Carbohydrate Metabolism

Question 1

Where does carbohydrate digestion begin?

What happens?

Answer 1

Mouth

Salivary alpha amylase in mouth (little starch broken)

Question 2

Where does digestion take place after the mouth and what are they brokendown to?

Answer 2

2nd part of duodenum
Exocrine pancreatic amylase at duodenum - 95% starch broken down
Oligo/disaccharides now

Question 3

What is the last stage of starch digestion?

Answer 3

End of duodenum
Membrane bound oligo/disaccharidases at duodenum broken down to monosaccharides
Glucose, fructose, galactose

Question 4

How is glucose and galactose absorbed?

Answer 4

2* active transposrt with Na+, SGLT-1(cotransporter)

Sodium glucose like transporter

Question 5

How is fructose absorbed?

Answer 5

Facilitated diffusion via GLUT 5 transporter

Question 6

How do all 3 leave the duodenum and enter blood?

Answer 6

Leave duodenum basolaterally by GLUT 2

Question 7

Where do monosaccharides go from the duodenum?

Answer 7

Diffuse into blood through capillary pores, to hepatic portal vein, to the liver

Question 8

What is the biggest comsumer of glucose?

Answer 8

Skeletal muscle as it makes up majority of the body

Question 9

Once monosaccharides are absorbed, what happens to them in the absorbative state (eaten)?

Answer 9

Glucose uptake by liver & stored as glycogen in liver + skeletal muscle

Question 10

Once monosaccharides are absorbed, what happens to them in the postabsorbative state (fasting)?

Answer 10

Glycogen stores broken down to glucose, from skeletal muscle & liver
Consumed by skeletal muscle