Development of the Nervous System

Question 1

notochord induces thickening in the overlying ectoderm, forming the _____

Answer 1

neural plate

Question 2

neural folds approach midline and fuse, forming ____ (forms dorsal to the notochord, along midsagittal axis)

Answer 2

neural tube

Question 3

neural tube starts to close at about the ____ level, and progresses cranially and caudally

Answer 3

5th somite

Question 4

cranial neuropore closes about day ___

Answer 4

25

Question 5

caudal neuropore closes about day ___

Answer 5

27

Question 6

_____ is a derivative of the neural crest cells

Answer 6

dorsal root ganglion

Question 7

embryonic ectoderm will form the ____

Answer 7

epidermis

Question 8

the neural tube (neuroectoderm) will form the _____

Answer 8

brain and spinal cord (CNS)

Question 9

the neural canal (neural groove) will from the _____ and _____

Answer 9

ventricles of the brain; central canal of spinal cord

Question 10

the neural crest will form:

Answer 10

• dorsal root/autonomic/CN ganglia
• bones of face (viscerocranium)
• melanocytes
• schwann cells
• leptomeninges (arachnoid and pia mater)
• adrenal medulla cells

Question 11

the caudal end of the neural tube will form the ____ and the cranial end of the neural tube will form the ____

Answer 11

spinal cord; brain

Question 12

the cells of the neural tube are _____

Answer 12

pseudostratified columnar neuroepithelium

Question 13

the three membranes that envelop the brain and spinal cord

Answer 13

the meninges

Question 14

dura mater embryonic origin

Answer 14

mesenchyme surrounding the neural tube

Question 15

arachnoid mater embryonic origin

Answer 15

neural crest

Question 16

pia mater embryonic origin

Answer 16

neural crest

Question 17

arachnoid mater and pia mater are often called _____ because of their similar embryonic origin

Answer 17

leptomeninges

Question 18

zones from luminal surface of the neural tube to the spinal meninges

Answer 18

ventricular zone or neuroepithelial zone –> intermediate zone or mantle zone –> marginal zone

Question 19

the ____ is where you ahve true neuroblasts and true neurons developing, and will eventually become the gray matter of the spinal cord

Answer 19

intermediate or mantle zone

Question 20

where glial cells are forming; will eventually become the white matter of the brain

Answer 20

marginal zone

Question 21

on the dorsal aspect of the developing spinal cord, ____ develop within the mantle/intermediate layer

Answer 21

alar

Question 22

the neurons within the mantle/intermediate layer have _____ function

Answer 22

afferent (sensory)

Question 23

on ventral aspect of developing spinal cord, ____develop within the mantle/intermediate layer

Answer 23

basal

Question 24

the neurons within the basal plates have ____ function

Answer 24

efferent (motor)

Question 25

the alar plates develop into the ____

Answer 25

dorsal sensory horn

Question 26

the basal plates develop into the _____

Answer 26

ventral motor horn

Question 27

motor nerve fibers collect into _____

Answer 27

ventral nerve roots

Question 28

_____ (sensory) originate outside the spinal cord (in the dorsal root ganglion) derived from _____

Answer 28

dorsal nerve roots; neural crest cells

Question 29

dorsal nerve root processes grow into _____

Answer 29

dorsal horns of the spinal cord

Question 30

distal processes of dorsal roots join ventral nerve roots to form a ____

Answer 30

spinal nerve

Question 31

dorsal root fibers of a spinal nerve are ____

Answer 31

sensory

Question 32

ventral root fibers of a spinal nerve are ____

Answer 32

motor

Question 33

a spinal nerve contains both ____ and ____ fibers

Answer 33

sensory; motor

Question 34

where would you perform a spinal tap or epidural?

