Exam Prep Ch27 Development Of The Nervous System

Chapter 27: Development of the Nervous System

Test Bank

Type: multiple choice question

Title: Chapter 27 Question 01

1. During nervous system development, the following factors control cell specification.

Feedback: Subhead: Development: General Considerations

Learning Objective: Discuss how combinatorial transcriptional codes determine the cell-type specific expression of individual genes.

Bloom’s Level: 1. Remembering

a. DNA polymerases

b. RNA polymerases

c. Ribosomes

d. Proteases

e. Transcription factors

Type: multiple choice question

Title: Chapter 27 Question 02

2. Reprogramming mature, differentiated somatic cells with Oct4, Sox2, Klf4, c-Myc can produce

Feedback: Subhead: Development: General Considerations

Learning Objective: Define induced pluripotent stem cells (iPSCs) and discuss at least two reasons why they are so useful to researchers.

Bloom’s Level: 1. Remembering

a. irreversible genetic loss.

b. actual embryonic stem cells.

c. a fertilized egg.

d. induced pluripotent stem cells (iPSCs).

e. immature differentiated somatic cells.

Type: multiple choice question

Title: Chapter 27 Question 03

3. Cell differentiation can be regulated by

Feedback: Subhead: Development: General Considerations

Learning Objective: Describe the role of cell-to-cell communication in shaping embryonic development of the nervous system.

Bloom’s Level: 1. Remembering

a. transcription factors.

b. juxtacrine signaling.

c. paracrine signaling.

d. all of the above.

e. none of the above.

Type: multiple choice question

Title: Chapter 27 Question 04

4. Which molecules do not act as a morphogen during nervous system development?

Feedback: Subhead: Development: General Considerations

Learning Objective: Describe the role of cell-to-cell communication in shaping embryonic development of the nervous system.

Bloom’s Level: 1. Remembering

a. Wnt

b. cAMP

c. FGFs

d. Shh

e. RA

Type: multiple choice question

Title: Chapter 27 Question 05

5. The following tools have been used to study to study cell fate mapping.

Feedback: Subhead: Development: General Considerations

Learning Objective: Explain what cell fate mapping is.

Bloom’s Level: 3. Applying

a. Lipophilic dyes

b. Ion channel blockers

c. cAMP analogues

d. Kinase inhibitors

e. Microtubule inhibitors

Type: multiple choice question

Title: Chapter 27 Question 06

6. This embryonic structure is known as the Spemann Organizer in amphibians.

Feedback: Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Describe the role of the Spemann organizer in neural induction.

Bloom’s Level: 1. Remembering

a. Neural plate

b. Notochord

c. Dorsal blastopore lip

d. Epidermis

e. Endoderm

Type: multiple choice question

Title: Chapter 27 Question 07

7. What type of experiment did Spemann use to study neural induction?

Feedback: Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Describe the role of the Spemann organizer in neural induction.

Bloom’s Level: 2. Understanding

a. Gene knockout

b. Antibody injection

c. Lipophilic dye labeling

d. Radioactive labeling

e. Transplantation

Type: multiple choice question

Title: Chapter 27 Question 08

8. According to the default model of neural induction, BMP

Feedback: Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Explain what the default model for neural induction is.

Bloom’s Level: 1. Remembering

a. induces neural fate in ectoderm.

b. maintains epidermal fate in ectoderm.

c. reduces phosphorylation of SMAD transcription factors.

d. binds to notch.

e. acts only intracellularly.

Type: multiple choice question

Title: Chapter 27 Question 09

9. Which gene is not a proneural gene?

Feedback: Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Define proneural genes.

Bloom’s Level: 1. Remembering

a. Delta

b. Neurogenin

c. Achaete scute

d. Atonal

e. Enhancer of split

Type: multiple choice question

Title: Chapter 27 Question 10

10. The neuroblast is determined by elevated levels of Delta during the

Feedback: Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Explain what lateral inhibition is, including the role that Notch-Delta signaling plays in it.

