Carb/Fat/Protein digestion and absorption

Question 1

How much of your nutrients are absorbed by the time a meal reaches the distal jejunum?

Answer 1

95%

Question 2

What is the purpose of segmenting contractions?

Answer 2

Mixing facilitation

Question 3

What three enzymes are responsible for disaccharide cleavage in the brush border?

Answer 3

Maltase
Sucrase
Lactase

Question 4

What product inhibits lactase activity?

Answer 4

Glucose

Question 5

What prevents protease degradation of brush border enzymes?

Answer 5

Heavy glycosylation

Question 6

What are the causes of lactose intolerance?

Answer 6

Secondary after injury to absorptive cells due to Crohn’s, celiac, or alcohol
Normal decrease in lactase activity

Question 7

What transporters are important in sequestering monosaccharides from bacteria?

Answer 7

SGLT1: Na-Glucose/Galactose cotransporter
GLUT5: Fructose transporter

Question 8

What type of transporter is SGLT1?

Answer 8

Secondary active transporter

Symporter

Question 9

What enzyme transports monosaccharides across basolateral membrane?

Answer 9

Glut2

Question 10

What initiates amino acid degradation in the stomach?

Answer 10

Pepsin

Question 11

If an enzyme is rich in this amino acid, it is resistant to digestion.

Answer 11

Proline

Question 12

What is often transported along with amino acids on the luminal side transporters?

Answer 12

Sodium

Question 13

What is transported with peptides with PEPT1? In what direction?

Answer 13

Protons

Opposite (antiporter)

Question 14

What is the cotransported ion with peptides?

Answer 14

Protons

Question 15

What is the process of protein absorption in infants like?

Answer 15

Endocytosis (passive immunity)

Question 16

What is the role of intestinal M cells?

Answer 16

Take up antigens and presents them to lymphocytes

Question 17

What cells secrete gastric lipase?

Answer 17

Chief cells

Question 18

Why is gastric lipase important in neonates?

Answer 18

Developmental delay of pancreatic enzyme expression

Question 19

What cells secrete pancreatic lipase and procolipase?

Answer 19

Acinar cells

Question 20

What activates colipase?

Answer 20

Trypsin

Question 21

What do bile acids do to lipase activity? What remedies that?

Answer 21

Bile acids inhibit lipase activity, collipase remedies it

Question 22

What is the role of phospholipase A2?

Answer 22

Cleaves phospholipids from cell membranes into fatty acids and lysophospholipids

Question 23

What enzyme hydrolyzes cholesterol esters?

Answer 23

Cholesterol esterase

Question 24

What is orlistat?

Answer 24

Pancreatic lipase inhibitor

Question 25

What is olestra?

Answer 25

Undigestable fat too big to be absorbed

Question 26

What is the role of bile salts and phospholipids?

Answer 26

Break up fat globules into droplets

Question 27

How do lipids enter enterocytes?

Answer 27

Nonionic diffusion
Collision with membrane
Carrier mediated transport

Question 28

What coats triglycerides to form chylomicrons?

Answer 28

Apoproteins

Question 29

Where does chylomicron synthesis occur in the enterocyte?

Answer 29

Smooth ER

Question 30

What cells secrete intrinsic factor? What does it do?

Answer 30

Parietal cells

Binds B12 and protects it from degrading

Question 31

What common drug interferes with absorption of B12?

Answer 31

Metformin