Gastrointestinal Systems

Question 1

What are the accessory structures of the duodenum?

Answer 1

The liver (forms bile), gall bladder (stores bile), pancreas

Question 2

Where is bile formed and stored?

Answer 2

Formed in the liver and stored in the gall bladder

Question 3

What does bile do?

Answer 3

Emulsify fat

Question 4

What is acidic chyme?

Answer 4

It’s neutralised by bicarbonate in pancreatic juice

Question 5

What else is added to chyme?

Answer 5

Intestinal juice

Question 6

What enzymes do the pancreas secrete and as what?

Answer 6

Proteolytic enzymes are secreted as Zymogens so they don’t digest the cells that produce them

Question 7

GI tracts functions are controlled by hormones such as?

Answer 7

Gastrin: controls gastric HCL secretion
Secretin: controls pancreatic bicarbonate
Cholecystokinin: pancreatic enzyme secretion, bile release by Gall Bladder, inhibits stomach
Motilin: stimulates gastric motility
Somatostatin: inhibits gastric acid secretion
G inhibitory peptide: potentiates insulin secretion

Question 8

What is the small intestine sub divided into?

Answer 8

Duodenum (25cm)
Jejunun (1.5m)
Ileum (2.5m)

Question 9

What’s the main site of enzymatic digestion and absorption?

Answer 9

Duodenum and jejunum

Question 10

What does the ileum do?

Answer 10

Absorbs nutrients

Question 11

How is the surface area increased for absorption?

Answer 11

So simple tube, with folds, with villi, and microvilli

Question 12

Explain the structure of intestinal Villi and how the surface area is increased?

Answer 12

Villi and microvilli on individual absorptive cells (enterocytes)increase surface area for absorption

Question 13

What is found in the cell membrane of microvilli?

Answer 13

Lactase,Maltase, nuclease, peptidases

Question 14

What is transported through epethelial cells to the hepatic portal venous system?

Answer 14

Amino acids and sugars

Question 15

How is fructose absorbed?

Answer 15

By facilitated diffusion

Question 16

How are glucose and amino acids absorbed?

Answer 16

They are co-transported with sodium involving secondary active transport

Question 17

What is a chylomicron?

Answer 17

Triglycerides packaged within a lipoprotein coat by the endolasmic reticulum

Question 18

What is fat absorbed as?

Answer 18

As chylomicrons which entree lymphatic vessels rather than blood capillaries

Question 19

How does co-transport with sodium involve a secondary active transport?

Answer 19

Use of ATP to pump sodium makes this a secondary active transport

Question 20

What provides facilitated diffusion?

Answer 20

Glut2 and Glut5

Question 21

Small peptides and amino acids are co-transported with?

Answer 21

With H+ and Na+

Question 22

What do chylomicrons enter?

Answer 22

Lymph vessels not blood!

Question 23

How do lipids diffuse?

Answer 23

Freely

Question 24

What’s the appendix and where’s it located?

Answer 24

A vestigial cecum found where the small and large intestines meet

Question 25

What is the function and structure of the colon?

Answer 25

It recovers water and ions, and it only has a few villi

Question 26

What does the colon mucosa do?

Answer 26

It has intestinal glands with mucous secreting cells

Question 27

What does the mammalian colon do?

Answer 27

It contains microbes which convert cellulose to fatty acids which are absorbed

Question 28

What does the rectum do?

Answer 28

Forms faeces

Question 29

What’s hydrolysis?

Answer 29

The enzyme assisted breakdown of food

Question 30

After you swallow food where does it go ?

Answer 30

The oesophagus

Question 31

After the oesophagus where does food go?

Answer 31

To the stomach

Question 32

What does the stomach do ?

Answer 32

• churning of food
• hydrolysis
• storage
• make chyme

Question 33

After the stomach where does food go?

Answer 33

The intestine (small intestine)- hydrolysis, absorption of nutrients

Then to the large intestine/colon:
Absorption of water/ions

Question 34

After the intestine where does food go ?

Answer 34

To the rectum:

Storage until time to expel the food via the anus through expulsion