Embryology Flashcards
What is the gene that is expressed at the base of limbs in a zone of polarizing activity?
SHH (sonic hedgehog gene)
MCH1 likes to bind to what type of T cell
CD8 Killer cells
What does the SHH gene do?
The sonic hedgehog gene regulates patterning along the anterior-posterior axis.
MCH 2 (II) binds to what kind of cells?
CD4 helper T cells
What two layers make up the bilaminar embryonic disc?
epiblast and hypoblast
What layer develops into ALLLL
Epiblast
Yolk sac will develop into what?
Allantois
The embryo exists as a bilaminar disk during the _______ week of development.
2nd
Describe the shunts of fetal circulation?
What structures are you bypassing in fetal circulation?
the liver once and the lungs twice….
(meaning you avoid using the liver in one of the shunts, and the lungs in two of the shunts)
the first pharyngeal cleft becomes what?
the external auditory meatus
The 2nd, 3rd, and 4th pharyngeal cleft becomes what?
temporary cervical sinuses
they are obliterated by proliferation of 2nd arch mesenchyme
During fetal development, _____ typically forms the CNS and brain, while _____ typically forms the PNS and non-neural structures nearby.
Neuroectoderm
neural crest cells
Pharyngeal arch 1; what cranial nerve might be affected?
CN 5
Trigeminal - mandibular branch, muscles of mastication
Pharyngeal arch 2; what cranial nerve might be affected?
CN 7
Facial
ADD MORE
Arch 3; what cranial nerve might be affected?
CN 9
Glossopharyngeal
ADD MORE
Arch 4; what cranial nerve might be affected?
CN 9 and 10
VAGUS
Superior laryngeal N
ADD MORE
Arch 4; what cranial nerve might be affected?
CN 10
VAGUS N; Superior laryngeal branch
Muscles: pahryngeal constrictors, cricothyroid, levator veli palatini
- posterior 1/3 tongue
Cartilage: thyroid
The fetal component of the placenta consists of which two cell types?
Cytotrophoblast; syncytiotrophoblast
Pharyngeal Arch 6; what cranial nerve might be affected?
SPEAK; Speech
VAGUS; recurrent and inferior laryngeal branch
MUscles: all intrinsic muscles of larynx except cricothyroid
Cartilage: sing and act, AND THYROID
1st pharyngeal pouch
EAR
Middle ear cavity, eustachain tube, mastoid aid cells
- contributes to endoderm-lined structures of the ear
2nd pharyngeal pouch
tonsils
- epithelial lining of palatine tonsils
3rd pharyngeal pouch
inferior parathroids, thymus
- dorsal wings - inferior parathyroids
- ventral wings - thymus
4th pharyngeal pouch
Superior Parathyroids
Dorsal wings - superior parathyroids
Ventral wings - parafollicular cells (C cells) of thyroid
The umbilical cord contains how many umbilical arteries and umbilical veins?
Two arteries and one vein
Do the umbilical arteries carry oxygenated or deoxygenated blood?
Deoxygenated blood
AFAB
default development (if no androgens present)
- mesonephric duct degenerates and the male remnantis appendix testes
- paramesonephric (mullerian) duct develops – develops into female internal structures
–> these are the fallopian tubes, uterus, proximal vagina
distal vagina is from what…
urogenital sinus
AMAB
needs androgens to develop
- paramesonephric duct DEgenerates (female remnant is gartner duct)
- mesonephric (Wolffian) duct develops – develops into male internal structures (except prostate)