11-24 NeuroEMBRYOLOGY Flashcards Preview

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Flashcards in 11-24 NeuroEMBRYOLOGY Deck (36):
1

A: What is Neurulation?

B: List the 5 Steps of Neurulation

C:
•What does the Rostral part of the neural tube become?
•What does the CAUDAL part of the neural tube become?
•What does the Lumen of the neural tube become? [2]

Neurulation
A: Formation & closure of the neural tube

B:
1st. Notochord induces overlying ectoderm to differentiate into NEUROectoderm-->form neural plate.

2nd. Notochord stays behind to form adult [nucleus pulposus] of intervertebral disk

3rd. Neural Plate folds to create neural tube --open at both ends = ANT and POST neuropores. (These neuropores connect neural tube lumen with amniotic cavity)

4th. {NEUROPORE CLOSE UP} ANT neuropore closes on day 25 and becomes [lamina terminalis]. ////POSTERIOR neuropore closes on day 27

5th. As Neural plate folds, some cells differentiate into [Neural Crest Cells]--->ends up forming cell columns on both sides of neural tube
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Rostral part----->Adult Brain :-)

CAUDAL part---->ADULT SPINAL CORD

Neural tube Lumen---->ventricular system of brain AND central canal of Spinal Cord

2

1) What happens if the ANT neuropore FAILS to close on day __ of Neurulation ?

2) What happens if the POSTERIOR neuropore FAILS to close on day ___ of Neurulation?

1) When ANT neuropore FAILS to close Day 25 = upper neural tube defects--->Anencephaly
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2. When POSTERIOR neuropore FAILS to close Day 27 = Lower neural tube defects--->[spina bifida with myeloschisis]

3

Neural crest cells differentiate from ______ of the ____ ____ and undergo prolific migration to ultimately form _______. This happens in Both the Cranial Region AND Trunk Region.

B: Describe the Neural Crest Cells development in each Region
Cranial [4]
TRUNK [ 6]

Neural crest cells differentiate from NEUROectoderm of the Neural tube and undergo prolific migration to ultimately form ADULT CELLS.

Cranial Region= Pharyngeal Arch stuff / pia&arachnoid / [pterygopalatine, otic and multiple sensory ganglia]

vs.

TRUNK Region= melanocytes / Schwann cells / Chromaffin of Adrenal Medulla / DRG / SCGT / Abd&pelvic parasympathetic ganglia(messier & Auerbach; CN10)

4

1. Neurocristopathy

2. What are 3 good examples of this?

1. Any dz related to maldevelopment of [Neural Crest Cells]

2.
*Medullary Carcinoma of Thyroid
*Schwannoma
*Neurofibromatosis type 1 (von Recklinghausen dz)

5

[Medullary Carcinoma of Thyroid] is a type of ______
A: Describe this Dz

B: How are the Carcinoma cells typically arranged?

[Medullary Carcinoma of Thyroid] is a type of NEUROCRISTOPATHY

A: endocrine neoplasm of parafollicular cells which secrete calcitonin and are from neural crest origin

B: Cells are usually arranged in cell nest surrounded by stroma bands that contain amyloid

6

[Schwannoma] is a type of ______
A: Describe this Dz

B: Where is this tumor commonly located? [2]

C: List clinical findings of this dz [2]

[Schwannoma] is a type of NEUROCRISTOPATHY

A: benign tumor of Schwann cells of neural crest origin that is well-circumscribed & encapsulated

B:
1) On Cerebellopontine angle near Vestibular branch of CN8 = "acoustic neuroma"
2) On [Trigeminal/CN5] due to its close approximation to [petrous ridge]

C:
*Tinnitus
*Hearing Loss

7

[Neurofibromatosis type 1] (AKA ___ _____ dz) is a type of ______
A: Describe this Dz [4]

B: What is the mode of inheritance for this dz

C: List clinical findings for this dz [4]

[Neurofibromatosis type 1] (AKA von Recklinghausen dz) is a type of NEUROCRISTOPATHY

A: Mutation in the NF1 gene---> INC in Neurofibromin
-->this inappropriately DOWN regulates p21 tumor suppressor -----> neurofibroma tumors!

B: AUTOSOMAL DOMINANT

C:
•neurofibroma tumors widely dispersed
•Proliferation of all elements of peripheral nerves
•[cafe au lait] pigmented skin lesions
•[Lisch nodule] pigmented iris hamartomas

8

A: Name & Describe the 3 PRIMARY Brain Vesicles and their 2 associated Flexures

B: When does this stuff develop?

