Flashcards
Brain development and degeneration draft
Flashcards do conjunto (100)
- 1Describe the key difference between prenatal neural migration and neural migration in adultsPrenatal migration and postnatal migration is the process in which cells are differentiated by a concentration gradient. The majority of neural migration occurs prenatally and in early childhood, as the concentration gradient is stronger in early development. Prenatally migrating neurons travel along radial glial cells whereas in adults they do not need to.
- 2Give one clear example of a function of Sonic Hedgehog during early embryonic neural developmentIt is involved in the formation of the neural tube and it forms a concentration gradient allowing for cell types to be differentiated.
- 3Explain one way in which neurotrophic factors are involved at the synapseNeurotrophic factors are involved with synaptic growth and change, specifically synaptic plasticity. Synaptic plasticity is the ability of synapses to strengthen and weaken over time.
- 4Name one glial cell type and explain its key function in the brainMicroglia are specialised cells capable of phagocytosis. Their function is to scavenge for and then engulf materials including dead neurons.
- 5Briefly explain one reason why a synapse or neuron might be prunedSynaptic pruning is thought to remove unnecessary neuronal structures from the brain to improve effective brain function. A synapse might be pruned if it is non-functional or inefficient.
- 6Briefly explain the difference between experience dependent and experience expectant plasticitySome early forming synapses are experience expectant, and so 'expect' experiences which act to prune them back or strengthen them. In contrast, later synaptic formation is more localised to regions involved in processing specific experiences. This is experience dependent plasticity.
- 7Briefly explain the differences between apoptosis and necrosis (e.g., when do they occur, how are they triggered, what are their cellular mechanisms)Necrosis is a form of unprogrammed cell injury caused by factors external to the cell such as infection. The cell dies by autolysis where the plasma membrane, organelles and nucleus leak their contents. In contrast, apoptosis is programmed cell death which occurs naturally. In apoptosis, cellular fragmentation occurs before it is engulfed by a phagocyte.
- 8What is a neurotrophic factor? Define it and include one example from developmentA neurotrophic factor is a biomolecule which supports the growth, survival, and differentiation of developing and mature neurons. An example is brain-derived neurotrophic factor (BDNF).
- 9What is "regressive growth"? Define it and include one example from developmentRegressive growth is the formation of many extra synapses during development, followed by the pruning of excess synapses (synaptic pruning). Associated with learning.
- 10How does the thickness of the cortex (mostly) change after middle childhood? Give one reason why this takes placeCortical thickness decreases after middle childhood. This is because synaptic pruning and regressive growth takes place to remove unnecessary synaptic connections.
- 11Give an example of non-mendelian inheritance and explain the way in which it is non-mendelianMosaicism is a form of non-mendelian inheritance and it is non-mendelian because either germ-line mutations or x inactivation can cause offspring to have differing phenotypes. Mosaicism is non-mendelian because it does not follow Mendel's laws in that the distribution of the phenotypes of offspring may be unpredictable due to mosaicism.
- 12Give two examples of mutations types and define themA nonsense mutation is a mutation which changes the base sequence to code for a stop codon. A deletion mutation is when genetic material is removed or deleted.
- 13Explain the inheritance of an x-linked disorder if the father (or the mother) is the carrier (be able to work out a chi square example for either scenario)With X-linked disorders, males are either carriers or non-carriers. However, females can be either affected, carriers, or non-carriers due to possessing two X chromosomes.
x x1
x xx x1
y xy xy - 14Explain the difference between genotype and phenotype (i.e., define both and explain the relationship between them)Genotype is the set of genes of an organism. Phenotype is the expressed characteristics of an organism. The phenotype of an organism is related to both its genotype and its environment.
- 15Using an example, explain the difference between expressivity and penetrancePenetrance is the likelihood of individuals with a specific genotype expressing that genotype, whereas expressivity is the extent to which a phenotype is expressed. An example is that a mutation may be 80% penetrant, meaning that it would give an 80% chance of contracting a genetic disease if you had that mutation. An example for expressivity would be if a certain gene caused severe illness in some people but not others- the expressivity of the gene would vary.
- 16Give an example of a gene environment interaction (and make clear how the interaction works)Genes for skin pigmentation which give a fair skin pigmentation interact with sunlight or ultra-violet radiation. This interaction can lead to increased risk of skin cancer.
- 17What happens during transcription? OR What happens during translation? (be able to explain the basic steps)Transcription is the conversion of DNA to RNA. DNA in the nucleus in unwound to allow transcription. This creates RNA, which then exits the nucleus to be translated.
