Embryology 2 Flashcards
Signaling from the primitive streak induces the formation of the ______
Notochord
Notochord
a longitudinal cellular tube within the mesoderm
Notochord process elongates by invagination of cells from the ______
Primitive pit
What are the functions of the notochord? (3)
- Induces overlying ectoderm to differentiate into neuroectoderm (Neural Plate)
- Induces formation of vertebral bodies
- Forms the nucleus pulposus of intervertebral disks
Notochord process extends _____ to the prechordal plate
Cranially
What are the stages of neurulation?
- Formation of the neural plate
- Formation of the neural folds
- Closure of neural folds to form neural tube
- Formation of neural crest
_____ gives rise to the central nervous system
Neural Tube
____ gives rise to the peripheral nervous system
Neural crest
The notochord induces overlaying _____ to form the ____
Ectoderm
Neural Plate
The neural plate invaginates to form the ____
neural groove
_____ flank the neural groove
Neural folds
______ fuse to form the neural tube
Neural folds
Describe closure of the neural tube
Closure begins in the midline and extends in both cranial and caudal directions
Cranial end of the neural tube becomes the ____, ___ and ____
Forebrain, midbrain and hindbrain
Caudal end of hte neural tube becomes the _____
Spinal cord
Describe the formation of the neural crest.
The neural folds begin to fuse and cells on the inner margin separate to form the neural crest, which lies between the neural tube and the overlaying surface ectoderm.
neural crest cells ultimately form what 2 things?
Spinal ganglia and ganglia of autonomic nervous sytem
What are the clinical implications of neural tube defects?
Failure of the neural tube to close at either end may result in defects of the brain and spinal cord
_____ mesoderm cells condense to form paired bodies called somites
Paraxial
In what directon do somites form?
Cranial to caudal
When does somite formation end?
End of week 5
What is the Coelom?
Horse-shoe shaped structure that is the precursor for the bodies cavities (pericardial, pleural, peritoneal)
What embryonic tissue layer gives rise to the coelom?
The lateral mesoderm
_____ forms the embryonic body wall
Somatopleure (layer of coelom)
_____ forms the embryonic gut
Splanchnopleure (layer of coelom)
When does the Coelom form?
Week 4
Folding of the embryo occurs in the ___ and ____ planes as a result of rapid growth
Median and Horizontal
Median folding produces ___ and ___ folds and results in the formation of what 2 embryonic structures?
Head and tail
Foregut and hindgut
Horizontal folding produces ____ and ____ folds and results in the formation of what embryonic structure?
Right and left
Midgut
Describe the process of the formation of the primordial heart.
Through median folding, cardiogenic mesoderm moves toward the ventral surface and gives rise to primordial heart.
_____ forms the urogenital ridge
_____ folding is responsible for the formation of the urogenital ridge.
Intermediate mesoderm
Horizontal
What are the 2 components of the urogenital ridge.
1) Nephrogenic cord (urinary system)
2) Gonadal ridge (internal genitalia)
What part of the developing embryo gives rise to the pharangeal arches?
Neural crest cells
What do the pharangeal arches ultimately become?
The structures of the face and neck
