Development of the nervous system Flashcards Preview

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Flashcards in Development of the nervous system Deck (46)
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1
Q

When does human brain development begin?

A

3rd week post conception and continues well into late adolescence/ early adulthood

2
Q

What do genes determine in the development of the brain?

A

Correct sequence and evolution of the brain from conception to neural proliferation, migration and reorganisation
Development of dendritic and axonal interconnections
Determine the development of synapses, receptors and neurotransmitters

3
Q

What can influence nervous system development intrauterine?

A

Maternal health and disease
Insults which may be continuous throughout pregnancy - alcohol exposure, cytomegalovirus
Placental function and fetal nutrition

4
Q

What can influence nervous system development extrauterine?

A

Physical factors such as nutrition, environmental toxins
Emotional and social factors e.g. neglect and lack of stimulation
Exposure to drugs, alcohol and other related substances

5
Q

What is considered the embryonic period?

A

Conception - 8 weeks

6
Q

What makes up the embryo?

A

Epiblast and hypoblast
Primitive streak and primitive node - cells migrate through the streak then rostral-caudal migration determined by nodal signalling

7
Q

What is gastrulation?

A

Formation of germ layers - ectoderm, mesoderm and endoderm

8
Q

What will ectodermal tissue become?

A

Skin
Nails
Hair
Neural

9
Q

What will mesodermal tissue become?

A

Muscle
Bone
Cartilage
Vascular system

10
Q

What will endodermal tissue become?

A

Gut

Respiratory system

11
Q

What is the first well defined neural structure to form?

A

Neural tube

12
Q

When does the neural tube form?

A

Day 20-27

13
Q

What lines the neural tube?

A

Neural progenitors - ventricular zone

14
Q

What will the hollow centre of the tube become?

A

Ventricular system and central channel of the spinal cord

15
Q

What will the anterior tube become?

A

Brain

16
Q

What will the caudal tube become?

A

Spinal cord

17
Q

What are the characteristics of the surface of the brain at week 9?

A

Initially smooth (lissencephalic) and gradually develops its folded appearance (sulcal and gyral pattern)

18
Q

What occurs during weeks 8-26 of foetal brain development?

A

Primary sulci e.g. longitudinal fissure, sylvian cingulate, parieto-occipital and calcarine, temporal

19
Q

What occurs during weeks 30-35?

A

Secondary sulci

20
Q

What occurs during weeks 36-post natal period and early infancy?

A

Tertiary sulci

21
Q

Why are gyri and sulci needed?

A

To accommodate the proliferating neuronal populations

22
Q

Where do neurones migrate to?

A

Neocortex

23
Q

What occurs when neurones reach their target cortical regions?

A

They develop processes which allow them to communicate and transmit information between neurones

24
Q

What do axons do?

A

Transmit signals from neurones
Guidance molecules determine path
Synapses develop when connected with another neuron

25
Q

What do dendrites do?

A

Gather info and transmit to neurones

Multiple dendrites from arbors around the neuron

26
Q

What percentage of neurones will die?

A

50% mostly prenatally

27
Q

What percentage of synaptic connections will be eliminated?

A

50%, postnatally and ongoing throughout life

28
Q

What occurs postnatally in brain development?

A

Postnatal proliferation and migration

Myelination

29
Q

What parts of the brain will develop post-natally?

A

Olfactory bulb
Dentate gyrus of the hippocampus
Glial progenitors become oligodendorocytes and astrocytes

30
Q

What cells will develop myelin sheaths?

A

Oligodendrocytes

31
Q

What is the purpose of a myelin sheath?

A
Increase axonal conduction dramatically
Maintain axonal integrity
Survival
Neuronal size
Axonal diameter
32
Q

What way will axons become myelinated?

A

Sequential manner from bottom to top and from back to front

33
Q

What impact does experience have on the development of the brain?

A

Essential for emergence of normal neocortical patterns
When input is lacking, the brain areas develop differently
Specific patterns of development reflect the kinds of input the infant and child receive
Enrichment and deprivation

34
Q

What are the developmental tasks of the adolescence?

A
Establish nurturing and intimate relationships
Development of identity
Future perspectives
Self-confidence
Self control
Social skills
35
Q

What occurs in the brain during adolescence?

A

Many synapses are eliminated
Increase in white matter volume
Changes in neurotransmitter systems

36
Q

What type of receptors is the brain full of?

A

Steroid receptors - therefore the rising gonadal hormone concentrations in teenage years affect the brain

37
Q

What differing effects do estrogen and androgens have on the brain?

A

Oestrogens make girls more prone to stress

Androgens make boys more resilient to stress

38
Q

What insults to the brain can occur?

A

Insults within first few weeks not compatible with life: neural tube formation, brain vesicles, migrational disturbances

39
Q

What problems can occur with neural tube formation?

A

Anencephaly

Spina bifida

40
Q

What is holoprosencephaly?

A

Failure of brain vesicles to form

41
Q

What are the different disorders of myelination?

A

Hypomyelination
Dysmyelination
Demyelination

42
Q

What is the PLP1 gene?

A

Encodes a transmembrane protein, the predominant myelin protein in the CNS. It is responsible for compaction, stabilization and the maintenance of myelin sheaths, oligodendrocyte development and axonal survival

43
Q

Where is the PLP1 gene located?

A

X chromosome

44
Q

What is the most severe PLP1 gene?

A

Pelizaeus-merzbacher

45
Q

What will pelizaeus-merzbacher present as?

A
Nystagmus
Hypotonia
Cognitive impairment
Severe spasticity
Ataxia
46
Q

What impact will malnutrition have on brain development?

A

Brain growth and volume
Myelination
Lack of energy and deprivation - lack of postnatal stimulation and experiences