Development

Question 1

When does the human CNS begin to form?

Answer 1

When the embryo is approximately 2-3 weeks old. (within 15 days of conception)

Question 2

What are the 5 processes in the development of neurons?

Answer 2

1. ) Proliferation
2. ) Differentiation
3. ) Migration
4. ) Myelination
5. ) Synaptogenesis

Question 3

Proliferation

Answer 3

Refers to the production of new neurons. (occurs in neonatal stage - first 14 days after conception)

Question 4

Differentiation

Answer 4

The process of a less specialized cell becoming a more specialized cell (neonatal stage)

Question 5

Migration

Answer 5

The movement of newly formed neurons to their eventual locations

• Occurs in a variety of directions throughout the brain
• Cells follow chemical paths in the brain of immunoglobins and chemokins

Question 6

Myelination

Answer 6

Glia produce the fatty sheath that covers the axons of some neurons

• Myelin speeds up the transmission of neural impulses
• Myelination occurs gradually for decades

Question 7

Synaptogenesis

Answer 7

Refers to the formation of synapses

-Occurs throughout the life as neurons are constantly forming new connections and discarding old ones.

Question 8

Neural Darwinism

Answer 8

The idea of the selection process of neural connections

• We initially form more connections than we need.
• The most successful axonal connections survive while the others fail to sustain active synapses

Question 9

Neurotrophin

Answer 9

Chemical that promotes survival and activity of neurons

-Axons that aren’t exposed to neurotropins undergo apoptosis

Question 10

Encephalocele

Answer 10

Brain/spinal cord not closing correctly during development (always fatal)

Question 11

Spina Bifida (Open Defect)

Answer 11

Far end of the neural tube not closing during development (not always fatal)

Question 12

FAS

Answer 12

• Hyperactivity & impulsiveness
• Varying degrees of mental retardation
• Motor problems and heart defects
• Facial abnormalities in an estimated 60%
• ADHD misdiagnosed for FAS*
• The dendrites of children born with FAS are short with few branches
• Exposure to alcohol in the fetus brain suppresses glutamate and ehances GABA (more impulsive behavior)
• Neurons recieve less excitation and exposure to neurotropins than usual and undergo apoptosis.

Question 13

Cocaine use during pregnancy

Answer 13

Children show a decrease in language skills, IQ scores, impaired hearing, low birth weight, and increased risk of SIDS

Question 14

Smoking during pregnancy

Answer 14

Children are at increased risk for low birth weight, SIDS, long term intellectual deficits, impairments of the immune system, increased risk of Alzheimer’s, ADHD, and epilepsy.