HUMAN DEVELOPMENT

1
HUMAN DEVELOPMENT
2
What is the Developmental Psychology?

• It is the field of study that examines patterns
  of growth, change, and stability in behaviour
  that occur throughout the entire human lifespan
  (Feldman, 2000, p. 5).
•  

3
Development

• refers to the changes over time in the body and
  in the thinking or other behavior of a person
  that are due both to biology and to experience.

4
When does human life begin?

• Human development begins at conception when the
  fathers sperm cell unites with the mothers ovum
  (egg cell). This one-cell (which is now
  fertilized) is called a zygote.
•  
• Conception happens through fertilization.  

5

•  
• Once the sperm makes its way inside the egg, the
  head of the sperm ruptures, spilling the genetic
  material from the father (23 chromosomes) into
  the egg. There it joins up with the genetic
  material from the egg (23 chromosomes) resulting
  in 46 chromosomes (23 pairs).
•  
• Genetic sex is decided by the father. Normal
  chromosomal configuration for the male is XY
  and XX for the female.
•  
• The time from conception to birth is the prenatal
  period.  

6
PRENATAL DEVELOPMENT
7
PRENATAL STAGES

• Divided into three stages
• Germinal stage,
• Embryonic stage
• Fetal stage 

8
  GERMINAL STAGE

• Once the sperm fertilizes the egg, the first new
  cell of the unborn child is called the zygote.
  It begin to move down the fallopian tube towards
  the uterus. As it travels it undergoes rapid
  cell growth and form into a hollow ball called a
  blastocyst.
• This process takes about two weeks and lasts from
  the time of fertilization until the blastocyst
  implants itself into the wall of the uterus.

9
(No Transcript)
10
THE EMBRYONIC STAGE
11
 THE EMBRYONIC STAGE

• This period lasts until the eighth week (lasts
  about six weeks weeks 2-8).
• Begins with the implantation of the zygote into
  the wall of the uterus. Most of the cell
  divisions, as well as the formation of organs,
  take place during this stage. By the end of this
  stage we can identify the face, eyes, ears,
  fingers, and toes.
• Two months after conception, this stage draws to
  a close.

12
FETAL STAGE 
13
FETAL STAGE 

• It lasts from week eight to birth next 7 months
  (months 3 to 9), which occurs about 40 weeks
  after conception the developing child is now
  called the fetus.
• Internal organs have developed, but not enough
  for the fetus to sustain life outside of the
  uterus. The brain has also developed.
• A crucial part of the developing child is the
  brain and the connections that are being made in
  preparation for later interaction with the world.
  

14
ENTRY

• After 9 months, 40 weeks, 270 days the fetus is
  ready to enter the world.

15
Environmental Influences on Prenatal Development

• Maternal Age
• Maternal Health and Nourishment
• Infectious Agents
• Smoking, Drinking and Drug Use
• Alcohol

16
Maternal Age

• Very young mothers are at a greater risk for
  having miscarriages or having children with birth
  defects.
• Research shows that the greatest success rate is
  for mothers in their twenties
• It is said that the incidence of prenatal defects
  or abnormalities increases with age, especially
  for first time mothers.

17
Theories cited to explain this phenomenon.

• 1. Older mothers have older ova. Through aging
  the ova might be more likely to be defective in
  ways that affect development.
• 2. Older mothers bodies are older too and this
  in itself may cause imperfect implantation.

18
Maternal Health and Nourishment

• Maternal malnutrition often leads to an increase
  in miscarriages, stillbirth, and premature
  births.
• Deficiencies in specific vitamins and minerals
  affect the prenatal organism. For example, a
  mothers calcium deficiencies affect the
  development of bones and teeth in the fetus.
  However, it is the mother who suffers the most.

19
Infectious Agents

• Mother can pass on diseases to their fetus
  through the placenta - Placenta is the structure
  in the uterus that protects and nourishes the
  growing child.
• Rubella German measles can cause blindness,
  deafness, or heart disease in the fetus if the
  mother contracts this illness during the first
  four weeks of pregnancy.
• Other diseases that can be transmitted to the
  infant include chicken pox, mumps, tuberculosis,
  malaria, syphilis, herpes AIDS.

20
Smoking

• How smoking affect the fetus is not known.
• It could be that it reduces the oxygen or the
  blood supply to the fetus.
• It could be that the tar and nicotine of smoking
  act directly as poisons.
• What is known is that cigarette smoking is a
  cause of retarded prenatal growth.

21
ALCOHOL

• Alcohol is also injurious to unborn children.
• Alcohol is quickly and directly passed through
  the placenta from the mother to the fetus.
• The fetus eliminates alcohol at half the rate of
  the mother.
• The bottom line is that alcohol gets in and stays
  in for a long time.

22
DRUGS

• Mothers who use or abuse psychoactive drugs
  during pregnancy cause considerable problems to
  their unborn children.
• Such children enter the world with low birth
  weights, difficulty regulating their sleep-wake
  cycles.
• Worst, they are born addicted and suffer the
  pains of withdrawal and require a hospital stay
  averaging 42 days.

23
What about the Fathers?

• The main issue revolves around factors affecting
  the quality of the fathers sperm at the moment
  of conception.
• For example, it was assumed that Down syndrome
  was more likely as the mothers age increased.
  We now recognize that the fathers age is related
  in some cases of DS.

24

• As many as 1/3 of all DS cases reflect
  difficulties with the fathers sperm and that the
  syndrome is more likely in children whose fathers
  have jobs working with toxic chemicals.
• Alcohol use by fathers has also been implicated
  as probable cause of prenatal and birth
  abnormalities.
• Problem is that nearly all this research has been
  on rats and mice.