Developmental Flashcards
How many neurons does the adult brain comprise?
The adult brain comprises of 80 billion neurons.
At what rate are neurons added during early embryonic life?
Neurons are added at a rate of 250,000 neurons/min.
What percentage of adult brain size is achieved by 2 years after birth?
Growth at 2 years after birth is 80% of the adult size.
How many other cells does a single neuron interact with on average?
A single neuron interacts with an average of 15,000 other cells.
What happens to the brain’s surface area from 5 to 9 months?
The brain at 5 months is quite smooth; by 9 months it starts growing the surface area.
What are the three parts of gastrulation?
Ectoderm, Mesoderm, and Endoderm.
What does the ectoderm develop into?
The ectoderm becomes your CNS, PNS, and skin.
What does the mesoderm develop into?
The mesoderm develops into the skeletal system, muscles, and vascular region.
What does the endoderm develop into?
The endoderm develops into the gut, lungs, and liver.
When does the neural tube start forming?
The neural tube starts forming at 4 weeks.
What does the neural tube form?
The neural tube forms the basis of the brain and spinal cord.
What develops from the rostral front part of the neural tube?
The rostral front part develops into 3 chambers that eventually become the ventricles.
What does the hindbrain form?
The hindbrain forms the cerebellum.
What are the three stages of neurodevelopment?
Neurogenesis, Neural migration, and Neural differentiation.
What happens during neurogenesis?
Progenitor (stem) cells divide by mitosis in the neural tube.
What is the process of neural migration?
Neurons migrate to the outside of the tube, guided by radial glia cells.
What occurs during neural differentiation?
Immature neurons differentiate into different types of specialized neurons.
What is synaptogenesis?
Over-production of synapses, redundancy, beginning from about 17 weeks after conception but mostly postnatal.
What is apoptosis in the context of neurodevelopment?
Clearing of neurons whose axons don’t find their targets, activated by genetic processes.
When does synapse reorganization occur?
Synapse reorganization occurs from 26 weeks until after birth.
What is myelination?
Myelination is produced by glial cells and involves a gradual increase in the myelin sheath surrounding the axons.
What is DNA?
DNA is packed into chromosomes in the nucleus of our cells and contains our genetic information
How many pairs of chromosomes do humans have?
Humans have 23 pairs of chromosomes.
What is a gene?
A gene is an area of DNA which codes RNA.
What do genes code for?
Genes code proteins, not behavior.
What are examples of genetically controlled characteristics?
Height and eye color.
What are examples of environmentally controlled characteristics?
Religion and language skills.
What are family studies in measuring heritability?
Histories recorded for family members compared as a function of relatedness.
What are adoption studies?
Comparing twin pairs raised together and separated at birth to remove environmental factors.
What are twin studies used for?
To assess heritability by comparing monozygotic (MZ) and dizygotic (DZ) twins.
What are genetic linkage studies?
Studies that require DNA collection to screen for regions associated with a disorder.
What are brain tumors?
Abnormal growth of cells affecting normal functions.
What are the two ways brain tumors affect normal functions?
Compression and infiltration.
How are brain tumors graded?
Graded according to aggressiveness from 1 to 5 by the WHO.
What are common symptoms of brain tumors?
Unexplained behavioral/psychiatric symptoms followed by neurological examination.
How are brain tumors diagnosed?
Diagnosed with brain imaging, such as MRI or CT.
What is a stroke?
A condition where blood supply to part of the brain is interrupted or severely reduced.
What are the types of strokes?
Haemorrhagic stroke, Ischemic stroke, and Transient ischemic attack.
What are risk factors for stroke?
High blood pressure, smoking, diabetes, obesity, and family history.
What are common symptoms of strokes affecting the frontal lobe?
Loss of flexibility in thinking, mood changes, sequencing problems, and inability to focus.
What are symptoms of strokes affecting the temporal lobe?
Language problems, agnosia, and attention/memory problems.
What are symptoms of strokes affecting the parietal lobe?
Alexia, agraphia, apraxia, and difficulties in hand-eye coordination.
What are symptoms of strokes affecting the occipital lobe?
Color/motion blindness, prosopagnosia, visual field loss, and blindsight.
What are symptoms of strokes affecting the cerebellum?
Dysergia, problems sequencing and coordinating rapid movement, and dysmetria.
What is Chronic Traumatic Encephalopathy (CTE)?
A disease affecting those with repeated concussive or sub-concussive brain injuries.
What are the characteristics of CTE?
Mood disorder, memory disturbances, behavioral changes, and dementia.
What is a traumatic brain injury (TBI)?
Injury caused by vehicle accidents, sports injuries, falls, and acts of violence.
What are the two mechanisms of TBI?
Direct strike to the head or sudden acceleration/deceleration causing diffuse shear forces.
What is Fragile X Syndrome?
The most common inherited form of intellectual disability.
What are symptoms of Fragile X Syndrome?
Delayed speech, mild to moderate intellectual disability, ADHD symptoms, and seizures.
What is Down Syndrome?
A chromosomal condition that occurs when there are 3 copies of chromosome 21.
What are the effects of Down Syndrome?
Mild to moderate intellectual disability, delayed language, and a variety of birth defects.
What is foetal alcohol syndrome (FAS)?
A disorder caused by alcohol intake during pregnancy affecting 1 in 1000 lives.
What are the effects of FAS?
Distinctive facial features, low height/weight, low brain volume, and brain damage.
What is Autism Spectrum Disorder?
A diagnosis based on persistent deficits in social communication and restricted behaviors.
What are genetic factors in Autism Spectrum Disorder?
High heritability within symptom groups and complex multi-gene interactions.
What environmental factors are associated with Autism Spectrum Disorder?
Paternal age, toxin exposure, and maternal infection/autoimmune diseases.
What genes are thought to be involved in autism?
Genes linked to GABA and oxytocin are thought to be involved in autism.
What hampers research on autism?
Research is hampered by the very diverse aetiology of autism, leading to small and inconsistent sample sizes.
What environmental factors are suggested to be linked to autism?
There are many suggested environmental factors with mixed evidence, such as gestational diabetes and birth order.
What environmental factors have clearer evidence linked to autism?
Paternal age, toxin exposure, and maternal infection/autoimmune diseases have clearer evidence linked to autism.
What neurological symptoms are associated with ASD?
ASD is associated with a range of neurological symptoms, including motor problems, sleep disorders, and epilepsy.
