UG-fetal period, pregnancy and the breast Flashcards
what occurs on week 12 of foetal development (2)?
- Rotation & herniation of the gut is complete large SA
- External genitalia form
what occurs on week 16 of foetal development?
- Kidneys begin to produce urine
- Fetal skin becomes impermeable
- Testicles descend (if Y is present)
what occurs on week 17 of foetal development?
Sucking reflex observed
what occurs on week 20 of foetal development (4)?
- Max no. oocytes produced (if no Y present)
- Terminal villi of placenta formed
- Hair begins to grow
- Grey matter in brain increases by x4
what occurs on week 21 of foetal development?
Nociception (pain detection)
what occurs on week 24 of foetal development?
Alveoli begin to develop
what occurs on week 25 of foetal development?
-Increase in fetal movements where ‘kicks’ are large limb movements
what occurs on week 28 of foetal development?
surfactant produced
what occurs on week 36 of foetal development?
renal development complete
which hormones does the placenta produce?
- beta hcG (human chorionic gonadotropin)
- hPl (human placental lactogen)
- progesterone and oestrogen (after a certain point)
what are the roles of the placenta?
- produces hormones
- Acts as a immunological barrier
- Allows for respiration & excretion of glucose and oxygen
how does the placenta act as an immunological barrier?
transferring maternal IgG to the fetus and filters out potentially harmful cytotoxic antibodies
does the placenta continue to develop during foetal development?
yes
what gives the placenta its large SA?
All the terminal villi (give the placenta a large surface area) will have been formed by 20 weeks.
what event occurs in week 16 that contributes to amniotic fluid?
- Fetal skin becomes impermeable
- Kidneys produce urine = contributes to amniotic fluid. Fetus will go through cycle of swallowing fluid & producing urine
when does amniotic fluid vol peak?
week 30 at 800ml
what happens to amniotic fluid vol at week 40?
decreases to 400ml
what are the functions of amniotic fluid?
- Cushion for fetus to be protected from surrounding maternal organs
- Shock absorber from any sudden movements
during foetal period what do bones mainly remain as?
Bones remain mainly as cartilage and ossify later
when do sutures in the skull fuse?
childhood
how can you identify the sex of a child on ultrasound?
- Identifying a penis
- girls may also show their labia majora and minora as a 3 line appearance.
when does the brain begin to rapidly increase in size?
from 20 weeks
when do lungs develop in the fetal period?
lungs are continuously developing even until after birth
where are type 2 pneumocytes found?
in lining of alveoli
what is surfactant?
- very important lipoprotein which makes sure the surface tension is low → higher surface tension will increase cohesion inside the alveoli, pulling them closed. .
- makes it easier for lungs to expand
which structure carries out breathing in the fetal period?
the placenta
what is different about fetal haemoglobin?
-has higher affinity for oxygen
why is fetal hb different to adult hb?
fetal haemoglobin needs to “steal” oxygen away from the mother’s haemoglobin when nearby in the placenta.
how does pulmonary vascular resistance change after birth?
- high in fetus
- decreases after birth
(pulmonary blood flow increases and o2 exchange can occur in the lungs)
how does systematic vascular resistance change after birth?
increase in systemic vascular resistance
this will increase pulmonary blood flow
what does the rise in systemic vascular resistance do to the heart?
close the foramen ovale & ductus arteriosus naturally
why are the foramen ovale & ductus arteriosus open in foetal development?
as they bypass undeveloped organs (lungs) = means blood doesn’t flow to organs that haven’t developed yet
how is lung fluid cleared?
- During labour, there is a thoracic squeeze = expels fluid and reduces lung volume
- During baby’s first cry, the lungs will fill with oxygen → this will move the lung fluid out of the lungs so the lungs can fill with oxygen
how would you describe foetal growth in the first 20 weeks?
linear
what is foetal overgrowth?
When growth is more than the 95th centile
what are some causes of foetal overgrowth?
idiopathic, diabetes, fetal overgrowth syndromes
what is foetal growth restriction?
