Embryology Flashcards
1
Q
The anterior pituitary, lens, and cornea are derived from which germ layer?
A
Surface ectoderm
2
Q
The posterior pituitary, retina, optic nerve, brain, and spinal cord are derived from which germ layer?
A
Neural tube
3
Q
The adrenal medulla, and autonomic and sensory nerves are derived from which germ layer?
A
Neural crest
4
Q
What are the primary brain vesicles?
A
- Forebrain or Prosencephalon
- Midbrain or Mesencephalon
- Hindbrain or Rhombencephalon
5
Q
What are the secondary brain vesicles?
A
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
6
Q
When do the primary brain vesicles form?
A
4 weeks
7
Q
When do the secondary brain vesicles form?
A
5 weeks
8
Q
What are the parts of the spinal cord during development?
A
- Neuroepithelial
- Mantle
- Marginal
9
Q
Where does the: dorsal root sensory nerve, sympathetic neuroblast cells, Schwann cells, odontoblast cells, leptomeninges, and mesenchyme of the pharyngeal arches come from?
A
Neural Crest Cells
10
Q
What neurological condition has the following:
- can be detected in utero
- surgery can repair the defect sometimes in utero, often after the birth
- Permanant neural tube defects often results in leg weakness/paralysis and bowel/bladder problems
A
Spina Bifida
11
Q
What developmental neurological condition has the following:
- Forebrain/stem exposed
- Not compatible with life
- Frog like appearance and open calvaria on ultrasound
- Polyhydraminos
A
Ancephaly
12
Q
What neurological developmental condition has the following:
- Brain/meninges herniate through the skull
- Commonest site is occipital bone
- Least common type of neural tube defect
A
Encephalocele
13
Q
AFP is made by ___ and excreted through the ___
A
The yolk sack; fetal kidneys
14
Q
High AFP indicate what?
A
Neural Tube Defects
15
Q
What developmental neurological condition has the following:
- Cephalic Malformation
- Failure of cleavage of prosencephalon
- Left/Right hemispheres fail to separate
- Usually occurs during 5-6 weeks
- Failure of signaling from SHH
- Cleft lip/palate and cyclopia
A
Holoprosencephaly
16
Q
What developmental neurological condition has the following:
- Cerebellar tonsils herniate through foramen magnum
- Associated with syringomyelia
- Usually no symptoms until adolescence or adults
- Headache due to me Ingram irritation (cough headache)
- Cereballar dysfunction
- Cranial nerve disfunction
A
Arnold Chiari Type I
17
Q
What developmental neurological condition has the following:
- herniation of vermis and tonsils
- almost have myelomeningocele
- blockage of aqueduct
- hydrocephalus
A
Arnold Chiari Type II
18
Q
What secondary vesicles does the prosencephalon form?
A
Telencephalon and Diencephalon
19
Q
What vesicle are the following derived from: cerebral hemispheres, caudate, putamen, amygdaloid, claustrum, lamina terminalis, olfactory bulbs, hippocampus?
A
Telencephalon
20
Q
What vesicle are the following derived from: epithalamus, subthalamus, thalamus, hypothalamus, mamillary bodies, neurohypophysis, pineal gland, globus pallidus, retina, iris, ciliary body, optic nerve (CN II), optic chasm, optic tract?
A
Diencephalon
21
Q
What vesicle is the following derived from: Midbrain?
A
Mesencephalon
22
Q
What secondary vesicles are derived from the Rombencephalon?
A
Metencephalon and Mylencephalon
23
Q
What vesicle are the following derived from: pons and cerebellum?
A
Metencephalon
24
Q
What vesicle is the following derived from: medulla?
A
Mylencephalon
25
What day does the cranial neuropore close?
Day 25
26
What day does the caudal neuropore close?
Day 27
27
What does the mantle layer make?
Gray matter
28
Whats does the marginal layer make?
White matter
29
What does the alar plate make?
Sensory neurons
30
What does the basal plate make?
Motor neurons
31
What vesicle does CN I (olfactory) derive from?
Telencephalon
32
What vesicle does CN II (Optic) derive from?
Diencephalon; forebrain
33
What vesicle does CN III (Oculomotor) and CN IV (Trochlear) derive from?
Mesencephalon; midbrain
34
What vesicle does CN V (Trigeminal), CN VI (Abducens), CN VII (Facial), CN VIII (Acoustic), CN IX (Glossopharyngeal), CN X (Vagus), and CN XI (Hypoglossal)?
Metencephalon and Mylencephalon;
| Hindbrain
35
What type of Arnold Chiari has only the tonsillar herniation? What is associated with this?
Type I;
36
What type of Arnold Chiari has the tonsils and vermis herniation? Has hydrocephalus and myelomeningocele?
Type II
37
What type of Arnold Chiari has cerebellar herniation into cervical myelomeningocele?
Type III
38
What type of Arnold Chiari has cerebellar agenesis with small posterior fossa?
Type IV
39
The position of the anterior neuropore is represented in the adult by what structure?
Lamina Terminalis
40
Dorsal sensory nerves derive from where?
Neural Crest Cells
41
Endogenous retinoid acid is important for what stage of differentiation of the developing CNS?
Craino-caudal axis differentiation of the neural tube; FGF also helps
Higher concentrados are at the cranial end of the neural tube
42
Which one is more specific: AFP or AChE?
AChE
43
When does the CNS develop?
3rd week
44
Im what direction does the fusion of the cervical region begin?
Cranio-caudal direction
45
What other embryologic structure does the neuropore communicate with?
The amniotic cavity
46
What part of the neural tube persists as the central canal of the spinal cord?
The lumen of the neural tube beyond the Rhombencephalon
47
What is the cavity of the Rhombencephalon?
