T1 L6: Secretions of the intestine, liver, gall bladder, and pancreas

Question 1

Where is vitamin B12 absorbed in the intestine?

Answer 1

In the ilium (Payers patches)

Question 2

What is secretin?

Answer 2

Secreted by S cells and it stimulates pancreatic and biliary bicarbonate secretion to produce high volume HCO3- rich pancreatic juice

Question 3

What is Cholecystokinin (CCK)?

Answer 3

Its secreted by I cells and it stimulates pancreatic and gall bladder secretion

Question 4

What is glucose dependent insulinotrophic peptide (GIP)?

Answer 4

Secreted by K cells and it inhibits acid secretion and insulin release is stimulated

Question 5

What do goblet cells secrete?

Answer 5

Mucus

Question 6

What do enteroendocrine cells secrete?

Answer 6

Secretin, cholecystokinin, or GIP

Question 7

What do Paneth cells secrete?

Answer 7

Lysozyme capable of phagocytosis

Question 8

Which secretory cells are found on villi?

Answer 8

absorptive enterocytes and goblet cells

Question 9

Which secretory cells are found in intestinal glands?

Answer 9

Enterocytes secreting isotonic fluid, entero-endocrine cells, Paneth cells

Question 10

Where are Brunner’s glands found?

Answer 10

Only in the duodenum

Question 11

What do Brunner’s glands secrete?

Answer 11

Mucus and HCO3-

Question 12

Where are stem cells found in the intestines?

Answer 12

In the base of crypts

Question 13

What is the turnover rate in the intestines?

Answer 13

3-6 days

Question 14

What is exocrine pancreatic juice made up of?

Answer 14

Bicarbonate and digestive enzymes

Question 15

What is produced in the alpha islets of Langerhans in the pancreas?

Answer 15

Glucagon

Question 16

What is produced in the beta islets of Langerhans in the pancreas?

Answer 16

Insulin

Question 17

What is produced in the delta islets of Langerhans in the pancreas?

Answer 17

Somatostatin

Question 18

What is produced in the F-cells in the islets of Langerhans in the pancreas?

Answer 18

Pancreatic polypeptide

Question 19

What does Somatostatin do?

Answer 19

It inhibits many digestive processes

Question 20

What does pancreatic polypeptide do?

Answer 20

It regulates pancreatic secretions

Question 21

What % of the pancreas is made up of exocrine acinar clusters secreting pancreatic juice?

Answer 21

99%

Question 22

What stimulates the production of ACh in acinar clusters of the pancreas?

Answer 22

Parasympathetic vagus nerve stimulation

Question 23

What makes up the pancreatic juice secreted by exocrine acinar clusters in the pancreas?

Answer 23

Water, electrolytes, sodium bicarbonate and pro-enzymes

Question 24

What stimulates the production of CCK in acinar clusters of the pancreas?

Answer 24

Chyme containing fat and proteins

Question 25

What stimulates the production of secretin in ductal cells of the pancreas?

Answer 25

H+ in chyme

Question 26

What is the function of trypsin inhibitor?

Answer 26

It prevents activation of trypsin to prevent pancreatic digestion

Question 27

Why are proteolytic enzymes secreted in inactive form?

Answer 27

To prevent autodigestion within the pancreas. They're activated in the brush border of the small intestine

Question 28

What do nucleases digest?

Answer 28

RNA and DNA into nucleic acids

Question 29

What are zymogens?

Answer 29

The inactive form of proteolytic enzymes

Question 30

What does trypsin do?

Answer 30

A type of proteolytic enzyme that goes on to activate other proteolytic enzymes

Question 31

How is trypsin activated?

Answer 31

The enzyme enterokinase cleaved hexapeptide to form active trypsin from trypsinogen in the brush border of the small intestine

Question 32

What is the brush border of the small intestine?

Answer 32

The border of the small intestine. The epithelium lining it

Question 33

What is the CFTR transporter for and what controls it?

Answer 33

For recycling of Cl-. Its under the stimulation of secretin

Question 34

Which nerve supplies the submandibular and sublingual glands?

