Endocrine Pancreas (Histology & Physiology)

Question 1

secretory products of endodocrine pancreas

Answer 1

Insulin & Glucagon

Question 2

cells that produce glucagon

Answer 2

Alpha cells

Question 3

cells that produce insulin

Answer 3

beta cells

Question 4

cells that produce somatostatin

Answer 4

delta cells

Question 5

cells the produce pancreatic peptide

Answer 5

F cells aka PP cells

Question 6

Insulin synthesis rxn

Answer 6

proinsulin –> insulin & C-peptide

Question 7

location of alpha, beta, delta, F cells

Answer 7

Islet of Langerhans center(ish) B cells peripheral inner ring(ish) D cells peripheral outer ring(ish) A cells

Question 8

1

Answer 8

exocrine pancreas with secretory acini

Question 9

2

Answer 9

islet of Langerhans

Question 10

3

Answer 10

duct of the exocrine pancreas.

Question 11

4

Answer 11

connective tissue septae

Question 12

What do Beta cells contain & produce

Answer 12

membrane-limited secretory granules with highly electron dense core. Full of insulin.

Question 13

General structure of insulin

Answer 13

peptide of 21 AAs in beta chain, 30 AAs linked by two disulphide bonds

Question 14

Major stimuli for insulin secretion (5)

Answer 14

1. ____ plasma glucose concentration
2. ____ plasma amino acids
3. ____ GI hormones (“gut factors”; probably mainly GIP).
4. ____ parasympathetic activity ,
5. ____ sympathetic activity (by SNS nerves to pancreas + circulating epinephrine)

Question 15

Major stimuli for insulin secretion (fill in blanks)

1. ____ plasma glucose concentration
2. ____ plasma amino acids
3. ____ GI hormones (“gut factors”; probably mainly GIP).
4. ____ parasympathetic activity ,
5. ____ sympathetic activity (by SNS nerves to pancreas + circulating epinephrine)

Answer 15

Major stimuli for insulin secretion

1. __^__ plasma glucose concentration
2. __^__ plasma amino acids
3. _^___ GI hormones (“gut factors”; probably mainly GIP).
4. _^___ parasympathetic activity ,
5. __v__ sympathetic activity (by SNS nerves to pancreas + circulating epinephrine)

Question 16

Major stimuli for glucagon secretion (4)

Answer 16

Major stimuli for glucagon secretion

1. ____ plasma glucose concentration
2. ____ plasma amino acids: Role: to prevent sudden hypoglycemia (from amino acid-induced insulin secretion) if you eat a high protein meal without carbohydrates, e.g., a piece of meat.
3. Other stimuli -see text Figure
4. NOTE: during & after a normal meal; you seldom see a change in [glucagon] when measured in PERIPHERAL BLOOD

Question 17

Major stimuli for glucagon secretion (fill in blanks)

1. ____ plasma glucose concentration
2. ____ plasma amino acids: Role: to prevent sudden hypoglycemia (from amino acid-induced insulin secretion) if you eat a high protein meal without carbohydrates, e.g., a piece of meat.
3. Other stimuli -see text Figure
4. NOTE: during & after a normal meal; you seldom see a change in [glucagon] when measured in PERIPHERAL BLOOD

Answer 17

Major stimuli for glucagon secretion

1. __v__ plasma glucose concentration
2. __^__ plasma amino acids: Role: to prevent sudden hypoglycemia (from amino acid-induced insulin secretion) if you eat a high protein meal without carbohydrates, e.g., a piece of meat.
3. Other stimuli -see text Figure
4. NOTE: during & after a normal meal; you seldom see a change in [glucagon] when measured in PERIPHERAL BLOOD. in peripheral blood. Probably not true in pancreas blood, but that goes through liver & is filtered out.

Question 18

Where is majority of insulin consumed & degraded?

Answer 18

Liver (80%) & degraded there & kidney.

Question 19

Where does insulin go after release from pancreas?

Answer 19

directly through liver

Question 20

Where does glucagon act?

Answer 20

almost totally on liver

Question 21

peripheral blood insulin and glucagon levels?

Answer 21

low and very low

Question 22

effect of insulin on brain? Intestinal mucosa? RBCs? Kidney tubules?

