Question 1

Which of the following functions as a local organizer to induce the development of the tectum and cerebellum in rostral and caudal postions, respectively?&#10;A) Zona limitans intrathalamica&#10;B) Midbrain-hindbrain boundary&#10;C) Anterior neural ridge&#10;D) Telencephalon

Accepted Answer

The Midbrain-hindbrain boundary (MHB) functions as a local organizer that induces the development of the tectum and cerebellum in rostral and caudal positions, respectively. This region is crucial for patterning the midbrain and anterior hindbrain during development.

Question 2

Which term refers to the segments of hindbrain tissue separated by lineage-restriction boundaries?&#10;A) Rhondomeres&#10;B) Rhabdomeres&#10;C) Rhombomeres&#10;D) Telomeres

Accepted Answer

Rhombomeres are segments of hindbrain tissue separated by lineage-restriction boundaries, playing a crucial role in the development of the vertebrate brain.

Question 3

On the basis of our knowledge of dorso-ventral patterning of the neural tube, how would you treat cultured embryonic stem cells in order to obtain motor neurons for regenerative medicine?&#10;A) Sonic hedgehog + retinoic acid&#10;B) Sonic hedgehog + Bone morphogenetic protein&#10;C) Bone morphogenetic protein&#10;D) Bone morphogenetic protein + retinoic acid

Accepted Answer

Motor neurons are derived from the ventral part of the neural tube, which is patterned by Sonic hedgehog (Shh) signaling. Retinoic acid is also involved in neural differentiation. Therefore, treating embryonic stem cells with Sonic hedgehog and retinoic acid can promote their differentiation into motor neurons.

Question 4

Which of the following is not true of neuroblast formation in the Drosophila embryo?&#10;A) Embryos that lack both Notch and Delta function do not develop neuroblasts&#10;B) Initially, all cells of the proneural cluster have the potential of becoming neuroblasts&#10;C) Cells in which the Notch receptor is activated become epidermal cells&#10;D) Cells that are Delta-expressing cells become neuroblasts

Accepted Answer

In Drosophila embryo development, Notch and Delta play crucial roles in the differentiation of cells into neuroblasts and epidermal cells through lateral inhibition. However, the statement that embryos lacking both Notch and Delta function do not develop neuroblasts is incorrect. In fact, the absence of Notch and Delta leads to a situation where too many cells adopt a neuroblast fate, as the lateral inhibition mechanism that normally restricts the number of cells becoming neuroblasts is disrupted.

Question 5

From which layer do all neurons and glia of the brain and spinal cord in a vertebrate embryo arise?&#10;A) Mantle zone&#10;B) Intermediate zone&#10;C) Ventricular zone&#10;D) Marginal zone

Accepted Answer

The neurons and glia of the brain and spinal cord in a vertebrate embryo arise from the ventricular zone. This layer is rich in neural stem cells that give rise to the central nervous system's components.

Question 6

As new neurons migrate outward to build up concentric layers of neural tissue in the brain and spinal cord, which layer consists of cell bodies and is referred to as gray matter?&#10;A) Ventricular zone&#10;B) Mantle zone&#10;C) Intermediate zone&#10;D) Marginal zone

Accepted Answer

The mantle zone consists of cell bodies and is referred to as gray matter. This layer is crucial in the development of the central nervous system, where it forms the bulk of the brain and spinal cord's regions that are involved in muscle control and sensory perception.

Question 7

As new neurons migrate outward to build up concentric layers of neural tissue in the brain and spinal cord, which layer consists of neuronal axons and is referred to as white matter?&#10;A) Ventricular zone&#10;B) Mantle zone&#10;C) Intermediate zone&#10;D) Marginal zone

Accepted Answer

The marginal zone consists of neuronal axons and is referred to as white matter because it contains myelinated axons that give this area a lighter appearance compared to the gray matter, which is made up of neuron cell bodies and dendrites.

Question 8

Which of the following is not true of targeting motor neurons to specific regions of the developing limb?&#10;A) The transcription factor, Lim1, provides motor neurons with positional identity within the spinal cord&#10;B) Motor neurons are guided by chemorepellents&#10;C) Motor neurons express specific receptors that guide their migration into the limb&#10;D) Inverting the neural tube results in failure of motor neurons to innervate their correct muscles

Accepted Answer

The answer of Which of the following is not true...

Question 9

Which of the following is true of commissural axon guidance in the neural tube?&#10;A) Changes in the Robo3 receptor are important for selectively preventing commissural neuron midline crossing&#10;B) Netrin-1 binds to its receptor, DCC, and is a chemorepellant.&#10;C) Robo1/2 is a receptor that attracts commissural neurons&#10;D) Commissural neurons are allowed to cross the midline multiple times

Accepted Answer

Changes in the Robo3 receptor are crucial for allowing, rather than preventing, commissural neuron midline crossing. Robo3 undergoes a functional switch that enables commissural axons to cross the midline by temporarily ignoring the repulsive guidance cue Slit.

Question 10

Which of the following is not associated with neuromuscular junctions?&#10;A) Acetylcholine receptors&#10;B) Synaptic cleft&#10;C) Synaptic vesicle&#10;D) Dopamine

Accepted Answer

Dopamine is a neurotransmitter associated with the brain's reward system and motor control, not directly involved in the neuromuscular junction. The neuromuscular junction involves acetylcholine as the primary neurotransmitter, not dopamine.

Deck 11: Development of the Nervous System