GI 4A - Gastrointestinal System

Question 1

How long and where is the duodenum?

Answer 1

10-12 inches, first part of the small intestines

Question 2

Where does the duodenum begin, travel, and end?

Answer 2

It begins at the pyloric valve, arcs around the head of the pancreas and passes to the left, and ends at a sharp bend called the duodenojejunal flexure (Junction)

Question 3

How long is the jejunum?

Answer 3

8 Feet long and extends from the duodenum to the ileum

Question 4

How long is the ileum and where does it join with the large intestines?

Answer 4

12 feet long and joins the large intestine at the ileocecal valve

Question 5

Maximal surface area is accomplished through_____, ______, and _______.

Answer 5

Plicae circulares, villi, and microvilli

Enterocytes have microvilli, a bunch of make a villus, and a bunch of villus makes a plicae circulares.

Question 6

What characteristics do surface absorptive cells possess?

Answer 6

possess a layer of closely packed microvilli, enzymes (brush boarded ie enterokinase), and transporters

Question 7

What characteristics do goblet cells possess?

Answer 7

mucous producers

Question 8

What characteristics do enteroendocrine cells possess?

Answer 8

Secrete CCK, secretin, GIP (DNES and APUD cells)

Question 9

What characteristics do regenerative cells possess?

Answer 9

Divide to replace themselves and the other types of epithelial cells

Question 10

What characteristics do paneth cells possess?

Answer 10

secrete the antibacterial enzyme lysozyme and other antibacterial agents

Question 11

What are the most common examples of polysaccharides?

Answer 11

Glycogen, starch, cellulose

Question 12

What does pancreatic amylase do in the duodenum?

Answer 12

degrades polysaccharides into disaccharides and “oligosaccharides”

Question 13

What is the family of enzymes that break down the disaccharides? And what are their specific names?

Answer 13

Disarrharidases
Maltase for maltose
Sucrase for sucrose
Lactase for lactose
a-dextrinase for a-dextrins but only does a little break downthe rest is crapped out

Question 14

Glucose + fructose =

Answer 14

Sucrose

Question 15

lactose = _____ + _______

Answer 15

galactose and glucose

Question 16

glucose + glucose =

Answer 16

Maltose

Question 17

How are Glucose and Galactose absorbed into the enterocyte?

Answer 17

via secondary active transport through a Na+ dependent cotransporter known as SGLT1. High luminal concentration of Na facilitates absorption of these sugars against their gradients.

Question 18

How is fructose absorbed into the enterocyte?

Answer 18

Facilitated diffusion via glucose transporter 5 (GLUT 5)

*doesn’t require Na+

Question 19

How are all monosaccharides transported out of enterocyte into capillaries?

Answer 19

GLUT 2 (facilitated diffusion)

Question 20

Whats the deal with Lactose intolerance?

Answer 20

No lactase to break down lactose = stink butt

Question 21

Where are the majority of amino acids cleaved off?

Answer 21

occurs mainly at the brush border with aminopeptidases and with active pancreatic enzymes

Question 22

What are the aminopeptidases?

Answer 22

Amino-oligopeptidase and dipeptidyl - aminopeptidase

and little ceaz one-peptidase

Question 23

What are the active pancreatic enzymes?

Answer 23

Typsin, chymotripsin, carboxypeptidases A/B, elastase

Question 24

How are amino acids transported?

Answer 24

Most aa or small peptides are transported via the same co-transport mechanism utilized by glucose. Some aa do not require Na co-transport instead they are transported in the same way fructose is moved, facilitated diffusion.