Notochord formation and neuralation

zainaboshodi's version from 2015-04-20 18:49


Question Answer
When does the notochordal process become a true notochord?After canalization and intercalation within the endoderm.
What are some of the functions of the notochord?Defining the primitive axis of the embryo (from oropharyngeal membrane to primitive node), rigidity, induces the formation of the neural tube and the vertebral column forms around the notochord.
How is the notochordal canal formed?As the notochordal process elongates, the primitive pit extends into it, forming the notochordal canal.
How is the notochordal plate formed?Prenotochordal cells become intercalated into the endoderm below and the chordal process fuses with the endoderm lying below.
What is neuralation?The process whereby the neural plate forms the neural tube.
What are some of the fates of neural crest cells?Drg, Ganglia of ANS and some of CN, sheaths of peripheral nerves, meninges, melanocytes, adrenal gland, skeletal and muscular components of the head
Where do somites originate?Columns of paraxial mesoderm which divide into paired bodies.
What are some of the things that somites give rise?Ribs, skull, vertebral column and axial skeleton
What are the three different component cell types of somite?Sclerotome, myotome and dermatome.
What do the sclerotome give rise to?Cells surrounding the neural tube, notochord and form vertebrae, ribs, tendons and cartilage.
What do the myotome give rise to?Provides a muscular component.
What do the dermatome give rise to?Dermis of the back.
What is visible at day 24?The neuropores are still open, the brain appears as 3 dilations and the 1st and 2nd branchial arches are visible.
At around what day does the cranial neuropore close?: 17-20
At around what day does the posterior neuropore close?: 26-29
What occurs in primary neuralation?: Folding and midline fusion of the neural plate, the tube is then covered by surface ectoderm which forms most of the spinal cord.
What occurs in secondary neuralation?: Remnants of the retreating primitive streak forms the tailbud. Mesenchymal cells of the tail bud form the 2nd neural tube. The lumen is continuous with that of the neural tube.
What is anencphaly?: When the vault of the skull doesn't close properly and a malformed brain is left exposed.
What is the prevalence of spina bifida?: 1 in 2000 live births.
How is spina bifida detected prenatally?: Increased alpha-feroprotein is present.
What is the recommended dose of folic acid for those attempting to get pregnant and throughout pregnancy?: 400ug per day

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