The fourth ventricle
48
What is the cavity of the Diencephalon?
The third ventricle
49
What is the cavity of the telencephalon?
The lateral ventricles
50
What does the lumen of the mesencephalon (cerebral aqueduct) do?
Communication of the third and fourth ventricle
51
How do the lateral ventricles communicate with the third ventricle?
By the interventricular foramen
52
What do the neuroblast cells arise from?
Neuroepithelial layer
53
What separates the basal from alar plates?
Sulcus limitans
54
What does the intermediary horn contain?
Sympathetic area (T1-L2)
55
What develops into multipolar and forms the central motor root of the spinal nerve?
Neuroblast cells seen in the mantle layer
56
What ascends and descends in the marginal layer as association neurons (sensory)?
The axons of the neurons from in the alar plate
57
Where do glioblasts arise from?
Neuroepithelial cells
58
Where do microclima cells originate?
Vascular mesenchyme
59
What do ependymal cells of the central canal of the spinal cord differentiate from?
Neuroepithelial cells
60
When is myelination of the neurons completed?
After the first year
61
What is a condition the neural grove fails to close completely and is exposed to the surface? When it affects the spinal cord it is called? When it affects the brain it is called?
Rachischisis; Myeloschisis; anencephalus
62
What is the condition that usually affects in the lumbosacral region spinal cord is normal, skin over the affected area contains tufts of hair (no increase in alpha fetal protein AFP)?
Spinabifida occulta
63
What is the condition where arachnoid and pia maters proturude through the bifid spines and form a cystic swelling (increase in AFP)?
Meningocele/ spina bifida cystica
64
What is the condition where a cystic sac contains spinal cord and its nerves. It is covered by thin friable vascular membrane. Commonly associated with other anomalies( Arnold Chiari malformation)?
Meningo-myelocele
65
What is the condition where there is agenesis of cerebellar vermis and splenium of corpus callosum, failure of luschka and magendie?
Dandy walker malformation
66
What homones are expressed in nonneural ectoderm, maintain and upregulate expression of PAX3 and PAX7 in the alar and roof plates?
BMP4 and BMP7
67
The mesencephalon’s alar plates form the anterior and posterior colliculi as relay stations for ___
Visual and auditory reflex centers, respectively
68
What forms the adenohypophysis, the intermediate lobe, and pars tuberalis, and the diencephalon forms the posterior lobe, the neurohypophysis, which contains neuroglia and receives nerve fibers from the hypothalamus.
Rathke pouch
69
Blockage of CSF in the ventricular system or subarachnoid space results in ___
Hydrocephalus
70
Which genes pattern the anteroposterior axis in the hindbrain and specify rhombomere identity.
HOX genes
71
Some transcription factors containing a homeodomain pattern the anteroposterior axis in the forebrain and midbrain regions, include ___
LIM1 and OTX2
72
The anterior neural ridge (ANS) and the rhombencephalic isthmus, secrete ___, which serves as the inducing signal for these areas.
FGF8
73
In response to this FGF8, the cranial end of the forebrain expresses ___, which regulates development of the telencephalon, and the isthmus expresses ENGRAILED genes that regulate differentiation of the cerebellum and the roof of the midbrain.
FOXG1
74
Which gene, secreted by nonneural ectoderm, induce and maintain expression of dorsalizing genes?
BMP4 and BMP7
75
The suprarenal (adrenal) gland is derived from two sources: (1) mesoderm from the posterior body wall that proliferates to form the ___ that is replaced by a second proliferation of these cells that form the ___
Fetal cortex; definitive cortex.
76
The suprarenal (adrenal) gland is derived from two sources: (2) neural crest cells that migrate from the neural folds and form the ___ of the gland.
Medulla
77
What plays a critical role in regulating HOX expression?
Retinoids (retinoic acid)
78
Early in development, the pia-arachnoid layers comprise the ___
Leptomeninges
79
The first of the crossing bundles to appear in the lamina terminalis is the ___. It consists of fibers connecting the olfactory bulb and related brain areas of one hemisphere to those of the opposite side
Anterior commissure.
80
The second commissure to appear is the ___. Its fibers arise in the hippocampus and converge on the lamina terminalis close to the roof plate of the diencephalon. From here, the fibers continue, forming an arching system immediately outside the choroid fissure, to the mamillary body and the hypothalamus.
Hippocampal commissure (fornix)
81
This important commissure appears by the 10th week of development and connects the nonolfactory areas of the right and the left cerebral cortices. Initially, it forms a small bundle in the lamina terminalis. As a result of continuous expansion of the neopallium, however, it extends first anteriorly and then posteriorly, arching over the thin roof of the diencephalon.
Corpus callosum
82
In addition to the three commissures developing in the lamina terminalis, three more appear outside of this region. Two of these are ___. They are just below and rostral to the stalk of the pineal gland. The third is the ___ which appears in the rostral wall of the diencephalon, contains fibers from the medial halves of the retina.
Posterior and habenular commissures; the optic chiasma
83
The cerebral cortex develops from the pallium, which has three regions:
(1) the paleocortex (paleopallium), (2) the archicortex (archipallium), and (3) the neocortex (neopallium)
84
What is associated with the olfactory cortex and forms the hippocampus and paleopallium, which are the oldest parts of the cortex?
The archipallium
85
In the ___, waves of neuroblasts migrate to a subpial position and then differentiate into fully mature neurons. When the next wave of neuroblasts arrives, they migrate through the earlier formed layers of cells until they reach the subpial position.
Neopallium
86
The ___, being a part of the wall of the hemisphere, likewise expands posteriorly and is divided into two parts: (1) a dorsomedial portion, the caudate nucleus, and (2) a ventrolateral portion, the lentiform nucleus, which is made up of the putamen and globus pallidus
Corpus striatum