Bloom’s Level: 3. Applying

a. specification of the neural plate.

b. process of lateral inhibition.

c. formation of the neural tube.

d. process of cell dissociation.

e. mutation of neurogenic genes.

Type: multiple choice question

Title: Chapter 27 Question 11

11. This molecule specifies posterior fate along the anteriorposterior axis.

Feedback: Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Summarize how development proceeds in the anterior and caudal portions of the neural tube.

Bloom’s Level: 1. Remembering

a. BMP

b. Wnt

c. Noggin

d. NGF

e. Shh

Type: multiple choice question

Title: Chapter 27 Question 12

12. This molecule determines the midbrain-hindbrain boundary.

Feedback: Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Summarize how development proceeds in the anterior and caudal portions of the neural tube.

Bloom’s Level: 1. Remembering

a. Shh

b. BMP

c. Follistatin

d. FGF8

e. RA

Type: multiple choice question

Title: Chapter 27 Question 13

13. Hox genes are

Feedback: Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Discuss the role of Hox genes in anteroposterior patterning and segmentation in the hindbrain.

Bloom’s Level: 2. Understanding

a. growth factors.

b. cell surface receptors.

c. transcription factors.

d. histon proteins.

e. tyrosine kinases.

Type: multiple choice question

Title: Chapter 27 Question 14

14. This embryonic structure induces the floor plate.

Feedback: Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Explain how dorsoventral neural fates in the spinal cord are induced.

Bloom’s Level: 1. Remembering

a. Notochord

b. Spemann organizer

c. Central canal

d. Roof plate

e. Neural plate

Type: multiple choice question

Title: Chapter 27 Question 15

15. This morphogen is involved in ventral patterning of the nervous system.

Feedback: Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Explain how dorsoventral neural fates in the spinal cord are induced.

Bloom’s Level: 1. Remembering

a. FGF

b. Shh

c. Wnt

d. BMP

e. EGF

Type: multiple choice question

Title: Chapter 27 Question 16

16. During development of the cortex, neurons migrate outward along the following cells.

Feedback: Subhead: Development of Cerebral Cortex

Learning Objective: State the two primary functions of radial glial cells.

Bloom’s Level: 1. Remembering

a. Fibroblasts

b. Microglia

c. Oligodendrocytes

d. Astrocytes

e. Radial glia

Type: multiple choice question

Title: Chapter 27 Question 17

17. The innermost layer in the developing vertebrate cortex is called the

Feedback: Subhead: Development of Cerebral Cortex

Learning Objective: Discuss why cortical development is described as proceeding in an “inside-out” fashion.

Bloom’s Level: 1. Remembering

a. cortical plate

b. marginal zone

c. intermediate zone

d. ventricular zone

e. subventricular zone

Type: multiple choice question

Title: Chapter 27 Question 18

18. Which of the following transcription factors determine the regional identity of the caudal portion of the cerebral cortex?

Feedback: Subhead: Development of Cerebral Cortex

Learning Objective: Explain how regional specification of cortical areas is initiated.

Bloom’s Level: 1. Remembering

a. Emx2

b. Sp8

c. Pax6

d. Couptf1

e. Hox3

Type: multiple choice question

Title: Chapter 27 Question 19

19. Which neuronal subtype exhibits tangential migration during cortical development?

Feedback: Subhead: Development of Cerebral Cortex

Learning Objective: Differentiate between radial migration and tangential migration of neurons.

Bloom’s Level: 1. Remembering

a. Pyramidal neurons

b. Purkinje neurons

c. Spiny neurons

d. Basket cells

e. GABAergic interneurons

Type: multiple choice question

Title: Chapter 27 Question 20

20. Neurogenesis in the adult brain was shown in this animal.

Feedback: Subhead: Development of Cerebral Cortex

Learning Objective: Name the key differences that distinguish neurogenesis in the developing versus the adult brain.

