Metabolism at special conditions Flashcards
what are the fuel sources utilised by the body under normal circumstances?
- Glucose : preferred method, only one used by RBC, medulla of kidney. 12g free glucose and 300g as glycogen in liver.
- FA : other than brain, RBC, CNS can use FA. stored as TAG 10-15kg in body. only in aerobic conditions, slow release.
what are the fuel sources utilised by the body under special circumstances?
eg : starvation
- Amino acid : muscle protein broken down, converted to glucose or ketone bodies, 2 week energy supply.
- ketone bodies : from FA, used when glucose lacking, BRAIN can use!
- lactate : anaerobic product, liver can convert back and TCA used in heart.
what are the energy stores of the body?
- glycogen : 400mg, made+stored in liver and muscle when glucose excess.
- fat : 10-15kg, stored as TAG in adipose.
- muscle protein : 6kg, in emergency, store filled by normal growth and repair.
what are the anabolic hormones of the body?
- INSULIN which promotes fuel storage.
- ( Growth hormones that increase in protein synthesis.)
- lack of insulin causes catabolic stage.
what are the catabolic hormones of the body?
- promotes release from stores and utilisation.
- glucagon
- adrenaline.
- cortisol.
- growth hormone increasing lipolysis and gluconeogenesis.
- thyroid hormones.
what does insulin inhibit and what does it promote?
- inhibit : gluconeogenesis, glycogenolysis, lipolysis.
- promotes : glucose uptake to muscle and adipose, glycolysis, glycogen synthesis, protein synthesis.
what are the effects of feeding on metabolism?
- increase un blood glucose leads to insulin release from beta cells in pancreas.
- increase glucose uptake via GLUT 4.
- promotes storage as glycogen.
- promotes amino acid uptake and protein synthesis.
- promotes lipogenesis and storage as TAG.
what are the effects of fasting on metabolism?
REFEEDING SYNDROME
- glucagon and cortisol release stimulated which stimulates,
- glycogenolysis in liver.
- lipolysis releasing FA.
- gluconeogenesis to maintain supply to brain.
- once fat stores depleted protein used and death due to loss of muscle mass (respiratory muscle and infection).
describe the metabolic changes in the early stage of pregnancy. ANABOLIC STAGE.
- prepare for rapid growth, birth, lactation.
- increase in maternal fat stores.
- small increase in insulin sensitivity (higher insulin) promotes anabolic stage.
- increased store of nutrients to meet future demands.
describe the metabolic changes in the late stage of pregnancy. CATABOLIC STAGE.
- decreased insulin sensitivity AKA increased resistance.
- this means increase in maternal glucose and free fatty acid concentration.
- greater substrate availability for foetal growth so mothers glucose utilisation reduced by switching to FA use.
*glucose principal fuel for foetus, facilitated via GLUT-1.
* foetus controls mothers metabolism via fetoplacental unit of placenta, foetal adrenal glands and foetal liver. controls maternal pituitary axis via placental proteins like anti-insulin.
(oestriol, progesterone hormones )
what is the function of anti-insulin hormone in pregnancy?
-
what is gestational diabetes?
- decrease where pancreatic B cells do not produce sufficient insulin to meet increased requirement in late pregnancy.
- causes : antibodies similar to type 1, genetic susceptibility to mature onset, B cell dysfunction in obesity and resistance (most likely).
what are the clinical implications of gestational diabetes?
- increased incidence of miscarriage, congenital malformation, fetal macrosomia, shoulder dystocia in baby so difficult delivery, gestational hypertension, pre-eclampsia.
- risk reduced if diagnosed and managed.
what is gestational diabetes?
- decrease where pancreatic B cells do not produce sufficient insulin to meet increased requirement in late pregnancy.
- causes : antibodies similar to type 1, genetic susceptibility to mature onset, B cell dysfunction in obesity and resistance (most likely).
- starting point for insulin resistance before pregnancy is crucial to assess development.
what are the clinical implications of gestational diabetes?
- increased incidence of miscarriage, congenital malformation, fetal macrosomia, shoulder dystocia in baby so difficult delivery, gestational hypertension, pre-eclampsia.
- risk reduced if diagnosed and managed with dietary modifications, insulin injections, USS to assess growth.
risks : maternal age, BMI, race/ethnicity, familial history, macrosomia history.
