The Fed State

Question 1

During a meal we ingest?

Answer 1

Proteins, carbohydrates and lipids

Question 2

Which period is the well fed state?

Answer 2

2-4 hours after normal meal

Question 3

Fuels (proteins, carbs, lipids) are oxidised for the body’s needs

Answer 3

Excess is transported to storage sites;
Increased glycogen and triacylglycerol synthesis;
Readily available substrates - anabolic state

Question 4

Oxidation or storage is determined by?

Answer 4

Insulin/glucagon ratio

Question 5

Conversion of carbohydrates into monosaccharides

Answer 5

Starch disgusted by salivary amylase;
Disaccharides/trisaccharides/monosaccharides digested by enzymes in brush border (intestine);
Monosaccharides absorbed by intestinal epithelial cells;
Transported to hepatic portal vein;

Question 6

Protein digestion

Answer 6

Proteins cleaved by pepsin in the stomach and proteolytic enzymes in the pancreas;
Absorbed into intestinal epithelial cells;
Transported to hepatic portal vein;
Free amino acids absorbed from blood used for protein synthesis and biosynthesis;

Question 7

Why is digestion of fats problematic?

Answer 7

Fats aren’t soluble

Question 8

Digestion of fats

Answer 8

Triacylglycerol- major lipids of diet;
Emulsified by bile salts;
Pancreatic lipase converts TAGs to fatty acids and 2-monoglycerols;
Absorbed and reformed into TAGs;
TAGs packaged with cholesterol, phospholipids, proteins. Into chlyomicrons;
Secreted into lymphatic system;
Enter bloodstream via thoracic duct;

Question 9

Hormones alter metabolic pathways by

Answer 9

Substrate availability;
Covalent modification of enzyme;
Allosteric regulation of enzymes;
Induction of enzyme synthesis;

Question 10

The liver

Answer 10

Veinous drainage of the pancreas and gut through the hepatic portal vein;
1st organ bathed in nutrients and insulin;
Takes up carbohydrates, lipids, amino acids - metabolites, stored, rerouted;

Question 11

Carbohydrate metabolism

Answer 11

Increased glucose uptake by hepatocytes - GLUT 2 has a high Km;
Increased phosphorylation of glucose - glucokinase creates glucose 6 phosphate;
Excess glucose converted to TAG - packaged into VLDLs;
Increase glucogenesis - glycogen synthase is activated (by dephosphorylation) and by its allosteric effector glucose 6 phosphate which converts glucose 6 phosphate to glycogen;