- 18Give an example of the functions of the promotor region and explain why the promotor region is importantThe promotor region initiates transcription. It contains transcription factors which bind to the promotor sequences, recruiting RNA polymerase, the enzyme which synthesises RNA.
- 19Explain the inheritance of a autosomal dominant trait (mendelian inheritance) and be able to work out a chi square exampleAn autosomal dominant trait is a trait which only requires one gene for the trait to be expressed in the phenotype.
- 20Explain (briefly!) what occurs during crossing over and how this process is related to neurodevelopmental disordersCrossing over is a step in meiosis where homologous chromosomes may share their genetic material. It is a potential point of vulnerability for genetic anomalies so can lead to neurodevelopmental disorders.
- 21What are two key differences between the ventral and dorsal pathways of the visual system?The ventral pathway is involved with the object and visual identification and recognition while the dorsal pathway is involved with determining the spacial location of objects relative to the viewer and speech recognition. The ventral pathway goes to the temporal lobe, while the dorsal pathway goes to the parietal lobe.
- 22What effect does the lack of the Elastin gene have in Williams syndrome (phenotypically)?A lack of Elastin is thought to cause the full cheeks, soft skin, premature ageing, and the puffiness around the eyes typically seen in Williams syndrome, as well as cardiovascular problems.
- 23Briefly explain the genetic origins of Williams SyndromeWilliams syndrome is caused by a deletion of over 25 genes in chromosome 7, which includes the deletion of the gene which codes for elastin.
- 24Describe the social phenotype of Williams Syndrome and give an example of "typical William Syndrome" social behaviourIndividuals with Williams syndrome are hyper-sociable and empathetic. However, they can have difficulties adapting their social behaviour to situations, and can struggle to sustain friendships. They also can be socially vulnerable as their behaviour will rarely change even if someone is abusive. Williams syndrome is also associated with higher anxiety levels. An example of Williams Syndrome behaviour would be someone with the disorder going to talk to everyone immediately in a room full of strangers.
- 25What are three distinguishing physical characteristics of people with Williams SyndromeSmall turned-up nose, full cheeks, puffiness around the eyes.
- 26Describe two negative consequences of the social phenotype in Williams SyndromeDue to their hyper-sociability, people with Williams Syndrome are at risk of bullying and social isolation. They are also socially vulnerable due to the fact that they will not adjust their behaviour even if someone is abusive towards them.
- 27Briefly describe relative strengths and weaknesses in Williams Syndrome (give two examples of each)People with Williams Syndrome generally have strong language abilities (after a slow start) and strong musicianship. However they also generally have a low IQ and weaknesses in visuospatial skills.
- 28Describe two brain regions that are preserved in Williams syndrome and what functions those areas are associated withThe anterior frontal regions which is involved with the use of language. The temporal limbic system which is involved with face recognition.
- 29Describe one alteration to the neurons themselves in Williams syndrome and what consequence that change may have.Neurons are typically disordered in Williams syndrome, they can be in the wrong region or layer. The pathways are therefore altered, and may cause different expressions.
- 30How is oxytocin altered in William Syndrome and what functional consequences might those changes have (in the brain and phenotypically)?Increased basal levels of oxytocin in Williams Syndrome. These increased oxytocin levels may contribute to the lack of social inhibitions in Williams Syndrome, as well as the lack of adaptive social behaviours. ?
- 31Describe one of the ways MeCP2 interacts with or alters BDNF and how that interaction is altered in Rett SyndromeMeCP2 binds to one of BDNF's promotor regions and represses transcription in inactive neurons. MeCP2 is released when the neuron depolarises. BDNF is produced and released from the cell, stabilising the synapse and keeping the cell alive. Without MeCP2 (in Rett Syndrome) – more cell death, more synaptic pruning, fewer neurons, fewer synapses.
- 32What is the difference between a missense and a nonsense mutation?A mis-sense mutation is where one codon in the DNA is changed to another. This results in a different protein coded for. A nonsense mutation is where a change in the DNA results in a stop codon and so no longer results in an amino acid.
- 33Why does "classic" Rett Syndrome rarely appear in boys?Due to the different chromosomal combination in males, boys with the Retts syndrome mutation typically have much more severe symptoms. Because of this, many die before birth or during infancy.
- 34Describe one role that normal MECP2 (the protein) plays in conditional learning/synaptic plasticity?MECP2 is important in regulating excitatory synapses and modulating synaptic plasticity.
