From a cell to a person Flashcards
what are the 3 stages of development
- germinal stage
- embryonic stage
- fetal stage
when is the germinal stage
0-2 weeks
what happens in germinal stage
- cell division 24-36 hours
- zygotę moves to uterus
- placenta begins to form
- blastocyst implants in uterus wall
when is embryonic stage
3-8 weeks
what happens in embryonic stage
- differentiation and migration
- organs develop, heart starts beating
when is fetal stage
9 weeks to birth
what are human sex cells called
gametes
how many chromosomes do human sex cells have
23 pairs
T or F gametes are haploid cells formed during meiosis
T
what sex cell determines the sex of the baby
sperm
what are monozygotic twins
identical, share all dna
what are dizygotic twins
fraternal, share half dna
how many dna do semi identical twins share
3/4
what is the ratio of m:f embryos at conception
50:50
T or F males are more likely to be miscarried or receive caesarean birth
T
which stage is the neural tube (CNS) developed
embryonic stage
at what point can the fetus cry breathe and swallow
by the 7th month
at what point does the foetus have a good chance of survival if born
28 weeks onwards
T or F areas near the head develop earlier than those farther away
T
four main developmental processes
- division
- migration
- differentiation
- cell death
what is cell division
mitosis
what is migration
cells move from their origin to different location in the embryo
what is cell differentiation
cell begins life as stem cells, they have the potential to develop into any type of cell
what is cell death
apoptosis
example of cell death
hand plate cells are programmed to die
what is amniotic sac
membrane filled with clear water fluid
what is the purpose of amniotic sac
allows foetus to move in gravity free environment and provides cushioning and constant temperature
what is the placenta
temporary organ that performs actions baby can’t do itself
what does the placenta do
produces hormones
what is placenta made of
semi permeable membrane
what can pass through placenta
oxygen, nutrition, alcohol, co2 waste, nicotine
brain size at birth % of full adult size
25%
what risks do premature birth propose
- physical
- cognitive
- clinical
what is perinatal period
before and after birth
at what point does fetes begin to move
5-6 weeks simple spontaneous movement 12 weeks most movements at birth will be present
what point does baby start to swallow
10-11 weeks
when does baby start to breathe
10 weeks
what is habituation
an infant shows a decrease in response to stimulus after it is repeated several times
what was the goal of habituation protocol (Lecanuett)
to study how infants process and respond to stimuli, and their ability to differentiate between familiar and new stimuli
example of habituation protocol
an infant is repeatedlt exposed to particular stimulus (e.g. sound or visual pattern). Over time, the infants response (like looking time or heart rate) decreases as they become habituated
what was the aim of conditioning protocol Decasper and spence
tested whether newborns could learn to change their behaviour based on sounds
what is operant conditioning?
learning process where an individual learns to associate a behaviour with a consequence. babies learn to control a sounnd like a voice by sucking pattern
how did the conditioning protocol work in Decasper and spence study?
babies were given a dummy connected to a device that controlled playback of a recorded voice. if the baby sucked on the dummy in a specific way it would trigger the playback of their mothers voice
