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WEEK 4 SEM 4 > Switching on and maintaining a fuel supply > Flashcards

Switching on and maintaining a fuel supply Flashcards

1
Q

How does the foetus get nutrition?

A
  • through the placenta

- glucose and amino acids= facilitated diffusion according to the diffusion gradient

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2
Q

What is the metabolism like in the womb?

A
  • anabolic
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3
Q

Which week is the rate of building up the body the highest?

A
  • 20 weeks of gestation
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4
Q

When the foetus is near term, how much glucose does it use per day?

A
  • 5g of glucose/kg/day
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5
Q

In the foetus, what is the dominant hormone?

A
  • insulin
  • insulin works as GH in the foetus (not to maintain blood sugar levels)
  • helps build body through anabolic processes
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6
Q

What are the main actions of insulin?

A
  • glucose uptake into body tissues e.g. muscles, fat, liver
  • decrease lipolysis (fat breakdown)
  • decrease amino acid release from muscles
  • decreases gluconeogenesis in the liver
  • decreases ketogenesis in the liver
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7
Q

After birth what does the metabolism need to be switched to?

A
  • from anabolism to catabolism

- bc outside the nutrient supply isnt continuous

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8
Q

What does outside feeding depend on?

A
  • nutrient supply depends on feeding period and fasting periods in between
  • when fasting, catabolism is important
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9
Q

What happens to feeding in the first 24 hours of it coming out?

A
  • very little milk is available

- so baby gets low nutrition supply

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10
Q

What is colustrum?

A
  • first milk produced by the mammary glands
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11
Q

What does the baby eat in the first day?

A
  • average colustrum intake = 7mls per feed in the first 24 hours
  • if baby has 6-8 feeds= about 30mls/kilo/day of milk intake in the firstday
  • this is too less than the 60mls/kilo/day routinely prescribed to newborn babies
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12
Q

How much food is prescribed to newborn babies in a day?

A

60mls/kilo/day routinely prescribed to newborn babies

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13
Q

What stores are there at birth by weight?

A
  • 1% glycogen

- 16% fat

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14
Q

What happens to glucose levels as the baby is born?

A
  • as baby is born, sharp drop in plasma glucose levels
  • even if baby is not fed, glucose levels come up to normal in plasma
  • this is bc of hormones like glucagon which surge in the plasma
  • glucagon activates gluconeogenesis (production of glucose from stores) and opposes insulin actions
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15
Q

What happens if glucose levels reach 2mg/dl?

A
  • in adults, person would be weak
  • babies are fine bc they can cope with hypoglycaemia
  • newborn baby has very low cerebral metabolic rate (as the baby develops, this metabolic rate increases)
  • so glucose demand is less
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16
Q

What are postnatal fasts?

A
  • breaks the baby has between feeds
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17
Q

What happens in postnatal fasts?

A
  • baby needs to utilise glucose from stores
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18
Q

What is gluconeogenesis?

A
  • process which provides glucose from body stores

- e.g.g from AA, glycogen, fats through lactate, pyruvate, alanine and glycerol

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19
Q

What is ketogenesis?

A
  • ketone bodies produced from fats

- newborn babies use ketone bodies (primary energy source= fuel for brain)

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20
Q

How is ketone used in adults?

A
  • primary energy sources for brain= GLUCOSE

= use KETONES when starving

21
Q

What does the enzyme glucose 6 phosphatase do?

A

glucose 6 phosphate to glucose

22
Q

What does the enzymes fructose 1, 6 bisphosphatase do?

A

fructose 1, 6 diphosphate to fructose 6 phosphate

23
Q

What is the structure of fats?

A
  • have 3 carbon backbone (triglyceride backbone)

- also have fatty acid tails

24
Q

How does the fatty acid tail determine the type of fat?

A
  • if fatty acid unsaturated= has double bond in it= has kink in tail= so fat doesnt pack very well= tends to be liquid e.g. olive oil
  • if fat is saturated= single bond= no kink in tail= fat can pack well= will be solid
25
Q

How is fat oxidised?

A
  1. remove glycerol group from fats
  2. remove C 2 at a time
  3. carbons bound to coenzyme A
  4. form acetyl CoA
    PROCESS CALLED B OXIDATION
  5. acetyl groups used to form ketone bodies e.g. acetone and B hydroxybutyrate= USED FOR CEREBRAL FUEL
  6. acetyl groups enter Kreb’s cycle- energy source or converted to pyruvate and goes through gluconeogenesis
26
Q

What is the difference with how much 1g of fat gives and how much 1g of glucose gives?

A
  • 1g of fat gives 9-10Kcals of energy

- 1g of glucose gives 4Kcals of energy

27
Q

What is breast milk made of?

A
  • 50% fat and 40% carbohydrate
28
Q

How is the milk broken down?

