11-24 NeuroEMBRYOLOGY Flashcards
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
Rostral part—–>Adult Brain :-)
CAUDAL part—->ADULT SPINAL CORD
Neural tube Lumen—->ventricular system of brain AND central canal of Spinal Cord
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
- ————————————————————————————–
- When POSTERIOR neuropore FAILS to close Day 27 = Lower neural tube defects—>[spina bifida with myeloschisis]
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)
- Neurocristopathy
2. What are 3 good examples of this?
- Any dz related to maldevelopment of [Neural Crest Cells]
- Medullary Carcinoma of Thyroid
- Schwannoma
- Neurofibromatosis type 1 (von Recklinghausen dz)
[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
[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
[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
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
- Mesencephalon (Midbrain) = remains as Mesencephalon
- rhombencephalon (hindbrain)—> metencephalon & myelencephalon
Flexures:
º[Cephalic midbrain flexure]= between Mesencephalon and metencephalon
PRIMARY VESICLE development = WEEK 4!
The 5 SECONDARY Brain vesicles form during Week __ and form ________. Describe what they form exactly?
- TELENCEPHALON [4]
- DIENCEPHALON [5]
- Mesencephalon [3]
- metencephalon [2]
- Myelencephalon
SECONDARY Brain vesicles = Week 6
- TELENCEPHALON = cerebral cortex/basal ganglia/hippocampus/amygdala
“BACH” - ## DIENCEPHALON = THALAMUS / hypoTHALAMUS / PINEAL GLAND / CHOROID PLEXUS / PITUITARY GLAND
- ## Mesencephalon = Tegmentum / Tectum / Peduncular Region
- metencephalon = pons / cerebellum
- Myelencephalon = Medulla
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
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
A: Sulcus Limitans [2]
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]
- ## Extends from Spinal Cord to rostral midbrainB: ((Caudal Eminence))
Arises from primitive streak, blends w/neural tube —> gives rise to sacral & coccygeal segments of spinal cord
- Myelination of Spinal Cord beings during month ____ in the _______ roots
- Oligodendrocytes accomplish myelination in the ___ vs. Schwann cells whom accomplish myelination in the _____
- Myelination of corticospinal tracts is not completed until after ___ years old and Myelination of [association neocortex] extends until you’re ____!
- Spinal Cord Myelination STARTS in month 4 within [Ventral Motor Roots]
- Oligodendrocytes accomplish myelination in the CNS! vs. Schwann cells whom accomplish myelination in PNS
- Myelination of Corticospinal tracts is not completed until after 2 years old….
and Myelination of [association neocortex] extends until you’re 30 YEARS OLD!
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]
[T or F] the Filum Terminale is a Neural-Active extension of the Spinal Cord
FALSE!!!!!
Filum Terminale is NON-NEURAL!
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.
————————————————————————————–
————————————————————————————–
Cerebellum:
Develops from rhombic lip (meTencephalic thickening @ rostral bordr of 4th ventricle). Histogenesis continues until after birth.
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
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
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.
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
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
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.
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
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 }
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** 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