A: PRIMARY Brain Vesicles:
1. PROSENCEPHALON (FOREBRAIN)--> TELENCEPHALON & DIENCEPHALONS

2. Mesencephalon (Midbrain) = remains as Mesencephalon

3. rhombencephalon (hindbrain)---> metencephalon & myelencephalon

Flexures:
º[Cephalic midbrain flexure]= between Mesencephalon and metencephalon

º[Cervical flexure] =between future spinal cord and myelencephalon
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PRIMARY VESICLE development = WEEK 4!

9

The 5 SECONDARY Brain vesicles form during Week __ and form ________. Describe what they form exactly?
1. TELENCEPHALON [4]
2. DIENCEPHALON [5]

3. Mesencephalon [3]

4. metencephalon [2]
5. Myelencephalon

SECONDARY Brain vesicles = Week 6

1. TELENCEPHALON = cerebral cortex/basal ganglia/hippocampus/amygdala
"BACH"
2. DIENCEPHALON = THALAMUS / hypoTHALAMUS / PINEAL GLAND / CHOROID PLEXUS / PITUITARY GLAND
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3. Mesencephalon = Tegmentum / Tectum / Peduncular Region
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4. metencephalon = pons / cerebellum
5. Myelencephalon = Medulla

10

The Spinal Cord develops from the ____ _____

What is the [ALAR Sensory Plate] ? [2]

Spinal Cord develops from the POSTERIOR NEUROPORE

[ALAR Sensory Plate]
•Dorsolateral thickening of intermediate zone of neural tube
•Gives rise to sensory neuroblast of Dorsal Horn --> eventually BECOMES spinal cord Dorsal Horn

11

The Spinal Cord develops from the _____ ______

What is the [BASAL Motor Plate]? [2]

Spinal Cord develops from the POSTERIOR NEUROPORE

[BASAL Motor Plate]
•Ventralateral thickening of intermediate zone of neural tube
•Gives rise to Motor neuroblast of Ventral AND Lateral Horns --> eventually BECOMES spinal cord Ventral Horn

12

A: Sulcus Limitans [2]

Sulcus Limitans Extends from _______ _______ to the _______ _______
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B: Caudal Eminence

Arises from _______ streak, blends w/_______ _______
---> gives rise to _______ & _______ segments of spinal cord

A: *Sulcus Limitans*
1. groove in lateral wall of neural tube (during week 4) that separates [ALAR Sensory Plate] from [BASAL Motor Plate]

2. Extends from Spinal Cord to rostral midbrain
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B: ((Caudal Eminence))
Arises from primitive streak, blends w/neural tube ---> gives rise to sacral & coccygeal segments of spinal cord

13

1. Myelination of Spinal Cord beings during month ____ in the _______ roots

2. Oligodendrocytes accomplish myelination in the ___ vs. Schwann cells whom accomplish myelination in the _____

3. Myelination of corticospinal tracts is not completed until after ___ years old and Myelination of [association neocortex] extends until you're ____!

1. Spinal Cord Myelination STARTS in month 4 within [Ventral Motor Roots]

2. Oligodendrocytes accomplish myelination in the CNS! vs. Schwann cells whom accomplish myelination in PNS

3. Myelination of Corticospinal tracts is not completed until after 2 years old....

and Myelination of [association neocortex] extends until you're 30 YEARS OLD!

14

A: Describe the 3 Positional changes of Spinal cord

B: What is Disparate growth and what 2 things does it lead to?

A:
1) At 8 weeks= spinal cord extends length of vertebral canal
2) At Birth = Conus Medullaris extends to L3
3) In ADULTS = CONUS MEDULLARIS terminates at L1-L2

B: Disparate growth = growth between vertebral column & Spinal Cord --->Cauda Equina formation {which contains Dorsal AND Ventral Roots} AND [filum terminale]

15

[T or F] the Filum Terminale is a Neural-Active extension of the Spinal Cord

FALSE!!!!!
Filum Terminale is NON-NEURAL!

16

Describe Brainstem Development
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Describe Cerebellum Development

Brainstem:
Fundamental floor plan in spinal cord extends rostrally into developing brain stem keeping spatial relationship of alar and basal plates intact.
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Cerebellum:
Develops from rhombic lip (meTencephalic thickening @ rostral bordr of 4th ventricle). Histogenesis continues until after birth.

17

A: Development of the CEREBRAL CORTEX occurs ______ and is dominated by the growth of the ________.

B: Describe the pattern of development and migration of cells

C: Why does White and gray mater lie at different levels in the Cortex vs. Spinal Cord?

