Special Circumstances Flashcards
What proportion of the fetal growth occurs in the last trimester?
2/3
When is the anabolic phase of pregnancy and why does this happen?
early pregnancy
increase nutrient stores in preparation for high demand from foetus
When does the catabolic phase of pregnancy occur?
late pregnancy
Why is there a small increase in insulin sensitivity in early pregnancy?
To increase fatty acid uptake so that stores of TAG are increased.
Why is insulin sensitivity in the mother decreased in late pregnancy?
nutrients are directed to foetus
less glucose is used by the mother
How do most substances travel across the placenta?
simple diffusion
Name a molecule type that requires active transport to cross the placenta
amino acids
Which transporter is required in the placenta for glucose?
GLUT1
What is the fetoplacental unit?
A new endocrine entity that can control the maternal hypothalmic pituitary axis.
Give examples of hypothalamic like hormones secreted by the placenta
CRH
GnRH
TRH
GHRH
Give examples of pituitary like hormones released from the placenta
ACTH
hCG
cCT
hPL
Which 2 steroid hormones are released from the placenta?
Oestriol and progesterone
What does the first half of pregnancy prepare the mother for?
rapid growth rate of the foetus
birth
lactation
How does maternal utilisation of nutrients change?
uses less glucose
utilise more fatty acids
What are the anti-insulin hormones that the fetoplacental unit releases?
CRH
hPL
progesterone
When can maternal hypoglycaemia occur and why?
between meals and at night time
due to the continuous fetal draw of glucose
How do oestrogens and progesterones affect beta cells?
They increase the sensitivity of beta cells to glucose. This results in beta cell hyperplasia and hypertrophy. Therefore more insulin in synthesised and secreted.
What happens if the beta cells do not respond normally to pregnancy?
The maternal blood glucose increases and the mother may get gestational diabetes.
What is overt diabetes?
Diabetes that was discovered in pregnancy but was present before.
What is gestational diabetes?
A disease in which the pancreatic beta cells do not produce sufficient insulin to meet increased requirement in late pregnancy.
What are the 3 known causes of gestational diabetes?
beta cell dysfunction
autoantibodies
genetic susceptibility
What does gestational diabetes increase the incidence of?
miscarriage
congenital malformation
fetal macrosomia (large body)
shoulder dystocia (shoulders stuck during birth)
hypertensive disorders eg. gestational hypertension/preeclampsia
What defines preeclampsia?
High blood pressure and protein in the urine whilst pregnant
What are the risk factors for gestational diabetes?
age BMI more common in Asians, Blacks and Hispanics family history of diabetes family history of macrosomia
What is the management for gestational diabetes?
calorie restriction
insulin injections if severe
regular ultrasounds to check on foetal development
What should be ensured in exercise?
rate of mobilisation = rate of utilisation
minimal disturbance to homeostasis
glucose supply to brain maintained
end products of metabolism removed quickly
How long do the ATP stores in muscle last?
approx 2 seconds
How long does creatine phosphate last?
approx 5 seconds
What accounts for the largest amount of ATP usage in exercise?
The myosin ATPase that is used for the sliding filament model of contraction.
How long could you exercise at low intensity using only the glycogen from the muscle and liver?
60 minutes
What is the principal organ for the regulation of glucose?
The liver because it recycles lactate.
Which transporters are used in the muscle for glucose uptake?
GLUT4
GLUT1
What is the cascade sequence for increased GLUT4 expression?
increased glucose in cell
increased AMP
AMPK activated
GLUT4 channels expressed on cell surface
How is ATP produced during a 100m sprint?
anaerobically because the body cannot deliver sufficient oxygen
lactate builds up
muscle store of glycogen is used
How is ATP produced in a medium intensity 1500m race?
some oxygen can be delivered so partly aerobic and partly anaerobic
fatty acids can be utilised
muscle glycogen is utilised
How is ATP produced during a marathon?
95% aerobic
muscle glycogen, liver glycogen and fatty acids are utilised
What happens to insulin and glucagon levels during a marathon?
insulin levels slowly decrease
glucagon levels increase
What hormones, other than glucagon, increase during a marathon?
adrenaline
growth hormone
cortisol
What are the benefits of exercise?
change in body composition glucose tolerance improves insulin sensitivity increases blood triglycerides decrease blood pressure falls psychological effects
What is the average weight gain of a pregnant women?
8kg
