Endocrine Pancreas 1

Question 1

T/F: The endocrine pancreas comprises the majority of the pancreas

Answer 1

FALSE - exocrine

Question 2

What hormones are produced in the endocrine pancreas

Answer 2

insulin
glucagon
somatostatin

Question 3

What tissues are insulin sensitive?

Answer 3

muscle
adipose tissue
liver

Question 4

Insulin and glucagon regulate glucose, ______, and _____ metabolism

Answer 4

amino acid
fatty acid

Question 5

The majority of the endocrine are _____ cells, which produce insulin

Answer 5

beta

Question 6

65% of the pancreas are beta cells, which is ______

Answer 6

insulin

Question 7

20% of the pancreas are alpha cells, which is ______

Answer 7

glucagon

Question 8

10% of the pancreas are delta cells, which is ______

Answer 8

somatostatin

Question 9

What does somatostatin do?

Answer 9

inhibit both insulin and glucagon release

Question 10

How are delta cells dispersed in the islets?

Answer 10

all around

Question 11

Hormones in the pancreas are secreted into _______ veins which then drain to the ________

Answer 11

portal vein
liver

Question 12

Give an example of a hormone around the periphery of the pancreas

Answer 12

pancreatic polypeptide

Question 13

What are the benefits of gap junctions? Where are there gap junctions between which cell types?

Answer 13

FAST!
alpha to alpha
alpha to beta
beta to beta

Question 14

Blood supply to pancreas arranged so that __________ from each cell type _______ other cell types

Answer 14

venous blood
bathe

Question 15

What kind of vessel enters the islet core?

Answer 15

arteries

Question 16

What kind of vessel is distributed throughout the inlet?

Answer 16

capillaries

Question 16

Which type of vessel converges around the rim?

Answer 16

veins

Question 16

Islets are innervated by _____, ________, and ________ neurons

Answer 16

adrenergic
cholinergic
peptidergic

Question 17

What are the conserved regions of insulin?

Answer 17

location of 3 disulfide bonds
ends of A chains
C-terminal residues of B chain

Question 18

A chain has ______ aa and B chain _______ aa

Answer 18

21 aa
30 aa

Question 19

Which chain of insulin is more important? Why?

Answer 19

B chain
biologically active

Question 20

How many bridges link A to B chain? There is a 3rd bridge in the _____ chain

Answer 20

2
A chain

Question 21

Insulin is synthesized as a _________ with 4 peptides. List them

Answer 21

preprohormone
signal peptide
A & B chains
connecting peptide (C peptide)

Question 22

Proinsulin is sent to the _____, where insulin folds and _______ form

Answer 22

ER
disulfide bridges

Question 23

The ______ packages insulin into granules and _______ (proteases) cut ______

Answer 23

golgi proteases C-peptide

Question 24

When proteases cut insulin, what are the 2 products?

Answer 24

insulin C-peptide! (it's still there)

Question 25

How is insulin metabolized in the liver?

Answer 25

enzymes break disulfide bonds A & B excreted in urine

Question 26

What is the most important stimulator of insulin secretion?

Answer 26

blood glucose

Question 27

Glucose is transported into the beta cell via _______ transporter. Which type of diffusion?

Answer 27

GLUT 2 facilitated diffusion

Question 28

What is glucose immediately phosphorylated by? What is a product?

Answer 28

glucokinase ATP

Question 29

Why is glucose immediately phosphorylated by glucokinase?

Answer 29

so it doesn't leave the cell

Question 30

ATP closes ______ channels. What happens?

Answer 30

K+ channels depolarizes membrane

Question 31

What does depolarization do during regulation of insulin secretion? It flows [into/out of] cell

Answer 31

opens voltage-gated Ca2+ channels into!

Question 32

What does an increase in intracellular Ca2+ cause?

Answer 32

exocytosis of insulin granules into venous blood

Question 33

______ is secreted in equal amounts to insulin

Answer 33

C-peptide

Question 34

T/F: C-peptide is excreted unchanged in urine

Answer 34

TRUE

Question 35

What 2 things are used to assess beta cell function?

Answer 35

blood insulin C-peptide being excreted unchanged in urine

Question 36

[Oral/Intravenous] glucose causes greatest insulin response due to "______" effect

Answer 36

oral glucose incretin

Question 37

Oral glucose stimulates _______

Answer 37

release of other hormones from enteric neurons/hormone cells in GIT stimulates insulin release

Question 38

List things that stimulate insulin secretion

Answer 38

amino acids keto acids ffa K+, Ca2+ GIP, vagal stimulation (Ach), drugs (sulfolnylurea) GLUCAGON

Question 39

List things that inhibit insulin secretion

Answer 39

fasting exercise somatostatin leptin

Question 40

What is the insulin receptor?

Answer 40

tyrosine kinase

Question 41

Insulin receptor has 2 subunits: _____ and _____. Define them

Answer 41

alpha: subunits are EXTRACELLULAR, connected by disulfide bonds between alphas, and alpha to beta beta: span the membrane

Question 42

Insulin binds [alpha/beta] subunits, causing conformational change and activates tyrosine kinase in [alpha/beta] subunits

Answer 42

alpha beta

Question 43

What does tyrosine kinase phosphorylate?

Answer 43

phosphates phospholipases G proteins

Question 44

Insulin receptor complex internalized by target cell to be ______, ________, or ________

Answer 44

degraded stored recycled

Question 45

Insulin receptors ______ or ______ regulate. Type II diabetes and obesity relate to ________

Answer 45

up or down regulate down regulate

Question 46

When nutrients are available, ____ makes sure those nutrients are stored

Answer 46

insulin

Question 47

What is used during fasting?

Answer 47

stored nutrients

Question 48

Insulin DIRECTLY stimulates glucose uptake into ______ and _______, but NOT ______

Answer 48

muscle fat NOT liver

Question 49

What are some insulin-independent transporters?

Answer 49

GLUT 1 GLUT 2 GLUT 3

Question 50

Where is GLUT 1 found?

Answer 50

liver red blood cells

Question 51

What helps with phosphorylation of glucose in the liver?

Answer 51

insulin

Question 52

Where is GLUT 2 found?

Answer 52

liver beta cells of pancrease

Question 53

What happens in chronic hyperglycemia?

Answer 53

see decreased number of GLUT 2 on beta cells which decreases insulin secretion

Question 54

Where is GLUT 3 found?

Answer 54

in brain

Question 55

What are insulin-dependent transporters?

Answer 55

GLUT 4

Question 56

Where is GLUT 4 found?

Answer 56

fat muscle heart

Question 57

T/F: Transport of glucose in intestines and kidneys is NOT regulated by insulin but is K+ dependent

Answer 57

FALSE - NA+

Question 58

Where is GLUT 5 found?

Answer 58

intestine