A: Development of CEREBRAL CORTEX occurs 4 MONTHS IN UTERO and is dominated by growth of the TELENCEPHALON

B: Cerebral Cortex demonstrates inside-out pattern in that later formed Neuroblast migrate peripherally beyond earlier-formed cells

C: After this migration, cell processes form and project Inward so that CORTEX WHITE MATER is DEEEEP to gray mater
but in Spinal cord...white mater is Superficial to gray mater

18

The Hypophysis (AKA ___ ____) is attached to the ______ by the _____ ____ and consist of 2 lobes.

B: Describe these 2 Lobes

Hypophysis (AKA PITUITARY GLAND) is attached to HYPOTHALAMUS by the [Infundibula STALK] and consist of 2 lobes.

B:
1) [ANT Adenohypophysis], PARS Tuberalis & PARS Intermedia = develops from Rathke's pouch-diverticulum of [stomodeum mouth cavity] and can become [craniopharyngioma]


2) [POST Neurohypophysis] = develops from [infundibulum stalk], neuroectodermal diverticulum of hypothalamus

19

Spina Bifida occurs when ___ ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 4 Variations.

Describe [Spina Bifida Occulta] (3)

Spina Bifida occurs when BONY VERTEBRAL ARCHES fail to form properly!---> VERTEBRAL DEFECTS usually in LUMBOSACRAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 4 Variations }
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**Spina Bifida Occulta**
-multiple dimples on back of infant accompanied with tuft of hair
-leaast severe and occurs in 10% of population

-Spinal cord is intact and bony vertebral bodies are present along entire vertebral column BUT bony spinous processes terminate at higher level since vertebral arches didn't form properly.

20

Spina Bifida occurs when ___ ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 4 Variations.

Describe [Spina Bifida w. Meningocele] (2)

Spina Bifida occurs when BONY VERTEBRAL ARCHES fail to form properly!---> VERTEBRAL DEFECTS usually in LUMBOSACRAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 4 Variations }
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**Spina Bifida w. Meningocele**
ºOccurs when meninges protrude thru vertebral defect and form sac filled with CSF!

ºSpinal cord remains in normal position

21

Spina Bifida occurs when ___ ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 4 Variations.

Describe [Spina Bifida w. Meningomyelocele]

Spina Bifida occurs when BONY VERTEBRAL ARCHES fail to form properly!---> VERTEBRAL DEFECTS usually in LUMBOSACRAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 4 Variations }
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** Spina Bifida w. Meningomyelocele **

Occurs when meninges AND SPINAL CORD protrude thru vertebral defect and form sac filled with CSF

22

Spina Bifida occurs when ___ ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 4 Variations.

Describe [Spina Bifida w. Rachischisis]
A: What causes this and When does this occur. What does it lead to?

B: How are NTDs like this detected?

C: How are they prevented?

D: Is this considered a Lower NTDs or Upper NTDs and why?

Spina Bifida occurs when BONY VERTEBRAL ARCHES fail to form properly!---> VERTEBRAL DEFECTS usually in LUMBOSACRAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 4 Variations }
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** Spina Bifida w. Rachischisis **
A: MOST SEVERE SB Caused by POST neuropore of neural tube failing to close during WEEK 4----> paralysis from level of the defect caudally

B: Can be diagnosed parentally by detecting elevated levels of [a-fetoprotein] in amniotic fluid

C: Prevented by pregnant women taking Folic Acid (0.4 mg/day)

D: THIS IS A LOWER NTDs! because it results from failure of POSTERIOR neuropore to close during week 4.

23

Cranial Bifida occurs when ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 3 Variations.

Describe [Cranial Bifida w. meningocele ]

Cranial Bifida occurs when BONY SKULL fail to form properly!---> SKULL DEFECTS usually in OCCIPITAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 3 Variations }
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** Cranial Bifida w. meningocele **
Occurs when meninges protrude thru the skull defect and form sac filled with CSF

24

Cranial Bifida occurs when ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 3 Variations.

Describe [Cranial Bifida w. meningoencephalocele ] (3)

Cranial Bifida occurs when BONY SKULL fail to form properly!---> SKULL DEFECTS usually in OCCIPITAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 3 Variations }
------------------------------------------------------------------------------------
** Cranial Bifida w. meningoencephalocele **

*Occurs when meninges AND BRAIN protrude thru skull defect and form sac filled with CSF
*Noticed within infant's 1st few days/weeks of life
*OUTCOME IS POOR! :-( ---> 75% die or severe retardation

25

Cranial Bifida occurs when ____ ____ fail to form properly--->____ defect usually in the ______ region.
It is primarily caused by Pregnant Mothers not taking enough ____ ______. There are 3 Variations.

