CNS Development Flashcards
What features are considered part of an intra-uterine environment?
- Maternal health and disease
- Insults during pregnancy
- Placental function and fetal nutrition
What features are included in the extra uterine environment?
- Nutrition, environmental toxins
- Emotional and social factors (e.g. neglect/lack of stimulation)
- Drug/alcohol exposure
What are the four periods of brain development?
The embryonic period (conception to week 9)
Fetal development (week 9 to 40/42)
Post natal development
The adolescent Brain
What tissues and structures come from the Ectoderm?
Skin nails hair and neural tissue
Muscle, bone, cartilage and the vascular system all originate from what embryonic layer?
Mesoderm
The Endoderm forms what structures in the body?
gut and respiratory system
What 2 layers arise from the inner cell mass of the embryo?
Epiblast
Hypoblast
The epiblast is a primitive form of the ectoderm. TRUE/FALSE?
TRUE
The hypoblast is a primitive form of the Mesoderm. TRUE/FALSE?
FALSE
primitive form of the ENDOderm
What is the first neural structure to form in the embryo and when does it form?
The neural tube
20-27 days
What type of cells form the neural plate?
Neural progenitor cells
What does the hollow centre of the neural tube become?
ventricular system and central channel of the spinal cord
What does the anterior /rostral tube become?
brain
What tube in the embryo forms the spinal cord
Caudal tube
How many primary brain vesicles are present in a 3-4 week embryo?
3
Prosencephalon (FOREBRAIN)
Mesencephalon (MIDBRAIN)
Rhombencephalon (HINDBRAIN)
How many secondary brain vesicles are present in a 5 week embryo?
5
What is the neocortex?
Most recent part of the cerebral cortex responsible for sight and hearing
What molecules are involved in signalling in the neocortex?
Emx2 and Pax6
What is the name given to the original smooth appearance of the brain?
lissencephalic
After how many weeks of foetal development are primary, secondary and tertiary sulci developed in the brain?
Primary Sulci (between weeks 8-26) Secondary Sulci (week 30-35) Tertiary Sulci (week 36)
Describe assymetrical cell division during the foetal period
Neural progenitor cells divide into one progenior cell and one neuron
Progenitor cells stay in ventricular zone for further division and neurons move out to neocortex
What is neuronal migration?
How neurons move from place where they are developed, to their final position in the brain
Give examples of methods of neuronal migration
Somal translocation
Radial glial guides
Tangential migration
What percentage of neurons will be lost pre-natally?
50%
What percentage of neuronal connections will be eliminated throughout life?
50%
In what direction does myelination occur?
from bottom to top and from the back to the front of the brain
Describe how the brain is reorganised during adolescence
- Many synapses are eliminated
- Increase in white matter volume
- Changes in neurotransmitter systems
