Phys 66: GI Absorption

Question 1

Major reaction of digestion

Answer 1

Hydrolysis

Question 2

Major diet carbs

Answer 2

Sucrose

Lactrose

Starches

Question 3

What happens to cellulose

Answer 3

Nothing, it cant be digested by humans

Question 4

Where does carbohydrate digestion begin

Answer 4

In mouth by saliva enzyme (ptyalin)

Question 5

Most of carbohydrate digestion is done by

Answer 5

Pancreatic amylase

Way more powerful than salivary amylase

Question 6

Hydrolysis of small glucose polymers is done by ____

via ____ enzymes
Where

Answer 6

Enterocytes

lactase, sucrase, maltase

intestine

Question 7

Pepsin function

Answer 7

Cleaves proteins into smaller peptides. Real work is done down the line by pancreatic enzymes but pepsin is needed to iniate

Question 8

Pepsin pH activity

Answer 8

Most active at pH 2-3

Inactive at pH 5

Question 9

Collagen is digested by (enzyme)

Answer 9

Pepsin

Question 10

Carboxylpolypeptidase function

Answer 10

Cleaves individual amino enzymes from peptide ends

Question 11

Hydrolysis of neutral fats is catalyzed by

Answer 11

Lipase

Question 12

First step of fat digestion

Answer 12

Emulsification of fat by bile acids and lecithin

Question 13

Tryglycerides are digested by

Answer 13

Pancreatic lipase

Question 14

Phospholipids hydrolized by

Answer 14

Phospholipase A2

Question 15

Total intestinal fluid absorption per day

Answer 15

8-9 liters

Question 16

Folds in small intestine AKA

Answer 16

Valvulae coniventes

or

Folds of kerkring

Question 17

Absorptive area of small intestine

Answer 17

250 sq meters… or a tennis court

Question 18

Lymph vessel inside of villi is called

Answer 18

“central lacteal”

Question 19

Brush border filaments are moved by

Answer 19

Actin filaments

Question 20

Water from chyme is absorbed via

Answer 20

Osmosis

Question 21

Sodium into intestinal epithelial cells absorbed via

Answer 21

SGLT1

Na/Amino acid co transport

Na+/H+ exchanger

Question 22

Aldosterone in intestine

Answer 22

Increases sodium absorption, water follows

Question 23

HCO3- is absorbed in duodenum and jejunum via what fashion

Answer 23

same as in kidneys

Question 24

Cholera toxin MOA

Answer 24

Stimulates sodium secretion in intestinal folds, water follows, you shit water

Question 25

PTH in intestine

Answer 25

Activates vitamin D, which then promotes calcium uptake

Question 26

Most of the absorption in colon occurs in

Answer 26

Proximal half

Question 27

Brown color of feces comes from

Answer 27

Billirubin derivatives

Question 28

Most vitamin K comes from

Answer 28

Bacteria in GI tract