test 2 Flashcards
morula
a mass of 12-16 cells that travels down the Fallopian tube into the uterus
blastula/blastocyte
a hallow ball of about 150 cells, implanting onto the uterine wall, then fully becomes imbedded into the wall
Which cell layer does the nervous system develop from?
ectoderm
neural plate
becomes neural tube and the neural crest cells
neural tube
becomes CNS, brain and spinal cord
neural crest cells
becomes PNS
what Is anencephaly?
failure of anterior tube to close, fatal
spina bifida
failure of posterior (bottom) tube to close
neuron proliferation
making of new neurons, 50,000-200,000 per second, from wk 6-17
migration
neurons move to specific parts of the central brain, influenced by genetics and biochemical environment. then gets a function
differentiation
transformation of cells, change based of new function or where they land. communicate with other neurons
synaptogenesis
-forming functional connections
-growing synapses
-increases rapidly after birth
-young children have many more then adults
myelination
-sheath formed on neuron in fetal period to speed transmission
-third trimester
-continues through early adulthood
how do neurons migrate?
they attach themselves to strands of glial fiber then slowly progress along the surface of the fiber
what happens in the nervous system during the 3rd trimester and the first 1-2 years of life?
the fetus gains weight and brain grows, the nervous system becomes more organized, more brain activity