Bloom’s Level: 1. Remembering

a. Chicks

b. Aplysias

c. Ferrets

d. Songbirds

e. Dolphins

Type: multiple choice question

Title: Chapter 27 Question 21

21. Transplantation experiments showed that

Feedback: Subhead: Neurogenesis versus Gliogenesis

Learning Objective: Explain what the progressive competence-restriction model of corticogenesis is.

Bloom’s Level: 2. Understanding

a. different progenitor cells give rise to distinct cell types in the cortex.

b. common progenitor cells gain more and more competence to create different cell types as development proceeds.

c. common progenitor cells have more and more restricted competence to develop into different cell types as time progresses.

d. common progenitor cells do not change their competence level during development.

e. None of the above

Type: multiple choice question

Title: Chapter 27 Question 22

22. McConnell and colleagues found evidence for the progressive competence restriction model by performing

Feedback: Subhead: Neurogenesis versus Gliogenesis

Learning Objective: Explain what the progressive competence-restriction model of corticogenesis is.

Bloom’s Level: 2. Understanding

a. transplantation experiments in ferrets.

b. transplantation experiments in amphibians.

c. transplantation experiments in mice.

d. viral labelling experiments in chick.

e. radioactive labelling experiments in rats.

Type: multiple choice question

Title: Chapter 27 Question 23

23. Which cell type is derived from neural crest cells?

Feedback: Subhead: Determination of Neuronal Phenotype

Learning Objective: Discuss why neural crest cells provide an ideal system for studying how neuronal phenotype is determined.

Bloom’s Level: 1. Remembering

a. Sensory neuron of dorsal root ganglion

b. Adrenal chromaffin cell

c. Schwann cell of dorsal root ganglion

d. Sympathetic neuron

e. All of the above

Type: multiple choice question

Title: Chapter 27 Question 24

24. Peripheral nervous system sympathetic neurons that innervate sweat glands switch their neurotransmitter from

Feedback: Subhead: Determination of Neuronal Phenotype

Learning Objective: Describe one example of neurotransmitter switching and of matching neurotransmitter receptor changes during development.

Bloom’s Level: 1. Remembering

a. glutamine to acetylcholine.

b. GABA to glycine.

c. acetylcholine to norepinephrine.

d. norepinephrine to GABA.

e. norepinephrine to acetylcholine.

Type: multiple choice question

Title: Chapter 27 Question 25

25. As embryonic Xenopus striated muscle cells mature, the following receptor type prevails.

Feedback: Subhead: Determination of Neuronal Phenotype

Learning Objective: Discuss changes in neurotransmitter receptor properties or in neurotransmitter actions during development.

Bloom’s Level: 1. Remembering

a. Acetylcholine

b. Epinephrine

c. Glutamine

d. Dopamine

e. GABA

Type: multiple choice question

Title: Chapter 27 Question 26

26. The fingerlike structures in the growth cone are called

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Explain what a growth cone is, and how it is analogous to a migrating cell.

Bloom’s Level: 3. Applying

a. lamellipodia.

b. ruffles.

c. filopodia.

d. arcs.

e. stress fibers.

Type: multiple choice question

Title: Chapter 27 Question 27

27. The protrusion and retraction of the lamellipodia and filopodia is driven by

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Explain what a growth cone is, and how it is analogous to a migrating cell.

Bloom’s Level: 1. Remembering

a. microtubules.

b. mitochondria.

c. vesicles.

d. F-actin.

e. neurofilaments.

Type: multiple choice question

Title: Chapter 27 Question 28

28. The following guidance cue mediates long-range attraction.

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Describe the different classes of molecules that mediate growth cone navigation.

Bloom’s Level: 1. Remembering

a. Semaphorin

b. Netrin-1

c. Laminin

d. NrCAM

e. Ephrin

Type: multiple choice question

Title: Chapter 27 Question 29

29. NrCAM belongs to this group of molecules.

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Describe the different classes of molecules that mediate growth cone navigation.

Bloom’s Level: 1. Remembering

a. Diffusible factors

b. Extracellular matrix molecules

c. Growth factors

d. Repulsive factors

e. Adhesion molecules

Type: multiple choice question

Title: Chapter 27 Question 30

30. DCC is a receptor for

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Describe the different classes of molecules that mediate growth cone navigation.