- 35List two cognitive and two physical aspects of the Rett phenotypePhysical aspects include lack of purposeful hand skills, and gait dysfunction. Cognitive aspects include difficulties with speech and communication and significant mental dysfunction.
- 36In "classic" Retts, outline the stages of the development of the disorder (give 1 or 2 key symptoms for each stage)The first stage is apparently normal development until 6-18 months, where normal developmental milestones are achieved. Next is arrest of developmental (6 months - 2.5 years), where growth stops and microcephaly develops. After this is rapid regression (1-4 years), where purposeful hand movement is lost and walking abilities are lost. Then there is stabilisation (3-10 years) where gradual slowing of motor functions occurs and anxiety develops. Late stage motor deterioration is the final stage and is characterised by decreased mobility and Parkinsonism.
- 37What is the main gene involved in Rett syndrome? What is the protein's main action or role in the cell?The main gene involved in Rett syndrome is MeCP2 which codes for the protein MeCP2. MeCP2 is a DNA binding protein which interacts with the DNA during transcription, and represses transcription.
- 38Briefly describe two changes to the neuron in Rett syndromeNeurons are smaller in Rett syndrome, and there is less branching of neurons in Rett syndrome. Fewer dendrites in Rett syndrome.
- 39Explain why Rett syndrome is considered a neurodevelopmental and not a neurodegenerative disease (be specific)Because there is no obvious degeneration, atrophy, or inflammation, no signs of gliosis, and no signs of neuronal migrational defects. Therefore it is neurodevelopmental not degenerative.
- 40Describe one piece of evidence that suggests that the dopaminergic system is altered in Rett syndrome and identify a symptom related to those changesL-dopa, a precursor for dopamine, has been found to improve rigidity during the motor deterioration phase. The symptom related to these changes are motor symptoms and rigidity.
- 41Outline two ways in which mosaicism can occur in Fragile X SyndromeIt's common for people with the full Fragile X mutation to have different repeat numbers in different cells, therefore some cells can have the pre-mutation instead. This is repeat mosaicism. Occasionally, people with the full mutation can have cells where FMR1 isn't fully methylated. The gene can be translated in these cells, and these cells can produce some FMRP. This is methylation mosaicism.
- 42Briefly explain one main functional role FMRP (the protein) plays in the cellIt is present at synapses and has been shown to act as a repressor on the translation of synaptic proteins.
- 43Briefly describe the social phenotype of fragile X syndrome (make sure to note any difference between males and females)Social aspects of fragile X syndrome include attention problems and hyperactivity, extreme shyness, and autistic-like behaviours such as repetitive behaviours, hand flapping/biting, gaze aversion, and transition problems. Symptoms in females are similar but usually less severe, although selective mutism can be a problem.
- 44Explain one molecular consequence at the synapse of missing FMRPLoss of FMRP means that translation of proteins is not reduced, and can lead to changes in mechanisms of plasticity.
- 45Write one or two sentences explaining "genetic responsibility" and how that concept relates to Fragile X SyndromeGenetic responsibility is the idea that mankind has a responsibility to apply the findings of genetic science to genetic disorders being inherited. It is relevant in Fragile X syndrome because Fragile X is not only inherited, but also increased in severity for every new generation.
- 46What is the molecular/cellular explanation for why girls are less affected in fragile X than boys (briefly explain how this works)?X-inactivation means that one of the X chromsomes in girls is protective to some degree against Fragile X. In boys there is only one X chromosome so symptoms are more severe.
- 47If a woman carries the fragile X premutation, what percentage of her sons will have fragile X? What percentage of her daughters? If the carrier of the premutation is the father, what percentage of his sons will carry the premutation? What percentage of his daughters?If a women carries the premutation then 50% of her offspring will carry the mutation. If the carrier is a father, none of his sons will carry the premutation, whereas 100% of his daughters will carry the premutation.
- 48List two gross brain changes in full-mutation fragile X and briefly explain how the neuron itself is alteredSynapses are not pruned properly and spines don't mature correctly and remain thin, meaning more synapses and more spines. Several parts of the brain grow faster than typical children. Normal neurons grown with fragile x glial cells become fragile x-like neurons.
- 49What are three characteristic symptoms in ASD that also frequently occur in Fragile X Syndrome?Repetitive movements, Hand flapping/hand biting, Gaze aversion.
- 50Briefly (but completely) describe the genetic change/mutation that causes full mutation Fragile X Syndrome?A mutation on the FMR-1 gene on the X chromosome leads to an increase in CGG repeats. A full mutation is over 200 repeats.
