Endocrine pancreas 1 - Insulin

Question 1

how is food intake balanced?

Answer 1

neural and chemical signalling of 2 hypothalamic centres - 
feeding centre (hunger and drive to eat)
satiety centre (fullness)

Question 2

glucostatic theory?

Answer 2

as BG increases, desire to eat decreases

Question 3

lipostatic theory?

Answer 3

as fat stores increase, desire to eat decreases

Question 4

what is leptin?

Answer 4

peptide hormone released by fat stores to depress feeding activity

Question 5

what is the cause of obesity?

Answer 5

increased energy intake and decreased energy output

rarely caused by metabolic disease

Question 6

other factors affecting eating?

Answer 6

psychological - e.g. comfort eating

convenience

Question 7

body energy calculation?

Answer 7

energy intake - energy output

Question 8

3 categories of energy output?

Answer 8

1) heat loss (50%)
2) mechanical - movement
3) cellular - e.g. growth and repair

Question 9

can we voluntarily regulate our energy output?

Answer 9

just those voluntary movements we make using skeletal muscle

Question 10

3 elements of metabolism

Answer 10

extracting energy
storing energy
using energy

Question 11

anabolic v.s. catabolic?

Answer 11

ana - build up (storage)

cata - break down (using energy)

Question 12

absorptive phase?

Answer 12

anabolic phase - we use energy taken from nutrients and store excess

Question 13

posto-absoprive phase?

Answer 13

fasted state - break down stores made in absorptive state state for energy use

Question 14

definition of obligatory glucose utiliser?

Answer 14

the brain has priority on any GLC in blood to function properly

Question 15

what energy sources can the brain use/not use?

Answer 15

USE -
GLC
ketones

NOT USE -
fats
carbs
proteins

Question 16

what is the downfall to breaking down proteins?

Answer 16

vulnerable to infections
physically weak
stop producing antibodies and enzymes

Question 17

results of untreated hypoglycaemia?

Answer 17

(<3mM)coma and death

Question 18

Glycogenolysis?

Answer 18

synthesising GLC from glycogen

stimulated by glucagon

Question 19

Gluconeogenesis?

Answer 19

synthesising GLC from amino acids

stimulated by glucagon

Question 20

clinical indication of diabetes?

Answer 20

sweet smelling urine - high GLC levels in urine

Question 21

what 2 processes does insulin stimulate?

Answer 21

lipogenesis

glycogenesis

Question 22

normal range of BG?

Answer 22

4.2 - 6.3 mM

basically 5 mM

Question 23

where are endocrine hormones produced in pancreas?

Answer 23

Islet of Langerhans

Question 24

what are the 4 types of Islet cells and what do they produce?

Answer 24

alpha cells produce GLUCAGON
beta cells produce INSULIN
delta cells produce SOMATOSTATIN
F cells produce pancreatic polypeptide

Question 25

actions of insulin?

Answer 25

``` increases - -GLC oxidation -glycogen synthesis -fat synthesis protein synthesis ```

Question 26

actions of glucagon?

Answer 26

increases - - glycogenolysis - gluconeogenesis - ketogenesis

Question 27

only hormone which lowers BG?

Answer 27

insulin

Question 28

how is excess GLC stored in liver and muscle cells?

Answer 28

glycogen

Question 29

how is excess GLC stored in liver and fat cells?

Answer 29

TAG - TriAcylGlycerols

Question 30

how does the mechanism of control of insulin secretion by BG work?

Answer 30

Beta cells have specific K+ ion channel, sensitive to ATP conc. - KATP channel

Question 31

describe the mechanism of control of insulin secretion by BG?

Answer 31

increase GLC - > GLC enters cells via GLUT - >increasing metabolism - >increasing ATP conc. - > KATP channel closes - >intracellular K+ conc increases - >cell depolarised - >voltage-dependent Ca2+ channels open - >insulin vesicle exocytosis into circulation

Question 32

how does insulin increase GLC uptake of cells?

Answer 32

binds to tyrosine kinase receptors on insulin-sensitive tissues

Question 33

transported for GLC in muscle and fat tissues?

Answer 33

GLUT4

Question 34

which tissues are insulin dependent?

Answer 34

ONLY fat and muscle

Question 35

describe the liver and GLC uptake?

Answer 35

via GLUT2 (insulin independent) BUT... GLC transport into liver cells is affected by insulin status more GLC is taken up by liver if insulin is present

Question 36

Anabolic actions of insulin?

Answer 36

Increases glycogen synthesis in muscle and liver Increases amino acid uptake into muscle, promoting protein synthesis. Inhibits proteolysis Stimulates lipogenesis and inhibits lipolysis. Inhibits the enzymes of gluconeogenesis in the liver

Question 37

other action of insulin?

Answer 37

Promotes K+ ion entry into cells by stimulating Na+/K+ ATPase