PSY1004 SEMESTER 2 - WEEK 3 Flashcards
define prenatal development
development of humans before they are born
define postnatal development
development of humans after they are born, usually in infancy
define neonate
an infant less than one month old
define differentiation
specialisation of cells allowing accumulation of more specific particular function
what is 22 GW referred as
age of viability, baby can survive
outline germinal period
0-10 gestation day
from single-cell zygote into morula into blastocyst
from conception to attached to uterine wall
what GW is the embryonic period
2-8 GW
what has happened by 8GW
embryo is fully attached to uterine wall, basic organs formed, sexual differentiations occur, begin respond direct stimulation (turns head in response to light mouth touches - reflexive)
what is gastrulation (2-8GW)
early embryo transform into very simple ball of cells into more complex embryo with multiple layers of different cell types
forms 3 distinct germ layers = mesoderm, endoderm, ectoderm
whats endoderm (gastrulation)
inner lining of some systems and organs such as liver, pancreas
whats mesoderm (gastrulation)
middle layer = bones, muscles, heart and circulatory system, internal sex organs
whats ectoderm (gastrulation)
outer layer = skin, brain, nervous system, becomes neural plate (differentiates into forebrain, midbrain, hindbrain), folds to become neural tube where all neurons comprising brain originate from single indentical cell layer in neural tube wall
what does forebrain comprise of?
cerebral hemispheres, thalamus, hypothalamus
what does midbrain comprise of?
superior and inferior colliculi, substantia nigra
what does hindbrain comprise of?
medulla oblongata, pons
what is present in 5-6 GW
basic structure of hindbrain, midbrain, forebrain
what time period is ‘foetal period’
9GW-birth
what happens at 14GW
division of brain hemispheres now visible
what happens at 26 GW
nerve cells generated, cortex begin to wrinkle, myelination
give indirect methods of studying prenatal development
- present loud sounds on abdominal surface and ask mother to report movements
- inference from non-human animal models
- autopsies of human embryos and foetuses
- inference from studies measuring perception and memory of neonates
state issues of indirect measures of prenatal development
animal models lacking applicability (differing gestations and development course)
both animal/human post-mortem highly regulated, very controversial which comes with its own issue
conceptual and practical problems
define direct measures for studying prenatal development
measure autonomic nervous system activity with/without an external stimuli`
give 2 direct measures of studying prenatal development
foetal ultrasound (good for studying behaviours, deformities, developmental problems)
foetal brain activity using fMRI (doesnt make sense until studying brains action, so only later GW)
brain development stage 1- explain primary neurulation
ectoderm become neural plate (patch of tissue on embryos dorsal surface that become nervous system)
development induced by chem signals, growth factors