of plasma proteins
Secretion and modifications of hormones

Question 19

What is the biliary system comprised of?

Answer 19

Liver, gall bladder and associated ducts

Question 20

What does the biliary system do?

Answer 20

Liver synthesises bile
Gallbladder stores bile
Common bile duct transports bile from liver to duodenum

Question 21

What is the liver anatomy and what do they do? (4)

Answer 21

Sinusoids: take up materials to make bile from blood
Hepatocytes secretes bile into bile canaliculi
Canaliculi drain into bile ducts
Bile ducts drain into common hepatic duct