- 51Where in the cell are the inclusions in FXTAS? Where are they found in the nervous system?Inside the nucleus and cytoplasm of the cell. They are found in neurons and glial cells in the peripheral nervous system.
- 52Name one neuropathological change that occurs in FXTAS and identify a symptom of the disease that is associated with that changeDegeneration of peripheral nerves is a change that occurs. A symptom of the disease associated with this is decreased reflexes.
- 53Name two molecules that are found in the inclusions in FXTAS and identify their usual roles in the cellTwo molecules involved mRNA and nuclear mRNA binding proteins. They are both usually involved in translational processes.
- 54What are two common phenotypes/symptoms of premutation carriers of fragile X (before the onset of FXTAS)Anxiety disorders and an increased risk of Autism Spectrum disorder in childhood are two symptoms of pre-mutation FXTAS.
- 55What is the relationship between CGG expansion length and FMR1 mRNA levels in premutation carriers?The longer the CGG expansion length, the higher the levels of FMR1 mRNA levels in pre-mutation carriers.
- 56Briefly define "transcriptional efficiency" and explain the consequence (in the cell) of increased transcriptional efficiency in pre-mutation carriers of fragile X who develop FXTASTranscriptional efficiency is the amount of mRNA that is made when the genes are transcribed. The increased transcriptional efficiency means that too much mRNA is being made. The larger repeat region on the mRNA means that it binds to too many proteins so the proteins lose normal function. This also creates inclusions and causes cell death.
- 57What disorder is FXTAS often misdiagnosed as? Name one likely reason why this mistake happens in the clinicOften misdiagnosed as Parkinson's disease. This may happen because the symptoms of hand tremor, walking difficulties and balance problems which are symptomatic of Parkinson's disease.
- 58List two cognitive changes and two physical/motor changes that occur in FXTASPhysical changes include hand tremors and walking difficulties. Cognitive changes can include impairment in executive function and mood dysregulation.
- 59What is the relationship between activation ratio and the symptoms of FXTAS? Briefly explain why this is the case.There is a positive relationship between activation ratio and the symptoms of FXTAS. The greater the number of x's that are activated, the more severe the symptoms of FXTAS.
- 60Explain the circumstances under which a person could experience FXTAS and full-mutation fragile X at the same timeDue to repeat mosaicism, in the same person some cells could have the premutation gene which others could have the FXTAS gene meaning they could experience FXTAS and full-mutation Fragile X at the same time.
- 61Briefly describe two motor and two non-motor symptoms of Huntington disease and be sure to mention at what disease stage they usually occurIn manifest Huntingdon's disease, two motor symptoms are muscle spasms and motor control difficulties with the mouth, tongue, and swallowing. Two cognitive symptoms are loss of executive function (so may struggle to drive) and the loss of the ability to recognise familiar objects.
- 62What is one effect of missing the normal Huntingtin protein in Huntington's disease?The normal Huntingtin protein seems to protect against programmed cell death (apoptosis), so the loss of the normal protein will likely cause cells to die.
- 63Briefly describe how and when the direct and indirect pathways in the basal ganglia are affected in Huntington diseaseThe loss of striatal GABA/D2-R neurons in the indirect pathway results in chorea. The loss of striatal GABA/D1-R neurons and cortical atrophy in the direct pathway results in akinesia.
- 64What gene causes Huntington disease and where is it located (e.g., which chromosome)?A mutated form of the Huntingtin gene, located on chromosome 4.
- 65Briefly describe the genetic and primary molecular changes that cause Huntington diseaseA mutated form of the Huntingtin gene causes excessive repeats of the CAG trinucleotide. These CAG repeats cause intracellular aggregates to form within the cell. Macro and micro-aggregates both form, but micro-aggragates alone are toxic to cells and cause cell death.
- 66Define chorea and give one example of what it might look like in Huntington diseaseChorea is uncontrolled involuntary movements. An example in Huntington's disease would be small unintentionally initiated arm movements.
- 67At what point does penetrance become 100% (with regards to the number of CAG repeats) in Huntington disease? What is the relationship between repeat number and disease severity in Huntington disease?Full penetrance is 40 CAG repeats or more. With more repeats, the severity of Huntington's disease symptoms tends to increase, and the age of onset tends to be earlier.
- 68Which parts of the brain are first to degenerate in Huntington (be specific about cell type)? Give one reason why this region/these cells are more vulnerableThe striatum is the first part of the brain to degenerate (caudate and putamen), specifically striatal neurons. Loss of small neurons precedes the loss of larger neurons. This is because these cells are the target of more glutaminergic activity, and this increased vulnerability to excitatory factors may lead to apoptosis.
