Chapter 2 Flashcards
epigenesis
the emergence of new structures and functions in the course of development.
Gametes (germ cells)
reproductive cells (egg and sperm) that contain only half the genetic material of all the other cells in the body.
Meiosis
cell division that produces gametes.
Conception
the union of an egg from the mother and a sperm from the father.
Zygote
a fertilized egg cell.
Embryo
name given to the developing organism from the 3rd to 8th week of prenatal development.
Fetus
name given to the developing organism from the 9th week to birth.
Four major developmental processes;
- ) mitosis
- ) cell migration
- ) cell differentiation
- ) apoptosis
Mitosis
cell division that results in two identical daughter cells.
Cell migration
the movement of newly formed cells away from their point of origin.
Cell differentiation
Embryonic stem cells start to specialize in terms of both structure and function.
Determinant of which type of cell a given stem cell will become;
- ) which genes in the cell are “switched on” or expressed.
2. ) the cell’s location, future development is influenced by neighbouring cells.
Apoptosis
genetically programmed cell death.
Androgen
a class of hormones that includes testosterone.
If present → male sex organs develop.
If absent → female genitalia develop.
Inner cell mass
after the 4th day of conception, cells arrange themselves into a hollow sphere.
Identical twins
- results from the zygote splitting in half,
- each of the two zygotes having exactly the same set of genes.
Fraternal twins
- result when two eggs are released into fallopian tube at the same time and fertilized by two different sperm
- only half their genes in common.
Implantation
- egg attaches itself to the lining of the uterus.
- cells start to differentiate.
- rest of cells become amniotic sac and placenta.
Top layer
becomes the nervous system, nails, teeth, inner ear, lens of the eyes, and the outer surface of the skin.
Middle layer
becomes muscles, bones, the circulatory system, the inner layers of the skin, and other internal organs.
Bottom layer
develops into the digestive system, lungs, urinary tract, and glands.
Neural tube
a groove formed in the top layer of differentiated cells in the embryo, eventually becomes the brain and spinal cord.
Amniotic sac
a transparent, fluid-filled membrane that surrounds and protects the fetus.
Placenta
- a support organ for the fetus
- keeps the circulatory systems of the fetus and mother separate
- semipermeable membrane permits the exchange of materials between them, i.e estrogen and progesterone.
estrogen
increases the flow of maternal blood to the uterus
progesterone
suppresses uterine contractions that could lead to premature birth.
Umbilical cord
a tube containing the blood vessels connecting the fetus and placenta.
Fetal breathing
- the movement of chest wall in and out.
- amniotic fluid is pulled into the lungs and then expelled.
Behavioural Cycles
- Rest activity cycles
- Circadian rhythms
- Quiet and active sleep states
Rest activity cycles
bursts of high activity alternating with little/no activity for a few minutes at a time. (at 10 weeks).
Circadian rhythms
less activity in the early morning and more activity in the late evening.
Quiet and active sleep states
at end of pregnancy, ¾ of fetuses time spent in REM sleep.
Fetal Experience - Sight and Touch
- Tactile stimulation as a result of grabbing umbilical cord, rubbing face and sucking thumb,
- Visual experience is minimal.
- Vestibular system functions before birth → fetuses respond to maternal movements
Fetal Experience - Taste
- fetus has a sweet tooth.
- fetus can detect flavours in amniotic fluid.
Fetal Experience - Smell
amniotic fluid comes into contact with the fetus’s odour receptors through fetal breathing
Phylogenetic continuity
idea that humans share certain characteristics with animals as a result of their evolutionary history.
Fetal experience - Hearing
Fetus’s heart rate decelerates briefly when the mother starts speaking (sign of interest).
Habituation
a simple form of learning that involves a decrease in response to repeated or continued stimulation.
Dishabituation
the introduction of a new stimulus rekindles interest following habituation to a repeated stimulus.
Prenatal Learning
- fetuses recognized the sound of their own mother’s voice.
- newborns can remember the scent of their amniotic fluid & flavours.
baby is born at;
38 weeks after conception.
The Birth Experience
- Baby rotates into head-down position.
- Painful uterine contractions.
- Baby experiences squeezing.
Squeezing is important because it;
- ) temporarily reduces the overall size of the fetus’s large head.
- ) stimulates the production of hormones that help the fetus withstand mild oxygen deprivation.
- ) forces amniotic fluid out of the lungs.
Fontanel
soft space between separate skull plates.
Moulding
elongation of the head.
All cultures pursue dual goals of;
- ) survival and health of both the mother & baby
2. ) ensuring the social integration of the new person.
Doulas
individuals trained to assist women in terms of both emotional and physical comfort during labour and delivery.
State
level of arousal and engagement in the environment, ranging from deep sleep to intense activity.
Six States of Arousal
- ) Crying (2 hours).
- ) Quiet sleep (8 hours).
- ) Active sleep (8 hours).
- ) Drowsing (1 hour).
- ) Alert awake (2.5 hours).
- ) Active awake (2.5 hours).
Sleep
- newborns spend 16 hours sleeping per day, 8 hours in REM.
- helps develop infants visual system
Rapid eye movement (REM) sleep
an active sleep state characterized by quick, jerky eye movements under closed lids and associated with dreaming in adults.
Non-REM sleep
deep sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate.
Myoclonic twitching
natural jerking movements in REM.
- gives infants opportunities to build sensorimotor maps.
Napping newborns may be _____ while asleep because …
- learning
- their brains do not become disconnected from external stimulation.
Operant conditioning methods of crying
the parent either ignores the infant’s cries (extinction) or slowly increases their delay in responding (graduated extinction).
Reasons for crying
- attention
- illness, pain and hunger.
Crying peaks at ______ and decreases at _________
6 to 8 weeks & 3 to 4 months.
Shaken baby syndrome
a form of child abuse which can result in severe head trauma or death.
Soothing
consoling a crying baby, involves moderately intense and repetitive stimulation.
Swaddling
a soothing technique that involves wrapping a baby tightly in clothes or a blanket.
Response to Distress
Mixed data;
- quick response may result to less crying.
- ignoring crying during first 9 weeks reduced crying for the next 9 weeks.
Colic
excessive, inconsolable crying by a young infant for no apparent reason.
- 1/10 babies experience it.
Reasons for colic
- allergic to mothers diet.
- formula intolerance.
- immature gut development.
- excessive glassiness.
