Von Bartheld: Development 1 (TMI... Don't Use This Deck) Flashcards
What is the 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
How does the neural tube form?
ectoderm invaginates and forms the neural PLATE, then the neural GROOVE, then the edges fuse and form the neural TUBE!
What induces the ectoderm to become neural ectoderm?
the notochord signals to the overlying ectoderm to become neuronal
What must be inhibited for neurectoderm to be induced?
BMP-4
*noggin and chordin inhibit this
What happens when neurulation does not proceed as planned?
spina bifida
When does neural tube closure occur?
in the 4th week *relatively early
What are some types of spina bifida?
spina bifida occulta
meningocele *neural tube intact, but meninges bulging out
meningomyelocele *neural tube bulging out
rachischisis *no neural tube formation
The most common human malformation
neural tube defects
*incidence 1-8/1000
What can cause neural tube defects?
teratogens, chromosomal, diabetes, hyperthermia
How do you diagnose neural tube defects prenatally?
alpha-fetoprotein
ultrasound
How can you prevent neural tube defects?
folic acid
*a lot of food is fortified w folic acid for this reason
What are some teratogens that affect neuronal development?
rubella cytomegalovirus toxoplasmosis x-rays hyperthermia epilepsy meds vit A overdose folic acid antagonists alcohol
During which weeks of development is there the greatest risk of malformation of the fetus?
3-8 weeks gestation
*organs are forming
What are these associated with? thin upper lip short palpebral fissures flat nasal bridge short nose elongated philtrum *distance b/w nose and lip
fetal alcohol syndrome
What occurs if the choroid fissure persists?
coloboma
The inner ear forms from the (blank) initially, which invaginates and forms the (blank) and then the (blank).
otic placode; otic pit; otic vesicle
What is the middle ear derived from?
endoderm
1st and 2nd pharyngeal arches *ossicles
What regulates the segmentation of the neuraxis?
Hox genes
The prosencephalon becomes what two things?
telencephalon and diencephalon
4 components of initial neural tube
prosencephalon
mesencephalon
rhombencephalon
spinal cord
Which portion of the developing neural tube does the optic cup come from?
the diencephalon
What does the pituitary develop from?
neural tube *posterior lobe
ectoderm *anterior lobe
What are the sources of neurons?
neural tube *ventricular zone
placodes
neural crest
stem cells
T/F: Neural crest contributes to cranio-facial development
True
The neural crest gives rise to cells which can migrate and attain different fates. What cells can they form?
pigment cells in skin chromaffin cells in adrenal medulla Schwann cells and satellite cells parasympathetic plexus in the gut odontoblasts *part of teeth
self-renewing; can give rise to ALL tissue and cell types (including germ cells)
embryonic stem cell
Self-renewing
Can give rise to full range of diploid, tissue-specific cell classes
somatic stem cell
self-renewing
can give rise to any diploid cell type in the CNS or PNS
neural stem cell