Embryo Development

Question 1

What is the term for neural tube formation?

Answer 1

Neuroulation

Question 2

What type of cells eventually develop into dorsal root and autonomic NS ganglion cells, adrenal medulla, schwann cells, and satellite cells?

Answer 2

neural crest cells

Question 3

The ______ develops into the tissue of the CNS.

Answer 3

neural tube

Question 4

The _____ develops into the ventricular system.

Answer 4

neurocoele

Question 5

The rostral opening of the neural tube, the rostral _______ closes completely in the middle of the 4th week.

Answer 5

neuropore

Question 6

The caudal ______ closes about 2 days after the rostral.

Answer 6

neuropore

Question 7

By the end of three weeks, 2 folks meet to form the neural ______ and a center opening called the _____.

Answer 7

neural tube

neurocoele

Question 8

At the 3rd week of development, the neural plate forms from a dorsal thickening of _______.

Answer 8

ectoderm

Question 9

A fatal deformity caused by complete failure of neural tubes to close is called:

Answer 9

anencephaly

Question 10

With anencephaly, important portions of the _____ do not develop.

Answer 10

Cb

Question 11

The CNS appears as an open furrow on dorsal surface of head and body with ____.

Answer 11

anencephaly

Question 12

A severe form of spina bifida is known as:

Answer 12

meningomyelocele

Question 13

_____ is caused by failure of caudal neuropore to close.

Answer 13

spina bifida

Question 14

Type I arnold-chiari malformation:

Answer 14

asymptomatic

Question 15

Spina bifida is frequently accompanied by ____ malformation.

Answer 15

arnold-chiari

Question 16

Type II arnold-chiari malformation:

Answer 16

accompanies meningomyelocele and often occurs with hydrocephalus

Question 17

Type III arnold-chiari malformation:

Answer 17

associated with severe neurological defect including encaphalocele

Question 18

Type IV arnold-chiari malformation:

Answer 18

agenesis of Cb

Question 19

With Arnold-chiari malformation, what structures are often elongated and pushed down into the foramen magnum?

Answer 19

Cb (tonsils)

and caudal brainstem

Question 20

What are the symptoms associated with arnold-chiari malformation?

Answer 20

headache
fatigue
weakness of facial muscles
dysphagia
dizziness
nausea
impaired coordination
in severe cases: paralysis

Question 21

Meningomyelocele is frequently accompanied by:

Answer 21

hydrocephalus

Question 22

Describe spina bifida occulta:

Answer 22

simple defect in closure of vertebrae

area of defect often indicated by tuft of excessive hair

Question 23

Define meninfocele:

Answer 23

herniation of meningeal membranes
appears as a cystic tumor
no CNS involvement

Question 24

With spina bifida, the nerve roots and SC along with menigneal coverings are ____.

Answer 24

herniated

Question 25

How many primary vesicles form as expansions of the neural tube during the 4th week?

Answer 25

3

Question 26

The primary vesicles that form during the 4th week are:

Answer 26

1. prosencephalon 2. mesencephalon 3. rhomencephalon

Question 27

The prosescephalon subdivides into:

Answer 27

telencephalon: forms cortex and basal forebrain diencephalon: forms thalamus and hypothalamus

Question 28

The mesencephalon remains as a primary vesicle and forms the:

Answer 28

midbrain

Question 29

The Rhombencephalon subdivides into the:

Answer 29

metencephalon: forms pons and Cb myelencephalon: forms medulla

Question 30

The cerebral vesicles are portions of the developing CNS related to:

Answer 30

brainstem and cerebrum

Question 31

The ventricular system develops from the:

Answer 31

neuralcoele

Question 32

The two primary vesicles subdivide to form a total of __ secondary vesicles.

Answer 32

5

Question 33

What is the most common developmental cause of hydrocephalus?

Answer 33

blockage of the cerebral aqueduct

Question 34

What level are the 2 lateral ventricles formed?

Answer 34

telencephalon

Question 35

What level is the 3rd ventricle formed?

Answer 35

diencephalon

Question 36

What level is the 4th ventricle formed?

Answer 36

rostral medulla/pons

Question 37

What level is the central canal formed?

Answer 37

SC/caudal medulla

Question 38

What level is the cerebral aqueduct formed?

Answer 38

midbrain

Question 39

During the 4th week, the ____ forms a groove in the inner wall of the neural tube.

