Psychology 144 Notes
Human Development
o What happens from the moment of conception to adulthood
o Interplay of biological and environmental factors
Prenatal Development
➢ Stages include: Germinal (0-2 weeks), Embryonic Stage (2-8 weeks) and Foetal (9-38 weeks)
Germinal Stage
1. Mature egg (ovum) is released from ovary
2. Cilia move ovum along fallopian tube
3. 1 sperm cell merges w/ & fertilizes ovum
4. Single cell (Zygote) continues to move down tube
5. Zygote divides into several identical cells
6. Cell division becomes more organized and specialized
7. Blastocyst implants into uterine wall
Embryonic Stage
➢ Start to see basic shapes of different organs.
➢ Abt. 3 weeks – start to see dots (where the eyes will form) and the formation of neural tube
(basis for brain and spinal cord).
➢ 4 weeks – heart throbbing
➢ 5 weeks – eyes contain corneas and lenses, arms and legs grow quickly
➢ 6 weeks – genitalia enlarge, and brain starts to connect electrical activity (responds to
stimulation)
➢ 7 weeks – see skeleton and fully developed limbs, bones are firm, muscles grow, the eyelids
are present but shut.
➢ 8 weeks – liver and spleen begin to work (can create and filter own blood cells)
Foetal Stage
➢ ~ 7months (week 8 – delivery)
➢ ~ 3/ 3.5 kg when delivered
➢ Viability = Capability to live outside the womb (~end of week 24)
Factors that Influence Prenatal Development
o Genetic Disorders
o Maternal nutrition
o Maternal stress and emotion
o Maternal drug use
o Maternal illness & psychopathology
o Culture, family & environmental toxins
Genetic Disorders
o Gene abnormalities
Human Development
o What happens from the moment of conception to adulthood
o Interplay of biological and environmental factors
Prenatal Development
➢ Stages include: Germinal (0-2 weeks), Embryonic Stage (2-8 weeks) and Foetal (9-38 weeks)
Germinal Stage
1. Mature egg (ovum) is released from ovary
2. Cilia move ovum along fallopian tube
3. 1 sperm cell merges w/ & fertilizes ovum
4. Single cell (Zygote) continues to move down tube
5. Zygote divides into several identical cells
6. Cell division becomes more organized and specialized
7. Blastocyst implants into uterine wall
Embryonic Stage
➢ Start to see basic shapes of different organs.
➢ Abt. 3 weeks – start to see dots (where the eyes will form) and the formation of neural tube
(basis for brain and spinal cord).
➢ 4 weeks – heart throbbing
➢ 5 weeks – eyes contain corneas and lenses, arms and legs grow quickly
➢ 6 weeks – genitalia enlarge, and brain starts to connect electrical activity (responds to
stimulation)
➢ 7 weeks – see skeleton and fully developed limbs, bones are firm, muscles grow, the eyelids
are present but shut.
➢ 8 weeks – liver and spleen begin to work (can create and filter own blood cells)
Foetal Stage
➢ ~ 7months (week 8 – delivery)
➢ ~ 3/ 3.5 kg when delivered
➢ Viability = Capability to live outside the womb (~end of week 24)
Factors that Influence Prenatal Development
o Genetic Disorders
o Maternal nutrition
o Maternal stress and emotion
o Maternal drug use
o Maternal illness & psychopathology
o Culture, family & environmental toxins
Genetic Disorders
o Gene abnormalities
