6.3 Digestion and Absorption of Carbs

Question 1

What is the order of carb digestion?

Answer 1

• Mouth: Salivary amylase breaks starch
• Stomach: HCL acid deactivates amylase (no more carb digestion)
• Small intestine: Pancreatic amylase + brush-border enzymes secrete carb digesting enzymes like lactase (di to mono saccharides)
• Large intestine: Undigested carbs broken down by bacteria
• Excreted

Question 2

We can only absorb _________ sugars

Answer 2

monosaccharide

Question 3

How is sugar absorbed in the small intestine?

Answer 3

We need a protein transporter on both sides of the cell via active transport (needs ATP)

Question 4

What is lactose intolerance caused by?

Answer 4

Insufficient secretion of the enzyme lactase. This means bacteria in the large intestine ferment the lactose to make methane.

Question 5

What are some symptoms of being lactose intolerant?

Answer 5

Cramps, bloating, diarrhea, and abdominal pain

Question 6

Once sugars are absorbed into the blood, a ______ response occurs

Answer 6

glycemic

Question 7

What is a glycemic response?

Answer 7

Spike on blood glucose that follows a meal once glucose enters the general circulation

Question 8

What are diets that cause a lower glycemic response associated with?

Answer 8

Lower risk of type 2 diabetes, CVD, and obesity

Question 9

What is the glycemic index?

Answer 9

A relative ranking of a food’s potential to spike blood sugar on a 100-point scale (glucose scores 100)

Question 10

Which is better, glycemic index or load? Why?

Answer 10

Load, is it takes into account how much carbs is actually in the food

Question 11

How does our body regulate blood glucose so it doesn’t stay too high (maintains glucose homeostasis)?

Answer 11

Insulin and glucagon (increases sugar) are secreted by the pancreas

Question 12

What can imbalanced blood glucose cause?

Answer 12

Hypoglycemia (low blood glucose, affects energy levels)

Hyperglycemia (high blood glucose, can lead to diabetes if chronic)

Question 13

What is the endocrine function of the pancreas?

Answer 13

Secrete insulin and glucagon (increases sugar) into the blood

Question 14

What is the exocrine function of the pancreas?

Answer 14

Secrete pancreatic juices into the digestive tract for digestion

Question 15

How does glucagon increase blood glucose?

Answer 15

• Glycogenolysis: Convert glycogen into glucose
• Gluconeogenesis: Convert amino acids into glucose
• Lipolysis: Breakdown stored lipids. Glycerol from triglycerides can be used to make glucose