Pancreas Physiology

Question 1

Mechanism of glucose-sensitive insulin secretion

Answer 1

Glc brought into β-cells via GLUT2 and GLUT4
Glc metabolized to ATP
ATP binds and blocks K+ channel
depolarization of cell
Ca2+ enters cell
insulin vesicles fuse with membrane
insulin released

Question 2

How do thiazides affect insulin release

Answer 2

thiazides bind and activate K+ channels on β-cells
hyperpolarization of cells
Ca2+ does not enter cell
no insulin secreted from cell
=> hyperglycemia

Question 3

What type of receptor is the insulin receptor

Answer 3

TK-tyrosine kinase

Question 4

Synthesis of insulin

Answer 4

synthesized as one long chain
C-peptide cleaved off and put into serum
remaining 2 peptide chains bonded by disulfide bonds

Question 5

Sympathetic activation increases insulin/glucagon secretion

Answer 5

glucagon

want more glucose in circulation

Question 6

How does vagal stimulation affect α-cells

Answer 6

activates α-cells

b/c glucagon needs to temper effects of insulin

Question 7

Role of glucagon after high protein meal

Answer 7

promote gluconeogenesis of aa

Question 8

What are incretins

Answer 8

incretins are GI hormones
they stimulate insulin secretion in high glucose situation
reason you get more insulin release when ingesting it rather than putting it in IV right away

Question 9

GLP-1

glucagon-like peptide-1 function

Answer 9

incretin

stimulates insulin in high glucose situation

Question 10

GIP

glucose-dependent insulinotropic peptide function

Answer 10

produced by K-cells

increases insulin secretion when ingesting food orally

Question 11

GLUT2

Answer 11

in β-cells

non-insulin dependent

Question 12

GLUT4

Answer 12

sk muscle and adipocytes

insulin-dependent

Question 13

Exercise and GLUT4

Answer 13

exercise induces GLUT4 movement into membranes

Question 14

GLUT1

Answer 14

present in BBB