ANATOMY, PHYSIOLOGY & PATHOLOGY NOTES OF THE
NERVOUS SYSTEM
AND SPECIAL SENSES
FOURTH EDITION
EMBRYONIC DEVELOPMENT OF THE NERVOUS SYSTEM
PRE- SUMMARIZED NOTES
,General Embryonic Development is Described as Either
Trimesters (3x 3-Month Periods):
First: - Foundations of Major Organs
Second: - Development of Organs
Third: - Rapid Growth & Fully Functional Organs.
OR... Anatomical Stages: **(These are more relevant)
Pre-Embryonic Period: 0-2 Weeks
Fertilisation
Blastocyst Formation & Implantation
Gastrulation
Embryonic Period: 3-8 Weeks
Development & Differentiation of 3 Germ Layers into foundations
of Organs.
Foetal Period: 9 Weeks → Birth.
Period of Growth, NOT Differentiation
, Some Useful Terminology:
o “Rostral” = Head
o “Caudal” = Tail
o “Dorsal” = Back
o “Ventral” = Front
o “Ganglia” = Groups of Nerve-Cell Bodies
o “Gyrus” = Elevations (Crests) of the folds on the Cerebral
Cortex.
NERVOUS SYSTEM
AND SPECIAL SENSES
FOURTH EDITION
EMBRYONIC DEVELOPMENT OF THE NERVOUS SYSTEM
PRE- SUMMARIZED NOTES
,General Embryonic Development is Described as Either
Trimesters (3x 3-Month Periods):
First: - Foundations of Major Organs
Second: - Development of Organs
Third: - Rapid Growth & Fully Functional Organs.
OR... Anatomical Stages: **(These are more relevant)
Pre-Embryonic Period: 0-2 Weeks
Fertilisation
Blastocyst Formation & Implantation
Gastrulation
Embryonic Period: 3-8 Weeks
Development & Differentiation of 3 Germ Layers into foundations
of Organs.
Foetal Period: 9 Weeks → Birth.
Period of Growth, NOT Differentiation
, Some Useful Terminology:
o “Rostral” = Head
o “Caudal” = Tail
o “Dorsal” = Back
o “Ventral” = Front
o “Ganglia” = Groups of Nerve-Cell Bodies
o “Gyrus” = Elevations (Crests) of the folds on the Cerebral
Cortex.
