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Flashcards in Neural Development Deck (58):
1

In what week of development does neurulation begin?

3

2

What induces formation of the nervous system?

Notochord

3

The notochord induces the overlying ectoderm to differentiate into _______ and form the _______?

Neuroectoderm
Neural plate

4

By the end of the third week, neural folds grow over midline and fuse to form the ____.

Neural tube

5

The neural plate gives rise to the _____ and _____.

neural tube (--> CNS neurons)
neural crest cells (---> PNS neurons)

6

What cells come from neuroectoderm?

CNS neurons
ependymal cells
oligodendroglia
astrocytes

7

What cells come from neural crest?

PNS neurons
Schwann cells

8

What cells come from mesoderm?

Microglia, like Macrophages, originate from Mesoderm

9

What does the neural tube give rise to?

Brain
Spinal cord
lower motor neurons
preganglionic neurons

10

The brainstem and spinal cord have two plates.
What are they?
What are their functions?
What is their orientation?
By what are they separated?

Alar plate = sensory = dorsal/posterior
Basal plate = motor = ventral/anterior
(SAME ORIENTATION IN SPINAL CORD)
sulcus limitans

11

Neural tube --> X primary vesicles --> Y primary vesicles

3
5

12

How many pairs of spinal nerves are there?

31 total

8 cervical
12 thoracic
7 lumbar
5 sacral
1 coccygeal

13

Forebrain -->

Forebrain --> Telencephalon + Diencephalon

Telecephalon -> Cerebral hemispheres + lateral ventricles

Diencephalon --> thalamus + third ventricle

14

Telecephalon --> ?

Diencephalon --> ?

Telecephalon --> Cerebral hemispheres + most of basal ganglia + lateral ventricles

Diencephalon --> thalamus + hypthalamus + STN + pineal gland + third ventricle

15

Midbrain --> mesencephalon -->

Midbrain + cerebral aqueduct

16

Hindbrain -->

Metencephalon + Myelencephalon

Metencephalon --> Pons + upper part of 4th ventricle + cerebellum

Myelencephalon --> Medulla + lower part of 4th ventricle

17

Metencephalon --> ?

Myelencephalon --> ?

Metencephalon --> Pons + upper part of 4th ventricle + cerebellum

Myelencephalon --> Medulla + lower part of 4th ventricle

18

What does the notochord become in adults?

The notochord becomes nucleus pulposus of the intervertebral disc in adults

19

What happens if the rostral neurospore fails to close (usu. happens at day 25)?

Anencephaly, causing polyhydraminos and increased alpha-veto protein

20

What happens if the caudal neurospore fails to close (usu. happens at 27D)?

Spinal bifida and increased alpha-feto protein

21

Anencephaly is ...

A gailure of the anterior neurospore to close; brain does not develop; incompatible w/ life; increased AFP

22

What is spina bifida?

Failure of the posterior neurospore to close

23

What is spina bifida oculta?

Mildest form;
vertebrae fail to form around spinal cord;
no increase in AFP;
Asymptomatic

24

What is spinal bifida with meningocele?

Meninges protrude through vertebral defected; increase in AFP

25

What is spin bifida with meningomyelocele

Meninges + spinal cord protrude through vertebral defect; increase in AFP

26

What is spina bifida with myelschisis?

Most severe; spinal cord can be seen externally

27

What is the mildest and what is the most severe form of spina bifida

Spina bifida occulta
Spina beifida with myeloschisissi

28

What is downward displacement of the cerebral tonsils through the foramen magnum?

Arnold Chiari Type I (most common and mostly asymptomatic)

29

What do you call downward displacement of cerebellar vermis and medulla through the foramen magnum? What other things would result?

Arnold Chiari Type II
4th V compression --> obstr. hydrocephalus
Frequent lumbar meningomyelocele
Frequent association with syringomyelia

30

What is Dandy-Walker malformation?

