Development Of The Nervous System

Front 1

At what week does neurulation occur in the fetus?

Back 1

Week 4

Front 2

What type of epithelium surrounds the central canal of the neural tube?

Back 2

neuroepithelium (a pseudostratified epithelium)

Front 3

What occurs in the neuroepithelium?

Back 3

Cell Division (contains cells at different stages in mitosis)

Front 4

Where are cells in the S and M phases of mitosis found (in reference to the central canal)?

Back 4

S phase --> farther from the central
M phase --> closest to the central canal

Front 5

In Neurulation:
chordin, noggin and sonic hedgehog mediate the formation of _______________?

Back 5

neuroectoderm

Front 6

Describe primary neurulation

Back 6

neural tube forms (by folding of the neural plate)

Front 7

Describe secondary neurulation

Back 7

Recanalization of a cord of mesenchyme to form the neural tube

Front 8

After closure of the neural tube the anterior and posterior neuropores close. Which one closes first?

Back 8

anterior (closes 1 day prior to posterior)

Front 9

Where does closure of the neural tube begin?

Back 9

midway along its length (then "zippers" caudally and rostrally)

Front 10

Summarize the 5 major stages in neurulation

Back 10

1. formation of neuroectoderm
2. primary neurulation
3. secondary neurulation
4. neural tube closure
5. subdivision into brain and spinal cord

Front 11

Cellular differentiation in the neuroepithelium gives rise to 3 zones: what are they?

Back 11

1. ventricular
2. intermediate
3. marginal

Front 12

The _________ layer of the neuroepithelium is the site of mitosis.

Back 12

Ventricular (layer)

Front 13

The __________ layer of the neuroepithelium develops into the gray matter of the mature spinal cord.

Back 13

Intermediate (layer)

Front 14

The ___________ layer of the neuroepithelium differentiates into the white matter of the mature spinal cord.

Back 14

Marginal (layer)

Front 15

The alar and basal plates are separated by the ________.

Back 15

Sulcus limitans

Front 16

the alar plate is associated with _________ (motor/sensory)functions, white the basal plate is associated with ___________ (motor/sensory) functions.

Back 16

1. sensory; becomes the gray matter of dorsal horn
2. motor; becomes the gray matter of the ventral horn

Front 17

3 essentials for dorsal-ventral patterning of the spinal cord:

Back 17

1. floor plate
2. BMP
3. Shh

Front 18

In dorsal-ventral patterning of the spinal cord:
Shh is secreted by ________. Function of Shh?

Back 18

floorplate cells
induces formation of ventral motorneurons

Front 19

In dorsal-ventral patterning of the spinal cord:
BMP induces the formation of __________?

Back 19

interneurons

Front 20

The neural crest arises from ___________ lying at the crest of the neural folds.

Back 20

neuroectoderm

Front 21

what are the 4 neural crest subdivisions?

Back 21

1. cranial neural crest
2. cardiac neural crest
3. trunk neural crest
4. vagal/sacral neural crest

Front 22

The following are derivatives of which portion of neural crest?
craniofacial mesenchyme
pharyngeal arches

Back 22

Cranial neural crest

Front 23

The following are derivatives of which portion of neural crest?
endothelium of aortic arches
aorta/pulmonary artery septum

Back 23

Cardiac neural crest

Front 24

The following are derivatives of which portion of neural crest?
melanocytes
dorsal root ganglia
sympathetic ganglia
adrenal medulla

Back 24

Trunk neural crest

Front 25

The following is a derivative of which portion of neural crest?
parasympathetic ganglia of gut

Back 25

Vagal/sacral neural crest

Front 26

What directs migration of the cells of the neural crest? (3)

Back 26

1. extracellular matrix composition
2. cell adhesion molecules (ie. integrins)
3. growth factors

Front 27

neurons of the PNS are derived from neuroepithelium on the __________.

Back 27

neural crest

Front 28

Where do neurons of the SYMPATHETIC nervous system leave the spinal cord? They leave via the ______________ (ventral/dorsal) root.

Back 28

T1 - L2
leave via the ventral root

Front 29

The neural crest gives rise to what portion of the sympathetic and parasympathetic nervous systems?

Back 29

gives rise to the postganglionic neurons of the sympathetic and parasympathetic nervous systems.

Front 30

Where do neurons of the PARASYMPATHETIC nervous system leave the spinal cord?

Back 30

S2 - S4

Front 31

The ventricles are derived from the ______________?

