Glucose homeostasis and the pancreas

Question 1

Insulin decreases plasma

Answer 1

glucose
AAs
FFAs (free fatty acids)
“anabolic:

Question 2

Glucagon increases plasma

Answer 2

glucose
ketones
“catabolic” ie breaking down

Question 3

B cells produce … which…

Answer 3

insulin

stimulates glucose utilisation and uptake

Question 4

Alpha cells produce.. which..

Answer 4

glucagon

Increases breakdown of glycogen and glucose release

Question 5

delta-cells produce.. which…

Answer 5

Somatostatin

Supresses GI motility and release of insulin and glucagon

Question 6

Structure of insulin

Answer 6

A chain 30 aa
B chain 21 aa
C peptide - inactive

Question 7

Insulin degraded by

Answer 7

insulinase in liver and kidneys

Question 8

Insulin is secreted in response to

Answer 8

changes in glucose/ATP

Question 9

Insulin secretion occurs via

Answer 9

calcium dependent exocytosis

Question 10

Insulin binding to the insulin receptor

Answer 10

dimerization
“ receptor tyrosine kinase”autophosphorylation
Effects on intracellular kinases/phosphatases
effects on key enzymes

Question 11

2 actions of insulin

Answer 11

Carbohydrate metabolism and lipid metabolism

Question 12

carbohydrate metabolism

Answer 12

facilitates glucose entry into muscle, adipose (GLUT)
Stimulates liver to store glucose as glycogen
Decreases conc of glucose in the blood

Question 13

Lipid metabolism

Answer 13

Insulin triggers uptake of glucose into liver
Promotes synthesis of fatty acids in the liver (when glycogen is saturated) leading to increase in lipoproteins in circulation to release FAs (triglyceride synthesis in adipocytes)
Inhibits breakdown of fat in adipose tissue
Promotes glycerol synthesis from glucose and incr triglceride synthesis

Question 14

Insulin stimulates

Answer 14

muscle glucose uptake

Question 15

rise in blood glucose triggers

Answer 15

B cells release insulin

Question 16

B cells release insulin triggers

Answer 16

incr rate of glucose uptake
Incr glucose utilization and ATP generation
Incr glycogenesis- formation of glycogen from sugar (liver, muscle)
Incr protein synthesis
Incr fat synthesis

All this causes blood glucose to decline

Question 17

How is glucose synthesised

Answer 17

Alpha cells of islets (a portion of tissue structurally distinct from surrounding tissues) synthesise and release glucagon:

Question 18

Glucagon

Answer 18

peptide hormone
released when blood glucose falls
Counter regulatory hormone to insulin
Stimulates glycogenolysis (break down glycogen)
Promotes gluconeogenesis (glucose from other sources)
Increases breakdown of fats (alternative energy source)

Question 19

what type of cell releases glucagon

Answer 19

Alpha cells

Question 20

Release of glucagon triggers

Answer 20

Incr glycogenolysis liver, skeletal muscle
Increased fats to fatty acids
Increased protein breakdown
Increased Gluconeogenesis (liver)

Question 21

When is glucagon released

Answer 21

Falling blood glucose

Question 22

Hypoglycaemia

Answer 22

Low blood glucose

Uptake of glucose by glucose dependent tissue not adequate to maintain tissue function

Question 23

Effects of hypoglycaemia

Answer 23

CNS sensitive: poor vision, slurred speech. confusion, coma death

Overactivity of ANS: palpitations, sweats, shakiness and hunger

Question 24

Diabetes is characterised by

Answer 24

hyperglycaemia

Question 25

Gestational diabetes

Answer 25

associated with pregnancy
Serious risks to mother and child
Incr risk of developing type 2

Question 26

Insulin effect on muscle

Answer 26

glucose and AAs uptake

Glucose converted to glycogen and amino acids to structural proteins

Question 27

which hormone increases uptake of glucose and where

Answer 27

insulin and muscle and Adipose

Question 28

Which hormone triggers lipogenesis and where

Answer 28

insulin and in the liver and adipose

Question 29

Lipolysis where and what hormone

Answer 29

Adipose and glucagon

Question 30

Amino acid uptake where and what hormone

Answer 30

muscle and insulin