Failure of foramina of Luschka and Magendie to open --> dilation of 4th ventricle; agenesis of cerebellar vermis and splenium of the corpus callosum

31

What is the most common cause of hydrocephalus?

Stenosis of the cerebral aqueduct
CSF accumulates in ventricles and subarachnoid space; increased head circumference

32

What is holoprosencephaly?

Incomplete separation of cerebral hemispheres. One ventricle in telencephalon; seen in trisomy 13 (Patau)

33

Which pharyngeal arches give rise to arteries that contribute to the blood vessels in the circle of Willis?

Pharyngeal arches 3 and 4

34

What does pharyngeal arch 3 give rise to?

The internal carotid bilaterally (--> MCA & ACA)

35

What does pharyngeal arch 4 give rise to?

The arch of the aorta and the right subclavian artery (--> vertebral arteries)

36

What doe pharyngeal arch 1 give rise to?

maxillary artery

37

What does pharyngeal arch 2 give rise to?

stapedial artery

38

What does pharyngeal arch 5 give rise to?

Degenerates early in fetal development

39

What does pharyngeal arch 6 give rise to?

Pulmonary arteries and ductus arteriosus

40

Which plate gives rise to the dorsal part of the spinal cord and becomes the sensory portion of the cord?

Alar

41

Which plate gives rise to the ventral part of the cord and and becomes the motor portion?

Basal

42

What gives rise to the spinal cord?

The neural tube

43

In which kind of spina bifida do only the meninges project through a defect in the verebral column and form a sac-like structure filled with CSF?

Meningocele

44

Which embryonic structure gives rise to the cerebral aqueduct?

Midbrain/Mesencephalon

45

Neuroepithelial cells give rise to early neural cells called glioblasts, which give rise to neuroglial cells including ...

Astrocytes and oligodendrocytes

46

Name seven cells that derive from the neural crest.

1. Pseudounipolar cells of spinal & cranial ganglia
2. Autonomic ganglia cells
3. Schwann cells
4. Chromaffin cells of the adrenal medulla
5. Odontoblasts
6. Melanocytes
7. Meninges (pia and arachnoid)

47

What derives from pharyngeal pouch 1?

Epithelial lining of auditory tube and middle ear cavity

48

What derives from pharyngeal pouch 2?

Epithelial lining of crypts of palatine tonsil

49

What derives from pharyngeal pouch 3?

Inferior parathyroid gland and thymus

50

What derives from pharyngeal pouch 4?

Superior parathyroid gland and ultimobrachial body

51

What is the only postnatal remnant of a pharyngeal groove or cleft?

External auditory meatus

52

What do you call it when pharyngeal pouches 3 and 4 fail to differentiate into the parathyroid glands and thymus?

DiGeorge sequence

53

What are the symptoms of DiGeorge?

CATCH-22
Cardiac abnormalities
Abnormal facies
Thymic aplasia
Cleft palate
Hypocalcemia/Hypoparathyroidism
22q11.2

54

The ________ does not develop in a pharyngeal pouch; instead it develops from midline endoderm of the oropharynx and migrates inferiorly along the path of the thyroglossal duct. Neural crest cells migrate into the ultimobranchial body to form parafollicular C cells of the thyroid.

Thyroid gland

55

What forms the thyroid gland?

The distal end of the thryroglossal duct forms the thyroid gland, while the proximal end normally degenerates.

56

Failure of a part of the duct to degenerate results in a ________, which is generally located in the midline, near the hyoid bone.

thryroglossal duct cyst

57

A 7 yo girl presents with a small mass on her anterior neck PE shows a mobile mass on the midline of the neck above the larynx that elevates upon protrusion of the tongue. The mass has most likely developed from a remnant of which embryonic structure?

Thryroglossal duct

58

A 9 yo girl presents with headache and neck pain. CT shows herniation of cerebellar tonsils through the foramen magnum by not other structural abnormalities.

Arnold-Chiari malformation Type I