This is a failure to reach the genetic growth potential
what are some causes of foetal growth restriction?
placental, infections, genetic/chromosomal
what does B-HCG do?
maintains the corpus luteum
what can B-HCG cause?
morning sickness
where is progesterone initially produced?
corpus luteum
what does progesterone do in pregnancy?
thickens cervical mucus and maintains uterus lining support pregnancy until pregnancy has implanted
where is oestrogen produced initially and what takes over?
- initially-corpus luteum
- placenta takes over
what is the role of oestrogen in pregnancy?
increases number of oxytocin receptors in uterus, increases vaginal discharge
outline the respiratory changes in pregnancy
- decreased residual volume
- increased tidal vol
- mild respiratory alkalosis
outline the renal changes in pregnancy
- 60% increased blood flow
- 50% increased GFR
- glycosuria is normal
- proteinuria <30mg is normal
outline the cardiovascular changes in pregnancy
- increased heart rate (20%) and stroke volume (30%)—>increases cardiac output (40%)
- increased total blood pressure
- more RBC but fewer RBC/dl due to peripheral vasodilation
- increased clotting factors in blood
outline the gastrointestinal changes in pregnancy
- delayed gut motility
- constipation increases
- increased alkaline phosphatase
outline the skeletal changes in pregnancy
- osteopenia (weak bones)
- increased osteoblast activity
what is parturition?
process of giving birth
what is labour?
sequence of actions where a baby & afterbirth (placenta) is expelled from the uterus during childbirth
how does labour begin?
- Painful uterine contractions = cause is ‘spontaneous’
- Cervical dilatation
- The ‘show’= release of mucus plug
- Rupture of the amniotic sac = water breaking
how many stages of labour are there?
3
what is the first stage of labour?
from onset of labour → full dilation
what are the 2 phases of the 1st stage of labour?
- Latent: up to 3cm
- Active: 3cm - 10cm dilated
what is the 2nd stage of labour?
full dilatation → delivery of fetus
what is the 3rd stage of labour?
birth of fetus → delivery of placenta
what is the role of oestrogen in labour?
increases oxytocin receptors on uterus, stimulates placenta to release prostaglandins
what is the role of oxytocin in labour?
stimulates uterine contraction, releases more prostaglandins
what is the role of relaxin in labour?
made by corpus luteum, increases flexibility of pubic symphysis, dilates (softens) uterine cervix
what does a neonatal breast contain?
lactiferous ducts but no alveoli
what are the characteristics of a breast during puberty?
- Little branching of lactiferous ducts
- Any slight enlargement: reflects growth of fibrous stroma & fat
what are the characteristics of a breast post puberty?
- Ducts become branched on stimulation by ovarian oestrogen
- Ends of branches form alveoli
- Breast enlargement: due to lipid accumulation by adipocytes
what does prolactin stimulate post pregnancy?
stimulates milk production
what does oxytocin stimulate post pregnancy?
stimulates milk ejection
what are the characteristics of the breast in pregnancy?
- Breast growth more uniform
- Increase oestrogen, prolactin & progesterone
- Size and pigmentation of nipples increase due to increased oestrogen
- Sebaceous glands produce lubricant
- Increased vascular branching & dilated veins = increased blood flow
What week does the amniotic fluid peak at? A-25 weeks B-27 weeks C-30 weeks D-32 weeks
C
What week is rotation & herniation of the gut complete? A-Week 10 B-Week 12 C-Week 15 D-Week 17
B
Which is Foramen Ovale or Ductus arteriosus
A-Between both atria
B-Between aortic arch & pulmonary artery
foramen ovale=A
ductus arteriosus=B
Which of the following liver function tests would be elevated in a healthily pregnant woman? A-ALT B-Alkaline phosphatase C-Albumin D-AST
B
Which of these is the right renal physiological changes during pregnancy? A-Decreased blood flow B-Decreased GFR C-Decreased urine frequency D-Low creatinine levels
D
What stage of labour is 3cm - 10cm dilation? A-Latent first phase B-Active first phase C-Second phase D-Third phase
B
what is hyperemesis gravidarum?
- extreme morning sickness caused by increased hcG in pregnancy
- causes severe dehydration
- treated in hospitals
