GI: Digestion and Absorption 1

Question 1

Name all of the peptide hormones that the duodenum secretes into the blood from endocrine cells in its mucosa.

Answer 1

Gastrin
CCK
Secretin
Motilin
Glucose- dependant insulino peptide (GIP)
Glucagon-like peptide- 1 (GLP-1)

Question 2

What cells secrete gastrin

Answer 2

G cells (remember this is also secreted in the stomach)

Question 3

What cells secrete CCK?

Answer 3

I cells

Question 4

What cells secrete secretin?

Answer 4

S cells

Question 5

What cells secrete motilin?

Answer 5

M cells

Question 6

What cells secrete GIP?

Answer 6

K cells

Question 7

What secretes GLP-1?

Answer 7

L cells

Question 8

What is the name of the digestive juice secreted in the small intestine?

Answer 8

Succus entericus

Question 9

What mechnisms control the secretion of digestive juice in the small intestine?

Answer 9

Distention
Gastrin
CCK
Secretin
Parasympathetic nerve activity enhances

Question 10

What is contained in secretin?

Answer 10

Mucus
Aqueous salt
No digestive enzymes

Question 11

What is segmentation?

Answer 11

Mixing of chyme in the duodenum- moves back and forth

Question 12

What muscle mediates segmentation?

Answer 12

Circular

Question 13

What initiates segmentation?

Answer 13

BER established in duodenum

At threshold this activates segmentation which is cause primarily by distention of the duodenum

Question 14

How is segmentation in the empty ileium triggered?

Answer 14

Gastrin release in stomach- gastroileal reflex

Question 15

What is the purpose of segmentation?

Answer 15

Allows time for absorption

Question 16

What enhances segmentation

Answer 16

parasympathetic stimulation

Question 17

What is peristalsis in the duodenum?

Answer 17

Occurs after all of the absorption has taken place BETWEEN meals
Clears out all of the debris from the small intestine

Question 18

What inhibitis peristalis in the duodenum?

Answer 18

Vagal activity and feeding
Gastrin
CCK

Question 19

What triggers peristalsis in the duodenum

Answer 19

Motilin

Question 20

What two types of secretions are there in the pancreas?

Answer 20

Endocrine- insulin and glucagon- into blood

Exocrine- digestive enzymes (aciner cells), aqueous Na HCO3 solution (duct cells) - secreted into the duodenum

Question 21

Where are pancreatic zymogenes stored?

Answer 21

Aciner cells

Question 22

Name the protease zymogens

Answer 22

trypsinogen
Chymotrypsinogen
Procarboxypeptidase

Question 23

Name the enxymes which are already active in the pancreas

Answer 23

Pancreatic amylase

Pancreatic lipase

Question 24

Where are pancreatic zymogens activated?

Answer 24

Duodenum

Question 25

What activates trypsinogen?

Answer 25

Enterokinase and trypsin

Question 26

What activates chymotrypsinogen and procarboxypeptidase?

Answer 26

Trypsin

Question 27

Name the active form of the pancreatic proteases

Answer 27

Trypsin Chymotrypsin Carboxypeptidases

Question 28

What is the purpose of the HCo3 solution secreted from pancreatic duct cells

Answer 28

Neutralises chyme to provide optiumum pH in duodenum for enzymes to work to break down food Protect mucosa

Question 29

What stimulates pancreatic juice secretion from the pancreas in the cephalic and gastric phases.

Answer 29

cephalic- vagal stimulation- aciner cells | gastric - distention evokes a vagovagal reflex- acinar and duct cells

Question 30

Describe how acid in the duodenal lumen affects the release of the alkaline solution from the pancreas?

Answer 30

Increased acid in duodenum Increase secretin from S cells Stimulates pancreatic duct cells Increase alkaline secretion

Question 31

Describe how fat and protein in the duodenal lumen increase digestive enzyme release from pancreas

Answer 31

Fat and protein in duodenal lumen Increased CCK release from I cells Stimulation of pancreatic acinar cells Increase digestive enzyme secretion

Question 32

What stimulates contraction of the gall bladder smooth muscle?

Answer 32

Chyme in duodenum ie acid and fat an protein

Question 33

What does fat and protein in the duodenal lumen cause to happen to the gall bladder?

Answer 33

Increases CCk release | Gall bladder contracts and spnincter of oddi opens