Question 1

________ Gives rise to the pars nervosa
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The infundibulum gives rise to the neurohypophysis.The infundibulum appears as a diverticulum of the floor of the diencephalon.Later,nerve fibers from the hypothalamus grow into the developing pars nervosa of the pituitary gland.

Question 2

________ Third ventricle
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The third ventricle is formed mainly from the cavity of the diencephalon.The anterior part of the third ventricle is derived from the cavity of the telencephalon.

Question 3

________ Efferent function
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

Neuroepithelial cells in the basal plates of the developing neural tube give rise to neurons (e.g. ,the motor neurons in the ventral horns of the spinal cord)that are concerned with efferent activities.

Question 4

________ Pons
A)Telencephalon
B)Diencephalon
C)Mesencephalon
D)Metencephalon
E)Myelencephalon

Accepted Answer

The pons is derived from the metencephalon.Nerve fibers that connect the cerebral and cerebellar cortices with the spinal cord pass through the marginal layer of the ventral region of the metencephalon.These fibers form a robust band of nerve fibers crossing to the other side.This accounts for the name pons,a Latin word meaning "a bridge." The walls of the metencephalon form the pons and cerebellum,and its cavity forms the superior part of the fourth ventricle.

Question 5

________ Unipolar afferent neurons
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

The unipolar spinal (dorsal root)ganglion cells arise by differentiation of neural crest cells,but they are not unipolar neurons.First bipolar neuroblasts form and then their processes unite to form unipolar neurons.The central process of this T-shaped axon grows into the spinal cord to form part of a dorsal root;the peripheral process forms part of the dorsal root,which joins the ventral root to form a mixed spinal nerve.

Question 6

________ Infundibulum
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The infundibulum gives rise to the neurohypophysis or pars nervosa of the pituitary gland.As the posterior pituitary develops,the neuroepithelial cells in the wall of the infundibulum proliferate and differentiate into pituicytes.

Question 7

________ Form ventral gray columns
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

The basal plates of the neural tube give rise to the ventral and lateral gray columns of nerve cells in the spinal cord.Axons of the ventral horn cells grow out of the spinal cord and form the ventral roots of spinal nerves.

Question 8

________ Hypothalamus
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The hypothalamus arises by proliferation of neuroblasts in the ventral wall of the diencephalon.The various nuclei that develop in it are concerned with endocrine activities and homeostasis.

Question 9

________ Internal capsule
A)A
B)B
C)C
D)D
E)E

Accepted Answer

As the cerebral cortex differentiates,fibers passing to and from it pass through the corpus striatum;this fiber pathway is the internal capsule.Projection fibers concentrated in the internal capsule fan out to form the corona radiata in the medullary center.Because of its adaptation to the contours of the masses of gray substance (matter)in the brain,the internal capsule develops an anterior limb,a genu,and a posterior limb,as seen on horizontal section.

Question 10

________ Olivary nuclei
A)Telencephalon
B)Diencephalon
C)Mesencephalon
D)Metencephalon
E)Myelencephalon

Accepted Answer

The olivary nuclei in the rostral part of the myelencephalon (open part of the medulla)are derived from neuroblasts that migrate from the alar plates.

Question 11

________ Produces cerebrospinal fluid (CSF)
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The choroid plexuses of the lateral,third,and fourth ventricles produce most of the CSF.The plexuses in the lateral ventricles are the largest and most important producers of CSF.Some CSF is formed by the pia mater on the external surface of the brain.

Question 12

________ Roof of primordial mouth cavity
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The epithelial roof of the primordial mouth cavity (stomodeum)is derived from ectoderm.As the head folds and the pharyngeal arches form during the fourth week,the surface ectoderm becomes depressed to form the primordial mouth cavity in the center of the facial primordia.The hypophysial pouch develops as a dorsal diverticulum of the oral ectoderm.

Question 13

________ Primordium of adenohypophysis
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The primordium of the adenohypophysis is the hypophysial (Rathke)pouch,a diverticulum from the ectodermal roof of the primordial mouth cavity.This diverticulum soon contacts the infundibulum,the primordium of the neurohypophysis.

Question 14

________ Neuroglia
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

Some neuroepithelial cells of the neural tube differentiate into glioblasts (spongioblasts).These cells give rise to oligodendroblasts and astroblasts,which eventually become oligodendrocytes and astrocytes.Oligodendrocytes are concerned with the formation of myelin sheaths within the central nervous system,and astrocytes provide nutrition and general support to the developing neurons.The formation of glial cells continues into adult life.

Question 15

________ Lentiform nucleus
A)A
B)B
C)C
D)D
E)E

Accepted Answer

As the cerebral cortex differentiates,nerve fibers passing to and from it pass through the swelling-corpus striatum-in the floor of each hemisphere.Soon these fibers divide the corpus striatum into two groups of nerve cells,the caudate and lentiform nuclei.

Question 16

________ Gracile nuclei
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

The gracile and cuneate nuclei develop from neuroblasts that migrate from the alar plates into the marginal zone of the myelencephalon.These nuclei are associated with correspondingly named tracts that enter the medulla from the spinal cord.

Question 17

________ Floor of the diencephalon
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The floor of the diencephalon gives rise to the infundibulum (the primordium of the neurohypophysis)and the mammillary bodies.The infundibulum gives rise to the median eminence,the infundibular stem,and the pars nervosa.The infundibulum initially has a thin wall,but its distal end soon becomes thickened as the neuroepithelial cells proliferate.These cells later differentiate into pituicytes.

Question 18

________ Primordium of the cerebral hemisphere
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The lateral diverticulum of the telencephalon gives rise to the right cerebral hemisphere.As it expands,it covers the diencephalon,midbrain,and hindbrain.It eventually meets the other hemisphere in the midline,flattening their medial surfaces.

Question 19

________ Sympathetic ganglion cells
A)Neural crest cells
B)Alar plates
C)Basal plates
D)Neuroepithelium
E)Spinal ganglion cells

Accepted Answer

Sympathetic ganglion cells are derived from neuroblasts that differentiate from neural crest cells.Some sympathetic neuroblasts migrate to the suprarenal glands where they differentiate into chromaffin cells of the suprarenal medulla.

Question 20

________ Invagination of pia mater
A)A
B)B
C)C
D)D
E)E

Accepted Answer

The choroid plexus of the lateral ventricle is formed by an invagination of vascular pia mater-tela choroidea-on the medial side of each cerebral hemisphere.The vascular connective tissue acquires a covering layer of epithelium from the ependymal lining of the ventricle.

Quiz 15: Nervous System

________ Gives rise to the pars nervosa

________ Third ventricle

________ Efferent function

________ Pons

________ Unipolar afferent neurons

________ Infundibulum

________ Form ventral gray columns

________ Hypothalamus

________ Internal capsule

________ Olivary nuclei

________ Produces cerebrospinal fluid (CSF)

________ Roof of primordial mouth cavity

________ Primordium of adenohypophysis

________ Neuroglia

________ Lentiform nucleus

________ Gracile nuclei

________ Floor of the diencephalon

________ Primordium of the cerebral hemisphere

________ Sympathetic ganglion cells

________ Invagination of pia mater