Developmental Milestones

Question 1

Primary brain vesicles and flexures
6weeks
10 weeks
3 months
5 months 
7 months 
9 months

Answer 1

6weeks - more flexures and swellings
10 weeks- cerebral expansion and commissures 
3 months - basic structures
5 months - CNS myelination
7 months - lobed cerebrum 
9 months - gyri and Sylvia

Question 2

How and when does myelin form?

Answer 2

Myelination proceeds PNS/ spinal cord and brain

Composition of myelin changes with functional consequences:

• galactolipids increase
• protein compounds increase

Begins 5months after birth in humans

Most completed by 2yrs
Myelin is renewed constantly

Question 3

Critical periods and damage associated:
Abnormalities that can occur at these times of infection:
6 weeks 
9 weeks
5th - 10th week
2nd trimester 
16 weeks +

Answer 3

Rubella (german measles) - this disease can travel through placenta to child

6 weeks - eye malfunction eg cataracts
9 weeks - deafness - organ of Corti
5th - 10th - cardiac malformation
2nd trimester - CNS disorders
16 weeks + - risk falls

Question 4

Fatal alcohol syndrome
How it’s caused?
Features?

Answer 4

Alcohol crosses placenta and fetus can’t clear alcohol, therefore feral levels higher

Results in:

• facial abnormality eg wider eyes
• microcephaly- loss of cells, reduced brain size
• loss of fibres= callosal agenesis
• irritability and motor and intellectual impairment

Question 5

Drugs of abuse
Opiates
Cocaine
Ecstasy 
Cannabis

Answer 5

Opiates - neonatal withdrawal
Cocaine -hypoxia, abortion, withdrawal and decreased cognition
Ecstasy - Long term effects on hippocampus
Cannabis- long term cognitive effects

Rhesus monkey studies found: reduction in neuronal density

Question 6

Maturation of Axon conduction velocity

Speeds at:
Neonate
1-6 months 
6-12 months
12-24 months 
Why is there this change in speed?

Answer 6

Speed increases with myelination 
Neonate peripheral nerve 20-25 m/s
1-6 months 33-50m/s
6-12 months 33-60m/s
12-24 months 40-60m/s

Due to increase in myelination

Question 7

Development of sensation
somatosensory input requires:
Fetuses feeling pain?
6-8 weeks
14-16 weeks
19+ weeks
23 weeks
24 weeks
25 weeks
28 weeks
29 weeks

define noxious

Answer 7

connection of receptors, sensory neurons, thalamus and cortex
6-8 weeks - subdermal, organised thalamus, dorsal root ganglion connection to spinal cord (non-noxious)
14-16 weeks - retinal inputs
19+ weeks - C-fibre (noxious stimuli) connection
23 weeks - reflex response to noxious stimuli
24 weeks - connections to thalamus from cortex, cortical responses
25 weeks - myelination
28 weeks - facial responses to heel lancing
29 weeks - evoked potentials in cortex
noxious = could potenially damage tissue

Question 8

Other senses devoloping:
Taste and smell
Hearing
Vision
Post- natal reflexes

Co-ordinated responses by what age?

Answer 8

Taste and smell - well developed at birth
Hearing - responsive at birth, good discrimination of lang sounds, locate sounds from 3days old
Vision- eyes open and sensitive at 7 months, least well developed at birth(retinal cells not mature and sparse, and optic nerves not yet myelinated), ocular dominance columns develop at 6 months = better acuity, colour vision at 2 months
Post- natal reflexes - moro (startle) reflex, trunk extension, cycle of limb extension(abduction from midline), stepping, palmor grip, swimming, babinski reflex(fan toes when sole stroked), rooting, sucking

about 5 months, 8-9 months attain object, 2yrs= adult motor patterns, language