Week 8 Flashcards
How do nutritional demands change in and ex etero? (4)
Move from continuous supply to fasting/feeding
Move from glucose/amino acids to fatty diets
Higher metabolic demand
Insulin moves from being dominant hormone to being counteracted
Overview of structure of placenta
Basic structural unit is chorionic villus, blood supply through uterine and ovarian arteries
Functions of the placenta include gas exchange, metabolic transfer, hormone secretion, and fetal protection. Nutrient and drug transfer across the placenta are by passive diffusion, facilitated diffusion, active transport, and pinocytosis.
What adaptations occur during third trimester? (5)
Liver efficiency increases (glucose to glycogen) Free fatty acids formed and stored Brown fat for perinatal energy White fat for insulation Fat stores increase from about 1% to 15%
Where is brown fat stored for perinatal energy? (4)
Neck, scapula, sternum, kidneys
What is the role of insulin in fetal life? (4)
Increase glucose uptake in muscle, liver and fat
Reduce lipolysis
Reduce amino acid release from muscle
Reduce gluconeogensis / ketogenesis in liver
What hormones prepare the body for breastfeeding during pregnancy? (4)
Oestrogen - increase number / size of ducts
Progesterone - increase number of alveoli
Human placental lactogen - alveolar development
Prolactin - prepares for breastfeeding
What prevents lactation pre-birth? When does this stop?
Inhibition of prolactin by oestrogen
Oestrogen rapidly falls within 48 hours post-birth
Important component of breast milk
Colostrum
What 2 reflexes control breast feeding?
prolactin and milk ejection reflex
Describe prolactin reflex
Suckling stimulates reflex
Stimulates anterior pituitary to release prolactin, which stimulates alveoli to secrete milk
Inhibited by stress / fear (due to dopamine release by hypothalamus)
Describe milk ejection reflex
Initiated by suckling
Mediated by oxytocin (hypothalamus and posterior pituitary)
Benefits of breastfeeding (4)
Free
Nutritionally balanced
Immunological support (gastroenteritis, antibodies, reduced rate of pertussis, NEC)
Long term benefits - obesity, allergies, atopic illnesses
Why don’t people breast feed?
Maternal choice
Medications
Infections - HIV with high viral load
Potential normal problems with breastfeeding - not pathological (4)
PV bleeding in newborn girls
Gynaecomastia - stimulation of breast buds
Small amounts of blood in baby vomit
Mastitis - sometimes requires antibiotics, commonly caused by staph, continue feeding/expressing
How to neonates transition between in / ex utero in terms of nutritional stores?
Cope with high rates of hypoglycaemia in first 6 hours (use of fatty acids, ketones, lactate, glycogen)
Conversion of existing fuel supplies
What are the key catabolic hormones during conversion in / ex utero? (4)
Adrenaline, cortisol, growth hormone, glucagon
What are the nutritional demands in a neonate? (5)
Brain (65% vs 30% adults) Growth Temperature Basic life maintenance (e.g. breathing) Infection
What factors can affect feeding in neonate? (6)
Infection Poor milk supply Jaundice Tongue-tie Cleft lip / palate Low tone / poor reflexes
What is IUGR? (3)
Intra-uterine growth retardation
Low birth weight
Reduced amount of fat
Low levels of reserve for conversion
What are the characteristics of an infant of a diabetic mother?
Macrosomic baby (growth stimulated by insulin) Neonatal hypoglycaemia (show normalise)
Two examples of inborn errors of metabolism?
MCADD - medium chain acyl-CoA dehydrogenase deficiency
Cannot break down fatty acids
Results in hypoglycaemia
Maple syrup urine disease
Unable to break down branch chain amino acids
Leads to build up
Presents with hypoglycaemia and acidosis
What is the purpose of foetal haemoglobin?
TO ensure oxygen moves from mother to baby - has higher affinity for oxygen
Babies have less 2,3-DPG
Describe path of foetal blood
Why?
Include foramen ovale, ductus arteriosus and ductus venosus
Priortise blood to brain and heart
What keeps ductus arteriosus open in utero? (2)
Prostaglandins (by placenta)
Low oxygen concentration
Describe abnormal circulation during transition period
Sometimes circulation reverts to foetal circulation (but there is no umbilical cord)
Shunts can remain open
In what conditions does ductus arteriosus remain open (patent)? (5)
Prematurity Babies with respiratory distress Down syndrome Rubella Congenital heart disease