Embryology Exam 2: Neural System Development

Front 1

What development generates the most complex structure within the embryo?

Back 1

neural development

Front 2

What is one of the earliest systems to begin and yet one of the last to be completed after birth?

Back 2

Neural development

Front 3

What system would most likely be affected by an in utero insult during pregnancy?

Back 3

nervous system (development of...)

Front 4

What is the source of many neural abnormalities?

Back 4

Neural tube defects are often attributed to FAILURE OF NEURAL TUBES to close

Front 5

T/F. The neural tubes in an embryo are initially open at each end.

Back 5

True

Front 6

How does the early central nervous system develop?

Back 6

It begins as a simple neural plate that folds to form a groove. Then it forms a tube. And each tube is initially open at each end. Eventually the tubes close. When they don't, neural defects occur.

Front 7

What two major classes of cells are generated in the neural tube? What generates them?

Back 7

1. neurons and glia
2. stem cells

Front 8

How do most congenital anomalies of the spinal cord occur? At what stage of development does this occur?

Back 8

1. Defective closure of the neural tube
2. This usually occurs during the 4th week!

Front 9

What tissues are affected by Neural Tube Defects (NTDs)?

Back 9

mostly overlying tissues, including 1. meninges
2. vertebral arches
3. muscles
4. skin

Front 10

What is an NTD?

Back 10

Failure of the neural tube closure either incorrectly or incompletely

Front 11

What term is often used to describe the defective fusion of the neural folds?

Back 11

dysraphism

Front 12

What is a preventative measure of NTDs?

Back 12

Supplementation of folate (folic acid) in maternal diet reduces incidence of NTDs

Front 13

What significant event helped reduce the rate of anencephaly and spina bifida in the U.S.? When did it occur?

Back 13

1. FDA authorized fortification of grain cereals with folic acid.
2. It was optional in March 1996, and mandatory in Jan. 1998.

Front 14

The neural tube cranial to the 4th pair of somites develops into what?

Back 14

the brain

Front 15

Which neural tube develops into the brain?

Back 15

the neural tube cranial to the 4th pair of somites

Front 16

Which three primary brain vesicles form the brain?

Back 16

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

Front 17

What forms the three primary brain vesicles?

Back 17

closure of the rostral neuropore

Front 18

What five secondary structures form from the three primary brain vesicles?

Back 18

1. telencephalon (forms cerebral hemispheres)
2. diencephalon (forms optic nerve)
3. Midbrain (mesencephalon) stays same.
4. metencephalon (behind brain)
5. myelencephalon (medulla brain)

Front 19

What secondary structures are formed by the prosencephalon?

Back 19

1. telencephalon (forms cerebral hemisphere)
2. diencephalon (forms optic nerve)

Front 20

What secondary structures are formed by mesencephalon?

Back 20

NONE, it stays the same

Front 21

What secondary structures are formed by the rhombencephalon?

Back 21

1. metencephalon (behind brain)
2. myelencepahlon (medulla brain)

Front 22

How are ventricles formed?

Back 22

the cavity within the neural tube will form contiguous space of the ventricles of brain and central canal of spinal cord

Front 23

What does the neural tube differentiate into?

Back 23

The CNS, consisting of the brain and spinal cord.
1. If its crainial-brain
2. caudal-spinal cord

Front 24

What initially fills the contiguous space of the ventricles?

Back 24

amniotic fluid

Front 25

What replaces amniotic fluid in the contiguous space of the ventricles?

Back 25

Cerebrospinal fluid (CSF)

Front 26

What secretes CSF?

Back 26

a modified vascular structure, known as the choroid plexus

Front 27

What is the function of the choroid plexus?

Back 27

to secrete CSF

Front 28

Where is the CSF located?

Back 28

the ventricles

Front 29

What forms the brain flexures? What are these three flexures called?

Back 29

1. rapid growth folds the neural tube
2. cervical flexure, midbrain flexure, and pontine flexure

Front 30

Which flexure is located between the brain stem and spinal cord?

Back 30

cervical flexure

Front 31

Which flexure pushes mesencephalon upwards?

Back 31

midbrain flexure

Front 32

Which flexure generates 4th ventricle?

Back 32

pontine flexure

Front 33

Which cells lie in the layer closest to the ventricular space?

Back 33

neural stem cells

Front 34

Where do neural stem cells lie?

Back 34

the ventricular layer

Front 35

Which neural layer is the closest to the ventricular space?

Back 35

the ventricular layer

Front 36

What cells are generate by the ventricular layer?

Back 36

1. neuroblasts
2. glioblasts

Front 37

Which neurons migrate along radial glial, and stop at the cortical plate?

Back 37

neuroblasts

Front 38

Which neurons first arise as glia?

Back 38

glioblasts

Front 39

T/F. Neurons and glia experience a rapid growth process.

Back 39

FALSE; they undergo a complex process of growth, differentiation and interaction over a long developmental time period.

Front 40

What does the neural tube develop into?

Back 40

the spinal cord

Front 41

What cells in the spinal cord arise from the ventricular zone?

Back 41

1. macroglial cells
2. neurons

Front 42

What cells make up the ventricular zone?

Back 42

cells of the neural tube

Front 43

When does cerebrospinal fluid begin to form?

Back 43

during the fifth week

Front 44

T/F. The pontinue flexure develops slowly since brain development is a lengthy process.

Back 44

False; it occurs as brain grows rapidly

Front 45

What are ectodermal placodes? What structures do they contribute?

Back 45

1. specialized ectodermal "patches" in the head region
2. sensory structures (i.e., otic placode/otocyst, nasal placode, lens placode) and teeth

Front 46

What sensory structures do ectodermal placodes contribute?

Back 46

1. otic placode (otocyst)
2. nasal placode
3. lens placode

Front 47

What determines the outcome for neural abnormalities?

Back 47

the position and degree of failure of fusion

Front 48

T/F. The the mode of neural fusion is the same in all species.

Back 48

False; the mode of fusion in humans appears to be different that many other animal species.

Front 49

Severity of the abnormality is dependent on what?

Back 49

its dependent on the level within the tube and degree of failure (to fuse)

Front 50

What is spina bifida?

Back 50

protrusion of the spinal cord and/or meninges

Front 51

How many births are affected by spina bifida?

Back 51

1/1000

Front 52

What are abnormalities that can occur during embryonic development?

Back 52

1. neural tube closure (spina bifida)
2. cephalic disorders (lissencephaly-smooth brain)
3. hydrocephalus-enlarged ventricles leads to large head
4. trisomy 21 has severe and variable effects on neurological development
5. neural tumors
6. autism spectrum disorder
7. Huntington's disease (HD)
8. Infections

Front 53

What is an example of a cephalic disorder?

Back 53

1. lissencepahly-smooth brain

Front 54

What is hydrocephalus?

Back 54

When enlarged ventricles leads to a large head

Front 55

What is a neurological disorder that occurs in children?

Back 55

autism spectrum disorder

Front 56

What is Huntington's Disease (HD)?

Back 56

an inherited disease that gives rise to progressive, selective (localized) neural cell death

Front 57

During which stage of human development can exposure to teratogens result in specific abnormalities?

Back 57

critical periods

Front 58

When are most embryonic systems susceptible?

Back 58

During the first trimester, or embryonic development

Front 59

T/F. The time when embryos are exposed to the teratogen doesn't matter.

Back 59

False; the earlier the exposure, the more severe the effects

Front 60

What is the longest critical period in the embryo?

Back 60

1. neural
2. genital

Front 61

Which system has complicated developmental origins?

Back 61

sensory systems