Chapter 35 Pancreas and carbohydrate metabolism

Question 1

What are the basic responses of pancreas, liver,adipose and muscle to fed , overnight fast and starvation

Answer 1

When the body Is fed :
The body just stores and the organs don’t have to work to make up for energy

When the body is overnight fasting :
1.Liver energy production
-Glycogenolysis
-Gluconeogenesis
-Fat oxidation (fat use)

2.Adipose energy production
-Lipolysis(release of fat)

3.Muscle energy production
-Glycogenolysis
-Proteolysis(low)

When the body is being starved :

1.Liver energy production
-Gluconeogenesis,Ketogenesis formation of Ketone bodies(KB)

2.Adipose energy breakdown
-Lipolysis

3.Muscle breakdown
-Proteolysis , release of AAs

Question 2

What are the functions of the exocrine and endocrine pancreas?

Answer 2

Exocrine pancreas secretes digestive enzymes :
-Inactive proteases are cleaved into active form in stomach and intestine and protein breakdown
-Lipases=Breakdown lipids
-Amylase=Breakdown of carbohydrates

Endocrine pancreas consists of Islets of langerhans

islet contain 5 major hormone secreting cell types:

Most Abundant
-30-40%, α cells (Glucagon)
-40-50%, β cells (Insulin)

Least abundant
-5-10% δ cells (Somatostatin)
-1-5% γ cells (Pancreatic Polypeptide)
-<1% ε cells (Ghrelin)

Question 3

How does high glucose stimulate insulin release?

Answer 3

1. GLUT1 receptor takes up glucose
2. Glucose is metabolized into ATP
3. Membrane depolarization Katp channels close, Ca2+ channel open
4. Insulin granules released by exocytosis

Question 4

How does insulin trigger glucose uptake?

Answer 4

It cant be done in the fasted state because there are no GLUT4 glucose transporters in the plasma membrane

In the fed state it can , insulin recruit GlUT 4 to the plasma membrane to promote glucose uptake

Question 5

How is insulin production or action disturbed in Type 1 Diabetes? Type 2 Diabetes?

Answer 5

in type 1 diabetes - beta cells are destroyed by autoimmunity , leading to insulin deficiency

In type 2 diabetes - Insulin resistance in adipose and liver leads to progressive failure of beta cell insulin secretion

Question 6

What are some treatments or clinical management approaches for type 1 diabetes ? type 2 diabetes?

Answer 6

type 1:managed with insulin replacement
-Injections or pump, but dosing challenges
-Islet transplantation, stem cell derived beta cell transplant
-Immunotherapy

Type 2: Is managed or treated in a variety of ways
-Bariatric Surgery , lifestyle change
-Medications that reduce insulin resistance
-Medications that enhance beta cell insulin secretion