Endocrine pancreas- histo and phys

Question 1

What 4 cells are found in the islets of langerhans? and what does each secrete?

Answer 1

Alpha: glucagon
Beta: insulin
delta: somatostatin
F: pancreatic polypeptide

Question 2

Proinsulin is cleaved to:

Answer 2

insulin and C-peptide

Question 3

What cells are located centrally in the islets?

Answer 3

B

Question 4

What cells are located around the outer periphery of islet?

Answer 4

A

Question 5

What cells are located around the periphery (inner layer) of islet?

Answer 5

D

Question 6

What are the 2 kinds of islets that can be distinguished?

Answer 6

B-rich: sharply delineated, oval, found throughout the pancreas
PP cell-rich: trabecular, irregular and restricted to posterior part of pancreatic head

Question 7

What is the function of pancreatic polypeptide?

Answer 7

self regulate the pancreas secretory activities, affects hepatic glycogen levels and GI secretions.

Question 8

When is pancreatic polypeptide secretion increased?

Answer 8

after a protein meal, fasting, exercise, and acute hypoglycemia

Question 9

When is pancreatic polypeptide secretion decreased?

Answer 9

somatostatin and IV glucose

Question 10

Pro insulin is converted into the mature hormone by the combined action of ____ and ___.

Answer 10

2 endoproteases and a carboxypeptidase

Question 11

T or F During and after a normal meal, you will see a change in glucagon in peripheral blood.

Answer 11

F- you will seldom see a change in peripheral blood

Question 12

What do GH and cortisol do to insulin secretion?

Answer 12

increase

Question 13

What does somatostatin, NE, and epi do to insulin secretion?

Answer 13

decrease

Question 14

Half life of insulin in the blood? Glucagon?

Answer 14

5 min; 5-10 minutes

Question 15

Where is insulin degraded?

Answer 15

80% liver and kidney
The rest in other target and non-target tissues.
Insulinase?

Question 16

Glucagon degradation?

Answer 16

most occurs in liver, peripheral concentration gg are low

Question 17

Both insulin and glucagon first go to the _____ where they exert their actions

Answer 17

Liver

Question 18

Glucagon only acts on the ____.

Answer 18

liver

Question 19

What 3 tissues are most affected by insulin?

Answer 19

Muscle, liver, adipose tissue

Question 20

What 4 tissues does insulin NOT stimulate glucose uptake?

Answer 20

brain, intestinal mucosa, RBC, kidney tubules

Question 21

What does glucagon do to cAMP and PKA activtiy?

Answer 21

Increase

Question 22

What does glucagon do to phosphorylase activity?

Answer 22

increase

Question 23

What does glucagon do to formation of F-2,6-BP?

Answer 23

decrease

Question 24

What are the major stimuli for insulin secretion?

Answer 24

increase plasma glucose concentration, increased amino acid concentration, increase GI horomes, increased parasympathetic activity, decreased sympathetic activity

Question 25

What inhibits insulin secretion#

Answer 25

EPI NE, somatostatin

Question 26

What are major stimuli increasing glucagon secretion?

Answer 26

``` increased plasma amino acids (to prevent sudden hypoglycemia if you eat a high protein meal) #hypoglycemia, NE, EPI, glucocorticoids, CCK, gastrin ```

Question 27

What are stimuli that decrease glucagon secretion?#

Answer 27

hyperglycemia, fatty acids, SS, insulin | ketone bodies

Question 28

What does GH do to insulin secretion?

Answer 28

Increase

Question 29

Pattern of insulin release

Answer 29

rapid oscillations

Question 30

Do you see glucagon changes in peripheral blood?

Answer 30

Not really. stays constant

Question 31

Speed and duration of glucagon actions

Answer 31

Fast

Question 32

Hepatic actions of glucagon

Answer 32

Inrease glycogenolysis, amino acid uptake, gluconeogenesis, ketogenesis

Question 33

Glucagon and catecholamines need prior action of _____ to function optimally in the liver.

Answer 33

Cortisol- stimulate synthesis of rate limiting enzyme

Question 34

T or F. Glucagon increases activity of PEPCK and pyruvate carboxylase.

Answer 34

T (these are the first 2 regulated enzymes of gluconeogenesis)

Question 35

Speed and duration of insulin activity

Answer 35

Some fast, like glucose uptake | Some slow like synthesis of some enzymes

Question 36

T or F Insulin is the most potent hormone.

Answer 36

T

Question 37

major actions of insulin on muscles

Answer 37

Increase glucose and aa uptake, increase ribosomal protein synthesis, increase synthesis of lipoprotein lipase, decrease protein breakdown, decrease release of aa

Question 38

Major actions of insulin on adipsoe tissue

Answer 38

glucose uptake, FA synthesis, glycerol phosphate synthesis, synthesis of lipoprotein lipase, TG synthesis, decrease lipolysis

Question 39

Major actions of insulin on liver

Answer 39

decrease release of glucose, increase lipid synthesis, increase protein syn., decrease ktogenesis