Pancreas

Question 1

whats unique about the pancreas in terms of glands?

Answer 1

it has an exocrine (main part, 98%) and endocrine portion

Question 2

endocrine portion of pancreas is mostly located where?

Answer 2

in the tail of pancreas (to the left)

Question 3

the gallbladder, liver and pancreas all have ducts that merge and enter what?

Answer 3

duodenum (1st part of small intestine)

Question 4

which organ secretes and synthesizes bile? where is it concentrated?

Answer 4

liver, it then travels to gallbladder via hepatic ducts (or common bile ducts) for it to be concentrated).

Question 5

what cells make up the endocrine system? exocrine? which is vascular which is avascular?

Answer 5

ilet of langerham make up endocrine and these are vascular (they have capillary system innervating it)
secretory acinis: avascular, blood supply is from surrounding CT

Question 6

what is the heirarchial organization of cells in exocrine duct systems?

Answer 6

1. centroacinar cells (type of squamous cell), top most cell forms smallest duct
2. simple low cuboid (intercalated duct, 1-2 centrocinar cells merge)
3. higher cuboid/low columnar (intralobular duct, several acini)
4. stratified cuboid or columnar (interlobular collecting duct to main duct, has two layers)

Question 7

what is unique about the first part of the intralobular duct?

Answer 7

it is striated due to basal infoldings to increase SA

Question 8

how can you tell apart endocrine from exocrine pancreas in a image?

Answer 8

endocrine stains lighter, exocrine stains darker

Question 9

how many cells per ilet?

Answer 9

100-1000 cells/ilet

Question 10

what is the septum?

Answer 10

collagenous CT that carries blood supply to nonvascular cells.

Question 11

what are the three principle cells in the ilets?

Answer 11

1. alpha cells (secrete and synthesize glucagon)
2. beta cells (secrete and synthesize insulin)
3. D (delta) cells (secrete and synthesize somatostatin)

Question 12

where are the three principle cells normally located in an ilet and what percent of each cell is normally present?

Answer 12

alpha (more toward periphery, dense core granules regular shape, 20-25%)
beta (60-80%, more in core, dense core granules are irregular dense core has insulin and Fe)
delta (5-10%, 2 forms 14 and 28 aa forms, inhibits insulin and glucagon release)

Question 13

what other products do beta cells secrete?

Answer 13

C peptide, amylin and proinsulin

Question 14

what is a fourth cell type in ilet but not very abundant? what are two other cell types present?

Answer 14

pancreatic polypeptide hormone (PP) 15%
G cells: synthesize gastrin, 1%
neurons (secrete VIP) and glial cells

Question 15

capillaries present in ilets are of what type?

Answer 15

fenestrated, discontinuous, leaky.

Question 16

insulin is made up of what two chains? the two chains are connected by what? what links are made between the two chains?

Answer 16

alpha: 21 AA
beta: 30 AA (main biological activity)
C peptide (this is cleaved in the golgi)
S-S links

Question 17

what are the major targets of insulin? which cells have receptors?

Answer 17

liver, skeletal muscle and adipose.

all cells have receptors

Question 18

processing of insulin starts where? what are the remaining steps?

Answer 18

at ribosome, preproinsulin is the first product from the ribosome. before it goes to the golgi for processing it becomes proinsulin, once C peptide (35AA) is cleaved it becomes mature insulin.

Question 19

pork insulin differed from humans by what? which caused?

Answer 19

1-3 AA

immune response in some cases which was problematic.

Question 20

glucose stimulates an increase in what intracellularly?

Answer 20

calcium and cAMP which causes secretory granules to line up and move to plasma membrane, once we get fusion of membranes, insulin is released.

Question 21

what are the two major blood sources to the pancreas?

Answer 21

1. celiac artery: supplies dorsal ancreas

2. superior mesenteric artery: supplies ventral pancreas

Question 22

what are the two separate systems supplying blood to the pancreas?

Answer 22

1. insuloacinar portal system supplies endocrine system then bathes exocrine system (it is a portal system therefore exception to the rule)
2. acinar system supplies exocrine part only and is a regular system

Question 23

what is unique about beta cells, what do they each have to be next too?

Answer 23

at least one capillary

Question 24

what are the two types of diabetes? what do both types have in common?

Answer 24

1. type 1: insulin dependent, destruction of beta cells, most prevalent type, usually in juvenilles
2. type 2: insulin independent, insulin levels are normal or even higher but the target tissue receptors are not working, usually in obese people
   both experience hyperglycaemia (excess of glucose in blood)