Switching On and Maintaining Fuel Supply Flashcards
Does foetal size change according to dietary intake of their mother?
No it is preserved relative to intake
If the mother does not eat enough, then it is the mother that loses weight not the baby
Reduction in fetal size can occur if the minimum number of calories are not taken in
How many grams of glucose does a foetus use per day?
5g/ kg/ day
Glucose and Amino acids move across the placenta by facilitated diffusion
Which hormone is the most dominant in the third trimester of the foetus?
Insulin
Due to hyperplasia of Beta cells of pancreas
Insulin levels rise for foetus to lay down fat stores
When is fat laid down during the pregnancy?
3rd trimester, important in first few days postnatally
Which hormone is dominant in the post-natal metabolic adaptation state (fasting state)?
Counter regulatory hormones
Glucagon
Cortisol
How does insulin act in the adult body?
Controls blood glucose levels
How does insulin act in the foetus?
Anabolic hormone
Removes glucose from circulation and stores it in tissues:
- Increases glucose uptake into muscle, fat + liver
- Decreases lipolysis
- Decreases amino acid release from muscle
- Decreases gluconeogenesis in liver
- Decreases Ketogenesis in liver
What does the baby rely on once it is born?
Breast Milk
Only a small amount is available initially
What is colostrum?
First milk that isn’t enough to meet baby’s energy requirements
Baby uses energy stores
The milk becomes more nutritious and fatty later on
Difference between pre-term and term babies?
Term babies have fat stores which they rely on initially
What is the energy requirement of a new born baby?
4-6g glucose/kg/day
What changes from fetal anabolic metabolic state to neonatal state?
Catabolic enzyme systems (not needed in utero) must be switched on in order for baby to reply on body stores between feeds
Which organ has the uses the highest amount of energy at rest?
The brain
How does the brain manage its high demand of energy?
Cerebral Metabolic Rate (CMR) is relatively low at birth
It increases as the brain develops
When does catecholamine surge occur?
At birth. Surge in adrenergic hormones which causes more glucagon to be secreted. Cutting the cord causes fall in gluclose and glucagon opposes it to activate gluconeogenesis and glycogenolysis
How are stores converted to fuels?
in womb, build up stores. After birth, catabolic processes increase availibility of substance by switched on catabolic hormones
Which hormones oppose anabolic actions of insulin promoting energy release after birth?
glucagon
adrenaline
coristol
growth hormone
when are the catabolic hormones switched on?
during labour and delivery. Surge in adrenaline switches on counter-regulatory catabolism and glucagon increases to switch off actions of insulin
What determines whether a baby is chubby or skinny?
Missed trimester = no fat being laid down
Term infant = fat laid down in final semester to get through metabolic changes
Baby is usually 16% fat
Why doesn’t the foetus need to convert stores to fuel?
Receives energy from placenta
Substrate is built up anabolically and stored in foetus under insulin
How does the baby get its energy once its born?
Switching on catabolic hormones (counter-regulatory)
Done in the foetus during labour and delivery
What processes occur during a postnatal fast?
Gluconeogenesis = making glucose from non carbohydrate sources (muscle + fat) e.g. lactate, pyruvate, alanine and glycerol
Ketogenesis = production of ketones from the breakdown of fat (normal metabolism esp in the brain)
What is an indication of insipient starvation?
Adult ketogensis
What is gluconeogenesis?
Glucose –> 2x Pyurvate
Anarobic
Pyruvate goes into krebs cylce
glycolysis in reverse is gluconeogenesis
