Fed, Fasted and Starvation

Question 1

What is the absorptive state known as?

Answer 1

Fed State, just after eating a meal and therefore are actively absorbing nutrients.

Question 2

What is the post absorptive state?

Answer 2

Fasted state, after nutrients and energy has already been absorbed and therefore you must acquire energy from the stores within the body.

Question 3

Where do the absorbed nutrients enter into first and which organ is required?

Answer 3

Portal blood first

First port of call is the liver

Question 4

In the liver what is glucose converted to?

Answer 4

Glycogen

Question 5

In muscle what is glucose converted to?

Answer 5

Glycogen

Question 6

In other tissues what can glucose be converted to?

Answer 6

Kerbs cycle energy

Question 7

In adipose tissue what can Glucose be converted to?

Answer 7

TG

Question 8

What are amino acids converted to in the liver?

Answer 8

Keto acids and energy

Question 9

What are amino acids converted to in the muscles?

Answer 9

Proteins

Question 10

What is the hormone controlling the switch between post absorptive and absorptive states?

Answer 10

Insulin.

Due to increased glucose and insulin in the blood

Question 11

Where is insulin secreted?

Answer 11

Beta cells of the islets of Langerhans in the pancreas.

Question 12

What is the trigger for insulin release?

Answer 12

High blood glucose and amino acid levels

Question 13

Which transported is responsible for glucose uptake into the beta cells?

Answer 13

GLUT2 which is insulin insensitive.

Question 14

What happens when glucose is transported into the beta cells.

Answer 14

Triggers generation of ATP from glucose metabolism and Ca influx
Raised intracellular Ca causes insulin exocytosis.

Question 15

After insulin is released what leads to glucose uptake in cells?

Answer 15

After insulin secretion
GLUT4 is recruited to cells and enables glucose to be up taken.
This leads to decreased blood glucose concentration and therefore removal of insulin

Question 16

What does insulin do when it is present in the liver after receptor is stimulated?

Answer 16

Makes no difference to GLUT2 on liver surface

Stimulates
Increased Glycogen synthesis
Increased Glycolysis
Decreased Glycogenolysis

Question 17

What is the role of insulin in muscle cells?

Answer 17

Drives GLUT4 to the cell membrane allowing for increased glucose uptake.
Increase glycogen synthesis
Increase glycolysis
Increase lipogenesis

Question 18

What is the role of insulin in adipocytes?

Answer 18

Drives GLUT4 is recruited to the membrane
Increased glucose up take
Increased Glycolysis and TG synthesis
Stimulate Lipogenesis and inhibit lipolysis

Question 19

What is being utilised when in the post absorptive state?

Answer 19

Utilisation of energy stores since glucose is not being absorbed from the GIT

Question 20

What reactions to ultilise energy from stores occur when in the post absorptive state?

Answer 20

Glucose supplying reactions (reactions generating glucose)

Glucose sparing reactions (reactions which generate other energy substrates such as FAs)

Question 21

What is the biggest contributor for energy in the post absorptive state?

Answer 21

Glucose sparing reactions

Question 22

What is a common example of a glucose supplying reaction and where do they occur?

Answer 22

Glycogenolysis
Gluconeogenesis

Occurs in the liver

Question 23

What examples are there for glucose sparing reactions?

Answer 23

Beta oxidation of fats from adipose tissue into Free FAs which enter the blood to be oxidised at other targets.

Question 24

What is diabetes mellitus characterised by?

Answer 24

High blood sugar

Question 25

What is Type 1 diabetes?

Answer 25

Young onset Destruction of beta cells and therefore loss of insulin Severe metabolic derangement due to inability to utilise glucose (effectively stuck in the fasted state)

Question 26

What are some characteristics of type 1 diabetes?

Answer 26

Use other fuels for energy (fasted state) | leads to marked weight loss and metabolic disturbance

Question 27

What is Type 2 diabetes?

Answer 27

Prevalence increases with age Insulin levels usually normal or high but has reduced action Treated with lifestyle (diet) or insulin

Question 28

What kind of damage does type 2 diabetes lead to?

Answer 28

Cause long term damage due to high glucose levels and lipid abnormalities. less Severe metabolic derangements

Question 29

What happens in type 1 diabetes in the liver?

Answer 29

Decreased glycogen synthesis | Increased glycogenolysis

Question 30

What happens in type 1 diabetes in adipocytes?

Answer 30

Decreased glucose uptake since GLUT4 is not being recruited Increased lipolysis Breakdown of fats releasing fatty acids into circulation (used as alternative energy source to glucose)

Question 31

What happens in type 1 diabetes in muscles?

Answer 31

Increased extracellular glucose as it cannot be absorbed since GLUT4 is not being recruited Breakdown of protein to amino acids as substrates for gluconeogenesis

Question 32

What does type 1 diabetes in muscles lead to?

Answer 32

Muscle wasting

Question 33

What are the problems with metabolic derangement caused by diabetes?

Answer 33

Level of glucose in blood is high because uptake is not stimulated. Insulin is not produced and therefore mediated inhibition of glycogenolysis and lipolysis cannot occur

Question 34

What is the major issue with diabetes affecting the liver?

Answer 34

1. Increased circulation of FAs directed to the liver where they are used in beta-oxidation. 2. Increase in Acetyl CoA generated in hepatocytes which inhibits Krebs pushing Acetyl CoA towards ketogenesis. 3. Ketones then used in extra hepatic tissues where it is reconverted into Acetyl CoA where it can then enter krebs outside of the liver.

Question 35

What are some clinical features of uncontrolled diabetes?

Answer 35

Polyuria (glucose reabsorption exceeded leading to glucosuria and thus more urination) Polydipsia(thirst) Dehydration ``` Infections (thrush) Weight loss (muscle and fat wasting) ``` Metabolic acidosis (due to ketones) leading to confusion or coma

Question 36

What treatments are there for uncontrolled diabetes?

Answer 36

Rehydration with IV saline Insulin Monitor correct serum electrolytes

Question 37

What is the impact of chronic diabetes?

Answer 37

High glucose may have other adverse metabolic effects as high glucose is toxic. Advanced Glycation (altering protein function) Sorbitol Toxicity (leads to glycation of other tissues)

Question 38

What are the long term metabolic consequences microvascular?

Answer 38

Retinopathy - leads to blindness / vision impairment Nephropathy - kidney damage leading to kidney failure Neuropathy - Decreased sensation as well as impaired immune and wound healing system

Question 39

What are some macrovascular complications?

Answer 39

Atherosclerosis strokes heart attacks