Von Bartheld: Development Flashcards
The central nervous system appears in the third week of human development as the (blank), a thickening of the ectoderm. The neural plate is induced by signals from the (blank).
neural plate; notochord
The neural plate folds inward, resulting in a neural groove, and the edges close in the midline to form the (blank). Fusion begins in the center and proceeds in both cranial (cephalic) and caudal (spinal) directions
neural tube
The closure of the neural tube occurs between day 25 and 27. This concludes a process called (blank)
neurulation
Failure of the neural tube to close results in abnormalities known as (blank). When they occur in the spinal cord, they are called (blank). When they occur at the cephalic end, the forebrain does not form (anencephaly). When the flow of CSF is obstructed, it accumulates resulting in (blank). When the meninges protrude, these defects are called (blank), when also nervous tissue protrudes, they are called (blank).
neural tube defects; spina bifida; hydrocephalus; meningocele; meningomyelocele
These cells migrate along distinct paths and give rise to a variety of structures in the body, including sensory and sympathetic ganglia, Schwann cells, adrenal secretory cells, pigment cells, odontoblasts, and mesenchymal cells (some bones of the skull and face).
neural crest cells
Some sense organs and sensory neurons are generated in ectodermal thickenings
called (blank). The olfactory and the auditory/vestibular sense organs are largely generated by placodes, while most of the eye forms in a different way. How?
placodes; by an outpocketing of diencephalon forming the optic vesicles
The retina is embryonically and functionally part of the (blank). The retina has (blank) glia, (blank) blood supply, and intracranial pressure is manifested (and most easily diagnosed) by observation of the retina (“papilledema”).
CNS; CNS; CNS
At 4-6 weeks, subdivisions of the brain include the (blank), consisting of the telencephalon and the diencephalon, the (blank) (midbrain) and the (blank), consisting of the metencephalon (pons and cerebellum), and myelencephalon (medulla).
prosencephalon; mesencephalon; rhombencephalon
The neural tube becomes patterned along the longitudinal axis into (blank). Expression of certain transcription factors correlates with distinct neuromeres. These are called (blank) genes and regulate the segmental development in embryos.
neuromeres; Hox (homeobox)
The eye develops from (blank) components (lens) and (blank) (entire retina).
placodal; neural tube
The inner ear begins to develop at 22 days from the (blank), a thickening of the surface ectoderm at the level of the rhombencephalon. The placode invaginates rapidly and forms the otic (blank). The otic vesicle gives rise to the saccule, cochlear duct, utricle, semicircular canals, and the endolymphatic duct. These are collectively known as the membranous labyrinth. The otic placode, together with the neural crest, also give rise to the auditory and vestibular ganglia.
otic placode; vesicle
What can cause severe damage to the organ of Corti?
Rubella virus
toxoplasmosis
What two things does the pituitary develop from?
an outpocketing of the oral cavity *Rathke’s pouch
a downward extension of the diencephalon *the infundibulum
What are the positional changes of the spinal cord?
Initially the spinal cord extends throughout the length of the embryo, and spinal nerves pass through the intervertebral foramina at the level of their origin. The vertebral columns lengthen more rapidly than the neural tube, and the terminal end of the spinal cord shifts to a higher level.
(blank) maintain the ectoderm and prevent it from turning into neurectoderm – its default pathway
BMPs
Agents that can interfere with neurulation include (blank). Another class of inducers are peptide growth factors such as fibroblast growth factor and transforming growth factor. When signaling by these molecules is altered, the formation of the nervous system is compromised.
vit A
The most sensitive periods for teratogenic actions are in the (blank) week in the first trimester.
3-5th
Sequence of neuronal development
neural induction | neural tube formation | generation of neurons and glia | axon growth from neurons | synapses made with targets | dendrite growth | myelination
Neurons of the adult human brain are generated over a time course of a few months from a small population of precursor cells. These cells are located in the (blank), the innermost cell layer surrounding the lumen of the neural tube
ventricular zone
Postmitotic cells leave the ventricular zone and migrate to their final destinations in the brain. Birthdating studies have shown that the cortex forms in an (blank) manner. The first neurons are eventually located in the (blank) layer, and later generations of neurons migrate through the older cell layers and come to lie in the (blank) layers.
inside-out; deepest; superficial
Lineage appears to play a much smaller role in specifying cell fate than (blank) which may begin as early as the final mitotic cycle.
cell-cell interactions
can indefinitely self-renew, and can give rise to ALL tissue and cell types, including germ cells.
embryonic stem cells
are self-renewing, and they can give rise to a full range of cell classes within certain tissues (e.g., neural and glial cell types).
neural stem cells
cannot self-renew continuously, and typically give rise to one class of progeny.
progenitor cells
