The Endocrine Pancreas

Question 1

What are the two Pancreatic buds? Where are they generated during development?

Answer 1

Dorsal and Ventral buds
Junction of Foregut and midgut

Question 2

When do the Exocrine and Endocrine functions of the pancreas begin respectively?

Answer 2

Exocrine- after birth
Endocrine- 10-15 weeks

Question 3

What cells perform the Endocrine activity of the Pancreas? Where do they release peptides into?

Answer 3

Islet cells/ Islets of Langerhan
Into portal vein

Question 4

What are the 3 cell types in the Islets of Langerhans? What does each secrets

Answer 4

Alpha cell- Glucagon
Beta cell- Insulin
Delta cell- Somatostatin

Question 5

How many amino acids does Insulin have? What are its functions?

Answer 5

51
Reduces glucose output by liver
Increases storage of glucose, fatty acids and Amino acids

Question 6

How many Amino acids does glucagon have? What is its function?

Answer 6

29
Mobilises glucose, fatty acids and Amino acids from stores

Question 7

What hormone stimulates the release of glucagon?

Answer 7

Ghrelin

Question 8

What 4 processes does Insulin decrease?

Answer 8

Glycogenolysis
Gluconeogenesis
Lipolysis
Breakdown of muscle

Question 9

What 4 things does Glucagon stimulate?

Answer 9

Glycogenolysis
Gluconeogenesis
Lipolysis
Muscle glycogenolysis

Question 10

What causes Insulin to be secreted by Beta cells in 5 steps?

Answer 10

1.Glucose enters B cell through GLUT2 glucose transporter
2.ATP produced
3.ATP sensitive K+ channels close causing 4.Membrane to depolarise
45Ca2+ channels open which results in Insulin secretory granules secreting insulin

Question 11

What does Proinsulin contain? Connected by what?

Answer 11

A and B chains
Joined by C peptide

Question 12

What are the links between A and B chains in proinsulin?

Answer 12

Disulfide bridges

Question 13

Why is insulin release called Biphasic Insulin release? Describe each phase

Answer 13

Split into two phases
First phase- rapid release of stored product
Second phase- Slower release of newly synthesised hormone

Question 14

What is the effect of Insulin on Fat and muscle cells? What does this cause?

Answer 14

Mobilization of GLUT4 to the cell surface
Glucose entry into cell

Question 15

What are the Short and Long term responses for Glucose >6 mmol/mol in blood?

Answer 15

Short- Glycogenesis
Long- Lipogenesis

Question 16

What are the short and Long term responses for Blood glucose <4 mmol/mol?

Answer 16

Short- Glycogenolysis
Long- Gluconeogenesis

Question 17

Other than the Islets of Langerhans, what other three structures sense blood glucose level?

Answer 17

Medulla, Hypothalamus and Carotid bodies

Question 18

What are the sensory cells in the gut wall that stimulate insulin?

Answer 18

Incretins

Question 19

2 examples of incretins?

Answer 19

Glucagon-like peptide (GLP-1)
Glucose-dependent Insulinotrophic

Question 20

Where does ingested glucose go to? What is the composition of glucose in each area?

Answer 20

40%- Liver
60%- periphery (mostly muscle)

Question 21

What is excess glucose converted into when the glycogen stores are full?

Answer 21

Lipids/ fats