Bloom’s Level: 1. Remembering

a. semaphoring.

b. NCAM.

c. netrin-1.

d. ephrin.

e. slit.

Type: multiple choice question

Title: Chapter 27 Question 31

31. Slit stimulates the protein synthesis of

Feedback: Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Discuss the role of local protein synthesis in the rapid turning decisions made by growth cones during navigation.

Bloom’s Level: 3. Applying

a. tubulin.

b. cofilin.

c. actin.

d. robo.

e. protein kinase C.

Type: multiple choice question

Title: Chapter 27 Question 32

32. Neurotrophic factors counteract

Feedback: Subhead: Growth Factors and Survival of Neurons

Learning Objective: Discuss the roles of apoptosis and synaptic reorganization in refining the pattern of innervation after axons reach their targets.

Bloom’s Level: 1. Remembering

a. endocytosis.

b. phagocytosis.

c. necrosis.

d. apoptosis.

e. acidosis.

Type: multiple choice question

Title: Chapter 27 Question 33

33. Which function is not known to be controlled by NGF?

Feedback: Subhead: Growth Factors and Survival of Neurons

Learning Objective: Summarize the experimental evidence that proved that nerve growth factor (NGF) is responsible for the survival of sympathetic neurons.

Bloom’s Level: 3. Applying

a. Axonal growth of DRG sensory neurons

b. Axonal growth of sympathetic neurons

c. Survival of sympathetic neurons

d. Local protein synthesis

e. Survival of hippocampal neurons

Type: multiple choice question

Title: Chapter 27 Question 34

34. Rita Levi-Montalcini and Stanley Cohen used _______ as source for purification of NGF.

Feedback: Subhead: Growth Factors and Survival of Neurons

Learning Objective: Summarize the experimental evidence that proved that nerve growth factor (NGF) is responsible for the survival of sympathetic neurons.

Bloom’s Level: 1. Remembering

a. chick embryonic brains

b. mouse salivary glands

c. chick embryonic eyes

d. pig brains

e. rat adrenal medulla

Type: multiple choice question

Title: Chapter 27 Question 35

35. Which experiment reduced the number of dying motoneurons in developing chick embryos?

Feedback: Subhead: Growth Factors and Survival of Neurons

Learning Objective: Describe the paradigm of NGF as a target-derived neurotrophic factor.

Bloom’s Level: 1. Remembering

a. Implanting an extra limb from another embryo

b. Removing a limb

c. Implanting a tail from another embryo

d. Implanting a head from another embryo

e. Removing the tail

Type: multiple choice question

Title: Chapter 27 Question 36

36. Brain derived growth factor (BDNF) binds this high-affinity receptor.

Feedback: Subhead: Growth Factors and Survival of Neurons

Learning Objective: Describe the paradigm of NGF as a target-derived neurotrophic factor.

Bloom’s Level: 1. Remembering

a. TrkA

b. TrkB

c. TrkC

d. TrkD

e. None of the above

Type: multiple choice question

Title: Chapter 27 Question 37

37. Temporal retina axons

Feedback: Subhead: Formation of Connections

Learning Objective: Outline the steps in synapse formation, using the vertebrate skeletal neuromuscular junction as an example.

Bloom’s Level: 2. Understanding

a. prefer posterior tectal membranes because they are attracted to them.

b. prefer anterior tectal membranes because they are attracted to them.

c. prefer anterior tectal membranes because they are repelled by posterior membranes.

d. prefer posterior tectal membranes because they are repelled by anterior membranes.

e. do not have a preference of anterior vs posterior tectal membranes.