Answer 22

none except part of hypothalamus. No. No. No.

Question 23

speed & duration of glucagon

Answer 23

fast & short

Question 24

hepatic actions of glucagon:

overall effect on glc production & secretion? plasma glc conc?

Answer 24

__^__ glycogenolysis·
___^_ amino acid uptake
___^_ gluconeogenesis
__^__ ketoneogenesis

glc production v, plasma glc v

Question 25

Glucagon & catecholamines need what to act first for optimal function in liver?

Answer 25

cortisol

Question 26

glucagon inflence on phosphorylase and glycogen synthetase activities?

Answer 26

Increase in phosphorylase activity
Decreases glycogen senthetase activity

Question 27

Insulin effect on glc uptake? synth of enzymes?

Answer 27

faster, slower

Question 28

potency of insulin compared to other hormones?

Answer 28

MOST, BEST, STRONGEST

Question 29

Insulin effects on anti-catabolic processes: what’s it do to these processes?

____ protein degradation
____ glycogenolysis
____ gluconeogenesis
____ lipolysis

Answer 29

__v__ protein degradation
__vv__ glycogenolysis
__v__ gluconeogenesis
__vv__ lipolysis

Question 30

Insulin effects in MUSCLE:

____ glucose uptake; mechanism

____ amino acid uptake

____ ribosomal protein synthesis: CONTROVERSIAL:
___ribosomal PS in some animals (in vivo & in vitro);
but ________ on human forearm muscle in vivo
____ synthesis of lipoprotein lipase (extracts FA from VLDL & chylomicrons) - these FAs are then used (preferentially to glucose) for energy generation by muscle
____ protein breakdown
____ release of amino acids

Answer 30

^ glc uptake (transporters in waiting)
^ aa uptake
^ protein synth (controversial, ^, not on human forearm muscle, so contradicting info)
^ synth of LPL
V protein brekdown
V release of aa

Question 31

Insulin effects in ADIPOSE:

____ glucose uptake
____ fatty acid synthesis (from glucose)
____ a-glycerol phosphate synthesis (from glucose)
____ synthesis of lipoprotein lipase (extracts FA from VLDL & chylomicrons)
____ TAG synthesis (from FA and a-glycerol phosphate)
____ lipolysis ( ___ activity of “hormone-sensitive lipase”)

Answer 31

__^__ glucose uptake
__^__ fatty acid synthesis (from glucose)
__^__ a-glycerol phosphate synthesis (from glucose)
__^__ synthesis of lipoprotein lipase (extracts FA from VLDL & chylomicrons)
__^^^__ TAG synthesis (from FA and a-glycerol phosphate)
__vvv__ lipolysis ( ___ activity of “hormone-sensitive lipase”)

Question 32

Insulin effects in LIVER:

___ release of glucose
___ lipid synthesis > TAG
but insulin > ___ synthesis of VLDL (& its apo B) and secretion of VLDL. THUS, insulin ___ hepatic TAG stores. This allows smooth transition in TAG metabolism from feeding (CMs) to fasting (VLDLs).
___ protein synthesis
___ ketogenesis

Answer 32

__v_ release of glucose
__^_ lipid synthesis > TAG
but insulin > __v__ synthesis of VLDL (& its apo B) and secretion of VLDL. THUS, insulin __^_ hepatic TAG stores. This allows smooth transition in TAG metabolism from feeding (CMs) to fasting (VLDLs).
__^_ protein synthesis
__v_ ketogenesis

Question 33

effect of insulin on target cell sensitivity?

Answer 33

decrease

Question 34

effect of glucagon on target cell sensitivity to insulin?

Answer 34

decreases, but opposite effect in liver!

Question 35

effect of epi & norepi on target cell sensitivity to insulin?

Answer 35

decreases, but opposite effect in liver!

Question 36

effect of GH, Cortisol, T3 on target cell sensitivity to insulin?

Answer 36

decrease, decrease, increase

Question 37

Effect of X on Beta cell excretion of insulin?

X = glucagon

Epi/norepi

GH

Cortisol

T3

Answer 37

v

^ (indirect)

^ (indirect)

^ (indirect)