What is the order of neurulation?
neural plate --> neural groove --> neural tube
What structure induces neurulation?
The caudal 1/3 of the neural plate develops in what?
future spinal cord
What are the last two parts of the neural groove to close during neurulation?
Cranial & caudal neuropores
which neuropore, cranial or caudal, closes last?
caudal neuropore (Day 27)
Where does secondary neurulation occur?
the sacrum and coccyx
What occurs during secondary neurulation?
the caudal eminence fuses with the caudal portion of the neural tube
What cells are derived from neuroectoderm?
neurons of the CNS, glial cells, ependyma
What type of glial cell is not derived from neuroectoderm?
microglial cells (macrophages); derived from mesenchymal cells
NCCs give rise to which part of the nervous system?
the peripheral NS including all ganglia outside of the CNS
The 4th pair of somites demarks what?
Marks which part of the NT will form the brain and which will form the spinal cord
What are the 3 divisions of the NT that will develop into the brain?
Prosencephalon/forebrain, mesencephalon/midbrain, rhombencephalon/hindbrain
The prosencephalon/forebrain divides to give rise to what 2 brain regions?
Telencephalon (cerebrum) and diencephalon
The mesencephalon/midbrain gives rise to what brain region?
The rhombencephalon/hindbrain gives rise divides into what brain structures?
metencephalon (pons) and myelencephalon (medulla)
When does the telencephalon begin to divide into two hemispheres?
by the 5th wk
What flexure is found between the midbrain & hindbrain?
What flexure is found between the hindbrain and the cervical region?
During what timeframe are the basal ganglia developing?
What structures are derived from the telencephalon? (6 major structures)
cerebral cortex, subcortical white matter, olfactory bulb/tract, basal ganglia, amygdala, hippocampus
What structures are derived from the diencephalon? (4)
thalamus, hypothalamus, epithalamus (pineal gland), and eyes (optic nerve)
Which 2 cranial nerves are derived from the midbrain?
oculomotor and trochlear
What structures are derived from the midbrain?
cerebral peduncles, tectum, tegmentum, substania nigra, and periaquedutal gray matter
What are the structures found in the tectum?
What is holoprosencephaly (HPE)?
incomplete separation of the cerebral hemispheres (errors during 5th wk)
What other malformations are associated with HPE?
facial malformations (cleft lip/palate), orbital hypotelorism
What two structures give rise to the pituitary gland?
1st PA ectoderm (Rathke's pouch) and neuroectoderm from forebrain (diencephalon)
the 1st PA ectoderm gives rise to which part of the pituitary gland?
anterior lobe (adenohypophysis)
Forebrain neuroectoderm gives rise to which part of the pituitary gland?
posterior lobe (neurohypophysis)
What separates the developing spinal cord into anterior and posterior plates?
the sulcus limitans