- 69What is the difference between micro and macro aggregates in Huntington Disease? Explain what these differences mean for how they act in the disease (e.g., what symptoms each are thought to be associated with)Micro-aggregates are only a few molecules of Huntingtin stuck together, while macro-aggregates are larger. Micro-aggregates are insoluble and are toxic to cells, causing cell death. Macro-aggregates also disrupt cell processes but do less damage.
- 70Describe one "molecular consequence" of Huntington DiseaseOne molecular consequence is the formation of macro and micro-aggregates. The macro-aggregates cause intracellular inclusions and the micro-aggregates are toxic and lead to cell death.
- 71Name one symptom that L-dopa is useful for, one symptom it does not help and one symptom it can cause in Parkinson DiseaseL-dopa is useful for reducing the tremors and motor symptoms of Parkinson's disease. It doesn't help with balance problems. Patients can develop dyskinesias from long term usage of L-dopa.
- 72List one piece of evidence that supports the idea that Parkinson disease could be a prion disorderTransplanted fetal nigral neurons transplanted 10-14 years earlier showed evidence of Lewy pathology, which suggested that protein aggregation had spread from affected to unaffected neurons in a prion-like manner.
- 73What are the "hallmark" (motor) symptoms of Parkinson disease?Bradykinesia (slowness of movement) and difficulty with initiating movement (akinesia), as well as a resting tremor.
- 74List two key differences between Parkinson Disease and Dementia with Lewy BodiesPatients with Dementia with Lewy Bodies tend to have Alzheimer's disease pathology as well as Lewy Bodies. Dementia is a late-stage symptom of Parkinson's disease, but is an early symptom of Dementia with Lewy bodies. Recurrent visual hallucinations are also a symptom in Dementia with Lewy Bodies but not in Parkinson's disease.
- 75Name two cognitive impairments that occur relatively early in Parkinson DiseaseTwo cognitive impairments that can occur early in Parkinson's disease are decreases in visuo-spacial abilities and attention difficulties.
- 76Briefly explain two key changes in the brain that occur in Parkinson DiseaseOne key change is the death of pigmented cells in the substantia nigra, leading to the lack of dopamine. Another is the formation of Lewy Bodies.
- 77Name one gene that has been identified as increasing the risk of developing Parkinson disease and what system it affects in the cellDuplications or triplications of the alpha-synnuclein gene have been shown to result in hereditary Parkinson's disease, and the alpha-synuclein protein is the main component of Lewy bodies seen in PD. Alpha-synuclein is mainly found in presynaptic vesicles and is thought to be involved with the clustering of synaptic vesicles and possibly with the regulation of dopamine release.
- 78What is the main reason that L-Dopa becomes less effective in the later stages of the disease?Because Parkinson's disease is progressive and involves the death of cells and synapses. This means that in the later stages of the disease simply replacing dopamine can no longer counteract all the symptoms. In addition to this, L-dopa can only treat some symtoms, but can't treat others such as balance problems.
- 79What is one "protective" environmental factor and one environmental risk factor in Parkinson Disease?A protective factor for Parkinson's is smoking, while a risk factor is environmental toxins such as pesticides.
- 80How does the tremor typically present differently in Parkinson Disease vs. FXTAS?While in Parkinson's disease, the tremor is present when the patient is still and tends to lessen or disappear with movement, the opposite is true for FXTAS (intention tremor).
- 81Name two potential biomarkers for Alzheimer Disease and describe how "promising" they are for early diagnosis.Tau levels in cerebrospinal fluid can be tested. Longitudinal MRI structural imaging can also be used to predict Alzheimer's disease. Both these biomarkers are promising for early diagnosis but more research is needed.
- 82Name three cognitive symptoms of Alzheimers and comment on the order in which they might typically appearAn early symptom would be losing track of appointments, a mid-stage symptom would be a progressive loss of memory for prior events. A late-stage symptom would be a complete loss of communication and speech abilities.
- 83Which neurotransmitter system is most implicated in Alzheimer Disease? Describe one piece of evidence that suggest that this is trueThe acetylcholine system is implicated because of the loss of cholinergic neurons. This loss is correlated with the deposition of amyloid-beta.