Answer 34

Super salivary nucleus (CN7 - the facial nerve)

Question 35

Which nerve supplies the parotid gland?

Answer 35

The inferior salivary gland (CN9 - the glossopharyngeal nerve). Has to go through the Ottic ganglia to get to the gland

Question 36

What do enteroendocrine G-celldo?

Answer 36

They respond to partially digested proteins and therefore the [H+] in the stomach, and then they will secrete gastrin in response

Question 37

What does gastrin do?

Answer 37

It stimulates parietal cells to release HCl and chief cells to release pepsinogen

Question 38

What do chief cells do?

Answer 38

They secrete pepsinogen that under a specific pH will turn into pepsin in the stomach

Question 39

Why do partially digested proteins result in a pH change?

Answer 39

H+ will bind to proteins so having a lot of proteins increases pH into more alkali

Question 40

What is somatostatin stimulated by?

Answer 40

Low pH

Question 41

What do parietal cells do?

Answer 41

They have carbonic anhydrase to produce HCl in the stomach

Question 42

What do ECL cells do?

Answer 42

Secrete histamine

Question 43

What do D-cells do?

Answer 43

Produce somatostatin

Question 44

Which nervous system control motility?

Answer 44

The enteric NS

Question 45

How does omeprazole work?

Answer 45

Inhibits H+/K+ ATPase

Question 46

How does Atropine work?

Answer 46

It inhibits muscarinic receptors and vagal stimulation of acid secretion

Question 47

What is the mechanism behind cholera?

Answer 47

The permanent activation of adenylyl cyclase so Cl- are constantly being pushed out and water will follow leading to dehydration

Question 48

What is the ionic composition of unstimulated secretion?

Answer 48

Low secretion rate and its similar in composition as plasma

Question 49

What is the ionic composition of stimulated secretion?

Answer 49

High secretion rate high in HCO3- and low in Cl-

Question 50

What is the mechanism behind cystic fibrosis?

Answer 50

The CFTR transporter is defective leading to the ducts being blocked with enzymes and mucus that will lead to fibrosis of the pancreas

Question 51

Which cells secrete intrinsic factor needed for vitamin B12 digestion?

Answer 51

Parietal cells

Question 52

What oral medication is given to those with the CFTR Cl- transporter?

Answer 52

Oral pancreatic enzyme supplements with each meal

Question 53

What is pancreatitis?

Answer 53

An inflammatory disease where pancreatic enzymes are activated within the pancreas leading to autodigestion. Most common causes are gall stones and alcohol abuse

Question 54

Which organ concentrates bile and how?

Answer 54

The gallbladder by reabsorbing water and electrolytes across the gall bladder mucosa

Question 55

What do Kupffer cells do?

Answer 55

They digest old RBC's

Question 56

What is Hepatocellular (congenital) jaundice?

Answer 56

The hepatocytes have altered function that prevents conjugation of bilirubin (making hydrophilic) so it can't be transported by albumin. Caused by Crigler-Najjar syndrome

Question 57

What is pre-hepatic jaundice?

Answer 57

Excessive RBC breakdown causing build up of bilirubin because the body can't keep up. Can happen with haemolytic anaemia

Question 58

What is Hepatocellular (congenital) jaundice?

Answer 58

The hepatocytes have altered function

Question 59

What is post-hepatic jaundice?

Answer 59

Obstruction of the bile duct. Caused by gall stones

Question 60

How is bile secretion regulated (3 ways)?

Answer 60

CCK causes gall bladder contraction. Secretin is released in response to acidic chyme and it causes ductal secretion of HCO3-. Vagal and ACh stimulation causes bile flow and gall bladder contraction

Question 61

What is enterohepatic circulation for?

Answer 61

Recycling of bile salts

Question 62

What are the common causes of glass stones?

Answer 62

Excessive water and bile salt reabsorption, excessive cholesterol, inflammation

Question 63

What is Cholelithiasis?

Answer 63

Gall stones