Pancreas

Question 1

Exocrine

Answer 1

secretions get dropped into a duct and the duct takes it to where it needs to go

Question 2

endocrine

Answer 2

dump secretions into blood and they go everywhere

Question 3

Anatomy of pancreas

Answer 3

• Head- mostly exocrine
• body- mostly endocrine
• Tail

Question 4

Islets of Langerhans

Answer 4

Group of Endocrine cells

• alpha- releases glucagon (18-20% of endocrine cells)
• beta- releases insulin (73-75% of endocrine cells)
• delta- somatostatin (4-6% of endocrine cells)

Question 5

What stimulates insulin secretion?

Answer 5

glucose

Question 6

What inhibits glucagon secretion?

Answer 6

insulin

Question 7

What is insulin composed of?

What is it synthesized from?

Answer 7

• Insulin is a peptide hormone
  
  • composed of A and B chain joined by disulfide bonds
• synthesis: preproinsulin→proinsulin→insulin + c peptide

Question 8

What is the half life of insulin?

where is it metabolized?

Answer 8

3-8 minutes

degraded by liver and kidney

Question 9

What does C-peptide measurement indicate?

Half life of C-peptied?

Answer 9

C-peptide is measured as an index of endocrine capacity of the pancreas

about 15 minutes

Question 10

What is the process for insulin secretion?

Answer 10

• glucose enters beta cell through GLUT2 transporter by diffusion
• glucose goes through glycolysis, turning ADP into ATP
• ATP is the ligand for the K channel. K channel closes.
  
  • cell starts to depolarize with K channel closed
• Once cell depolarizes to threshold of voltage gated calcium channel, Ca channel opens and Ca rushes in
• Calcium causes release of insulin vesicles and the making of more insulin

Question 11

When is glucagon released?

What is the target organ for glucagon?

Answer 11

when insulin levels are low

Target: liver

Question 12

How does glucagon work when it gets to the liver?

Answer 12

• Glucagon binds to a GCPR (G_s)
• GPCR stimulates adenylyl cyclase and increases cAMP and thus PKA to phosphorylate target proteins

Question 13

How does insulin get glucose into the cell?

Answer 13

• insulin binds to the GPCR
• GLUT4 transporter is recruited to the plasma membrane and facilitates glucose into the cell along with amino acids, K, Mg, and Phosphate.

Question 14

GLUT1

Answer 14

widely distributed; gets glucose into cells all over

Question 15

GLUT2

Answer 15

• found on Beta cells, kidney, intestines, liver
• low affinity, high capacity
• does not rely on insulin to transport glucose

Question 16

GLUT3

Answer 16

supplies neurons with glucose

Question 17

GLUT4

Answer 17

• Found in muscle and fat
• depends on insulin to get glucose into the cells

Question 18

GLUT5

Answer 18

Intestines

can also transport fructose

Question 19

SGLT1, SGLT2

Answer 19

Sodium dependent glucose transporters

found in Intestines and Kidney

Na-glucose co-transporters

Question 20

Effects of insulin

Answer 20

• decreased appetite
• decreased glucagon
• increased glucose uptake by muscles and fat
• increased glycolysis
• increased glycogen synthesis
• increased triglyceride synthesis
• increased amino acid uptake
• increased protein synthesis

Question 21

Effects of lack of Insulin

primarily because of glucagon

Answer 21

• increased appetite
• increased glucagon
• decreased glucose uptake by muscle and fat
• increase blood glucose
• increase gluconeogenesis
• increased lipolysis
• increased protein breakdown
• increase glycogenolysis
• Increase ketone body production
• decrease protein synthesis

Question 22

What happens to:

insulin

glucagon

free fatty acids

blood glucose

liver glycogen

blood ketone bodies

As hours of starvation increases?

Answer 22

Question 23

Type 1 Diabetes mellitus

Answer 23

Autoimmune destruction of Beta cells

about 10% of diabetes

Question 24

Type 2 diabetes mellitus

Answer 24

Insulin resistance

about 90%

Question 25

Mature onset diabetes of youth (MODY)

Answer 25

* Genetic defect in insulin production or release * insulin will help, but not as much as oral meds that increas K channel sensitivity * about 2% of young diabetics

Question 26

Gestational diabetes

Answer 26

**Any** diabetes identified during pregnancy \*precursor to actual diabetes

Question 27

How does Type 1 diabetes happen?

Answer 27

* Pancreatic Beta cells get destroyed. * person gets some kind of bug * body makes antigen * proteins coming off the beta cell matches antigens too closely * Beta cell gets attacked by immune system * body continues to make the beta cells, but they all get killed by the antibodies

Question 28

lipolysis

Answer 28

breakdown of fat

Question 29

glycogen synthesis

Answer 29

liver making glycogen from glucose

Question 30

gluconeogenesis

Answer 30

making glucose from non carbohydrates; lactate, glycerol, amino acids \*Important to get glucose to the brain. Everything else can survive on ketones. Happens in liver.