Endocrine Pancreas

Question 1

Hormones of the Pancreas

Answer 1

Insulin
Glucagon
Somatostatin
Pancreatic Polypeptide

Question 2

Pancreas Hormones Functions

Answer 2

All involved in the metabolism of ALL 3 major nutrients (CHO, fat, protein)
Over-arching function is to ensure efficient storage AND utilization of ALL 3 nutrients in order to maintain the plasma glucose level within an adequate but narrow range
Glucose Glycogen
Fatty Acids Triglycerides
Amino Acids Protein

Question 3

Pancreatic Islets (of Langerhans) Vasculature

Answer 3

Volume: Only 1-2% of pancreatic tissue

Receive 10-15% of pancreatic blood flow

Question 4

Pancreatic Islets Innervation

Answer 4

Receives both sympathetic and parasympathetic supply

Question 5

Pancreatic Islets Cell Types

Answer 5

1. Alpha Cells (20-25%): produce glucagon
2. Beta Cells: (60-70%, most numerous): produce insulin
3. Gamma Cells (<10%, small numbers): produce somatostatin
4. F or PP cells (only a few cells): produce pancreatic polypeptide

Question 6

Islet Structure Importance

Answer 6

Blood enters center of islet first-> picks up insulin and passes to periphery
Relates to paracrine feedback control of hormones secretion because insulin levels affect the activity of other islet cells

Question 7

Pancreatic Polypeptide

Answer 7

Talks to enzyme side of pancreas
Has both intra and extra-islet activity, overall effects REDUCES digestion of foodstuffs
-Intrapancreatically: promotes intra-islet homeostasis, decrease production of pancreatic enzymes
-Extra-pancreatic activity: inhibits gall bladder contraction and small intestinal activity

Question 8

Pancreatic Somatostatin

Answer 8

Talks to endocrine side of pancreas
Paracrine regulator of secretion of pancreatic hormones
Potent INHIBITOR of secretion of ALL hormones including itself
Sum of effects basically slows rate of digestion/absorption of nutrients-> avoids excessive blood nutrient levels, prolongs time of availability of nutrients from a given meal

Question 9

Insulin and Glucagon collectively

Answer 9

Reciprocal actions on metabolism

Balance between them keeps blood glucose in normal range (both present simultaneously)