A
  • lactose is broken down into glucose

- fat is broken down by lipase which is in breast milk

29
Q

What happens in the fed state of the baby?

A
  • baby just eaten
  • full of glucose
  • glucose needs to be stored
  • glycogen in muscles, amino acids for proteins, fat etc.
30
Q

What happens in a fasting state of the baby?

A
  • after feeding and absorbing finished
  • blood glucose goes down
  • insulin is stopped
  • cortisol and glucagon rise
  • they mobilize the stores

FATS broken to FREE FATTY ACIDS= go to liver= converted to ketones or glucose

MUSCLES yield AMINO ACIDS and LACTATE= go to liver= convert to glucose

31
Q

What are diseases relating to metabolism in a baby?

A
  • glucose demand > supply
  • hyperinsulinism
  • glucagon, adrenaline, cortisol failure
  • enzyme deficiencies in pathways
32
Q

At how many weeks does the foetus grow the quickest?

A

20 weeks so the demand for glucose is the highest

33
Q

What happens if a baby is born preterm at 24 weeks?

A
  • baby growing very quickly= has high metabolic demands
  • metabolism completely set on anabolic
  • takes while for baby to switch to catabolic
  • the stores the baby has have low nutrients and poor fat absorption
34
Q

How much fat does a baby absorb?

A

babies only absorb about 70% of the fat they intake, and the smaller the baby is the lesser the fat is absorbed

35
Q

How do you feed a preterm baby?

A
  • start with small amounts of breast milk
  • gradually increase
  • by 7-10 days of life= will be on full feed (breast milk)
  • also give IV glucose, amino acids and fats
36
Q

What happens if a full term baby is skinny?

A
  • means they havent grown as must as they should in utero
  • they have small nutrient stores
  • so gluconeogenic pathway is immature
37
Q

How are skinny babies managed?

A
  • support by breast feeding
  • keep an eye on them (so they dont develop hypoglycaemia)
  • if hypoglycaemic, give IV glucose
38
Q

Why is a baby of a diabetic mother fat?

A
  • mother diabetic
  • high maternal glucose
  • facilitated diffusion in placenta
  • foetus has high glucoe
  • foetus has high insulin= works as GH (lays stores down)
  • so baby overgrowth= FAT BABY
39
Q

What happens to the baby of a diabetic mother?

A
  • hepatomegaly (enlarged liver)
  • lots of subcutaneous fat stores
  • look disproportionate and bigger than normal (macrosomia)
40
Q

When the baby of a diabetic mother is born, what does it have?

A
  • higher than normal insulin levels
  • lead to hypoglycaemia
  • reduced ketogenesis = DANGEROUS
41
Q

What are causes of hyperinsulinaemia?

A
  • Beckwith Wiedemann

- Islet cell dysregulation

42
Q

What is Beckwith Wiedemann?

A
  • macroglossia= large tongue
  • macosomia= larger than normal
  • midline abdominal defects (exomphalos, umbilical hernia, diastasis recti)
  • ear creases/ear pits
  • hypoglyacemic
43
Q

What happens in Islet cell dysregulation?

A
  • hyperactive islet cells (which produce insulin)
  • blood sugar is hard to control in these babies
  • MIGHT NEED TO DO pancreatectomy to control blood glucose= remove pancreas to get control of blood glucose
44
Q

What is CAH?

A
  • 21 hydroxylase deficiency
  • enzyme in the steroid hormone synthesis pathway
  • usually converts steroids to cortisol and aldosterone
  • bc of deficiency in the enzyme= too much testosterone and there is virilization of the female
  • cortisol deficiency- HYPOGLYCAEMIA
  • aldosterone deficiency- salt wasting crisis-hyponatrimeia
  • baby is boy from outside but has no testes
45
Q

What is Waterhouse-friderichsen?

A
  • severe adrenal haemorrhage with adrenal gland dysfunction secondary to sepsis or hypoxia
46
Q

What are inborn errors of metabolism?

A
  • Glycogen storage disease type I

- Galactosaemia

47
Q

What happens in glycogen storage disease type 1?

A
  • deficiency of the rate limiting enzyme glucose 6 phosphatase
  • converts glucose 6 phosphate to glucose
  • replenishes the blood with glucose (need for brain)
  • patient has hypoglycaemia and lactic acidosis
  • older child= hepatomegaly= bc of excess glycogen stores
  • managed by giving corn starch feeds- slowly release glucose
48
Q

What is galactosemia?

A
  • lactose is broken down to galactose and glucose in the body
  • galactose is then broken down to glucose by galactose 1 phosphate uridyl transferease (Gal-1-put) which is missing in galactosaemia
  • leads to toxic levels of galactose 1 phosphate
  • patient will present with
    −hypoglycemia
    −jaundice and liver disease
    −poor feeding and vomiting
    −cataracts and brain damage
    −e coli sepsis

WEEK 4 SEM 4 (6 decks)

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