Describe [Cranial Bifida w. meningoHYDROencephalocele ]

Cranial Bifida occurs when BONY SKULL fail to form properly!---> SKULL DEFECTS usually in OCCIPITAL region. It's primarily caused by Pregnant Mothers not taking enough FOLIC ACID.
{ 3 Variations }
------------------------------------------------------------------------------------
** Cranial Bifida w. meningoHYDROencephalocele**

Happens when meninges, BRAIN AND PART OF VENTRICLE protrude thru skull defect

26

ANENCEPHALY/meroANENCEPHALY is a severe ____ NTD that occurs when _________----> failure of ____ ____ ____ and ____ ___ to form.

B: Are infants with Anencephaly viable?

C: How is this Diagnosed?

D: How is this "treated" ?

ANENCEPHALY/meroANENCEPHALY is a severe UPPER NTD that occurs when [ANTERIOR neuropore] fails to close----->failure of [lamina terminalis] and [bony cranial vault] to form

B: NO! If not Stillborn, infants born with this survive for few hours-few weeks (Most common Dz in Stillborns)

C: Diagnosed via US

D: No tx BUT therapeutic abortion is usually performed

27

A: What causes [Arnold-Chiari Malformation] ?

B: what are some Key Clinical signs [4]

C: This Malformation is commonly associated with what 4 other Dz?

A: Occurs when [caudal vermis], [cerebellar tonsils] and [medulla oblongata] herniate thru foramen Magnum

B:
1. Syrinx in Cervical Spinal Cord
2. Stretching of CN9, CN10, CN11
3. Vocal Cord Paralysis
4. Laryngeal stridor

C: Also associated with
º[lumbar meningomyelocele]

ºplatybasia (bone malformation at skull base)

ºoccipitovertebral joint malformation

º obstructive hydrocephalus (blocked magendie & Luschka)

28

A: Dandy-Walker Syndrome

B: Clinical Signs

A: DWS= noncommunicating/nonobstructive hydrocephalus associated with atresia of [Foramen Magendie] and [Foramen Luschka]

B:
1) Dilation of 4th ventricle
2) Agenesis of cerebellar vermis and small cerebellar hemispheres
3) Occipital meningocele
4) Agenesis of Corpus Callosum Splenium

29

A: Filum Terminale Syndrome

B: This Syndrome is associated with ___ tumors or ______

C: How do MD improve condition?

Filum Terminale Syndrome
occurs when TETHERED, Thick and Short filum terminale forms--->weakness & sensory deficits in LE and neurologic bladder

B: Usually associated with LIPOMATOUS tumors or MENINGOMYELOCELES

C: Better after transection

30

Craniostenosis

Premature closing of Cranial Sutures

31

___ __ is the most frequent chromosomal abnormality and leading cause of ____ ______

B: What 5 Characteristic physical features of this dz

TRISOMY 21 is most frequent Chromosomal Abnormality and leading cause of MENTAL RETARDATION

B:
1) Flat facial profile
2) Slanting palpebral fissures
3) Epicanthic folds
4) open mouth
5) short stature and round head

32

Lissencephaly agyria

Forebrain Malformation in which # of gyri DEC or are just ABSENT!! --->results in Smooth-surfaced brain = SEVERE neurological impairment rarely viable

33

A: Microcephaly

B: Clinical signs [3]

C: Causes [3]

Forebrain Malformation in which Cortical neurons DEC
--->simplification of Cortical Gyri

B:
1. STRIKING REDUCTION in head size
2. Brain weighs less than 300 g (normal is ~1300 g)
3. Seizures & Motor dysfunction

C:
*HIV-1
*Chromosomal abnormalities
*Fetal Alcohol Syndrome

34

Holoprosencephaly

incomplete separation of 2 cerebral hemispheres causing SINGLE TELENCEPHALIC MASS! Associated with Trisomy 13, midline facial problems and cyclopia

35

Agenesis of [Corpus Callosum] may include absence of _____ and ______ commissures. It is often accompanied with ______ ____ ____. Pt may appear normal but often have ____ and _______

Agenesis of [Corpus Callosum] may include absence of ANTERIOR and HIPPOCAMPAL commissures. It's often accompanied with MISSHAPEN LATERAL VENTRICLES. Pt may appear normal but often have FOCAL SEIZURES and MENTAL RETARDATION

36

What VENTRICLES/PASSAGE does each of the Primary Brain Vesicles form? They do this in Week ___

A: Prosencephalon Forebrain = ______ + ______

B: Mesencephalon midbrain = ______

C: Rhombencephalon Hindbrain = ______

Primary Brain Vesicles = Week 4!
A: Prosencephalon Forebrain = [Interventricular Foramen of Monroe] + 3rd Vt

B: Mesencephalon midbrain = [Cerebral Aqueduct of Sylvius]

C: Rhombencephalon Hindbrain = 4th Vt