Type: multiple choice question

Title: Chapter 27 Question 38

38. Which protein causes acetylcholine receptor clustering?

Feedback: Subhead: Formation of Connections

Learning Objective: Outline the steps in synapse formation, using the vertebrate skeletal neuromuscular junction as an example

Bloom’s Level: 1. Remembering

a. NCAM

b. NGF

c. Wnt

d. Noggin

e. Agrin

Type: multiple choice question

Title: Chapter 27 Question 39

39. Mutations in neurexins have been implicated in

Feedback: Subhead: Formation of Connections

Learning Objective: Compare and contrast neuroligins and neurexins.

Bloom’s Level: 3. Applying

a. autism.

b. myasthenia gravis.

c. spina bifida.

d. multiple sclerosis.

e. peripheral neuropathy.

Type: multiple choice question

Title: Chapter 27 Question 40

40. Which property affects elimination of synapse after the initial formation?

Feedback: Subhead: Formation of Connections

Learning Objective: Define pruning and identify two things it accomplishes.

Bloom’s Level: 3. Applying

a. Temperature

b. Nutrition

c. Neuronal activity

d. Level of myelination

e. Size of the synapse

Type: multiple choice question

Title: Chapter 27 Question 41

41. The human brain has an increased size and complexity compared to other mammals mainly because of

Feedback: Subhead: What Makes Us Human: The Development of the Human Brain

Learning Objective: Name two mechanisms of cortical neurogenesis that may be linked to the increased size and complexity of the human brain.

Bloom’s Level: 2. Understanding

a. human cells are larger than cells from other mammals.

b. human neurons have a lower rate of cell death.

c. neurogenesis still occurs postnatally.

d. the ratio of neurons to glia cells is different in humans.

e. human neurons make more synapses in average compared to other mammals.

Type: multiple choice question

Title: Chapter 27 Question 42

42. This human-specific gene can induce the formation of additional neural progenitor cells and thereby a thicker cortex.

Feedback: Subhead: What Makes Us Human: The Development of the Human Brain

Learning Objective: Name two mechanisms of cortical neurogenesis that may be linked to the increased size and complexity of the human brain.

Bloom’s Level: 1. Remembering

a. ARHGAP11B

b. GAP43

c. Sox3

d. Shh

e. CREB

Type: multiple choice question

Title: Chapter 27 Question 43

43. Human brain organoids are developed from

Feedback: Subhead: What Makes Us Human: The Development of the Human Brain

Learning Objective: Explain what 3D brain organoids are and why they are such powerful research tools

Bloom’s Level: 1. Remembering

a. differentiated neurons.

b. glial cells.

c. adult human brain tissue.

d. embryonic human brain tissue.

e. induced pluripotent stem cells.

Type: essay/short answer question

Title: Chapter 27 Question 44

44. Explain why zebrafish has become a popular model system to study nervous system development.

Feedback: Zebrafish has many benefits as a model system to study general development but also nervous system development. Zebrafish are vertebrates with high fecundity that can be maintained at relatively low cost. A single breeding can result in 100-200 embryos that are clear and develop outside the mother. This allows easy access for imaging of fluorescent proteins. There are established methods for making transgenic and knock-out lines.

Subhead: Development: General Considerations

Learning Objective: Explain what cell fate mapping is.

Bloom’s Level: 3. Applying

Type: essay/short answer question

Title: Chapter 27 Question 45

45. Design an experiment that provides evidence that BMP4 is maintaining the ectoderm state during gastrulation.

Feedback: By expressing a truncated version of the BMP4 receptor in Xenopus embryos, you can show that ectoderm cells change their fate into neural fate when BMP4 signaling is blocked by the truncated receptor. This provides evidence that BMP4 is maintaining the ectoderm state during gastrulation.

Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Identify the embryonic period when a specific region of the ectoderm becomes fated to generate neural tissue.

Bloom’s Level: 3. Applying

Type: multiple choice question

Title: Chapter 27 Question 46

46. During neural tube formation, the neural tube ultimately separates from the ectoderm. Provide a molecular mechanism that explains how this separation occurs.

Feedback: Neural tube cells switch expression of cell adhesion molecules from E-cadherin to N-cadherin. As a result, the neural tube cells do not adhere anymore to the ectoderm cells.

