development

Question 1

when does gastrulation occur? what is the outcome?

Answer 1

• the third week

- three layers are formed

Question 2

during gastrulation, what cells are migrating and ultimately form all three layers?

Answer 2

epiblast

Question 3

what gives rise to the CNS?

Answer 3

neural tube

Question 4

what gives rise to the PNS?

Answer 4

neural crest

Question 5

what are the neural derivatives of the neural crest?

Answer 5

• posterior root ganglia
• sympathetic chain ganglia
• prevertebral ganglia
• enteric ganglia
• para ganglia of CN 7,9,10
• sym ganglia of CN 5,7,8,9,10

Question 6

what are some non neural derivatives of the neural crest?

Answer 6

• schwann cells
• melanocytes
• pia and arachnoid of the meninges

Question 7

hirschprung disease is due to what?

Answer 7

-failure of migration of parasympathetic ganglion from cells from the neural crest

Question 8

what are the three primary brain vesicles?

Answer 8

• proencephalon(forebrain)
• mesencephalon (midbrain)
• rhombencephalon(hindbrain)

Question 9

on the fifth week, the three primary brain vesicles divide into what five secondary brain vesicles?

Answer 9

1. Telencephalon (forebrain)
2. Diencephalon (forebrain)
3. mesencephalon (Midbrain)
4. Metencephalon (hindbrain)
5. Myelencephalon (hindbrain)

Question 10

what are the four flexures?

Answer 10

1. Cervical: between hindbrain and spinal cord
2. Mesencephalic: bend in neural tube at the level of mesencephalon
3. telencephalic: between the diencephalon and telencephalon
4. Pontine flexure: divides the hindbrain into metencephalon and myelencephalon

Question 11

the telencephalon expands to form what?

Answer 11

cerebral hemispheres

Question 12

metencephalon gives rise to what?

Answer 12

• pons

- cerebellum

Question 13

the diencephalon gives rise to what?

Answer 13

• thalamus
• hypothalamus
• optic cup

Question 14

the myelencephalon gives rise to what?

Answer 14

-medulla

Question 15

what is the process of forming the neural tube from the neural plate called?

Answer 15

neurulation

Question 16

what initiates the formation of the neural tube?

Answer 16

-notochord formation during gastrulation induces formation of neural plate, which then starts the development of the neural tube

Question 17

what is the first step of neural system development?

Answer 17

formation of the neural plate

Question 18

what pathology results from failure of the rostral end of the neural tube (anterior neuropore) to close?

Answer 18

anencephaly

Question 19

what pathology results from failure of the posterior neuropore to close?

Answer 19

myeloschisis

Question 20

what is cranioshisis?

Answer 20

failure of the back of the skull to close

Question 21

what is meningocele?

Answer 21

the cyst structure from failure of the back of the skull to close contains meninges

Question 22

what is meningoenchephalocele

Answer 22

the cyst structure from failure of the back of the skull to close contains meninges and the brain

Question 23

what is meningohydroencephalocele?

Answer 23

the cyst structure from failure of the back of the skull to close contains meninges, brain, and part of the ventricular system

Question 24

what is the alar plate in the developing spinal cord?

Answer 24

• posterior cell masses that become the dorsal horn

- sensory

Question 25

what is the basal plate in the developing spinal cord?

Answer 25

- anterior cell masses that become the ventral horn | - motor

Question 26

what develops in the intermediate zone of the spinal cord?

Answer 26

the sympathetic nervous system

Question 27

what is the sulcus limitans?

Answer 27

the groove that separates the alar and basal plates

Question 28

how are the alar and basal plates arranged in the brainstem?

Answer 28

-the alar plates rotate dorsolaterally to give the plates a medial to lateral orientation

Question 29

the alar and basal plates, which one has afferent fibers and which one has efferent?

Answer 29

Alar-afferent | Basal-efferent

Question 30

what does the cerebellum arise from?

Answer 30

rhombic lip

Question 31

what is dandy-walker syndrome? what would the CT show? what are the clinical signs?

Answer 31

- dilation of the fourth ventricle, incomplete development of midline portion of cerebellum - CT shows enlarged posterior fossa with a midline cyst - developmental delay, big head, hydrocephalus

Question 32

what is chiari malformation? what is the difference between I and II?

Answer 32

- herniation of the cerebellar vermis and tonsils through the foramen magnum - skull is abnormally small and compresses brain downward - type I: develops as the skull and brain are growing - type II: malformation is present at birth

Question 33

what is prosencephalization?

Answer 33

differentiation of prosencephalon into the diencephalon and telencephalon

Question 34

what is holoprosencephaly? what is the difference between alobar and semilobar?

Answer 34

- failure of prosencephalon to undergo cleavage - Alobar: no lobes, single forebrain ventricle - Semilobar: partial separation

Question 35

fetal alcohol syndrome is associated with what?

Answer 35

holoprosencephaly

Question 36

what is lissencephaly? pachygyria? micrgyria?

Answer 36

Lissencephaly: no gyri formed Pachygyria: excessive gyri growth Microgyria: deficient gyri growth

Question 37

what are some signs of fetal alcohol syndrome?

Answer 37

- short - low body weight - small head - mental retardation - hypertelorism (eyes far apart)

Question 38

what is the consequence of defective development of cerebral aqueduct?

Answer 38

- aqueduct stenosis | - hydrocephalus

Question 39

what do radial glia do?

Answer 39

-they act as cell guides to allow neuroblasts to migrate away from the luminal surface and develop the layers of the cerebral cortex.

Question 40

what is the difference between spina bifida occulta and spina bifida aperta?

Answer 40

occulta: skin is intact, marked by a patch of hair aperta: skin is not closed over the vertebral defect

Question 41

what is spina bifida?

Answer 41

-failure of vertebral arches to close

Question 42

what is meningocele?

Answer 42

-spina bifida and meninges and CSF

Question 43

what is meningomyelocele?

Answer 43

-spina bifida and meninges and CSF and spinal neural tissue

Question 44

what should moms take to prevent spina bifida?

Answer 44

folic acid

Question 45

what are the common diseases that can cause congenital nervous system defects?

Answer 45

``` T-toxoplasmomsis O-other agents(HIV, syphilis) R-rubella C-cytomegalovirus H-herpes simpex virus ```

Question 46

Zika virus has been associated with what in newborns in america?

Answer 46

microcephaly