Fed, Fasted and Starvation

Question 1

What is the absorptive state?

Answer 1

Food in the GI tract

Nutrients being absorbed into blood and lymph

Question 2

What is the post absorptive state?

Answer 2

Fasting state

Nutrients not being absorbed

Question 3

What do absorbed nutrients enter first?

Answer 3

The portal blood

Question 4

What organ do absorbed nutrients reach first?

Answer 4

Liver

Question 5

What nutrients are in the portal blood?

Answer 5

Monosaccharides
Amino acids
Lipids

Question 6

Which tissues are hormone-sensitive with regards to energy metabolism?

Answer 6

Liver
Muscle
Adipose tissue

Question 7

Where will glucose in the blood end up?

Answer 7

Liver to store as glycogen
Adipose tissue to form triglycerides
Muscle to store as glycogen
Other tissues for krebs cycle

Question 8

Where will amino acids in the blood end up?

Answer 8

In the liver to be converted to keto acids and release energy
In muscle to create proteins

Question 9

Where will triglycerides in the blood end up?

Answer 9

In adipose tissue

Question 10

What triggers a switch from post absorptive to absorptive state?

Answer 10

Increased glucose and insulin in the blood

Question 11

What triggers release of insulin and from where?

Answer 11

Secreted by beta cells of the islets of Langerhans in the pancreas
Trigger is high blood glucose and amino acids

Question 12

What takes up glucose into beta cells?

Answer 12

GLUT-2 transporter

Question 13

What does uptake of glucsose into beta cells trigger?

Answer 13

Generation of ATP from glucose metabolism

Ca2+ influx

Question 14

What causes insulin exocytosis?

Answer 14

Intracellular Ca2+ increase

Question 15

Outline the feedback control of insulin after a meal

Answer 15

Blood glucose concentration increases
Insulin secretion stimulated
Glucose uptake into cells by GLUT-4
Blood glucose concentration falls
Stimulus for insulin secretion removed
Blood insulin concentration falls

Question 16

What do muscles and adipose tissue need for glucose entry to cells?

Answer 16

Insulin

Question 17

Which transporter is stimulated by insulin?

Answer 17

GLUT4

Question 18

What is the effect of insulin on GLUT4?

Answer 18

GLUT4 is a transporter stored within the cell

Insulin stimulates translocation to the plasma membrane

Question 19

What concentrations of glucose are seen in diabetes patients?

Answer 19

High extracellular

Low intracellular

Question 20

What does insulin promote?

Answer 20

Glucose disposal into muscle and adipose tissue

Question 21

What enzymes does insulin activate in the liver?

Answer 21

Glucokinase
Glycogen synthase
Phosphofuctokinase
Pyruvate dehydrogenase
Acetyl CoA carboxylase
Fatty acid synthase

Question 22

What enzymes does insulin inhibit in the liver?

Answer 22

Glycogen phosphorylase

Glucose 6 phosphatase

Question 23

What does insulin trigger in muscle?

Answer 23

Increased glucose uptake
Glycogen synthesis
Glycolysis

Question 24

What enzymes does insulin activate in adipose tissue?

Answer 24

Pyruvate dehydrogenase
Acetyl CoA carboxylase
Lipoprotein lipase

Question 25

What enzyme does insulin inhibit in adipose tissue?

Answer 25

Hormone sensitive TG lipase

Question 26

What is utilised in the post absorptive state?

Answer 26

Glucose stores as none is being absorbed in the GI tract

Question 27

What are the two ways energy is obtained in the post absorptive state?

Answer 27

Glucose-supplying reactions | Glucose-sparing reactions

Question 28

What are glucose-sparing reactions?

Answer 28

Reactions which generate other energy substrates such as fatty acids and ketone bodies

Question 29

Why are reactions essential during the post absorptive stage?

Answer 29

To preserve plasma glucose levels for brain function

Question 30

In what two ways does the liver supply glucose?

Answer 30

Glycogenolysis | Gluconeogenesis

Question 31

What controls glucose-supplying reactions?

Answer 31

Fall in insulin levels | Increase in hormones

Question 32

What hormones are involved in glucose-supplying reactions?

Answer 32

Epinephrine Glucagon Cortisol Growth hormone

Question 33

What effect does epinephrine have?

Answer 33

Increases glycogen breakdown in muscles, adipocytes and the liver

Question 34

What effect does glucagon have?

