MET PBL 1

Question 1

What is blood glucose rnage

Answer 1

 Maintained in a narrow 3-5 millimoles/litre range.

Question 2

what is glucose the comeplte source of

Answer 2

 Glucose is often the complete source of metabolic energy in normal conditions in:
o The nervous system.
o Red Blood Cells.

Question 3

what happens post meal to glucose and insulin

Answer 3

Post-Meal: pancreases stimulates insulin release.

 Glucose uptake by insulin-responsive tissues
o Blood levels return to normal.

Question 4

what happens in the post absorptive site to glucose

Answer 4

Glycogenolysis
o Glycogen stores in the liver
o Glucogenic AAs (alanine, glutamine) and other 3C compounds (glycerol, lactate, pyruvate).

 Gluconeogenesis of body proteins.

Question 5

what initially causes weight loss

Answer 5

Weight Loss: glycogen has a large water constant, and very rapid initial weight loss due to the bodies glycogen
stores being depleted than a loss of fat tissue.

Question 6

what can be used as a source of energy instead of glucose

Answer 6

fats

Question 7

what tissues cannot use fats as a source of energy

Answer 7

o Brain: requires glucose and is unable to use fats directly.
o Renal medulla and red blood cells.

Question 8

the body is unable to….

Answer 8

convert fats to glucose

Question 9

what is ketogensis

Answer 9

• this is when the liver produces ketone bodies from acetyl-CoA

Question 10

describe how keotgensis work

Answer 10

o ketones circulate in the blood and can be
converted back to acetyl CoA
o Cannot replace as glucose, are however
effective to a certain extent.
 E.g. replace ~50% of brains usage
reducing overall glucose demand.

Question 11

what is reduction in glucose demand important

Answer 11

prevents proteins from being used

Question 12

what is ketosis

Answer 12

this is excessive ketone production

Question 13

what is ketoacidosis

Answer 13

• when ketones are presents in the blood

- causes bad breath due to excess acetoacetate generating acetone

Question 14

what causes bad breath in ketoacidosis

Answer 14

• causes bad breath due to excess acetoacetate generating acetone

Question 15

How can the body produce glucose if there is none in the body

Answer 15

• Gluconegoensis
• glucose is still required to maintian the NS in ketogensis
• therefore the body produces it from glucogenic amino acids
• these are found in muscles and can cause muscle wastage

Question 16

name the three forms of serious protien energy malnutrition

Answer 16

marasmus
Kwashiorkor
Marasmic KW

Question 17

what is Marasmums

Answer 17

• childhood form of starvation - there is an increased risk in children under the age of 1
• nutritional deprivation loss of calories and proteins - has onset of months to years
• low mortiality

Question 18

what are the clinical features of marasmus

Answer 18

 Obvious muscle wasting
 Low blood glucose
 Low body temperature
 Haemoglobin is low, low plasma albumin.
 No oedema.

Question 19

what is kwashiorkor

Answer 19

this is when you have adequate calorie intake but grossly inadequate protein intake
- this is because the diet consists largely of carbohydrate

Question 20

what does Kwashiorkor diet lead to

Answer 20

o Diet consists of food largely carbohydrate
 Leads to body protein being broken down and not replaced.
o Loss of plasma proteins: water flow out of bloodstream into tissues (oedema).
 Swollen abdomen is most obvious.
 Increased by suppressed albumin production.

 Onset of weeks to months
 High mortality.

Question 21

What are the clinical features of Kwashiorkor

Answer 21

 Enlarged liver
 Oedema of the abdomen
 Skin lesions and hair loss

Question 22

What is marasmic Kwashiorkor

Answer 22

Marasmic-kwashiorkoris a mixed form of bothmarasmusandkwashiorkorand is characterized by the
presence of both wasting and bilateral pitting oedema.

Question 23

What is refeeding syndrome

Answer 23

This is a potentially fatal shift in fluids and electrolytes when a malnoruished patient is fed

Question 24

What is the most importent deficiency in refeeding syndrome

Answer 24

hypophophatemia - phosphate deficiency is the most important feature

Question 25

what are the clinical features of refeeding syndrome

Answer 25

 Abnormal sodium and fluid balance
 Changes in glucose, protein and fat metabolism
 Thiamine deficiency (B1)
 Hypokalaemia and hypomagnesaemia.

Question 26

what is the mechanism of action of refeeding sydnroem

Answer 26

Mechanism of Action
 Increased insulin and decreased glucagon secretion in response to rising blood sugar.

 Glycogen, fat and protein synthesis are stimulated in response
o Phosphate and magnesium (minerals) and thiamine are taken into cells
 Water follows
o Potassium absorption into cells through Na+ K+ ATP symporter
 Pumps glucose into the cell.

 Decreased serum levels of these substances due to these processes.
o These are already depleted in the body due to malnutrition.

Question 27

How do you prevent refeeding sydnrome

Answer 27

Malnourished patients (5+ days) should be slowly be refed.
Potassium, phosphate, calcium and magnesium should be given.

Question 28

what is a weight watches diet

Answer 28

Weight Watchers Diet
 Point based system aimed at reducing overall calorie intake.
 Switch from glucose to fat metabolism but no significant ketogenesis.
o Main fat loss from body fat (gradual weight loss).
 Group support

Question 29

What is the glycemic index

Answer 29

This is a measure of how much a food changes blood glucose level
High gI = big rise
low GI - small rise

Question 30

what does a low GI diet do

Answer 30

small rise in blood glucose foods

- useful in diabetes

Question 31

describe low GI foods

Answer 31

Low GI foods = often take longer to digest (release sugar over time rather than in one hit).
o People feel less hungry  reduce overall food intake.
o Decrease in insulin secretion which reduces fat storage

Question 32

describe an atkins diet

Answer 32

 Ketogenic diet (promotes use of ketone bodies).

 Carbohydrate restricted
o Low insulin levels (prevents fat storage).
o Slight intake = prevents gluconeogenesis from body proteins

 Maintains protein intake.
 Linked most closely to starvation
o Avoids complication because of proteins in the diet.

Question 33

what diet is linked most closley to starvation

Answer 33

atkins diet - it avoids complciations as there is a little bit of glucose present and proteins in the diet preventing you from entering ketogensis and starvation

Question 34

What is starvation

Answer 34

Starvation = muscle wasting will occur in addition to fat loss due to body protein being used.
 Body can live for around 2 months (depends on prior fat states).

Question 35

What is the role of liver in normal energy intake

Answer 35

 Gluconeogenesis from amino acids, glycerol.

 Ketogenesis (sole site in the body).

Question 36

how does starvation increase your risk of infection

Answer 36

 Immunodeficiency = hallmark of malnutrition/undernourishment
o Undernourished children principally die of common infections.
 Energy is required for activation and sustaining immune responses
 Great susceptibility to HIV/AIDs, tuberculosis and malaria.
 Most commonly: infectious diarrhea, which further compromises nutrition

Question 37

Explain the symptoms

Answer 37

Low haemoglobin - low protien will limit Hb production

Low white cell count - this causes a weakened immune system

low platelets - coaugaltion problems, low due to thrombopieitin produced in the liver which regulates them this is a protein

Low albumin - protien in the diet

low sodium, low magneisum, low phopshate - refeeding syndrome

normal potassium in serum overall - might not be normal intracellulary may be low

Question 38

what does low serum electolytes casue

Answer 38

cardiac failure