ANAT 312 neural developement - incomplete

  1. first week of human development
    • day 0 fertilization in the tubes
    • day 6 blastocyst formation (trophoblast/blastocoele/inner cell mass)
    • day 7-10 implantation in the lining of the uterine wall
    • day 8 formation of embryonic disc (bilaminar disc) of the implanted blastocyst (epiblast/dorsal columnar layer - hypoblast/ ventral cuboidal layer)
  2. gastrulation
    • developement of the three germ layers
    • occurs during the 3rd week of development
    • epiblast (forms all 3 germ layers) cells migrate through the primitive streak laterally and cranially between the epiblast and hypoblast and become incorparated in the hypoblast |(polonaisien movement)
    • bilaminar embryo becomes trilaminar as the ectoderm, mesoderm and endoderm form
    • primitive streak closes off forming the noto chord which is a mesodermal structure that signals neuralation (primitive node at the tip)
  3. neuralation
    • formation of the neural tube (ectodermal structure)
    • occurs from 3rd-4th week
    • induced by noto chord
    • ectoderm thickins forming the neural plate (only above the notochord) day 17
    • neural plate folds forming the neural groove day 18
    • neural tube separates from ectodermal surface (leaves behind crest cells) day 20
    • neural groove closes off and forms the neural tube (contains CSF) day 22
    • anterior neuro pore closes day 24
    • posterior neuro pore closes day 26 (both helped be vitamin b12/ folic acid)
  4. neural crest cells
    • form:
    • sensory ganglia of cranial nerves 5,7,9,10
    • post ganglionic neuraons of the ANS
    • Glial cells
    • Schwann cells
    • Satelite cells of PNS
  5. clinical problems
    • anencephaly- failiure of anterior neuropore closure and disruption of the surrounding somites
    • spina bifida- failiure of posterior neuropore closure and disruption of surrounding somites
    • spina bifida occulta - large birth mark and hair where missing bone is located
    • meningocele - fluid filled sace forms behind the spine
    • myelomeningocele - spinal cord and cord covering protrude behind the spine
  6. developement of the spinal cord
    • formed from caudal 1/3 of the neural tube
    • 1 - migratio of neuroblast cells from ventricular zone to the mantle zone
    • 2 - differentiation of neuroblast cells to neuron cell bodies in mantle zone and the differentiation of glioblast celss into neuroglial cells (astrocytes and oligodendrocytes)
    • 3 - axonal growth from the neuron cells bodies out into the marginal zone
Card Set
ANAT 312 neural developement - incomplete
neural developement