9.29 Germ Layers 1 Flashcards
the notochord induces overlying ectodermal tissue to form the _______ (the precursor of the CNS)
neural plate
peripheral neurons are formed from the _________ cells
neural crest cells
failure of fusion of the neural tube at the cranial end
anencephaly
failure of fusion of the neural tube at the caudal end
spina bifida
where are neural crest cells located?
at the crests of the neural plate that form the neural folds
the dorsal root ganglia come from what kinds of neural precursor cells?
neural crest cells
the PNS come from what kinds of neural precursor cells?
neural crest cells
most of the bones and cartilage of the face come from what kinds of neural precursor cells? NOTE: NOT MUSCLE
neural crest cells
melanocytes come from what precursor cell?
neural crest cells
the CT of the aortic arch arteries and the septum separating aorta and pulmonary vessel come from what kinds of neural precursor cells?
neural crest cells
cells of the CNS come from what kinds of neural precursor cells?
neural plate cells
cells migrate through the _______ arches, which are the routes of neural crest cells into their facial structures
pharyngeal arches
neural crest cells in neurofibromatosis ________. What does this cause?
over proliferate.
It causes benign tumors in the brain (Schwann cells) and the skin (melanocytes)
insufficient neural crest contribution to the face. Deficiency in neural crest cells, causes severe facial defects.
Trencher-Collins Syndrome
Teacher-Collins Syndrome shows ________ neural crest cell contribution to the ______
insufficient
face
in ___________ syndrome, facial alterations, hair pigmentation abnormalities. Mostly due to defects in Sox10 of Pax3 genes
Waardenberg Syndrome
mammary glands and the pituitary gland, and sweat glands come from which germ layer?
ectoderm
the paraxial mesoderm eventually forms ______
somites
the intermediate mesoderm eventually forms what? (2 things)
the urinary and reproductive system
what are the three regions of mesoderm?
paraxial, intermediate, and lateral mesoderm
what do somites form in the embryo?
primitive musculature
somites are next to the __________
neural tube
the formation of a somite involves a transient structure: the __________
somitomere
except for the ___ pairs of somitomeres at the _______ end, all somitomeres become somites
7
cranial
________, a region of tissue from the somite, migrates all around the neural tube and makes the bones of the vertebra
sclerotome
after the sclerotome leaves from the somite, the dermamyotome differentiates into the ________ and the _________
dermatome
myotome
the ______ (a section of the somite) makes the dermis of the skin
dermatome
the _________ (a section of the somite) makes the body muscles
myotome
what are two examples of segmentation in the human embryonic body plan?
- repeating structure of the somites
- Rhombomeres of the brain
Spine, etc.
muscle of the face comes from ________ ___________
cranial somitomeres
