development of the face Flashcards
(37 cards)
what day does neural plate formation occur at
day 17 -
what day does the formation of the neural folds, neural groove occur on
day 18
why does spina bifida happen?
because the posterior neuropore of the neural tube doesn’t close. why it doesnt close is becaause of a lack of folate. folate is KEY in the closing of the ant and post neural tube
folate: folic acid (vit B9)
when do the neuroporesclose (which order)
ant neuropore closes at day 24
post neuropore closes at day 26
what are the basic steps of neuralation
- ectodermal proliferation
- neural plate formation due to the formation of the neural folds and grooves
- neural crest cell formation at edges of neural folds
- neural tube formation
- closing of the ant and post neuropores
how does the neural tube form?
edges of the neural folds fuse with one another, neural grove moves down (invaaginates) so now this tube becomes underneath the ectoderm and within the mesoderm.
neural crest cells sit on top of the neural tube underneath the ectoderm
what end of the neural tube is the anterior neuropore at?
cranail end
what end of the neural tube is the posterior neuropore at?
caudal end
where is the notochord developed from?
mesoderm cells form it after gastrulation is complete
what membrane forms the oral cavity
buccopharangeal membrane
what does the ectoderm form in the pharyngeal apparatus
pharyngeal clefts
what does the mesoderm form in the pharyngeal apparatus?
pharyngeal arches
what does the endoderm form in the pharangeal apparatus
pharangeal pouches
what is the stomodeum
gap between developing face of the embryo and the first pharyngeal arch
where is the buccophaarangeal membrane located
within the stomedeum
when and how does the developing embryo fold?
the embryo will start folding so that the caudal and cranial end almost meet at 4 weeks
what structures are in each pharangeal arch?
artery
cartilage
nerve
which nerves innervate every pharangeal arch
PA1 = TRIGEMINAL
PA2 = FACIAL
PA3 = GLOSSOPHARANGEAAL
PA4 = VAGUS
PA6 = RECCURANT LARANGEAL NERVE
how does the ectomesenchyme form
neural crest cells migrate to the mesoderm forming the ectomesenchyme ->which is an important connective tissue for different structures
function of the ectomesenchyme?
form of mesenchyme , consisting of neural crest cells -> this forms the tissues of the head and neck including: bone, cartilage, connective tissue and dentine
what does the first pharyngeal arch form
mandible
maxilla
what tissues of the tooth do ectomesenchyme cells make
all tissues except enamel
what pharyngeal arch is affected by failure of neural crest cell migration
First arch syndromes are congenital defects caused by a failure of neural crest cells to migrate into the first pharyngeal arch. They can produce facial anomalies. Examples of first arch syndromes include Treacher Collins syndrome and Pierre Robin syndrome.
what is treacher collins syndrome and what is it caused by
- autosomal dominant condition
- caused by a mutation in the TCOF1 gene
- this gene is required to make a protein (treacle) that plays a critical role in formation of bone and tissues of the face
