Pancreas

Question 1

The pancreas is both _____ & ______ gland.

Answer 1

exocrine & endocrine

Question 2

Pancreas is located where?

Answer 2

Located in the retroperitoneum at the level of the 2nd lumbar vertebrae.

Question 3

Pancrease measures about ___________cm in length

Answer 3

12.5 - 15cm

Question 4

Exocrine pancreatic secretion is composed of:

Answer 4

• enzymes
• water
• electrolytes
• bicarbonate

Question 5

Exocrine pancreatic secretion is delivered where?

Answer 5

To the duodenum (ampulla of Vater - D2) via the pancreatic duct of Wirsung.

Question 6

Endocrine secretions include

Answer 6

• insulin
• glucagon
• somatostatin

Question 7

Pancreas divided into 5 parts:

Answer 7

1. Head
2. Uncinate process
3. Neck
4. Body
5. Tail

Question 8

Head of the pancreas

Answer 8

lies to the right of the superior mesenteric artery

Question 9

Uncinate process

Answer 9

• variable posterolateral extension of the head
• passes behind the retropancreatic vessels & anterior to the inferior vena cava & aorta.

Question 10

Neck

Answer 10

portion of the gland overlying the superior mesenteric vessels.

Question 11

Body & Tail

Answer 11

• lie to the left of the mesenteric vessels
• there is no meaningful anatomic division between the body & tail.

Question 12

Ductal anatomy - 85%, 10%, 5%

Answer 12

85% of individuals = the pancreatic duct & the CBD enters the duodenum through a common channel.

10% of individuals = each duct enters the duodenum through a separate ampulla.

5% of individuals = both ducts enter the duodenum through the same ampulla but via separate channels.

Question 13

3 variations of Retroduodenal bile duct anatomy

Answer 13

(A) The duct is partially covered by pancreatic tissue.
(B) The duct is completely covered by the pancreas.
(C) The duct runs freely behind the pancreas.

Question 14

Pancreas is composed of 2 types of tissues:

Answer 14

1. Acini
2. Islets of Langerhans

Question 15

Acini

Answer 15

• roughly 99% of the exocrine cells are arranged in clusters = acini.
• produces digestive enzymes

Question 16

Islets of Langerhans / Pancreatic islets consists of 4 types of hormone-secreting cells:

Answer 16

1. Alpha / A cells
   - approx. 25% of pancreatic islet cells.
   - secretes glucagon
2. Beta / B cells
   - approx. 60% of pancreatic islet cells
   - secretes insulin & amylin
3. Delta / D cells
   - approx. 8% of pancreatic islet cells
   - secretes somatostatin
4. F cells
   - approx. 7% of pancreatic islet cells
   - secretes pancreatic polypeptide

Question 17

Function of Somatostatin

Answer 17

• acts in a paracrine manner to inhibit both insulin & glucagon release from neighboring A & B cells.
• acts as a circulating hormone to slow the absorption of nutrients from the GIT
• inhibits the secretion of GH

Question 18

Function of Pancreatic Polypeptide

Answer 18

inhibits:
- somatostatin secretion,
- gallbladder contraction,
- & secretion of digestive enzymes by the pancreas.

Question 19

The arterial supply to the duodenum & pancreas is derived from the?

Answer 19

Celiac artery

Question 20

The pancreas is innervated by:

Answer 20

1. Sympathetic fibers from the splanchnic nerves = inhibitory effect
2. Parasympathetic fibers from the vagus = stimulates exocrine & endocrine function

= both of which give rise to intrapancreatic periacinar nerve plexuses.

Question 21

Negative feedback regulation of the secretion of glucagon & insulin.
(8)

Answer 21

1. Hypoglycemia stimulates alpha cells to secrete glucagon.
2. Glucagon acts on liver cells to:
   - convert glycogen into glucose
   - form glucose from lactic acid & certain amino acids
3. Glucose is released by liver cells which raises blood glucose levels to normal.
4. If blood glucose continues to rise, hyperglycemia inhibits the release of glucagon.
5. Hyperglycemia stimulates beta cells to secrete insulin.
6. Insulin acts on various body cells:
   - accelerates facilitated diffusion of glucose into cells.
   - speeds conversion of glucose into glycogen
   - increases uptake of amino acids & increases protein synthesis.
   - speeds synthesis of fatty acids
7. Blood glucose level fails
8. If blood glucose continues to fall, hypoglycemia inhibits release of insulin.