Subhead: Early Morphogenesis of the Nervous System

Learning Objective: Describe, in general terms, how the neural plate folds to become a closed neural tube.

Bloom’s Level: 2. Understanding

Type: multiple choice question

Title: Chapter 27 Question 47

47. Hoxb-1 has been implicated in the formation of rhombomere R4 during vertebrate hindbrain development. How would you design an experiment to test this hypothesis? What could be a potential problem with the approach?

Feedback: Create a Hoxb-1 knockout mouse by homologous recombination and assess developing homozygote mice whether R4 rhombomere has been formed without the Hoxb-1 gene. A problem could be that mice are not viable when lacking Hoxb-1 completely. In that case, one could focus the analysis on heterozygotes.

Subhead: Patterning along the Anteroposterior and Dorsoventral Axes

Learning Objective: Discuss the role of Hox genes in anteroposterior patterning and segmentation in the hindbrain.

Bloom’s Level: 5. Evaluating

Type: multiple choice question

Title: Chapter 27 Question 48

48. Radial glial cells give rise to neurons during brain development. Please provide some experimental evidence for this fact.

Feedback: Goetz and colleagues have provided experimental evidence with isolated radial glial cells. These cells were taken from a transgenic mouse expressing green fluorescent protein (GFP) under the control of the glial fibrillary acidic promoter. Freshly isolated cells (from E14 cortex) showed radial glial phenotype, surprisingly, after 7 days in culture almost 70% of the sorted cells were neurons. Later, Kriegstein and colleagues provided in vivo evidence by intraventricular injections of a retrovirus encoding GFP to label proliferating precursor cells in the E15 mouse cortex. Time-lapse imaging showed that labeled radial glia cells generated neurons that migrated along radial glial fibers outward.

Subhead: Development of Cerebral Cortex

Learning Objective: Discuss the evidence showing that radial glial cells constitute the major neural stem cell pool in the developing brain.

Bloom’s Level: 3. Applying

Type: multiple choice question

Title: Chapter 27 Question 49

49. Explain how retrospective birth-dating provided evidence of adult neurogenesis in the human brain.

Feedback: During the time of nuclear weapon tests of 1955–1963, the amount of 14C increased sharply in the environment and was taken up by human bodies through the food chain. A comparison of the amount of 14C in the atmosphere over the years with the amount of 14C in the DNA of hippocampal neurons of people of different ages indicates that neuronal proliferation also occurs in specific regions adult human brains.

Subhead: Development of Cerebral Cortex

Learning Objective: Explain how retrospective birth-dating provided evidence of adult neurogenesis in the human brain

Bloom’s Level: 5. Evaluating

Type: essay/short answer question

Title: Chapter 27 Question 50

50. What is the experimental evidence provided from studies in the rat retina that neurogenesis happens before gliogenesis?

Feedback: Cepko and colleagues used a retrovirus encoding beta-galactosidase. They injected the virus behind the retina early in developing rat embryos and the assessed the retina of adult rats by staining. The found that when labeling was done early in development, different cell types were labeled including neurons and glial cells; however, when labeling occurred later in development, the labeled cells were restricted to cells developing later such as Muller cells.

Subhead: Neurogenesis versus Gliogenesis

Learning Objective: Describe how cell-lineage studies in the rat retina provided evidence that neurogenesis consistently precedes gliogenesis.

Bloom’s Level: 4. Analyzing

Type: essay/short answer question

Title: Chapter 27 Question 51

51. Explain how it was demonstrated experimentally that neural crest cells assume a cell fate that is determined by the environment.

Feedback: Nicole Le Douarin transplanted premigratory neural crest cells from quail into chick embryos. When the transplanted cells were placed into a different region of the host, the transplanted cells assumed the fate of host neural crest cells normally found in that region. For example, cells in segment 12 are to become a sympathetic ganglion cell. When transplanted to a region of segments 18–24, however, cells from segment 12 became chromaffin cells.

