Week 4 - The biology of the developing nervous system Flashcards
(99 cards)
1
Q
What is a congential condition?
A
A condition which arises as a result of abnormal development and is therefore present at birth
2
Q
What is a zygote?
A
A single cell created by the fusion of the sperm and egg
3
Q
What does the term diploid mean?
A
The name given to a cell that carries two complete paired sets of chromosomes
4
Q
What is a gamete?
A
A reproductive cell (sperm/egg)
5
Q
What is a haploid cell?
A
One which carries only one set of unpaired chromosomes
6
Q
What are somatic cells?
A
All cells other than the reproductive cells (gametes)
7
Q
What are the two main phases of the cell cycle?
A
- Interphase
- Mitotic phase
8
Q
Broadly speaking, what happens during the interphase part of the cell cycle?
A
The cell prepares to divide
9
Q
Broadly speaking, what happens during the mitotic phase of cell division?
A
The cell divides
10
Q
The S phase is part of which stage of cell division?
A
The mitotic phase
11
Q
What happens during S phase?
A
The DNA within the cell is replicated, producing two complete copies
12
Q
What does the term cytokinesis refer to?
A
The cell membrane pinching in around the middle of the cell and the cell splitting into two daughter cells
13
Q
Is symmetrical or asymmetrical cell division the most important type?
A
Asymmetrical - it provides opportunity for cells to diversify into different types
14
Q
What is a morula?
A
The ball of cells that reaches the uterus 3-4 days post fertilisation
15
Q
What is a blastocyst?
A
The ball of cells that implants into the wall of the uterus
16
Q
How is a blastocyst different from a morula?
A
A blastocyst has two different types of cells in it
17
Q
What are the outer cells of blastocysts called?
A
Trophoblasts
18
Q
What do trophoblasts go on to form after implantation?
A
The placenta
19
Q
How many cells does the morula consist of?
A
16
20
Q
What is gastrulation?
A
The formation of 3 distinct tissue source layers via cell diversification in a developing embryo
21
Q
What are ectoderm cells?
A
Cells which will form skin, hair and the lining of structures such as the nose and mouth, and the nervous system
22
Q
What are mesoderm cells?
A
A type of cell that forms the muscles, skeleton and blood
23
Q
What are endoderm cells?
A
A type of cell that forms the lining of the respiratory tract, digestive tract and bladder
24
Q
Around how long post fertilisation does the development of the nervous system begin?
A
18 days
25
In the developing nervous system, what is the tissue source layer that the neural plate arises from?
The ectoderm
26
What is the neural groove?
The first step in the formation of the nervous system
27
What is the role of the notochord during nervous system development?
It plays an important role in diverisfying and migrating cells
28
What orientation does the term ventral refer to?
Bottom or lower
29
What does the Sonic hedgehog gene do?
It codes one signal used by the notochord to help cells orient themselves during development
30
What is the reason for the name of the ‘Sonic hedgehog’ gene?
A mutant gene first found in fruit fly embryos causes the embryo to present a stunted and spiky appearance
31
What is the meaning of the term neural tube defect (NTD)?
Congenital conditions that occur when the neural tube does not close, leaving the neural tissue exposed to amniotic fluid
32
What happens if the neural tube does not close during development?
The neural tube will be exposed to amniotic fluid and neural tube defects are likely to occur
33
What is anencephaly?
A neural tube defect where the neural tube fails to close anteriorly
34
What condition occurs if the neural tube fails to close posteriorly?
Spina bifida
35
What are the three types of spina bifida?
- Spina bifida occulta
- Meningocele
- Myelomengocele
36
Of the three types of spina bifida, which is the most serious and why?
Myelomeningocele
It can cause severe disability, including paralysis of lower limbs
37
Low levels of which micronutrient can be a risk factor for spina bifida to occur?
Folic acid
38
Taking folic acid has been shown to reduce the risk of spina bifida by how much?
Up to 70%
39
What is the definition of genotype?
The complete code contained within the chemical composition of DNA
40
What does heritability refer to?
The extent to which a variation of a particular characteristic in a population can be determined solely by genes
41
With regards to heritability, what does a value of 1 mean?
That all of the variation in a population is determined by genes rather than environment
42
What does the term ‘fetal alcohol spectrum disorders’ (FASD) refer to?
A set of health conditions that occur in offspring that is related to the maternal consumption of alcohol
43
Which type of cells are most likely to be damaged by maternal alcohol consumption?
Brain and spinal cord cells - other cells take higher concentrations of alcohol to be damaged
44
In Western countries, roughly how many pregnancies are thought to be affected by FSAD?
1 in 500
45
Of all the possible substances of abuse, which can have the most wide-ranging consequences on the developing baby?
Alcohol
46
What characteristic facial feature can be seen in children with FASD?
Flattened nose bridge
Lack of ridge on upper lip
47
What can FASD sometimes be misdiagnosed as?
Autism spectrum disorder
48
Why are children with FASD sometimes misdiagnosed as having ASD?
Because the symptoms can manifest in very similar ways
49
What are the main symptoms FASD can cause?
