Insulin and metabolic reglation\

Question 1

3 pancreas endocrine cells and what they produce

Answer 1

1. B cell - insulin, amylin, c-peptide
2. a cell - glucagon
3. omega cell - somatostatin

Question 2

what triggers insulin release

Answer 2

glucose levels

Question 3

what is the path by which glucose releases insuling in B cell

Answer 3

1. glucose in > glycolysis and ATP production
2. ATP inhibits K channel (less K out) reducing membrane potential
3. membrane depolarization leads to Ca influx
4. exocytosis of insulin post-Ca influx

Question 4

how is insulin synthesized in B-cell

Answer 4

1. DNA>mRNA>preproinsulin
2. prepro has signal sequence removed and 3 disulfides formed > proinsulin
3. proinsuling has c-peptide released and left with insulin

Question 5

what is timing of insulin after meal (2)

Answer 5

1. intial spike of exocytosis

2. slow gain as more is created after

Question 6

6 stimulators of insulin

Answer 6

1. glucose (major)
2. AAs
3. FFAs
4. GLP-1
5. glucagon
6. Ach

Question 7

3 inhibitors of insulin

Answer 7

1. somatostatin
2. insulin
3. norepinepherine

Question 8

how does microRNA inhibit insulin

Answer 8

binds to and inhibits translation of myotrophin mRNA, which is needed for secretion of vesicle

Question 9

what are insulin’s role in anabolic processes (5)

Answer 9

1. recruitment of glucose trnasporters for uptake
2. stim glycogen synsthesis and inhib glycogen breakdown
3. increase FA synthesis
4. upregulate glucokinase
5. increase AA uptake and protein synthesis

Question 10

how does insuling promote gulcose uptake

Answer 10

insulin binding triggers vesicle carryin GLUT4 transporter to go to cell membrane surface

Question 11

aside from insulin, what else can recruit transporters

Answer 11

exercise

Question 12

how does insulin signalling work?

Answer 12

1. insulin binds to receptor
2. tyrosine kinase activated protein kinases
3. protetin kinase phosphoryalte other proteins, causing them to signal

Question 13

how does insulin reverse effects of glucagon and epi

Answer 13

1. both glucagon and epi phosphorylate glycogen phosphorylase a, which leads to glycogen breakdown
2. insulin activates protein phophotase, which dephosphorylates thise enzyme, inhibiting glycogen breakdown

Question 14

how does glucose enter the liver

Answer 14

down concentration gradient

Question 15

how are low intracellular glucose level maintained (3)

Answer 15

1. glucose phosphoryalted
2. glycogen synthesis
3. reduced glycogen breakdown

Question 16

3 proteins involved

Answer 16

1. GLUT2
2. glucokinase
3. glycogen synthase

Question 17

what is glucagon released

Answer 17

what gluc. drops below 100mg/dL

Question 18

how does glucagon prevent hypoglycemia

Answer 18

increases liver glycogenolysis and gluconeogenisis

Question 19

what is glucagon signalling pathway

Answer 19

GCPRs and phosphorylation cascade

Question 20

2 other results of glucagon

Answer 20

1. beta oxidatiokn

2. ketogenisis

Question 21

3 possible products of proglucagon and where from/functions

Answer 21

1. glucagon - a cells of panc
2. GLP-1 - endocrine of small int. - insulin release
3. GLP-2 - intestine endocrine - inhibit food intake

Question 22

what do somatostatins do

Answer 22

inhibit endo and exocrine secretions

Question 23

how is amylin secreted

Answer 23

from islet with insulin

Question 24

location and Function of amylin action (3)

Answer 24

1. stomach - slows emptying and slows acid secretion
2. brain - decreases appetite
3. pancreas - decrease glucagon secretions

Question 25

what is type 1 diabetes

Answer 25

autoimmune destruction of B cells

Question 26

what must be regulated in type 1 (3)

Answer 26

1. insulin 2. carb intake 3. physical activity

Question 27

7 risk factors for diabetic hypoglycemia

Answer 27

1. bad insulin dosing 2. skipped meals of snacks 3. reduced dietary carbs 4. increased glucose usage (excercise) 5. decreased gluconeogenisis (alcohol) 6. increased insulin sensititvety 7. decreased insulin clearance (renal)

Question 28

how to treat hypoglycemia

Answer 28

glucose

Question 29

4 Sx of hyperglycemia

Answer 29

1. fluid intake and thisrt 2. frequent urination 3. high ketones (sweet breath) 4. glucosuria 5. rapid deep breath (acidosis) 6. high blood tonicity (results in K loss)

Question 30

how does hyperglycemia cause retinal damage

Answer 30

glucose converted to sorbitol

Question 31

how does hyperglycemia cause ketosis

Answer 31

excess fat breakdown leads to ketones

Question 32

what happens when not enough glucose in cell

Answer 32

break down fat and protein instead

Question 33

where does ketogenisis occur

Answer 33

in mitochondira when acetyl CoA levels rise

Question 34

what are the 3 ketone bodies produced

Answer 34

1. acetoacetate 2. 3-hydroxybutyrate 3. acetone

Question 35

what are ketone used for

Answer 35

alternative E source by bain, heart and muscle

Question 36

how does body use ketone bodies as fuel

Answer 36

1 3-hydroxybutyrate converted to 2 actyl CoA

Question 37

why does citric acid cycle slow without glucose

Answer 37

pyruvate not replensihed

Question 38

what are consequences of high ketones

Answer 38

drop in blood pH - ketoacidosis

Question 39

how is ketoacidosis treated

Answer 39

life threatening - bicarb injections

Question 40

what is path of ketogenisis

Answer 40

1. no glucose so FFA are release from adipose 2. FFAs undergo B-oxidation in liver 3. ketone bodies formed

Question 41

how does diabetes effect water balance

Answer 41

1. high glucose and ketone > hypertonicity 2. dehydration due to hypertonicity 3. polyuria to get rid of water in blood 4. water loss leads to hypotension 5. low BP can lead to loss of consciousness 6. kidney failure due to excessive processing