Back 31

neural tube lumen

Front 32

The alar plate ultimately gives rise to ___ (#) nuclei and they are all _________. (afferent/efferent)

Back 32

4 nuclei
all afferent

Front 33

The basal plate ultimately gives rise to ___ (#) nuclei and they are all _________. (afferent/efferent)

Back 33

3 nuclei
all efferent

Front 34

The forebrain (prosencephalon) gives rise to the _________ and ________

Back 34

telencephalon
diencephalon

Front 35

"Contents" of the telencephalon?

Back 35

lateral ventricles
cerebral hemispheres

Front 36

"Contents" of the diencephalon?

Back 36

thalamus (+assoc. structures)
third ventricle

Front 37

The mesencephalon gives rise to _____________.

Back 37

nothing. It remains mesencephalon.

Front 38

"contents" of the mesencephalon?

Back 38

midbrain
cerebral aqueduct

Front 39

The hindbrain gives rise to __________ and _____________.

Back 39

metencephalon (rostral)
myelencephalon (caudal)

Front 40

"contents" of the metencephalon?

Back 40

Pons
Cerebellum
Upper part of 4th ventricle

Front 41

"contents" of the myelencephalon?

Back 41

medulla
Lower part of 4th ventricle

Front 42

The alar plate of the myelencephalon gives rise to 4 caudal nuclei. Name them.

Back 42

1. Gracile nucleus
2. Cuneate nucleus
3. Spinal Trigeminal nucleus (CN V)
4. Olivary nucleus

Front 43

What does the olivary nucleus contain?

Back 43

contains cerebellar relay nuclei

Front 44

The alar plate of the myelencephalon gives rise to 4 rostral nuclei. Name them.

Back 44

1. vestibulocochlear nucleus
(CN VIII)
2. spinal trigeminal nucleus
(CN V)
3. Solitary nucleus
(CN VII, IX, X)
4. olivary nucleus

Front 45

The basal plate gives rise to 3 nuclei. Name them.

Back 45

1. dorsal motor nucleus of CN X/inferior salivatory nucleus of CN IX
2. nucleus ambiguus (CN IX, X, XI)
3. Hypoglossal nucleus (CN XII)

Front 46

the telia choroidea and choroid plexus can be found _____________.

Back 46

At the roofplate

Front 47

Where would the pontine nucleus be found and what is it's function?

Back 47

found in the Pons
function - cerebellar relay

Front 48

Describe the development of the cerebellum (General)

Back 48

cerebellum--> from alar plate
dorsal part of alar plate gives rise to rhombic lips which expand to form the cerebellum.

Front 49

Cerebellar cortex and dentate nuclei are derived from _______________.

Back 49

neuroblasts of the alar plate

Front 50

The cerebral peduncles are found in the _______________.

Back 50

Mesencephalon

Front 51

The diencephalon has no ____________. Instead it has ___________ and ________.

Back 51

epithalamic sulcus
hypothalamic sulcus

Front 52

What two structures does the epithalamus give rise to?

Back 52

1. choroid plexus
2. pineal gland

Front 53

The dorsal thalamus is a relay center for ____________, whereas the ventral thalamus is a relay center for _____________.

Back 53

1. auditory and visual reflexes
2. motor fibers from cerebral cortex

Front 54

Function of hypothalamus?

Back 54

Control homeostatic functions (sleep, temp, hunger, emotions, glandular secretion, fluid & electrolyte balance)

Front 55

The optic cups are formed from _______________, and they give rise to __________ (5).

Back 55

from an outpocketing on the diencephalon wall.
Give rise to: retina, optic nerve, optic chiasm, iris, ciliary body

Front 56

Describe the formation of the cerebral hemispheres. Include formation of the cerebral cortex.

Back 56

derived from bilateral telencephalic vesicles. C.Cortex is formed by migration of neuroblasts from deep to the periphery.

Front 57

Describe formation of the corpus striatum.
What does the above structure give rise to?

Back 57

forms as a thickening of the floor of the telencephalic vesicles.
Gives rise to the basal ganglia.

Front 58

Commissures are formed via the _____________.

Back 58

formed via the lamina terminalis

Front 59

T/F: corpus callosum is a commissure

Back 59

True; therefore it is formed via the lamina terminalis

Front 60

What section of the brain are the olfactory bulb and nerve derived from?

Back 60

telencephalon (CN I)

Front 61

What section of the brain is CN II derived from?

Back 61

diencephalon

Front 62

In general, CNs are derived from the _____________. What are the two exceptions?

