#2ndyearbiology

1. NEURULATION
11 DECEMBER

2.  On the Dorsal surface of Gastrula, over the
notochord, presumptive neural ectoderm is
present in the form of band.
 As gastrula elongates, the band thickness to form
a neural plate.
 In chick embryo of 18 hr, neural plate was seen
as flat, thickened area of ectoderm.
 In embryos of 21-22 hr, a longitudinal folding has
occurred, establishing the neural Groove in the
mid dorsal line, on either side of neural folds.
 In 24 hours embryo, the folding of neural plate is
visible.
 The embryo is now termed as Neurula.

3.  The anterior end of neural groove is widest and
forms the future brain and rest of portion is future
Spinal Cord.
 In the meantime, the neural plate sinks and the
neural folds grow towards one another and meet in
middorsal line, fuse and convert the neural groove
into neural tube.
 At the end of neural tube, a small opening called
ANTERIOR and POSTERIOR Neuro-pores are also
seen, which close later on.
 With the formation of neural tube, there is
formation of central nervous system and the cavity
enclosed is known as Neuro-coel.
 This whole process is known as Neurulation.

8. Thank You