Brains and Bodies

Question 1

State the different stages of Prenatal Body Development

Answer 1

• Germinal stage
• Embryonic stage
• Foetal stage

Question 2

Explain the germinal stage of body development

Answer 2

Germinal: 0-2 weeks

• single cell zygote rapidly divides
• forms blastocyst which then implants in wall - forms embryonic disk (brain)

Question 3

Explain the embryonic stage of body development

Answer 3

Embryonic: 2-8 weeks

• cell differentiate - divide, cluster and specialisation
• formation of external and internal structures; all essential and basic

Question 4

Explain the foetal stage of body developemnent

Answer 4

Foetal: 8-38 weeks

• organ systems develop, grow and operate
• functioning and operation

Question 5

Describe prenatal brain development during 2-4 weeks (embryonic stage)

Answer 5

• basic structures are formed
• the embryonic disk split into 3 layers
• neural tube forms the ectoderm

Question 6

Describe prenatal brain development after 4 weeks

Answer 6

• formation of the hindbrain, midbrain, forebrain (which controls basic functioning)

Question 7

What happens after 10 weeks in prenatal brain development?

Answer 7

• development of cerebral cortex
• Stage 1: rapid neuron production - PROLIFERATION
• Stage 2: CELL MIGRATION from neural tube to final location
  Stage 3: increases mass and function by myelinisation and synaptogenesis
• Brain activity increases and movements become more controlled (primary and sensory zones defined)
• susceptible to both internal and external

Question 8

Describe genetic risks to development

Answer 8

• excess/ missing material - failure to conceive
• parts of genetic code missing/deleted (some survivable)
• joining; inheritance of two defective genes

Question 9

Describe environmental risks to development

Answer 9

• teratogens (agents) that pose risk
• drug, deficiencies, disease
• causes abnormalities
• romanian orphans

Question 10

How may genes and environment interact to impact development?

Answer 10

Meaney et al: inactive genes swtiched on by environmental triggers- rhesus monkeys - maternal stress directly related to expression of stress genes in the offspring

Diamond, 2009 - even before conception - stress may alter genes in ova

Question 11

How may birth risk development?

Answer 11

• premature, underdeveloped organs may lead to cognitive deficits at 6 years (Wolke and Meyer, 1999)
• problems with breathing independently - anoxia - lead to brain development

Question 12

Briefly explain postnatal body development

Answer 12

• relatively slow - about 25 years to complete
• rapid in first two years and adolescence
• human motor control is slow
• birth to 18 months - simple reflexes to jumping and running
• weakness enables proximity to carers - enabling attachment

Question 13

Briefly explain postnatal brain development

Answer 13

• rapid - by 3 years, 80% of adults
• caused by synaptogenesis (connections and firing) and myelinization (coating)
• forms connections and refines - synaptic pruning and strengthening - efficient pathways