Answer 39

sulcus limitans

Question 40

The sulcus limitans divides the tube into an ___ plate and a ___ plate.

Answer 40

alar (dorsal) | basal (ventral)

Question 41

In the SC, the ____ plate is the dorsal horn for sensory fxn.

Answer 41

alar

Question 42

In the SC, the ____ plate is the ventral horn for motor fxn.

Answer 42

basal

Question 43

Development of the 4th ventricle in the brainstem causes the alar plate to shift laterally to form the _____.

Answer 43

sensory nuclei

Question 44

Development of the 4th ventricle in the brainstem causes the _____ nuclei associated with the basal plate to line up most medially with nuclei of mixed nerves in between.

Answer 44

purely motor

Question 45

What structure undergoes the most dramatic development?

Answer 45

telencephalon (cortex)

Question 46

The basal part of the telencephalon, adjacent to the diencephalon develop into the ____.

Answer 46

basal ganglia

Question 47

The part of the cortex that overgrows the diencephalon is called the:

Answer 47

insula

Question 48

The pattern of growth of the telencephalon structures accounts for its "__"-shaped appearance.

Answer 48

"C" shape

Question 49

The cells of the neuroepithelium surround the ____ and cause cell proliferation when they undergo mitosis.

Answer 49

neurocoele

Question 50

The area that undergoes mitosis is known as the:

Answer 50

germinal zone

Question 51

What are the two types of stem cells that can be identified after early mitosis and what do they become?

Answer 51

nueroblasts: become nerve cells glioblasts: become glial cells

Question 52

At some point in the development, neuroblasts become _____ (they can no longer undergo mitosis).

Answer 52

postmitotic

Question 53

What is the pattern of migration?

Answer 53

central (neurocoele) to superficial

Question 54

Neurons migrate to the cortex along a path set by _____ cells, which act like scaffolding for the neurons to climb.

Answer 54

radial glial

Question 55

The ___ cells orient perpendicularly to the surface of the brain so the pattern of migration is away from the seminal center like spokes extending from the hub of a wheel.

Answer 55

radial glial

Question 56

Neurons of the Cb don't complete migration until:

Answer 56

4 months post-natal

Question 57

PNS is myelinated by schwann cells that develop from:

Answer 57

neural crest cells

Question 58

When does PNS and CNS myelination begin?

Answer 58

4th month of fetal life

Question 59

When does myelination process complete?

Answer 59

early adulthood

Question 60

CNS myelination of fibers coincides with the time:

Answer 60

they start to function

Question 61

Some motor tracts and cortical fibers myelinate by:

Answer 61

1 year

Question 62

Muscles, bone and dermis develop from:

Answer 62

mesoderm

Question 63

By the 20th day, ____ form from the mesoderm.

Answer 63

somites

Question 64

The first somite appears in the ____ region.

Answer 64

cervical

Question 65

Somite development proceeds in which orientation?

Answer 65

caudally

Question 66

By the end of the 5th week, there are ___ pairs of somites.

Answer 66

42-44

Question 67

Name the number of pairs of somites by region:

Answer 67

``` 4 occipital 8 cervical 12 thoracic 5 lumbar 5 sacral 8-10 coccygeal ```

Question 68

By the beginning of the 4th week, the cells of the somite most ventral and medial migrate to surround the ____.

Answer 68

notocord

Question 69

The cells surrounding the notochord that will develop into vertebrae are called the _____.

Answer 69

sclerotome

Question 70

The somites that do not form the slerotome form the:

Answer 70

myotome | dermatome

Question 71

From each somite develops:

Answer 71

1. bone (from sclerotome) 2. muscle (from myotome) 3. part of dermis (from dermatome)

Question 72

When do limb muscles begin to develop near the base of the limb bud?

Answer 72

7th week

Question 73

Initally, the migration of myotome and dematome forms the limb bud in a ____ fashion.

Answer 73

segmental

Question 74

As limb bud lengthens, myotomes and dermatomes loose their segmentation and fuse so that individual muscles of the limb are derived from more than one ____.

Answer 74

somite | explains how muscles are enervated by more than one SC level

Question 75

What accoutns for the mature dermatomal pattern?

Answer 75

1. each dermatome associated with specific spinal nerve | 2. dermatomes that migrate to the limb bud eventually loose connection with axial portion as the limb bud lengthens