- Language deficicts
- Attention problems
- Social problems
- Problems with sensory integration
- Poor reasoning
50
What conditions can often be co-morbid with FASD?
- ADHD
- Autism
51
During embryo development, what three regions does the neural tube segment into?
- Prosenchephalon
- Mesencephalon
- Rhombencephalon
52
During embryo development, what does the prosencephalon go on to become?
The forebrain
53
During embryo development, what does the mesencephalon go on to become?
The midbrain
54
During embryo development, what does the rhombencephalon go on to become?
The hindbrain
55
What are the five segments that form during secondary segmentation in embryo development?
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
- Myelencephalon
56
What are neuromeres?
The segments in the developing nervous system
57
What is the prosencephalon?
The segment of the developing neural tube that goes on to form the forebrain
58
What is the mesencephalon?
The segment of the developing neural tube that goes on to form the midbrain
59
What is the rhombencephalon?
The segment of the developing neural tube that goes on to form the hindbrain and spinal cord
60
What is cell fate?
The final identity of type of a cell at the end of its cell lineage
61
What does totipotent mean?
A cell that is capable of becoming any type of cell within an organism, INCLUDUING placental cells
62
What is the trophoblast?
The layer of cells in a developing embryo that goes on to form the placenta
63
What does pluripotent mean?
A cell that is capable of becoming any type of cell within an organism, EXCEPT placental cells
64
What are the two tissue types that the blastocyst is formed of?
- Trophoblast cells
- Inner cell mass
65
What are bipotential progenitor cells?
Cells that can become one of two types of cell
66
What are progenitor cells?
Cells that become a specific type of cell
67
What are the only conditions under which it is permitted for embryos to be created, stored and used in a lab?
- Improving understanding of embryonic development processes
- Improving detection / understanding of human disease
- Developing treatments for human disease
- Providing advancesin understanding miscarriage, contracption techniques, treating infertility
68
What are radial glial cells?
Glial cells that provide a type of structural scaffold for migrating neurons to move along
69
How are neurons of the human adult cortex arranged?
In layers
70
How are the neurons of the cerebral cortex arranged?
In layers
71
When do the layers of the cerebral cortex start to form?
Around 6 weeks after fertilisation
72
What is the outer subventricular zone (oSVZ)?
A developmental region of the ventricular zone in the developing nervous system that is unique to primates
73
What is the outer subventricular zone important in the development of?
Cortical development
74
What is the inside-first outside-last principle of cortical development?
The way in which the cortex develops in its layered arrangement
75
During cortical development, which layers develop first and which last?
- First: innermost layers close to the ventricular zone
- Last: outermost layers
76
What are the two forms of cell migration in the human nervous system?
- Radial migration
- Tangential migration
77
What are the two types of cells that bipotential progenitor cells may go on to form?
- Neuron progenitor cells
- Glial progenitor cells
78
In which direction do neural progenitor cells move during radial migration?
Outwards from the ventricular zone surface
79
During tangential migration, in which direction do neural progenitor cells move?
Outwards and sideways
80
What is the pial surface?
The outer edge of the developing neural tube
81
What is nucleokinesis?
The process that occurs when the nucleus of a migrating cell moves into the leading arm
82
What is the name for the process in which neuronal migration occurs?
Leading process
83
How does neuronal migration occur?
Neurons extend an arm which is able to sense chemical signals arising in the surrounding tissue
84
What is the chemical known as semaphorin 3A used by neurons for?
To determine how far away from the pial surface they are
85
What is chemotactic guidance?
The use of chemical cues as a guide during cell migration
86
What are the two neuronal processes (projcetions from the cell body)?
- Axons
- Dendrites
87
Of the two neuronal cell body projections (processes), which one receives information from synapses and passes it on to the cell body for processing?
Dendrites
88
Of the two neuronal cell body projections (processes), which one passes on the integrated information from the cell body to different synapses?
Axons
89
What is meant by the term neurite?
A collective term given to either an axon or a dendrite of a neuron
90
Why are dendrites and axons collectively referred to as neurites sometimes?
Because it is difficult to tell during development whether an extended process arising from a developing neuron is a dendrite or a neuron
91
What is a growth cone?
The end of a growing axon that causes the axon to elongate and reach other neurons to form synaptic connections
92
What are filopodia?
Thin projections extending frmo the edge of migrating cells that sense the surrounding environment
93
What term is used to describe the formation of new synaptic connections?
Synaptogenesis
94
What component of a cell is responsible for making proteins?
The ribosome
95
Where are instructions located for making proteins
In the DNA in the nucleus of the cell
96
How does the ribosome get the instructions it needs to begin making the proteins that will be involved in neuronal communication?
Through mRNA, which transcribe the coded instructions from DNA and carry them to the ribosome
97
What is a key molecule for signalling synaptogenesis?
Brain-derived neurotrophic factor (BDNF)
98
What is brain-derived neurotrophic factor (BDNF)?
A key molecule for signalling synaptogenesis and neurogenesis
99
Brain-derived neurotrophic factor (BDNF) is thought to play a key role in which condition?
Depression
