.
Notochord
Limbs
Primitive streak
Neural crest cells
Chorion
Morula
Epiblast
Embryoblast
Trophoblast
The embryonic disk is composed of two layers
The intermediate mesoderm forms the heart
The endodermal layer migrates into the primitive streak to form the somites
The endodermal layer gives rise to the simple columnar cells lining the stomach
The cardiogenic area lies at the base of the primitive streak
Gonads
Buccopharyngeal membrane
Cardiogenic area
Somites of the back
Medullary region of the adrenal gland
Bones of the arm
Cartilage of the trachea
Simple columnar cells of the stomach
Melanocytes of the skin
Epidermis of skin
Telencephalon, lateral ventricles, cerebral cortex
Colliculi, cerebral aqueduct, tectum
Fourth ventricle, myelencephalon, pons
Hypothalamus, third ventricle, optic vesicles
Rathke’s pouch, infundibulum, hypophysis
Failure of cranial neuropore to close
Hydrocephalus
Abnormal histogenesis in the spinal cord
Teratogenic insult to neural crest cells
Spina bifida with meningomyelocele
Endoderm
Mesoderm
Ectoderm
Neural crest cells
Amniotic fluid is primarily derived from maternal blood
A reduced volume of amniotic fluid is called Oligohydramnios
The fetus contributes urine to the amniotic fluid
Amniotic fluid contains nutrients and is the main nutritional support for the fetus
The fetus swallows its own amniotic fluid which is important for maintaining the correct volume of fluid in the amnion
Gonads
Buccopharyngeal membrane
Cardiogenic area
Somites of the back
Medullary region of the adrenal gland
The embryonic disk is composed of two layers
The endodermal layer gives rise to the skin
The endodermal layer migrates into the primitive streak to form the somites
The intermediate mesoderm forms the kidneys and gonads
The cardiogenic area lies at the base of the primitive streak
Bones of the arm
Cartilage of the trachea
Simple columnar cells of the stomach
Parafollicular cells of the thyroid gland
Epidermis of skin
Formation of the intraembryonic coelom
Lateral folding
Formation of the intermediate mesoderm
Longitudinal folding
Formation of the head fold
Umbilical artery
Pulmonary artery
Aorta
Femoral artery
Internal carotid artery
Spongy layer of the decidua basalis
At the chorionic plate
Between the chorion and the amnion
Between the smooth chorion (chorion leave) and the decidua parietalis
At the umbilical cord
Somatic sensory
Visceral sensory
Special sensory
Motor
Sympathetic
Rectus abdominis
Pectoralis major
Sternocleidomastoid
Inner intercostal
Rectus capitis posterior minor
Saddle anesthesia
Hydrocephalus
Sphincter paralysis
Arnold-Chiari malformation
Acrania
Failure of cranial neuropore to close
Hydrocephalus
Abnormal histogenesis in the spinal cord
Teratogenic insult to neural crest cells
Spina bifida occulta
The cranial neuropore closes on the 27th day of gestation
A fetus with anencephaly caused by a failure of the cranial neuropore to close can also result in oligohydramnios
The caudal neuropore closes on the 25th day of development
The cranial and the caudal neuropore close simultaneously around the 26th day of development
Prior to closure of the neurpores the neural tube is in open communication with the surrounding amniotic fluid
Spina bifida with meningomyleocele
Spina bifida occulta
Spina bifida with meningocele
Spina bifida with rachiscisis
Spina bifia cystica