- 84What is tau protein, how is it involved in Alzheimers and what function does it normally play in the neuron?Tau proteins are proteins which are mostly found in neurons in the CNS. Their function is to stabilise microtubules. Tau levels are higher in CSF in AD. The tau hypothesis proposes that microtubule disintegration caused by tau abnormalities causes the disease.
- 85Briefly explain how APP is involved in Alzheimers and how it is related to beta amyloid accumulationAPP is the precursor molecule to amyloid beta, the main component of plaques in the brains of AD patients. While amyloid beta levels in the brain are higher in AD, APP levels are actually lower than normal in neuronal cell bodies. This loss of APP may contribute to dementia.
- 86What region of the brain is most often first affected in Alzheimers and how does that damage manifest cognitively?The hippocampus and surrounding areas are the first areas to be affected. As the hippocampus is heavily involved with memory this damage leads to memory problems.
- 87Name one protein that accumulates in Alzheimer Disease and describe where that accumulation occursAmyloid-beta protein accumulates at the synapse in Alzheimer's disease.
- 88Describe one genetic risk factor for Alzheimer Disease (which gene, what are the molecular results of a mutation in the gene, and what kind of risk does it confer).The APP gene is implicated in AD type 1. Several mutations in the APP gene can result in AD. Between 15 and 20 percent of early-onset familial AD is as a result of an APP mutation. It is autosomal dominant and a mutation can cause abnormal amounts of beta-amyloid fragments.
- 89Describe one non-genetic risk factor for Alzheimer's disease and explain *why* it is a risk factor.Age is a big risk factor is AD because in the natural process of ageing, neurons die, oxydative stress increases, and plaques and tangles develop around neurons.
- 90In Alzheimer's, what relatively early neuropsychiatric symptoms are related to damage to the amygdala?Increased anxiety and emotional changes are likely to be related to amygdala damage.
- 91How are Down Syndrome and Alzheimer Disease associated? Be sure to include both genetic and molecular information.There is a higher prevalence of Alzheimer's disease among people with Down syndrome. This may be due to the APP being present on the chromosome 21, the same chromosome which there are two copies of in Down's syndrome. As there would be an extra APP gene, there would be a higher chance of an APP mutation which would increase Alzheimer's risk.
- 92Name one way in which synapses are altered in Down SyndromeThere are more inhibitory synapses in Down Syndrome. Decreases in dendritic arbor development lead to reduced synaptic plasticity.
- 93Briefly explain the genetic differences between the 3 variants of Down SyndromeTrisomy 21 DS is where a child has three copies of chromosome 21 instead of the usual two copies in every cell. Mosaic Down Syndrome is caused abnormal cell division after fertilisation. Some cells have an extra copy of chromosome 21 and some don't. Translocation Down Syndrome is when part of chromosome 21 attaches to another chromosome, typically during meiosis. Children with translocation DS typically have two chromosome 21s but also have some genetic material from chromosome 21 attached to another chromosome.
- 94Briefly explain Robertsonian Translocation, using Translocation Down Syndrome as an exampleA Robertsonian translocation involves breaks at the extreme ends of the short
arms of two chromosomes. Centric fusion of the long arms creates a larger
chromosome plus 2 acentric
fragments. This can occur on chromosome 21 and 14 causing translocation DS. - 95Briefly describe the social phenotype of Down SyndromePeople with DS are often highly sociable. Most early social skill develop at normal times. Mutual gaze is slow to develop, joint attention is delayed, imitation is strong. Difficulties in emotional recognition.
- 96What are two medical consequences for children with Down Syndrome?Soft tissue can result in sleep apnea. Obesity in DS is more common than the general population.
- 97Briefly describe the physical phenotype of Down Syndrome (not including medical complications)Physical features can include flattened facial features, small head, short neck, protruding tongue, upward slanting eyes, unusually shaped ears.
- 98What are two things that increase the likelihood of obesity in people with Down Syndrome.Hypothyroidism due to acquired autoimmune dysfunction. Decreased resting metabolism- unclear why.
- 99Explain the roles that cell adhesion molecules play in the brain and why this might be relevant to Down Syndrome.Cell adhesion molecules stick cells together to build cell structures and allow for cell migration. When the gene that encodes cell adhesion molecules is over-expressed, it can result in DS.
- 100Describe how dendrites change across development, from birth to adulthood, in Down SyndromeIn people with DS, there is more dendritic branching and dendritic length among infants. However, dendrite arbor development decreases slowly to lower than normal levels after early childhood. Continued reductions throughout adulthood.
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- FlashCards sobre Brain development and degeneration draft, criado por Ted Noble em 02-01-2018.
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