Pre- and perinatal development
Development prior to and after birth
Terms
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- Sex hormones released if testes present in embryo
- androgens e.g. testosterone
- Foetus's length and weight at 6 months
- 33cm, and 1kg
- Foetus's length and weight at 3 months
- 7-8cm, and 90grams
- Average birth length/weight
- 50cm, and 2.8kg
- number of cells after the first week of conception
- 100
- most important reflexes immediately after birth
- rooting, sucking and swallowing
- Zygote
- cell formed at conception, lasts 2 weeks.
- Embryo stage
- from 2 weeks to 8 weeks after conception
- Smoking during pregnancy can lead to
- a decrease in oxygen, therefore miscarriages, low birth weights, and premature birth
- Foetus's length and weight at 2 months
- 3cm, and 28grams
- Gonads develop into
- ovaries or testes
- Chemical cause of birth defects
- tetragens, e.g. antibiotics, alcohol
- Ingestion of alcohol during pregnancy can cause
- pre- and post-natal growth defecits, deformation of eyes and mouth, brain and central nervous system abnormalities and heart deformation - all symptoms of foetal alcohol syndrome
- Foetal stage
- lasts 7 months - begins with appearance of bone cells.
- The tetragen tetracycline can lead the infant to have
- bone irregularities and discoloured teeth
- Brain 'plasticity'
- if the brain is damaged between infancy and 6-7 years of age, the child can recover the lost function quickly.
- Length of pregnancy
- 266 days/38 weeks
- Giedd et al (1999)
- longitudinal study - from 4 - 20 years of age. Tested at 2 year intervals using MRI scans. Found white matter increased steadily over time, whilst grey matter increased irregularly - peaking before adolescence and in specific brain regions. The frontal lobe peaked at 12, the parietal lobe at 16, and the occipital lobe at 20.
- Important milestones that occur 4 months after conception
- sleeping and waking regularly, strong movements and heart beat can be heard using stethescope.
- Foetus's length and weight at 4 months
- 18cm, and 180grams.
- Important milestones that occur 3 months after conception
- bones and muscles begin to develop, foetus starts kicking.
- When embryo's heart starts beating
- 1 month after conception
- Foetus has high chance of survival if born in this month
- the 7th month after conception