Answer 34

L3

Question 35

originally, embryonic spinal cord is the length of the _____, and spinal nerves exit vertebral column at their correct level of origin

Answer 35

vertebral canal

Question 36

the ____ will lengthen faster than ____ so that in the adult, the spinal cord ends _____ vertebrae (______)

Answer 36

vertebral column; spinal cord; between L1 and L2; (conus medullaris)

Question 37

brain development has same basic organization as spinal cord: distinct ____ and ____ plates

Answer 37

alar; basal

Question 38

higher center in brain means there is accentuation of ____ and regression of _____

Answer 38

alar plates; basal plates

Question 39

the brain develops from 3 primary vesicles:

Answer 39

1. forebrain (prosencephalon) 2. midbrain (mesencephalon) 3. hindbrain (rhombencephalon

Question 40

from 3 primary vesicles, the brain differentiates into ___ secondary vesicles

Answer 40

5

Question 41

the forebrain differentiates into:

Answer 41

telecephalon and diencephalon

Question 42

the midbrain differentiates into:

Answer 42

mesencephalon

Question 43

the hindbrain differentiates into:

Answer 43

metencephalon and myelencephalon

Question 44

adult derivatives of the telencephalon

Answer 44

walls- cerebral hemispheres | cavities- lateral ventricles

Question 45

adult derivatives of the diencephalon

Answer 45

walls- thalami, etc. | cavities- third ventricle

Question 46

adult derivatives of the midbrain

Answer 46

walls- midbrain | cavities- aqueduct

Question 47

adult derivatives of the hindbrain

Answer 47

walls- medulla | cavities- lower part of fourth ventricle

Question 48

in the myelencephalon, shift of medulla walls changes position of plates so that ____ will become medial to _____

Answer 48

basal plates (motor); alar plates (sensory)

Question 49

in the myelencephalon, cells in ____cluster to form 3 bilateral cell columns with _____ nuclei

Answer 49

alar plate; afferent (sensory)

Question 50

in the myelencephalon, cell bodies in the ____ cluster to form 3 bilateral cell columns with _____ nuclei

Answer 50

basal plate; efferent (motor)

Question 51

in the mesencephalon, the basal plate contains two groups of ____; the marginal layer of basal plate enlarges to form _____

Answer 51

motor nuclei; crus cerebri

Question 52

in the mesencephalon, the alar plate (sensory) is initially two ______

Answer 52

longitudinal elevations

Question 53

in the mesencephalon, the alar plate divides into ___ and _____

Answer 53

superior; inferior colliculi

Question 54

in the diencephalon, there are 3 pairs of swellings in the ____ wall of the ____

Answer 54

lateral; third ventricle

Question 55

the caudal part of the roofplate becomes the _____

Answer 55

epithalamus

Question 56

in the diencephalon, the alar plates form:

Answer 56

thalamus and hypothalamus

Question 57

the telencephalon forms the two _____

Answer 57

cerebral hemispheres

Question 58

in the telencephalon, the neural canal forms the two ____

Answer 58

lateral ventricles

Question 59

the telencephalon surface grows rapidly to form the lobes as well as _____ (elevations) separated by ____ (deep grooves) and _____(shallow grooves)

Answer 59

gyri; fissues; sulci

Question 60

embryonic origin of sympathetic NS

Answer 60

all ganglia as well as the sympathetic trunk originate from neural crest cells

Question 61

embryonic origin of parasympathetic NS

Answer 61

postganglionic neurons derived from neural crest cells

Question 62

myelinated axons in the PNS have series of ____ lined up along the axon, each having a wrapped coating of myelin insulating axon

Answer 62

Schwann cells

Question 63

unmyelinated axons in the PNS are encased by _____; there is no wrapped coating of myelin surrounding axon

Answer 63

schwann cell cytoplasm

Question 64

myelination in the PNS involves ____ (derived from neural crest cell

Answer 64

schwann cells

Question 65

one schwann cell per one _____ of one axon

Answer 65

internodal segment

Question 66

myelination in the CNS involves ____ derived from _____ of the spinal cord

Answer 66

oligodendrocytes; neuroepithelial cells

Question 67

one oligodendrocyte can myelinate up to ____

Answer 67

50 axons