Embryology Stuff Flashcards
What are the developmental stages seen in weeks 1-2?
Zygote
Morula
Blastula
Bilaminar disc
What are the developmental stages seen in weeks 3-8?
Gastrualtion
Folding
Organogenesis
When does gestational age begin?
From 1st day of last normal menstrual period
When does embryonic age begin?
At fertilization
What are the two cell layers in the week of w 2’s?
Cytotrophoblast
Syncytiotrophoblast
Which cell layer produced HCG?
Syncytiotrophoblast
The syncytiotrophoblast is lacking what?
A cell boundary
What is the 1st sign of gastrulation?
Primitive streak
Where does the primitive streak form?
On the caudal end in the former epiblast
The cells of the primitive streak migrate and give rise to what?
Mesoderm
The primitive node is the originiation of the cells that will migrate toward the cranium and form what?
The notochord
From what does the nerual plate form?
Ectoderm
What does ectoderm give rise to?
Epidermis
Central and peripheral NS
Eyes
Internal ears
What does endoderm give rise to?
Epithelial linings of respirator and digestive tracts
Glands
Liver
Pancreas
What does mesoderm give rise to?
Muscles
Blood cells/lining of vessels
Smooth muscle
Serosa
As the notochord forms, the embryo lengthens which direction?
Caudal/cranially
Notochord instructs formation of what?
Neural plate
What are the landmarks on the neural plate?
Folds and grooves
The neural plate folds at the midline to form what?
Neural tube
Where do neural crest cells come from?
Cells from edge of fusing neural tube migrate and become neural crest cells
What do neural crest cells give rise to?
CT of head & neck Bones & muscles of head and neck Entire PNS Melanocytes Plays role in ectomesenchyme in tooth formation
Neural tube becomes what?
Brain and spinal cord
At what age does the “Japanese-American greeting” take place?
4th to 8th week
When does organogenesis begin?
4th to 8th week
What migrates above the prechordal plate to form the heart?
Mesoderm and neural crest cells
Somites are instructed by notochord to form what?
Mesoderm on dorsal aspect that will become muscle and bone
What contributes to the formation of the pharyngeal arches?
Neural crest
Where are rhombomeres found?
Transient structures in hindbrain area of neurotube
What is the main contributor toe the pharyngeal arches?
Neural crest cells
What forms mesenchymal cells and microglia?
Comes from bone marrow
What never is associated with the 1st pharyngeal arch?
CN V
What muscles are associated with the 1st pharyngeal arch?
Muscles of mastication
Mylohyoid
Anterior belly of digastric
What are the associated areas of the 1st pharyngeal arch?
Mandible and maxilla tissue
Meckles cartilage
What does Meckle’s cartilage form?
Bones of ear
Some ligaments
What do the grooves of the 1st pharyngeal arch form?
External auditory meatus
What does the pouch of the 1st pharyngeal arch form?
Tympanic membrane
Tympanic cavity
Mastoid antrum
Eustachian tube
What is the nerve associated with the 2nd pharyngeal arch?
CN VII
What muscles are associated with the 2nd pharyngeal arch?
Muscles of facial expression
Stapedius
Stylohyoid
What are the associated areas of the 2nd pharyngeal arch?
Reichert’s cartilage (styloid process, stylohyoid ligament, lateral horne of hyoid
What do the grooves of the 2nd pharyngeal arch form?
Nothing!
What do the pouches of the 2nd pharyngeal arch form?
Contribute to tonsils
What forms the anterior tongue?
Lateral and midline swellings (1st pharyngeal arch)
Where do the muscles of the tongue come from?
Occipital myotomes - use CN XII
What gives rise to the maxillary process and palatal shelves?
Frontonasal prominence and mandibular arch
What does meckel’s cartilage do in the mandible?
Nothing!
Palatal shelves come up vertically from what>
Maxillary prominence