Answer 34

Increases glycogen breakdown and gluconeogenesis in the liver

Question 35

What effect does cortisol have?

Answer 35

Increase gluconeogenesis in the liver and decreases glucose uptake

Question 36

What does growth hormone do?

Answer 36

Decreases glucose uptake

Question 37

How much ATP is produced by beta-oxidation?

Answer 37

34

Question 38

Where are ketone bodies produced?

Answer 38

In the liver

Question 39

Where do ketone bodies go?

Answer 39

From the liver to tissues for use in the Krebs cycle

Question 40

What is a charecteristic of diabetes mellitus?

Answer 40

High blood sugar

Question 41

What happens to the ratio of hormones in someone suffering from diabetes mellitus?

Answer 41

Increased ratio of hormones that increase blood sugar to insulin (glucagon, adrenaline, growth hormone)

Question 42

What is the cause of the shift in hormones?

Answer 42

Either insulin deficiency or insulin resistance

Question 43

What is type 1 diabetes?

Answer 43

Young onset Destruction of beta cells and loss of insulin production Metabolic derangement by inability to utilise glucose Switch to other fuels leads to marked weight loss Also hyperlipidaemia and ketoacidosis

Question 44

What is type 2 diabetes?

Answer 44

Prevalence increases with age Insulin levels usually normal or high but with reduced action (resistance) Treated with lifestyle changes, insulin stimulators or insulin Less of an effect as some insulin action still present Causes long-term damage due to high glucose levels and lipid abnormalities

Question 45

What is the relationship between obesity and type 2 diabetes?

Answer 45

Obesity is present in 55% of sufferers

Question 46

What happens in the liver of someone with diabetes?

Answer 46

Decreased glycogen synthesis | Increased glycogenolysis

Question 47

What happens in adipose tissue of someone with diabetes?

Answer 47

Decreased glucose uptake | Increased lipolysis

Question 48

What happens in the muscle tissue of someone with diabetes?

Answer 48

Increased extracellular | Breakdown of protein to amino acids as substrates for gluconeogenesis

Question 49

What happens to levels of acetyl coA in diabetes sufferers?

Answer 49

Increased by the b-oxidation of fatty acids

Question 50

What is the effect of increased acetyl coA levels?

Answer 50

Inhibits the Krebs cycle | Used for ketogenesis

Question 51

What is the effect of high ketone levels?

Answer 51

Acidosis

Question 52

What are clinical features of uncontrolled diabetes?

Answer 52

``` Polyuria Polydipsia Blurred vision Infections Weight loss Ketosis Confusion Coma ```

Question 53

How is uncontrolled diabetes treated?

Answer 53

Rehydration with intravenous saline Insulin injections Monitor serum electrolytes Treatment of symptoms such as infection

Question 54

What is the impact of chronic diabetes?

Answer 54

Effects of high blood glucose Thought to cause enzymatic glycation of proteins, altering their function Sorbitol toxicity, sorbitol is produced from glucose by aldol reductase. Further glycation of tissues

Question 55

What is retinopathy?

Answer 55

Growth of friable and poor quality new blood vessels in the retina Macular edema Leads to severe vision loss or blindness

Question 56

What is nephropathy?

Answer 56

Damage to the kidney that can lead to chronic renal failure eventually requiring dialysis Diabetes is the most common cause of adult kidney failure worldwide

Question 57

What is neuropathy?

Answer 57

Abnormal and decreased sensation in the feet and then fingers and hands With damaged blood vessels it can lead to diabetic foot (delayed wound healing, infection, gangrene)

Question 58

What are the consequences of atherosclerosis?

Answer 58

Strokes Heart attacks Peripheral vascular disease

Question 59

What is hyperlipidaemia?

Answer 59

Common in diabetes High circulating fatty acid concentration Atherogenic

Question 60

What is hepatic steatosis?

Answer 60

Fatty liver

Question 61

What causes hepatic steatosis?

Answer 61

Fatty acids taken up by liver and converted to triaglycerol | Deposited in the liver

Question 62

What are long term treatments of diabetes?

Answer 62

``` Lipid lowering drugs Reduced blood pressure Aspirin Avoid smoking Diet Home monitoring Adjustment of tablets/insulin ```

Question 63

Why is diabetes seen in cystic fibrosis patients?

Answer 63

CF gene creates CFTR protein Blockage of pancreatic ducts Ductal obstruction leads to pancreatic tissue distruction