L6: The Endocrine Pancreas

Question 1

Prevalance of Exocrine vs. Endocrine cells in the pancreas?

Answer 1

98% Exocrine
2% Endocrine

Question 2

What occupies the majority of the Islet of
langerhans?

Answer 2

Beta Cells

Question 3

Significance of arrangement of Islet of Langerhands cells?

Answer 3

Core of Beta Cells asnd Perimeter of Alpha + Minor Cells

Blood enters CORE of the Islet => Beta cells can regulate the cells downstream of blood flow

Question 4

____________________ can synchronize beta cell insulin secretion

Answer 4

Cell cell communication via Calcium gap junctions can synchronize beta cell insulin secretion

Question 5

Mechanism of Beta Cell Glucose sensing and secretion of Insulin from Pancreatic Beta Cells?

Answer 5

Glucose enters beta cells through GLUT-2 => metabolized by glycolysis producing ATP=> ATP CLOSES K+ channel and OPENS CA2+ channel => Calcium rushes into the cell => exocytosis of insulin-containing granules

Question 6

What causes MODY (maturity onset diabetes of young)?

Answer 6

Glucokinase Mutations (Responsible for conversion of Glucose to Glucose 6-Phosphase)

Question 7

Sulphonylurea blocks ___________ and stimulates ____________ secretion.

Answer 7

Sulphonylurea blocks K+ channels and stimulates insulin secretion => Used as therapy for diabetics

Question 8

Insulin is an _______ hormone, it promotes utilisation and storage of energy when it is abundant

Answer 8

Insulin is an anabolic hormone, it promotes utilisation and storage of energy when it is abundant

Question 9

Metabolic Actions of Insulin in Muscles?

Answer 9

Increased Glucose Uptake
Increased Glycogenesis
Increased Glycolysis
Increased Protein Synthesis
Decreased Protein Breakdown

Question 10

Metabolic Actions of Insulin in Adipocytes?

Answer 10

Increased Glucose Uptake
Increased Lipogenesis
Decreased Lipolysis

Question 11

Metabolic Actions of Insulin in Liver?

Answer 11

Increased Glycolysis
Increased Glycogen Synthesis
Decreased Gluconeogenesis
Decreased Glycogenolysis

Question 12

What is the main insulin-responsive glucose transporter in skeletal muscle?

Answer 12

GLUT4

Glucose cannot freely diffuse: transported needed. Glut 4 (Muscle cells) when stimulated by insulin is added to the muscle cell membrane allowing uptake of glucose

Question 13

Excess acetyl CoA generated from ___________ of fatty acids is converted to ketone bodies (_______________ and __________) via ______________.

Answer 13

Excess acetyl CoA generated from Beta Oxidation of fatty acids is converted to ketone bodies (acetoacetate and hydroxybutyrate) via ketogenesis.

Question 14

Regulation of FA Synthesis and Oxidation?

Answer 14

Hormones (Insulin/Glucagon) regulate sensitivity of rate-limiting enzyme acetyl CoA carboxylase (ACC) by reversible phosphorylation / dephosphorylation

Question 15

Where is the only place Ketone Bodies are formed?

Answer 15

Liver Mitochondria

Question 16

Major energy source for the brain during starvation?

Answer 16

Ketone Bodies

Question 17

Where/How can ketone bodies be used as an energy source?

Answer 17

Released by liver and used as an alternative source of fuel for brain, heart and muscle: water-soluble transportable form of FAs’ converted to acetyl-CoA and oxidised by TCA cycle in target tissue

Question 18

Water-soluble transportable form of FAs’?

Answer 18

Ketone Bodies

Question 19

Hormones leading to increased plasma glucose?

Answer 19

Glucagon
Epinephrine
Cortisol
Growth Hormone

Question 20

_____________ are partially depleted, even during short fasts

Answer 20

Liver glycogen stores are partially depleted, even during short fasts

Question 21

Cause of the majority of complications seen with Type 2 Diabetes?

Answer 21

Vascular complications major cause of ill health and death:
diabetic nephropathy
diabetic retinopathy
diabetic neuropathy

^ All arise from damage caused by chronic hyperglycemia to small blood vessels

Question 22

Metabolic Derangement associated with Diabetes Type 1?

Answer 22

• Hyperglycemia
• Protein breakdown - insulin essential for muscle genesis
• Ketoacidosis - ketone body production ‘starvation in the midst of plenty’