Back 62

derived from the alar and basal plates.
exceptions:CN I(telencephalon), II (diencephalon)

Front 63

G phase

Back 63

What stage of mitosis are the yellow cells undergoing?

Front 64

Mitosis (they are undergoing division)

Back 64

What mitotic stage are these cells in?

Front 65

S phase of mitosis

Back 65

What phase of mitosis are these cells in?

Front 66

At what embryonic age is the developing eye visible?

Back 66

>22 days

Front 67

Complete the summary of eye development: Optic grooves evaginate to form ______1____. (These contact surface ectoderm to induce lens formation). They then evaginate to form the retina. The _____2_____ enters through the retinal fissure. (The retinal fissure is a ______3________). Axons grow through the retinal fissure and fill the lumen of the _______4______. The axons then extend into the brain.

Back 67

1. Optic vesicles
2. Hyaloid artery
3. groove at the inferior aspect of the optic vesicle
4. optic stalk

Front 68

The cornea is forms from what 3 layers?

Back 68

1. Layer of surface ectoderm
2. Stroma (continuous w/ sclera)
3. Epithelial layer at anterior chamber

Front 69

The embryonic precursor of the:
retina
posterior layer of iris
optic nerve
is?

Back 69

Neuroectoderm of the forebrain

Front 70

The embryonic precursor of the:
lens
corneal epithelium
is?

Back 70

Surface ectoderm of head

Front 71

The embryonic precursor of the:
fibrous and vascular layers of the eye
is...

Back 71

mesoderm (between neuroectoderm and surface ectoderm)

Front 72

The embryonic precursor of the:
choroid
sclera
corneal epithelium
is...

Back 72

Neural crest cells (that migrate into mesenchymal cells)

Front 73

The optic cup is essential for proper eye development. Why is this?

Back 73

There has to be an interaction between the lens and retina. The retina is formed from the optic cup.
Therefore: no optic cup --> no retina --> no retina/lens interactions --> --> = improper eye development

Front 74

1. At what embryological age does the retinal fissure close?
2. What is the consequence of this closure?
3. What happens if there is incorrect closure?

Back 74

1. Week 6/7
2. the edges of the iris fuse
3. coloboma of the iris ("keyhole" pupil)

Front 75

There are two types of lens fibers. What are they and what are their characteristics?

Back 75

1. Primary lens fibers - they last the lifetime of the eye.
2. Secondary lens fibers - continue to form in adulthood

Front 76

1. What is the blood supply to the developing lens?
2. What happens to this blood supply as the fetus develops?

Back 76

1. Distal Hyaloid artery
2. artery dissappears and blood supply is lost to the lens and capsule.

Front 77

The lens is covered by a capsule. What is found in this capsule in early developmental stages?

Back 77

vascular mesenchyme. Contents of capsule degenerate once blood supply is lost

Front 78

The sclera is continuous with the ___________ of the optic nerve.

Back 78

Dura mater

Front 79

Name 3 teratogens that alter eye development.

Back 79

1. cytomegalovirus
2. rubella virus
3. syphilis microorganism

Front 80

Complete this summary of ear development:
by week_*_ the otic vesicle forms from ______2_______. The otic vesicle goes on to form the _______3_________. Middle ear epithelium forms from the endoderm of _____4_____. The ossicles are derived from the ____5____ pharyngeal arches. The first pharyngeal cleft forms the ____6_____, and the tympanic membrane develops from ____7_____, _________ and ___________.

Back 80

1. 4
2. surface ectoderm
3. inner ear
4. the 1st pharyngeal pouch
5. 1st and 2nd pharyngeal arches
6. external auditory meatus
7. ectoderm,
mesenchyme and
endoderm (all from the 1st pharyngeal pouch).

Front 81

Development of the inner ear is induced by __________ and ___________.

Back 81

notochord and paraxial mesoderm

Front 82

The otic vesicle forms two regions: the dorsal _________ portion, and the ventral _____________ portion.

Back 82

dorsal utricular
ventral saccular

Front 83

The otic capsule ossifies after the inner ear reaches __________. This occurs at and embryological age of approx. _________ wks.

Back 83

adult size
~ 20-22 wks
Yes, the inner ear STOPS growing for life after 22 wks of age!

Front 84

The meatal plug is initally solid. It later degenerates to form the lumen of _______.

Back 84

The meatus

Front 85

The auricle is developed from the __1__ and __1__ pharyngeal pouches. These pouches form prominences known as 6 ____2____.
The last portion of the auricle to develop is the ___3_____.

Back 85

1. 1st and 2nd
2. auricular hillocks
3. ear lobe