Human Development
Prenatal Development
Conception to parturition (birth)
Stages:
I. Germinal
II. Embryonic
III. Foetal
Course:
I. - First two weeks of gestation
- Conception -> implantation on uterine wall
- Implantation: blastocyst comes into connection with uterine
wall and by day twelve buried into uterine tissue
- Blastocyst wall cells & uterine coating cells merge to construct
placenta (permits oxygen, nutrients, and other elements to travel
between mother and baby's blood without letting it mix)
, - Umbilical cord is cells that connect embryo and placenta
- Alternative cells form yolk sac (manufactures blood cells until
embryo's blood producing cells configured)
- Amnion is a fluid-filled pouch that provide for movement
- Cells that form the anatomy are in position
II. - Implantation achieved from week two and lasts for six weeks (end
of week eight)
- Embryo's cells shaping basics for all organs
- Third week after impregnation, neurons shape neural tube from
which brain and spinal cord form, as well as a primordial heart and
the precursor of kidneys, and three pouches (digestive system)
- Fourth week: end of neural tube proliferates and forms brain, spots
(that will form the eyes) emerge and heart beats. Spinal cord and
ribs grow. Face obtains form and endocrine system grows.
- Fifth week, embryo is five mm. Arms and legs growing quickly.
Eyes contain corneas and lenses. Lungs enlarge.
- Sixth week, brain begins to create electrical activity. Genitalia
enlarge.
- Seventh week, embryo moves instinctively. Observable skeleton
and fully developed limbs. Eyelids close and ears entirely shaped.
- Eighth week, liver and spleen work and the embryo can create and
filter own blood cells. Heart well developed, links between brain and
body created. Digestive and urinary system working.
- Organogenesis complete
III. - two months to birth
- Rapid bodily growth, muscles and bones begin to form
- Skeletal structures harden
- Organs grow and gradually begin to function
, - Final three months: brain cells multiply fast, layer of fat deposited
under skin, respiratory system matures and central nervous system
gains increasing control of functions
- Between week twenty-three-twenty-five, foetus reaches
threshold of viability where they can survive at the event of
premature birth which can lead to neurodevelopmental impairments
and sensory deficits
Environmental Factors
Genetic
○ Gene abnormalities (defective genes)
○ Chromosomal abnormalities (segment of chromosomal DNA irregular)
Maternal Nutrition
○ Vital role in growth of neural tube and inadequate quantities lead to
illnesses. Number calories critical. Creates nutrient rich environment for
growth. Increases chance of positive outcome.
Maternal Stress & Emotion
○ Increased stress: increased stillbirths, impaired immune system,
vulnerability to infectious diseases, slow motor development and below
average cognitive development.
Maternal Drug Use
○ Foetal alcohol syndrome (FAS): collection of congenital (inborn)
problems associated with excess alcohol use during pregnancy ->
microcephaly, heart defects, irritability, hyperactivity, delayed motor
development and impaired cognitive development
Prenatal Development
Conception to parturition (birth)
Stages:
I. Germinal
II. Embryonic
III. Foetal
Course:
I. - First two weeks of gestation
- Conception -> implantation on uterine wall
- Implantation: blastocyst comes into connection with uterine
wall and by day twelve buried into uterine tissue
- Blastocyst wall cells & uterine coating cells merge to construct
placenta (permits oxygen, nutrients, and other elements to travel
between mother and baby's blood without letting it mix)
, - Umbilical cord is cells that connect embryo and placenta
- Alternative cells form yolk sac (manufactures blood cells until
embryo's blood producing cells configured)
- Amnion is a fluid-filled pouch that provide for movement
- Cells that form the anatomy are in position
II. - Implantation achieved from week two and lasts for six weeks (end
of week eight)
- Embryo's cells shaping basics for all organs
- Third week after impregnation, neurons shape neural tube from
which brain and spinal cord form, as well as a primordial heart and
the precursor of kidneys, and three pouches (digestive system)
- Fourth week: end of neural tube proliferates and forms brain, spots
(that will form the eyes) emerge and heart beats. Spinal cord and
ribs grow. Face obtains form and endocrine system grows.
- Fifth week, embryo is five mm. Arms and legs growing quickly.
Eyes contain corneas and lenses. Lungs enlarge.
- Sixth week, brain begins to create electrical activity. Genitalia
enlarge.
- Seventh week, embryo moves instinctively. Observable skeleton
and fully developed limbs. Eyelids close and ears entirely shaped.
- Eighth week, liver and spleen work and the embryo can create and
filter own blood cells. Heart well developed, links between brain and
body created. Digestive and urinary system working.
- Organogenesis complete
III. - two months to birth
- Rapid bodily growth, muscles and bones begin to form
- Skeletal structures harden
- Organs grow and gradually begin to function
, - Final three months: brain cells multiply fast, layer of fat deposited
under skin, respiratory system matures and central nervous system
gains increasing control of functions
- Between week twenty-three-twenty-five, foetus reaches
threshold of viability where they can survive at the event of
premature birth which can lead to neurodevelopmental impairments
and sensory deficits
Environmental Factors
Genetic
○ Gene abnormalities (defective genes)
○ Chromosomal abnormalities (segment of chromosomal DNA irregular)
Maternal Nutrition
○ Vital role in growth of neural tube and inadequate quantities lead to
illnesses. Number calories critical. Creates nutrient rich environment for
growth. Increases chance of positive outcome.
Maternal Stress & Emotion
○ Increased stress: increased stillbirths, impaired immune system,
vulnerability to infectious diseases, slow motor development and below
average cognitive development.
Maternal Drug Use
○ Foetal alcohol syndrome (FAS): collection of congenital (inborn)
problems associated with excess alcohol use during pregnancy ->
microcephaly, heart defects, irritability, hyperactivity, delayed motor
development and impaired cognitive development