Subhead: Determination of Neuronal Phenotype

Learning Objective: Explain how transplantation experiments demonstrated that the fate of neural crest cells is determined largely by local environmental signals.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 27 Question 52

52. Some cells in the developing nervous system are called “guidepost cells”. Explain their function.

Feedback: Guidepost cells act as landmarks for developing axons where the axons typically make abrupt and specific turns. They have been initially identified in developing grasshoppers.

Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Explain what guidepost cells are and how they function.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 27 Question 53

53. Do all axonal guidance cues use protein synthesis as a mechanism to control axon guidance?

Feedback: No, not all guidance cues regulate axonal guidance via controlling protein synthesis. Furthermore, this mechanism does not occur in all cells.

Subhead: Axon Outgrowth and Growth Cone Navigation

Learning Objective: Discuss the role of local protein synthesis in the rapid turning decisions made by growth cones during navigation

Bloom’s Level: 5. Evaluating

Type: essay/short answer question

Title: Chapter 27 Question 54

54. Nerve growth factor (NGF) promotes the survival of sympathetic neurons. Can you describe three experiments that provide evidence for this function of NGF?

Feedback:

a. Injection of antibodies against NGF into newborn mice results in loss of the sympathetic neurons.

b. Adding purified NGF to cultured sympathetic neurons is required for their survival.

c. Knockout mice that lack NGF do not develop a functional sympathetic nervous system.

Subhead: Growth Factors and Survival of Neurons

Learning Objective: Summarize the experimental evidence that proved that nerve growth factor (NGF) is responsible for the survival of sympathetic neurons

Bloom’s Level: 6. Analyzing

Type: essay/short answer question

Title: Chapter 27 Question 55

55. Describe an experiment that demonstrated that NGF can be taken up by neurite terminals of sympathetic neurons and retrogradely transported to the cell body.

Feedback: Sympathetic neurons were cultured in the center compartment of the Campenot chamber system. NGF needs to be added to the cell bodies in the center compartment to ensure initial neuronal survival; however, once neurites reach the side compartment, NGF does not need to be added to the central compartment anymore. NGF addition to the neurites in the side compartment is sufficient to maintain neurite growth and survival of the neurons. This experiment provides evidence that NGF can be taken up by neurite endings and retrogradely transported to the cell body.

Subhead: Growth Factors and Survival of Neurons

Learning Objective: Describe the paradigm of NGF as a target-derived neurotrophic factor

Bloom’s Level: 3. Applying

Type: essay/short answer question

Title: Chapter 27 Question 56

56. How can the human brain establish such a complex connectivity with a limited set of proteins?

Feedback: Axons find their targets in a step-wise fashion. Each step is determined by a few guidance factors. Initially, axons are extending together as bundles before they split up into different target areas. Furthermore, regulated expression of receptors and co-receptors can create diversity with a limited set of proteins.

Subhead: Formation of Connections

Learning Objective: Outline the steps in synapse formation, using the vertebrate skeletal neuromuscular junction as an example

Bloom’s Level: 6. Creating

Type: essay/short answer question

Title: Chapter 27 Question 57

57. Explain the function of pruning.

Feedback: Pruning is removal of unneeded synapses and ensures complete target innervation as well as allows for correction of mistakes in synapse formation.

Subhead: Formation of Connections

Learning Objective: Define pruning and identify two things it accomplishes

Bloom’s Level: 4. Analyzing

Type: essay/short answer question

Title: Chapter 27 Question 58

58. Human brain organoids have become a useful model system to study human brain development and disorders. However, there are some limitations in this system to faithfully recapitulate human brain development. Please explain.

Feedback: Whereas human brain organoids have some similarities to normal human brains, including layer formation, cell migration and morphology, and neuronal activity, brain organoids also show differences in the regional organization of the brain. They clearly do not have the same structures as normal human brains.

Subhead: What Makes Us Human: The Development of the Human Brain

Learning Objective: Explain what 3D brain organoids are and why they are such powerful research tools

Bloom’s Level: 4. Analyzing